Check out my profile on Research Gate and on Google Scholar or explore my full publication list below. Most papers are available online through the public repository at HAL CNRS
2021 |
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Anna Kawamoto; Jean-François Le Galliard; Arnaud Badiane The role of social costs as a mechanism enforcing the honesty of ultraviolet-reflecting signals in a lizard Journal Article Biological Journal of the Linnean Society, 2021, ISSN: 0024-4066. Abstract | Links | BibTeX | Tags: competition, sexual selection, UV coloration @article{kawamoto_role_2021, title = {The role of social costs as a mechanism enforcing the honesty of ultraviolet-reflecting signals in a lizard}, author = {Anna Kawamoto and Jean-François Le Galliard and Arnaud Badiane}, url = {https://doi.org/10.1093/biolinnean/blab008}, doi = {10.1093/biolinnean/blab008}, issn = {0024-4066}, year = {2021}, date = {2021-05-13}, urldate = {2021-05-13}, journal = {Biological Journal of the Linnean Society}, abstract = {According to animal signalling theory, social costs incurred by aggressive conspecifics are one mechanism maintaining signal honesty. Although our understanding of signal evolution has much improved for pigment-based colours, the mechanisms maintaining the honesty of structural colour signals, such as ultraviolet (UV), remain elusive. Here, we used the common lizard (Zootoca vivipara) to test whether the honesty of UV-reflecting signals displayed on male throats is under social control. To do so, we staged agonistic interactions between non-manipulated focal males and opponents of either larger or smaller body size. We manipulated the UV component of the male throat colour patch to create small cheaters with UV-enhanced throats, large cheaters with UV-reduced throats, and their respective controls. In support of a conventional signal hypothesis, focal males were aggressive towards large cheaters and became submissive when these large cheaters retaliated, and were less submissive against small cheaters. However, that focal males were not more aggressive towards small cheaters contradicts our initial predictions. We confirm that male UV reflectance and bite force were good predictors of contest outcomes in control conditions. Overall, we provide partial evidence suggesting that social costs enforce UV signal honesty in common lizards.}, keywords = {competition, sexual selection, UV coloration}, pubstate = {published}, tppubtype = {article} } According to animal signalling theory, social costs incurred by aggressive conspecifics are one mechanism maintaining signal honesty. Although our understanding of signal evolution has much improved for pigment-based colours, the mechanisms maintaining the honesty of structural colour signals, such as ultraviolet (UV), remain elusive. Here, we used the common lizard (Zootoca vivipara) to test whether the honesty of UV-reflecting signals displayed on male throats is under social control. To do so, we staged agonistic interactions between non-manipulated focal males and opponents of either larger or smaller body size. We manipulated the UV component of the male throat colour patch to create small cheaters with UV-enhanced throats, large cheaters with UV-reduced throats, and their respective controls. In support of a conventional signal hypothesis, focal males were aggressive towards large cheaters and became submissive when these large cheaters retaliated, and were less submissive against small cheaters. However, that focal males were not more aggressive towards small cheaters contradicts our initial predictions. We confirm that male UV reflectance and bite force were good predictors of contest outcomes in control conditions. Overall, we provide partial evidence suggesting that social costs enforce UV signal honesty in common lizards. | |
Jean-François Le Galliard; David Rozen-Rechels; Anjélica Lecomte; Clémence Demay; Andréaz Dupoué; Sandrine Meylan Short-term changes in air humidity and water availability weakly constrain thermoregulation in a dry-skinned ectotherm Journal Article PLOS ONE, 16 (2), pp. 1-17, 2021. Abstract | Links | BibTeX | Tags: lizard, thermoregulation, water balance @article{10.1371/journal.pone.0247514, title = {Short-term changes in air humidity and water availability weakly constrain thermoregulation in a dry-skinned ectotherm}, author = {Jean-François Le Galliard and David Rozen-Rechels and Anjélica Lecomte and Clémence Demay and Andréaz Dupoué and Sandrine Meylan}, url = {https://doi.org/10.1371/journal.pone.0247514}, doi = {10.1371/journal.pone.0247514}, year = {2021}, date = {2021-01-01}, journal = {PLOS ONE}, volume = {16}, number = {2}, pages = {1-17}, publisher = {Public Library of Science}, abstract = {Thermoregulation is critical for ectotherms as it allows them to maintain their body temperature close to an optimum for ecological performance. Thermoregulation includes a range of behaviors that aim at regulating body temperature within a range centered around the thermal preference. Thermal preference is typically measured in a thermal gradient in fully-hydrated and post-absorptive animals. Short-term effects of the hydric environment on thermal preferences in such set-ups have been rarely quantified in dry-skinned ectotherms, despite accumulating evidence that dehydration might trade-off with behavioral thermoregulation. Using experiments performed under controlled conditions in climatic chambers, we demonstrate that thermal preferences of a ground-dwelling, actively foraging lizard (Zootoca vivipara) are weakly decreased by a daily restriction in free-standing water availability (less than 0.5°C contrast). The influence of air humidity during the day on thermal preferences depends on time of the day and sex of the lizard, and is generally weaker than those of of free-standing water (less than 1°C contrast). This shows that short-term dehydration can influence, albeit weakly, thermal preferences under some circumstances in this species. Environmental humidity conditions are important methodological factors to consider in the analysis of thermal preferences.}, keywords = {lizard, thermoregulation, water balance}, pubstate = {published}, tppubtype = {article} } Thermoregulation is critical for ectotherms as it allows them to maintain their body temperature close to an optimum for ecological performance. Thermoregulation includes a range of behaviors that aim at regulating body temperature within a range centered around the thermal preference. Thermal preference is typically measured in a thermal gradient in fully-hydrated and post-absorptive animals. Short-term effects of the hydric environment on thermal preferences in such set-ups have been rarely quantified in dry-skinned ectotherms, despite accumulating evidence that dehydration might trade-off with behavioral thermoregulation. Using experiments performed under controlled conditions in climatic chambers, we demonstrate that thermal preferences of a ground-dwelling, actively foraging lizard (Zootoca vivipara) are weakly decreased by a daily restriction in free-standing water availability (less than 0.5°C contrast). The influence of air humidity during the day on thermal preferences depends on time of the day and sex of the lizard, and is generally weaker than those of of free-standing water (less than 1°C contrast). This shows that short-term dehydration can influence, albeit weakly, thermal preferences under some circumstances in this species. Environmental humidity conditions are important methodological factors to consider in the analysis of thermal preferences. | |
Andréaz Dupoué; Audrey Trochet; Murielle Richard; Mahaut Sorlin; Michaël Guillon; Jules Teulieres-Quillet; Clément Vallé; Cyrielle Rault; Maud Berroneau; Matthieu Berroneau; Olivier Lourdais; Pauline Blaimont; Romain Bertrand; Gilles Pottier; Olivier Calvez; Olivier Guillaume; Hugo Le Chevalier; Jérémie Souchet; Jean-François Le Galliard; Jean Clobert; Fabien Aubret Genetic and demographic trends from rear to leading edge are explained by climate and forest cover in a cold-adapted ectotherm Journal Article Diversity and Distributions, 27 (2), pp. 267-281, 2021. Abstract | Links | BibTeX | Tags: climate change, colonization, ectotherms, gene flow, inbreeding, structuration @article{https://doi.org/10.1111/ddi.13202b, title = {Genetic and demographic trends from rear to leading edge are explained by climate and forest cover in a cold-adapted ectotherm}, author = {Andréaz Dupoué and Audrey Trochet and Murielle Richard and Mahaut Sorlin and Michaël Guillon and Jules Teulieres-Quillet and Clément Vallé and Cyrielle Rault and Maud Berroneau and Matthieu Berroneau and Olivier Lourdais and Pauline Blaimont and Romain Bertrand and Gilles Pottier and Olivier Calvez and Olivier Guillaume and Hugo Le Chevalier and Jérémie Souchet and Jean-François Le Galliard and Jean Clobert and Fabien Aubret}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/ddi.13202}, doi = {https://doi.org/10.1111/ddi.13202}, year = {2021}, date = {2021-01-01}, journal = {Diversity and Distributions}, volume = {27}, number = {2}, pages = {267-281}, abstract = {Abstract Aim Determining whether altitudinal shifts in species distributions leave molecular footprints on wild populations along their range margins from rear to leading edge. Location South-west France. Methods We compared the demographic and genetic variation in 42 wild populations of the Western oviparous subclade B2 of a cold-adapted lizard (Zootoca vivipara louislantzi). These populations can be divided into four ecological units across altitudinal clines in South-west France (rear edge: <100 m, admixture zone: 100–500 m, continuous range: 500–1,300 m and leading edge: >1,300 m above sea level). Results Within the rear edge were found the highest levels of inbreeding, genetic differentiation and evidence of interrupted gene flow compared to central or colonizing areas. Within the leading edge, altitudinal range expansion occurred over the last centuries and populations showed relatively low genetic diversity. These demographic and genetic trends were better explained by inhospitable (warm and dry) climate conditions and forest cover. Main conclusions This empirical evidence illustrates that molecular footprints of climate conditions and habitat quality on wild population trends can be perceived after recent events, which should be of particular importance to accurately understand and anticipate human-induced global change on wild species and ecosystems.}, keywords = {climate change, colonization, ectotherms, gene flow, inbreeding, structuration}, pubstate = {published}, tppubtype = {article} } Abstract Aim Determining whether altitudinal shifts in species distributions leave molecular footprints on wild populations along their range margins from rear to leading edge. Location South-west France. Methods We compared the demographic and genetic variation in 42 wild populations of the Western oviparous subclade B2 of a cold-adapted lizard (Zootoca vivipara louislantzi). These populations can be divided into four ecological units across altitudinal clines in South-west France (rear edge: <100 m, admixture zone: 100–500 m, continuous range: 500–1,300 m and leading edge: >1,300 m above sea level). Results Within the rear edge were found the highest levels of inbreeding, genetic differentiation and evidence of interrupted gene flow compared to central or colonizing areas. Within the leading edge, altitudinal range expansion occurred over the last centuries and populations showed relatively low genetic diversity. These demographic and genetic trends were better explained by inhospitable (warm and dry) climate conditions and forest cover. Main conclusions This empirical evidence illustrates that molecular footprints of climate conditions and habitat quality on wild population trends can be perceived after recent events, which should be of particular importance to accurately understand and anticipate human-induced global change on wild species and ecosystems. | |
Jacques Roy; François Rineau; Hans J De Boeck; Ivan Nijs; Thomas Pütz; Samuel Abiven; John A Arnone III; Craig V M Barton; Natalie Beenaerts; Nicolas Brüggemann; Matteo Dainese; Timo Domisch; Nico Eisenhauer; Sarah Garré; Alban Gebler; Andrea Ghirardo; Richard L Jasoni; George Kowalchuk; Damien Landais; Stuart H Larsen; Vincent Leemans; Jean-François Le Galliard; Bernard Longdoz; Florent Massol; Teis N Mikkelsen; Georg Niedrist; Clément Piel; Olivier Ravel; Joana Sauze; Anja Schmidt; Jörg-Peter Schnitzler; Leonardo H Teixeira; Mark G Tjoelker; Wolfgang W Weisser; Barbro Winkler; Alexandru Milcu Ecotrons: Powerful and versatile ecosystem analysers for ecology, agronomy and environmental science Journal Article Global Change Biology, 27 (7), pp. 1387-1407, 2021. Abstract | Links | BibTeX | Tags: biodiversity, controlled environment facilities, ecosystem functioning, ecosystem process measurements, environmental simulations, experimentation, global change, research infrastructures @article{https://doi.org/10.1111/gcb.15471, title = {Ecotrons: Powerful and versatile ecosystem analysers for ecology, agronomy and environmental science}, author = {Jacques Roy and François Rineau and Hans J De Boeck and Ivan Nijs and Thomas Pütz and Samuel Abiven and John A Arnone III and Craig V M Barton and Natalie Beenaerts and Nicolas Brüggemann and Matteo Dainese and Timo Domisch and Nico Eisenhauer and Sarah Garré and Alban Gebler and Andrea Ghirardo and Richard L Jasoni and George Kowalchuk and Damien Landais and Stuart H Larsen and Vincent Leemans and Jean-François Le Galliard and Bernard Longdoz and Florent Massol and Teis N Mikkelsen and Georg Niedrist and Clément Piel and Olivier Ravel and Joana Sauze and Anja Schmidt and Jörg-Peter Schnitzler and Leonardo H Teixeira and Mark G Tjoelker and Wolfgang W Weisser and Barbro Winkler and Alexandru Milcu}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.15471}, doi = {https://doi.org/10.1111/gcb.15471}, year = {2021}, date = {2021-01-01}, journal = {Global Change Biology}, volume = {27}, number = {7}, pages = {1387-1407}, abstract = {Abstract Ecosystems integrity and services are threatened by anthropogenic global changes. Mitigating and adapting to these changes require knowledge of ecosystem functioning in the expected novel environments, informed in large part through experimentation and modelling. This paper describes 13 advanced controlled environment facilities for experimental ecosystem studies, herein termed ecotrons, open to the international community. Ecotrons enable simulation of a wide range of natural environmental conditions in replicated and independent experimental units while measuring various ecosystem processes. This capacity to realistically control ecosystem environments is used to emulate a variety of climatic scenarios and soil conditions, in natural sunlight or through broad-spectrum lighting. The use of large ecosystem samples, intact or reconstructed, minimizes border effects and increases biological and physical complexity. Measurements of concentrations of greenhouse trace gases as well as their net exchange between the ecosystem and the atmosphere are performed in most ecotrons, often quasi continuously. The flow of matter is often tracked with the use of stable isotope tracers of carbon and other elements. Equipment is available for measurements of soil water status as well as root and canopy growth. The experiments ran so far emphasize the diversity of the hosted research. Half of them concern global changes, often with a manipulation of more than one driver. About a quarter deal with the impact of biodiversity loss on ecosystem functioning and one quarter with ecosystem or plant physiology. We discuss how the methodology for environmental simulation and process measurements, especially in soil, can be improved and stress the need to establish stronger links with modelling in future projects. These developments will enable further improvements in mechanistic understanding and predictive capacity of ecotron research which will play, in complementarity with field experimentation and monitoring, a crucial role in exploring the ecosystem consequences of environmental changes.}, keywords = {biodiversity, controlled environment facilities, ecosystem functioning, ecosystem process measurements, environmental simulations, experimentation, global change, research infrastructures}, pubstate = {published}, tppubtype = {article} } Abstract Ecosystems integrity and services are threatened by anthropogenic global changes. Mitigating and adapting to these changes require knowledge of ecosystem functioning in the expected novel environments, informed in large part through experimentation and modelling. This paper describes 13 advanced controlled environment facilities for experimental ecosystem studies, herein termed ecotrons, open to the international community. Ecotrons enable simulation of a wide range of natural environmental conditions in replicated and independent experimental units while measuring various ecosystem processes. This capacity to realistically control ecosystem environments is used to emulate a variety of climatic scenarios and soil conditions, in natural sunlight or through broad-spectrum lighting. The use of large ecosystem samples, intact or reconstructed, minimizes border effects and increases biological and physical complexity. Measurements of concentrations of greenhouse trace gases as well as their net exchange between the ecosystem and the atmosphere are performed in most ecotrons, often quasi continuously. The flow of matter is often tracked with the use of stable isotope tracers of carbon and other elements. Equipment is available for measurements of soil water status as well as root and canopy growth. The experiments ran so far emphasize the diversity of the hosted research. Half of them concern global changes, often with a manipulation of more than one driver. About a quarter deal with the impact of biodiversity loss on ecosystem functioning and one quarter with ecosystem or plant physiology. We discuss how the methodology for environmental simulation and process measurements, especially in soil, can be improved and stress the need to establish stronger links with modelling in future projects. These developments will enable further improvements in mechanistic understanding and predictive capacity of ecotron research which will play, in complementarity with field experimentation and monitoring, a crucial role in exploring the ecosystem consequences of environmental changes. | |
Alexis Rutschmann; Andréaz Dupoué; Donald B. Miles; Megía R. Palma; C Lauden; Murielle Richard; Arnaud Badiane; David Rozen‐Rechels; Mathieu Brevet; Pauline Blaimont; Sandrine Meylan; Jean Clobert; Jean-François Le Galliard Intense nocturnal warming alters growth strategies, coloration, and parasite load in a diurnal lizard Journal Article Journal of Animal Ecology, n/a , 2021, ISSN: 1365-2656. Abstract | Links | BibTeX | Tags: coloration change, ectotherms, energetic balance, nocturnal temperatures, oxidative stress @article{rutschmann_intense_2021, title = {Intense nocturnal warming alters growth strategies, coloration, and parasite load in a diurnal lizard}, author = {Alexis Rutschmann and Andréaz Dupoué and Donald B. Miles and Megía R. Palma and C Lauden and Murielle Richard and Arnaud Badiane and David Rozen‐Rechels and Mathieu Brevet and Pauline Blaimont and Sandrine Meylan and Jean Clobert and Jean-François Le Galliard}, url = {https://besjournals.onlinelibrary.wiley.com/doi/abs/10.1111/1365-2656.13502}, doi = {https://doi.org/10.1111/1365-2656.13502}, issn = {1365-2656}, year = {2021}, date = {2021-01-01}, urldate = {2021-04-30}, journal = {Journal of Animal Ecology}, volume = {n/a}, abstract = {1. In the past decades, nocturnal temperatures have been playing a disproportionate role in the global warming of the planet. Yet, they remain a neglected factor in studies assessing the impact of global warming on natural populations. 2. Here, we question whether an intense augmentation of nocturnal temperatures is beneficial or deleterious to ectotherms. Physiological performance is influenced by thermal conditions in ectotherms and an increase in temperature by only 2°C is sufficient to induce a disproportionate increase in metabolic expenditure. Warmer nights may expand ectotherms’ species thermal niche and open new opportunities for prolonged activities and improve foraging efficiency. However, increased activity may also have deleterious effects on energy balance if exposure to warmer nights reduces resting periods and elevates resting metabolic rate. 3. We assessed whether warmer nights affected an individual’s growth, dorsal skin colouration, thermoregulation behaviour, oxidative stress status and parasite load by exposing yearling common lizards (Zootoca vivipara) from four populations to either ambient or high nocturnal temperatures for approximately five weeks. 4. Warmer nocturnal temperatures increased the prevalence of ectoparasitic infestation and altered allocation of resources toward structural growth rather than storage. We found no change in markers for oxidative stress. The thermal treatment did not influence thermal preferences, but influenced dorsal skin brightness and luminance, in line with a predicted acclimation response in colder environments to enhance heat gain from solar radiation. 5. Altogether, our results highlight the importance of considering nocturnal warming as an independent factor affecting ectotherms life-history in the context of global climate change.}, keywords = {coloration change, ectotherms, energetic balance, nocturnal temperatures, oxidative stress}, pubstate = {published}, tppubtype = {article} } 1. In the past decades, nocturnal temperatures have been playing a disproportionate role in the global warming of the planet. Yet, they remain a neglected factor in studies assessing the impact of global warming on natural populations. 2. Here, we question whether an intense augmentation of nocturnal temperatures is beneficial or deleterious to ectotherms. Physiological performance is influenced by thermal conditions in ectotherms and an increase in temperature by only 2°C is sufficient to induce a disproportionate increase in metabolic expenditure. Warmer nights may expand ectotherms’ species thermal niche and open new opportunities for prolonged activities and improve foraging efficiency. However, increased activity may also have deleterious effects on energy balance if exposure to warmer nights reduces resting periods and elevates resting metabolic rate. 3. We assessed whether warmer nights affected an individual’s growth, dorsal skin colouration, thermoregulation behaviour, oxidative stress status and parasite load by exposing yearling common lizards (Zootoca vivipara) from four populations to either ambient or high nocturnal temperatures for approximately five weeks. 4. Warmer nocturnal temperatures increased the prevalence of ectoparasitic infestation and altered allocation of resources toward structural growth rather than storage. We found no change in markers for oxidative stress. The thermal treatment did not influence thermal preferences, but influenced dorsal skin brightness and luminance, in line with a predicted acclimation response in colder environments to enhance heat gain from solar radiation. 5. Altogether, our results highlight the importance of considering nocturnal warming as an independent factor affecting ectotherms life-history in the context of global climate change. | |
2020 |
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 | Andréaz Dupoué; Pauline Blaimont; David Rozen‐Rechels; Murielle Richard; Sandrine Meylan; Jean Clobert; Donald B Miles; Rémi Martin; Beatriz Decencière; Simon Agostini; Jean‐François Le Galliard Water availability and temperature induce changes in oxidative status during pregnancy in a viviparous lizard Journal Article Functional Ecology, 34 (2), pp. 475-485, 2020, ISSN: 0269-8463, 1365-2435. Links | BibTeX | Tags: antioxidant capacity, ectotherms, oxidative stress, performance, temperature @article{dupoue_water_2020, title = {Water availability and temperature induce changes in oxidative status during pregnancy in a viviparous lizard}, author = {Andréaz Dupoué and Pauline Blaimont and David Rozen‐Rechels and Murielle Richard and Sandrine Meylan and Jean Clobert and Donald B Miles and Rémi Martin and Beatriz Decencière and Simon Agostini and Jean‐François Le Galliard}, editor = {David Costantini}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/1365-2435.13481}, doi = {10.1111/1365-2435.13481}, issn = {0269-8463, 1365-2435}, year = {2020}, date = {2020-02-01}, urldate = {2020-02-11}, journal = {Functional Ecology}, volume = {34}, number = {2}, pages = {475-485}, keywords = {antioxidant capacity, ectotherms, oxidative stress, performance, temperature}, pubstate = {published}, tppubtype = {article} } |
Andréaz Dupoué; Frédéric Angelier; Cécile Ribout; Sandrine Meylan; David Rozen-Rechels; Beatriz Decencière; Simon Agostini; Jean-François Le Galliard Chronic water restriction triggers sex-specific oxidative stress and telomere shortening in lizards Journal Article Biology Letters, 16 (2), pp. 20190889, 2020, ISSN: 1744-9561, 1744-957X. @article{dupoue_chronic_2020, title = {Chronic water restriction triggers sex-specific oxidative stress and telomere shortening in lizards}, author = {Andréaz Dupoué and Frédéric Angelier and Cécile Ribout and Sandrine Meylan and David Rozen-Rechels and Beatriz Decencière and Simon Agostini and Jean-François Le Galliard}, url = {https://royalsocietypublishing.org/doi/10.1098/rsbl.2019.0889}, doi = {10.1098/rsbl.2019.0889}, issn = {1744-9561, 1744-957X}, year = {2020}, date = {2020-01-01}, urldate = {2020-02-26}, journal = {Biology Letters}, volume = {16}, number = {2}, pages = {20190889}, keywords = {}, pubstate = {published}, tppubtype = {article} } | |
Yann Dusza; Enrique P Sanchez-Cañete; Jean-François Le Galliard; Régis Ferrière; Simon Chollet; Florent Massol; Amandine Hansart; Sabrina Juarez; Katerina Dontsova; Joost van Haren; Peter Troch; Mitchell A Pavao-Zuckerman; Erik Hamerlynck; Greg A Barron-Gafford Biotic soil-plant interaction processes explain most of hysteric soil CO2 efflux response to temperature in cross-factorial mesocosm experiment Journal Article Scientific Reports, 10 (1), pp. 1–11, 2020, ISSN: 2045-2322. Abstract | Links | BibTeX | Tags: @article{dusza_biotic_2020, title = {Biotic soil-plant interaction processes explain most of hysteric soil CO2 efflux response to temperature in cross-factorial mesocosm experiment}, author = {Yann Dusza and Enrique P Sanchez-Cañete and Jean-François Le Galliard and Régis Ferrière and Simon Chollet and Florent Massol and Amandine Hansart and Sabrina Juarez and Katerina Dontsova and Joost van Haren and Peter Troch and Mitchell A Pavao-Zuckerman and Erik Hamerlynck and Greg A Barron-Gafford}, url = {https://www.nature.com/articles/s41598-019-55390-6}, doi = {10.1038/s41598-019-55390-6}, issn = {2045-2322}, year = {2020}, date = {2020-01-01}, urldate = {2020-01-22}, journal = {Scientific Reports}, volume = {10}, number = {1}, pages = {1--11}, abstract = {Ecosystem carbon flux partitioning is strongly influenced by poorly constrained soil CO2 efflux (Fsoil). Simple model applications (Arrhenius and Q10) do not account for observed diel hysteresis between Fsoil and soil temperature. How this hysteresis emerges and how it will respond to variation in vegetation or soil moisture remains unknown. We used an ecosystem-level experimental system to independently control potential abiotic and biotic drivers of the Fsoil-T hysteresis. We hypothesized a principally biological cause for the hysteresis. Alternatively, Fsoil hysteresis is primarily driven by thermal convection through the soil profile. We conducted experiments under normal, fluctuating diurnal soil temperatures and under conditions where we held soil temperature near constant. We found (i) significant and nearly equal amplitudes of hysteresis regardless of soil temperature regime, and (ii) the amplitude of hysteresis was most closely tied to baseline rates of Fsoil, which were mostly driven by photosynthetic rates. Together, these findings suggest a more biologically-driven mechanism associated with photosynthate transport in yielding the observed patterns of soil CO2 efflux being out of sync with soil temperature. These findings should be considered on future partitioning models of ecosystem respiration.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Ecosystem carbon flux partitioning is strongly influenced by poorly constrained soil CO2 efflux (Fsoil). Simple model applications (Arrhenius and Q10) do not account for observed diel hysteresis between Fsoil and soil temperature. How this hysteresis emerges and how it will respond to variation in vegetation or soil moisture remains unknown. We used an ecosystem-level experimental system to independently control potential abiotic and biotic drivers of the Fsoil-T hysteresis. We hypothesized a principally biological cause for the hysteresis. Alternatively, Fsoil hysteresis is primarily driven by thermal convection through the soil profile. We conducted experiments under normal, fluctuating diurnal soil temperatures and under conditions where we held soil temperature near constant. We found (i) significant and nearly equal amplitudes of hysteresis regardless of soil temperature regime, and (ii) the amplitude of hysteresis was most closely tied to baseline rates of Fsoil, which were mostly driven by photosynthetic rates. Together, these findings suggest a more biologically-driven mechanism associated with photosynthate transport in yielding the observed patterns of soil CO2 efflux being out of sync with soil temperature. These findings should be considered on future partitioning models of ecosystem respiration. | |
Rémy Josserand; Claudy Haussy; Simon Agostini; Beatriz Decencière; Jean-François Le Galliard; Sandrine Meylan Chronic elevation of glucorticoids late in life generates long lasting changes in physiological state without a life history switch Journal Article General and Comparative Endocrinology, 285 , pp. 113288, 2020, ISSN: 0016-6480. Abstract | Links | BibTeX | Tags: immunity, maternal effect, metabolism, oxidative stress, stress, triglycerides @article{josserand_chronic_2020, title = {Chronic elevation of glucorticoids late in life generates long lasting changes in physiological state without a life history switch}, author = {Rémy Josserand and Claudy Haussy and Simon Agostini and Beatriz Decencière and Jean-François Le Galliard and Sandrine Meylan}, url = {http://www.sciencedirect.com/science/article/pii/S0016648019300929}, doi = {10.1016/j.ygcen.2019.113288}, issn = {0016-6480}, year = {2020}, date = {2020-01-01}, urldate = {2019-09-26}, journal = {General and Comparative Endocrinology}, volume = {285}, pages = {113288}, abstract = {Chronic stressors have profound impacts on phenotypes and life history strategies on the short term, but delayed effects of stress experienced late in life remain poorly investigated in wild populations. Here, we used a combined laboratory and field experiment to test if chronic stress late in life has immediate and delayed effects on physiological and demographic traits in the common lizard, Zootoca vivipara. We increased plasma corticosterone levels in adults and yearlings during three weeks of the post-reproductive season. We quantified immediate responses in the laboratory, delayed intra-generational effects in field enclosures one month and one year later during the next reproductive season, and delayed inter-generational effects in the first generation of offspring. Our phenotypic assays included metabolism, immune capacities, lipid metabolism and oxidative stress. Relative to placebos, lizards treated with corticosterone had higher body condition and lower oxidative damages but an increased skin swelling response directly after the manipulation. Delayed responses in field enclosures were of three types. First, we found catch-up growth for body mass such the placebos had similar body conditions one month after the laboratory manipulation. Second, we found persistent differences in oxidative damages during one month but not one year later. Third, during the next reproductive season, corticosterone-treated females had higher levels of plasma triglycerides, whereas corticosterone-treated individuals had a higher skin swelling response. We found no delayed inter-generational effects on demographic traits of offspring. Our study demonstrates the potential for long-lasting physiological consequences of chronic corticosterone enhancement despite no obvious changes in life history.}, keywords = {immunity, maternal effect, metabolism, oxidative stress, stress, triglycerides}, pubstate = {published}, tppubtype = {article} } Chronic stressors have profound impacts on phenotypes and life history strategies on the short term, but delayed effects of stress experienced late in life remain poorly investigated in wild populations. Here, we used a combined laboratory and field experiment to test if chronic stress late in life has immediate and delayed effects on physiological and demographic traits in the common lizard, Zootoca vivipara. We increased plasma corticosterone levels in adults and yearlings during three weeks of the post-reproductive season. We quantified immediate responses in the laboratory, delayed intra-generational effects in field enclosures one month and one year later during the next reproductive season, and delayed inter-generational effects in the first generation of offspring. Our phenotypic assays included metabolism, immune capacities, lipid metabolism and oxidative stress. Relative to placebos, lizards treated with corticosterone had higher body condition and lower oxidative damages but an increased skin swelling response directly after the manipulation. Delayed responses in field enclosures were of three types. First, we found catch-up growth for body mass such the placebos had similar body conditions one month after the laboratory manipulation. Second, we found persistent differences in oxidative damages during one month but not one year later. Third, during the next reproductive season, corticosterone-treated females had higher levels of plasma triglycerides, whereas corticosterone-treated individuals had a higher skin swelling response. We found no delayed inter-generational effects on demographic traits of offspring. Our study demonstrates the potential for long-lasting physiological consequences of chronic corticosterone enhancement despite no obvious changes in life history. | |
David Rozen-Rechels; Arnaud Badiane; Simon Agostini; Sandrine Meylan; Jean-François Le Galliard Water restriction induces behavioral fight but impairs thermoregulation in a dry-skinned ectotherm Journal Article Oikos, 129 (4), pp. 572–584, 2020, ISSN: 1600-0706. Abstract | Links | BibTeX | Tags: activity, body temperature, dehydration, space use, squamate reptiles, water availability @article{rozen-rechels_water_2020, title = {Water restriction induces behavioral fight but impairs thermoregulation in a dry-skinned ectotherm}, author = {David Rozen-Rechels and Arnaud Badiane and Simon Agostini and Sandrine Meylan and Jean-François Le Galliard}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/oik.06910}, doi = {10.1111/oik.06910}, issn = {1600-0706}, year = {2020}, date = {2020-01-01}, urldate = {2020-02-11}, journal = {Oikos}, volume = {129}, number = {4}, pages = {572--584}, abstract = {Behavioral fight responses to desiccation risk are important to predict the vulnerability of terrestrial animals to climate change and yet, they have received little attention so far. In terrestrial ectotherms, behavioral regulation of the water balance (i.e. hydroregulation) is likely to be plastic and may tradeoff with thermoregulation behavior because water loss rates are generally higher in warmer environments and body temperatures. When low water availability and heat stress cause physiological dehydration, we expect to highlight a shift to behavioral water-conservation strategies including changes in activity patterns, micro-habitat selection and thermoregulation strategies. Here, we compared the behavior of adult common lizards Zootoca vivipara in indoor arenas that either had a permanent access to water or underwent a one-week long experimental water restriction. Water-restricted lizards reduced their behavioral activity, selected more often cooler and wetter refuges during daytime, and performed less accurate thermoregulation than control lizards. The activity of water-restricted gravid females shifted towards the cooler and wetter early hours of the day. In addition, they had lower body temperatures and preferred lower body temperatures at the end of the experiment (i.e. thermal depression). Water-restricted lizards suffered from a mild physiological dehydration and had a lower mass change. Heat stress was simulated every second day, which led to a range of heat avoidance and water conservation strategies independent from water restriction. Altogether, these results confirm that chronic water restriction and dehydration induce responses towards water conservation that conflict with thermoregulation accuracy.}, keywords = {activity, body temperature, dehydration, space use, squamate reptiles, water availability}, pubstate = {published}, tppubtype = {article} } Behavioral fight responses to desiccation risk are important to predict the vulnerability of terrestrial animals to climate change and yet, they have received little attention so far. In terrestrial ectotherms, behavioral regulation of the water balance (i.e. hydroregulation) is likely to be plastic and may tradeoff with thermoregulation behavior because water loss rates are generally higher in warmer environments and body temperatures. When low water availability and heat stress cause physiological dehydration, we expect to highlight a shift to behavioral water-conservation strategies including changes in activity patterns, micro-habitat selection and thermoregulation strategies. Here, we compared the behavior of adult common lizards Zootoca vivipara in indoor arenas that either had a permanent access to water or underwent a one-week long experimental water restriction. Water-restricted lizards reduced their behavioral activity, selected more often cooler and wetter refuges during daytime, and performed less accurate thermoregulation than control lizards. The activity of water-restricted gravid females shifted towards the cooler and wetter early hours of the day. In addition, they had lower body temperatures and preferred lower body temperatures at the end of the experiment (i.e. thermal depression). Water-restricted lizards suffered from a mild physiological dehydration and had a lower mass change. Heat stress was simulated every second day, which led to a range of heat avoidance and water conservation strategies independent from water restriction. Altogether, these results confirm that chronic water restriction and dehydration induce responses towards water conservation that conflict with thermoregulation accuracy. | |
David Rozen-Rechels; Andréaz Dupoué; Sandrine Meylan; Kenza Qitout; Beatriz Decencière; Simon Agostini; Jean-François Le Galliard Acclimation to water restriction implies different paces for behavioral and physiological responses in a lizard species Journal Article Physiological and Biochemical Zoology, 93 (2), pp. 160–174, 2020, ISSN: 1522-2152. Links | BibTeX | Tags: activity, body temperature, exploration, metabolism, squamate reptiles, water availability, water loss @article{rozen-rechels_acclimation_2020, title = {Acclimation to water restriction implies different paces for behavioral and physiological responses in a lizard species}, author = {David Rozen-Rechels and Andréaz Dupoué and Sandrine Meylan and Kenza Qitout and Beatriz Decencière and Simon Agostini and Jean-François Le Galliard}, url = {https://www.journals.uchicago.edu/doi/abs/10.1086/707409}, doi = {10.1086/707409}, issn = {1522-2152}, year = {2020}, date = {2020-01-01}, urldate = {2019-12-11}, journal = {Physiological and Biochemical Zoology}, volume = {93}, number = {2}, pages = {160--174}, keywords = {activity, body temperature, exploration, metabolism, squamate reptiles, water availability, water loss}, pubstate = {published}, tppubtype = {article} } | |
Andréaz Dupoué; Mahaut Sorlin; Murielle Richard; Jean-François Le Galliard; Olivier Lourdais; Jean Clobert; Fabien Aubret Mother-offspring conflict for water and its mitigation in the oviparous form of the reproductively bimodal lizard, Zootoca vivipara Journal Article Biological Journal of the Linnean Society, 129 (4), pp. 888–900, 2020. @article{dupoue_mother-offspring_2020, title = {Mother-offspring conflict for water and its mitigation in the oviparous form of the reproductively bimodal lizard, Zootoca vivipara}, author = {Andréaz Dupoué and Mahaut Sorlin and Murielle Richard and Jean-François Le Galliard and Olivier Lourdais and Jean Clobert and Fabien Aubret}, url = {https://academic.oup.com/biolinnean/article-abstract/129/4/888/5809298?redirectedFrom=fulltext}, doi = {https://doi.org/10.1093/biolinnean/blaa012}, year = {2020}, date = {2020-01-01}, journal = {Biological Journal of the Linnean Society}, volume = {129}, number = {4}, pages = {888--900}, keywords = {}, pubstate = {published}, tppubtype = {article} } | |
Arnaud Badiane; Mélissa Martin; Sandrine Meylan; Murielle Richard; Beatriz Decencière Ferrandière; Jean-François Le Galliard Male ultraviolet reflectance and female mating history influence female mate choice and male mating success in a polyandrous lizard Journal Article Biological Journal of the Linnean Society, 130 (3), pp. 586–598, 2020. @article{badiane_male_2020, title = {Male ultraviolet reflectance and female mating history influence female mate choice and male mating success in a polyandrous lizard}, author = {Arnaud Badiane and Mélissa Martin and Sandrine Meylan and Murielle Richard and Beatriz Decencière Ferrandière and Jean-François Le Galliard}, url = {https://academic.oup.com/biolinnean/article-abstract/130/3/586/5847665?redirectedFrom=fulltext}, doi = {https://doi.org/10.1093/biolinnean/blaa061}, year = {2020}, date = {2020-01-01}, journal = {Biological Journal of the Linnean Society}, volume = {130}, number = {3}, pages = {586--598}, keywords = {}, pubstate = {published}, tppubtype = {article} } | |
David Rozen‐Rechels; Pauline Farigoule; Simon Agostini; Arnaud Badiane; Sandrine Meylan; Jean-François Le Galliard Short-term change in water availability influences thermoregulation behaviours in a dry-skinned ectotherm Journal Article Journal of Animal Ecology, 89 (9), pp. 2099-2110, 2020, ISSN: 1365-2656. Abstract | Links | BibTeX | Tags: activity, body temperature, dehydration, squamate reptiles, thermoregulation, water availability @article{rozenrechels_short-term_2020, title = {Short-term change in water availability influences thermoregulation behaviours in a dry-skinned ectotherm}, author = {David Rozen‐Rechels and Pauline Farigoule and Simon Agostini and Arnaud Badiane and Sandrine Meylan and Jean-François Le Galliard}, url = {https://besjournals.onlinelibrary.wiley.com/doi/abs/10.1111/1365-2656.13279}, doi = {10.1111/1365-2656.13279}, issn = {1365-2656}, year = {2020}, date = {2020-01-01}, urldate = {2020-08-03}, journal = {Journal of Animal Ecology}, volume = {89}, number = {9}, pages = {2099-2110}, abstract = {Mechanistic models of terrestrial ectotherms predict that climate warming will induce activity restriction due to heat stress and loss of shade, leading to the extinction of numerous populations. Such models rely on the assumption that activity patterns are dictated by simple temperature thresholds independent of changes in water availability. However, changes in water availability may further influence thermoregulation behaviour of ectotherms through dehydration risk perception, changes in water balance or changes in microclimatic conditions. Here, we experimentally assess the interactive effects of thermal conditions and water availability on activity patterns, shade selection and thermoregulation efficiency in a model ectothermic species. Thermoregulation behaviour of adult common lizards Zootoca vivipara was monitored in outdoor mesocosms as we manipulated water availability, providing water as mist in the morning and free-standing water during the daytime. We recorded operative temperatures and micro-meteorological conditions to infer thermal constraints and dehydration risk. Activity and shade selection were better predicted by continuous changes in thermal conditions and dehydration risk, respectively, than by threshold functions. In addition, water supplementation increased activity in males and reduced shade selection in both sexes, most probably as a behavioural response to the perception of a stronger dehydration risk. Water supplementation also influenced the thermal quality of the environment, which in turn altered daily activity patterns and thermoregulation statistics. This demonstrates that dual effects of heat and water stress on activity patterns may lead to stronger activity restriction as a result of climate change than currently predicted.}, keywords = {activity, body temperature, dehydration, squamate reptiles, thermoregulation, water availability}, pubstate = {published}, tppubtype = {article} } Mechanistic models of terrestrial ectotherms predict that climate warming will induce activity restriction due to heat stress and loss of shade, leading to the extinction of numerous populations. Such models rely on the assumption that activity patterns are dictated by simple temperature thresholds independent of changes in water availability. However, changes in water availability may further influence thermoregulation behaviour of ectotherms through dehydration risk perception, changes in water balance or changes in microclimatic conditions. Here, we experimentally assess the interactive effects of thermal conditions and water availability on activity patterns, shade selection and thermoregulation efficiency in a model ectothermic species. Thermoregulation behaviour of adult common lizards Zootoca vivipara was monitored in outdoor mesocosms as we manipulated water availability, providing water as mist in the morning and free-standing water during the daytime. We recorded operative temperatures and micro-meteorological conditions to infer thermal constraints and dehydration risk. Activity and shade selection were better predicted by continuous changes in thermal conditions and dehydration risk, respectively, than by threshold functions. In addition, water supplementation increased activity in males and reduced shade selection in both sexes, most probably as a behavioural response to the perception of a stronger dehydration risk. Water supplementation also influenced the thermal quality of the environment, which in turn altered daily activity patterns and thermoregulation statistics. This demonstrates that dual effects of heat and water stress on activity patterns may lead to stronger activity restriction as a result of climate change than currently predicted. | |
George A Brusch; Rodrigo S B Gavira; Robin Viton; Andréaz Dupoué; Mathieu Leroux-Coyau; Sandrine Meylan; Jean-Franc cois Le Galliard; Olivier Lourdais Additive effects of temperature and water availability on pregnancy in a viviparous lizard Journal Article Journal of Experimental Biology, 223 (19), 2020, ISSN: 0022-0949. Abstract | Links | BibTeX | Tags: antioxidant capacity, dehydration, oxidative stress, reproduction, temperature @article{Bruschjeb228064, title = {Additive effects of temperature and water availability on pregnancy in a viviparous lizard}, author = {George A Brusch and Rodrigo S B Gavira and Robin Viton and Andréaz Dupoué and Mathieu Leroux-Coyau and Sandrine Meylan and Jean-Fran{c c}ois Le Galliard and Olivier Lourdais}, url = {https://jeb.biologists.org/content/223/19/jeb228064}, doi = {10.1242/jeb.228064}, issn = {0022-0949}, year = {2020}, date = {2020-01-01}, journal = {Journal of Experimental Biology}, volume = {223}, number = {19}, publisher = {The Company of Biologists Ltd}, abstract = {One of the greatest current threats to biodiversity is climate change. However, understanding of organismal responses to fluctuations in temperature and water availability is currently lacking, especially during fundamental life-history stages such as reproduction. To further explore how temperature and water availability impact maternal physiology and reproductive output, we used the viviparous form of the European common lizard (Zootoca vivipara) in a two-by-two factorial design manipulating both hydric and thermal conditions, for the first time. We collected blood samples and morphological measurements during early pregnancy and post-parturition to investigate how water availability, temperature and a combination of the two influence maternal phenology, morphology, physiology and reproductive output. We observed that dehydration during gestation negatively affects maternal physiological condition (lower mass gain, higher tail reserve mobilization) but has little effect on reproductive output. These effects are mainly additive to temperature regimes, with a proportional increase in maternal costs in warmer environments. Our study demonstrates the importance of considering combined effects of water and temperature when investigating organismal responses to climate changes, especially during periods crucial for species survival such as reproduction.}, keywords = {antioxidant capacity, dehydration, oxidative stress, reproduction, temperature}, pubstate = {published}, tppubtype = {article} } One of the greatest current threats to biodiversity is climate change. However, understanding of organismal responses to fluctuations in temperature and water availability is currently lacking, especially during fundamental life-history stages such as reproduction. To further explore how temperature and water availability impact maternal physiology and reproductive output, we used the viviparous form of the European common lizard (Zootoca vivipara) in a two-by-two factorial design manipulating both hydric and thermal conditions, for the first time. We collected blood samples and morphological measurements during early pregnancy and post-parturition to investigate how water availability, temperature and a combination of the two influence maternal phenology, morphology, physiology and reproductive output. We observed that dehydration during gestation negatively affects maternal physiological condition (lower mass gain, higher tail reserve mobilization) but has little effect on reproductive output. These effects are mainly additive to temperature regimes, with a proportional increase in maternal costs in warmer environments. Our study demonstrates the importance of considering combined effects of water and temperature when investigating organismal responses to climate changes, especially during periods crucial for species survival such as reproduction. | |
Thomas Tully; Jean-François Le Galliard; Jean-Pierre Baron Micro-geographic shift between negligible and actuarial senescence in a wild snake Journal Article Journal of Animal Ecology, 89 (11), pp. 2704-2716, 2020. Abstract | Links | BibTeX | Tags: ageing, life-history trade-off, pace and shape, phenotypic plasticity, reproductive effort, survival @article{https://doi.org/10.1111/1365-2656.13317, title = {Micro-geographic shift between negligible and actuarial senescence in a wild snake}, author = {Thomas Tully and Jean-François Le Galliard and Jean-Pierre Baron}, url = {https://besjournals.onlinelibrary.wiley.com/doi/abs/10.1111/1365-2656.13317}, doi = {https://doi.org/10.1111/1365-2656.13317}, year = {2020}, date = {2020-01-01}, journal = {Journal of Animal Ecology}, volume = {89}, number = {11}, pages = {2704-2716}, abstract = {Abstract While it has long been known that species have contrasted life expectancy (pace of mortality) and generation time (pace of reproduction), recent studies have also uncovered that the shape of adult age trajectories of mortality and reproduction can vary remarkably among species along a continuum of senescence ranging from strong deterioration (senescence), insignificant deterioration (negligible senescence) to improvement with advancing age (negative senescence). As for many long-lived ectotherms with asymptotic growth and increasing reproductive output with age, snakes are good candidates for negligible senescence to occur. Yet, intraspecific variation in the pace and shape of actuarial and reproductive senescence across wild populations of these species remains to be explored. Here, we used 37 years of mark–recapture data in two nearby habitats inside a meadow viper Vipera ursinii population to quantify life expectancies, generation times and the shape of actuarial and reproductive senescence. Female vipers maintained stable reproductive performances at old ages, even when accounting for the predicted increase of fertility with body size, providing evidence for negligible reproductive senescence in both habitats. Males had a higher adult mortality and a shorter life expectancy on average than females and actuarial senescence shifted from negligible senescence in the optimal habitat to strong senescence in the sub-optimal habitat. Overall, these results demonstrate that micro-geographic environmental variation can generate qualitative shifts in actuarial senescence patterns. This highlights that taking into account the within-species plasticity of age-dependent trajectories could prove useful in better understanding what determines the evolution of life-history age trajectories.}, keywords = {ageing, life-history trade-off, pace and shape, phenotypic plasticity, reproductive effort, survival}, pubstate = {published}, tppubtype = {article} } Abstract While it has long been known that species have contrasted life expectancy (pace of mortality) and generation time (pace of reproduction), recent studies have also uncovered that the shape of adult age trajectories of mortality and reproduction can vary remarkably among species along a continuum of senescence ranging from strong deterioration (senescence), insignificant deterioration (negligible senescence) to improvement with advancing age (negative senescence). As for many long-lived ectotherms with asymptotic growth and increasing reproductive output with age, snakes are good candidates for negligible senescence to occur. Yet, intraspecific variation in the pace and shape of actuarial and reproductive senescence across wild populations of these species remains to be explored. Here, we used 37 years of mark–recapture data in two nearby habitats inside a meadow viper Vipera ursinii population to quantify life expectancies, generation times and the shape of actuarial and reproductive senescence. Female vipers maintained stable reproductive performances at old ages, even when accounting for the predicted increase of fertility with body size, providing evidence for negligible reproductive senescence in both habitats. Males had a higher adult mortality and a shorter life expectancy on average than females and actuarial senescence shifted from negligible senescence in the optimal habitat to strong senescence in the sub-optimal habitat. Overall, these results demonstrate that micro-geographic environmental variation can generate qualitative shifts in actuarial senescence patterns. This highlights that taking into account the within-species plasticity of age-dependent trajectories could prove useful in better understanding what determines the evolution of life-history age trajectories. | |
2019 |
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Gabrielle Names; Mélissa Martin; Arnaud Badiane; Jean-François Le Galliard The relative importance of body size and UV coloration in influencing male-male competition in a lacertid lizard Journal Article Behavioral Ecology and Sociobiology, 73 (7), pp. 98, 2019, ISSN: 1432-0762. Abstract | Links | BibTeX | Tags: @article{names_relative_2019, title = {The relative importance of body size and UV coloration in influencing male-male competition in a lacertid lizard}, author = {Gabrielle Names and Mélissa Martin and Arnaud Badiane and Jean-François Le Galliard}, url = {https://link.springer.com/article/10.1007/s00265-019-2710-z}, doi = {https://doi.org/10.1007/s00265-019-2710-z}, issn = {1432-0762}, year = {2019}, date = {2019-01-01}, urldate = {2020-01-22}, journal = {Behavioral Ecology and Sociobiology}, volume = {73}, number = {7}, pages = {98}, abstract = {Communication via color signals is common in natural systems. Ultraviolet (UV)-blue patches located on the outer-ventral scales of some lacertid lizards are thought to be involved in male-male competition. However, the mechanisms that maintain their honesty remain unknown. Here, we use the common wall lizard Podarcis muralis to test whether the lateral UV-blue spots are conventional signals, the honesty of which is guaranteed by receiver-dependent costs, and discuss their potential role as an amplifier of body size. We first described the morphology and reflectance properties of lateral UV-blue spots in common wall lizards and investigated how they influence male-male competition. Spot size and number, UV chroma, and conspicuousness (calculated using vision models) were significantly greater in adult males relative to adult females and adult males relative to juveniles. Total spot area (and not spot number) of adult males was positively correlated with body size. We conducted staged competition encounters between focal males and smaller or larger rivals with control or manipulated spots. Spots were enlarged in small rivals and reduced in large rivals to disrupt the phenotypic correlation between spot area and body size. Aggressiveness and dominance were positively influenced by body size in control encounters. Spot manipulations resulted in greater submission and less aggressiveness in focal males. These results contradict the predictions associated with conventional signals and amplifiers, but suggest that spots contributed to opponent evaluation during short-distance encounters between competing males.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Communication via color signals is common in natural systems. Ultraviolet (UV)-blue patches located on the outer-ventral scales of some lacertid lizards are thought to be involved in male-male competition. However, the mechanisms that maintain their honesty remain unknown. Here, we use the common wall lizard Podarcis muralis to test whether the lateral UV-blue spots are conventional signals, the honesty of which is guaranteed by receiver-dependent costs, and discuss their potential role as an amplifier of body size. We first described the morphology and reflectance properties of lateral UV-blue spots in common wall lizards and investigated how they influence male-male competition. Spot size and number, UV chroma, and conspicuousness (calculated using vision models) were significantly greater in adult males relative to adult females and adult males relative to juveniles. Total spot area (and not spot number) of adult males was positively correlated with body size. We conducted staged competition encounters between focal males and smaller or larger rivals with control or manipulated spots. Spots were enlarged in small rivals and reduced in large rivals to disrupt the phenotypic correlation between spot area and body size. Aggressiveness and dominance were positively influenced by body size in control encounters. Spot manipulations resulted in greater submission and less aggressiveness in focal males. These results contradict the predictions associated with conventional signals and amplifiers, but suggest that spots contributed to opponent evaluation during short-distance encounters between competing males. | |
Andréaz Dupoué; Olivier Lourdais; Sandrine Meylan; François Brischoux; Frédéric Angelier; David Rozen-Rechels; Yoan Marcangeli; Béatriz Decencière; Simon Agostini; Jean-François Le Galliard Some like it dry: Water restriction overrides heterogametic sex determination in two reptiles Journal Article Ecology and Evolution, 9 (11), pp. 6524–6533, 2019. @article{dupoue_like_2019, title = {Some like it dry: Water restriction overrides heterogametic sex determination in two reptiles}, author = {Andréaz Dupoué and Olivier Lourdais and Sandrine Meylan and François Brischoux and Frédéric Angelier and David Rozen-Rechels and Yoan Marcangeli and Béatriz Decencière and Simon Agostini and Jean-François Le Galliard}, url = {https://onlinelibrary.wiley.com/doi/full/10.1002/ece3.5229}, doi = {https://doi.org/10.1002/ece3.5229}, year = {2019}, date = {2019-01-01}, journal = {Ecology and Evolution}, volume = {9}, number = {11}, pages = {6524--6533}, keywords = {}, pubstate = {published}, tppubtype = {article} } | |
David Rozen-Rechels; Andréaz Dupoué; Olivier Lourdais; Simon Chamaillé-Jammes; Sandrine Meylan; Jean Clobert; Jean-François Le Galliard When water interacts with temperature: Ecological and evolutionary implications of thermo-hydroregulation in terrestrial ectotherms Journal Article Ecology and evolution, 9 (17), pp. 10029–10043, 2019. Links | BibTeX | Tags: behaviour, body temperature, performance, physiological adjustments, water balance @article{rozen-rechels_when_2019, title = {When water interacts with temperature: Ecological and evolutionary implications of thermo-hydroregulation in terrestrial ectotherms}, author = {David Rozen-Rechels and Andréaz Dupoué and Olivier Lourdais and Simon Chamaillé-Jammes and Sandrine Meylan and Jean Clobert and Jean-François Le Galliard}, url = {https://onlinelibrary.wiley.com/doi/full/10.1002/ece3.5440}, doi = {https://doi.org/10.1002/ece3.5440}, year = {2019}, date = {2019-01-01}, journal = {Ecology and evolution}, volume = {9}, number = {17}, pages = {10029--10043}, keywords = {behaviour, body temperature, performance, physiological adjustments, water balance}, pubstate = {published}, tppubtype = {article} } | |
2018 |
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Jean Clobert; André Chanzy; Jean-François Le Galliard; Abad Chabbi; Lucile Greiveldinger; Thierry Caquet; Michel Loreau; Christian Mougin; Christian Pichot; Jacques Roy; Laurent Saint-André How to Integrate Experimental Research Approaches in Ecological and Environmental Studies: AnaEE France as an Example Journal Article Frontiers in Ecology and Evolution, 6 , 2018, ISSN: 2296-701X. Abstract | Links | BibTeX | Tags: climate change, information system, modelling, open-access platforms, research infrastructure @article{clobert_how_2018, title = {How to Integrate Experimental Research Approaches in Ecological and Environmental Studies: AnaEE France as an Example}, author = {Jean Clobert and André Chanzy and Jean-François Le Galliard and Abad Chabbi and Lucile Greiveldinger and Thierry Caquet and Michel Loreau and Christian Mougin and Christian Pichot and Jacques Roy and Laurent Saint-André}, url = {https://www.frontiersin.org/articles/10.3389/fevo.2018.00043/full?&utm_source=Email_to_authors_&utm_medium=Email&utm_content=T1_11.5e1_author&utm_campaign=Email_publication&field=&journalName=Frontiers_in_Ecology_and_Evolution&id=255505}, doi = {10.3389/fevo.2018.00043}, issn = {2296-701X}, year = {2018}, date = {2018-01-01}, urldate = {2018-04-21}, journal = {Frontiers in Ecology and Evolution}, volume = {6}, abstract = {Human activities have altered continental ecosystems worldwide and generated a major environmental crisis, prompting urgent societal questions on how to best produce goods while at the same time securing sustainable ecological services and raising needs to better understand and predict biodiversity and ecosystems dynamics under global changes. To tackle these questions, experimentation on ecosystems is necessary to improve our knowledge of processes and to propose scientifically sound management strategies. Experimental platforms able to manipulate key factors of global change and including state of the art observation methodologies are available worldwide but how to best integrate them has been rarely addressed. Here, we present and discuss the case of the national research infrastructure AnaEE France dedicated to the study of continental ecosystems and designed to congregate complementary experimental approaches in order to facilitate their access and use through a range of distributed and shared services. The conceptual design of AnaEE France includes five modules. Three modules gather experimental facilities along a gradient of experimental control ranging from highly controlled Ecotron facilities, semi-natural field mesocosms to in natura experimental sites covering major continental ecosystems (forests, croplands, grasslands and lakes). In addition, AnaEE France also includes shared instruments that can be implemented in experiments and analytical platforms specifically dedicated to environmental biology. To promote reuse of data, generalize results and improve predictive models, AnaEE France further gathers modelling and information systems. The implementation of AnaEE France allowed for mutual synergies, improved the technical skills, stimulated new experiments and helped our scientific community to enter into the big data sharing era.}, keywords = {climate change, information system, modelling, open-access platforms, research infrastructure}, pubstate = {published}, tppubtype = {article} } Human activities have altered continental ecosystems worldwide and generated a major environmental crisis, prompting urgent societal questions on how to best produce goods while at the same time securing sustainable ecological services and raising needs to better understand and predict biodiversity and ecosystems dynamics under global changes. To tackle these questions, experimentation on ecosystems is necessary to improve our knowledge of processes and to propose scientifically sound management strategies. Experimental platforms able to manipulate key factors of global change and including state of the art observation methodologies are available worldwide but how to best integrate them has been rarely addressed. Here, we present and discuss the case of the national research infrastructure AnaEE France dedicated to the study of continental ecosystems and designed to congregate complementary experimental approaches in order to facilitate their access and use through a range of distributed and shared services. The conceptual design of AnaEE France includes five modules. Three modules gather experimental facilities along a gradient of experimental control ranging from highly controlled Ecotron facilities, semi-natural field mesocosms to in natura experimental sites covering major continental ecosystems (forests, croplands, grasslands and lakes). In addition, AnaEE France also includes shared instruments that can be implemented in experiments and analytical platforms specifically dedicated to environmental biology. To promote reuse of data, generalize results and improve predictive models, AnaEE France further gathers modelling and information systems. The implementation of AnaEE France allowed for mutual synergies, improved the technical skills, stimulated new experiments and helped our scientific community to enter into the big data sharing era. | |
David Rozen-Rechels; Andréaz Dupoué; Sandrine Meylan; Beatriz Decencière; Sophie Guingand; Jean-François Le Galliard Water restriction in viviparous lizards causes transgenerational effects on behavioral anxiety and immediate effects on exploration behavior Journal Article Behavioral Ecology and Sociobiology, 72 (2), pp. 23, 2018, ISSN: 1432-0762. Abstract | Links | BibTeX | Tags: maternal effect, squamate reptiles, stress, thigmotaxis, water availability @article{rozen-rechels_water_2018, title = {Water restriction in viviparous lizards causes transgenerational effects on behavioral anxiety and immediate effects on exploration behavior}, author = {David Rozen-Rechels and Andréaz Dupoué and Sandrine Meylan and Beatriz Decencière and Sophie Guingand and Jean-François Le Galliard}, url = {https://doi.org/10.1007/s00265-018-2443-4}, doi = {10.1007/s00265-018-2443-4}, issn = {1432-0762}, year = {2018}, date = {2018-01-01}, urldate = {2019-09-13}, journal = {Behavioral Ecology and Sociobiology}, volume = {72}, number = {2}, pages = {23}, abstract = {Behavioral plasticity induced by maternal effects is crucial in adjusting offspring phenotype to match the environment. In particular, changes in water availability during development may initiate a range of behavioral responses, such as natal dispersal, but the contribution of maternal effects from water stress in explaining behavioral variation has been overlooked so far. In this study, we examined behavioral plasticity of juvenile common lizards (Zootoca vivipara) in response to changes in pre-natal and post-natal hydric conditions. We exposed pregnant mothers either to a moderate water restriction or to ad libitum access to water. We used neutral arena tests to measure repeatedly activity and space use behaviors of their offspring, either in dry or wet soil conditions, at two distinct life stages (juveniles and yearlings) in order to quantify behavioral flexibility, age differences, and personalities (consistent inter-individual differences). Juveniles and yearlings had greater exploration scores in dry than wet conditions regardless of the pre-natal conditions. Pre-natal water restriction and dry post-natal conditions enhanced thigmotaxis (i.e., a behavior related to anxiety) in juveniles. Maternal environment did not influence behavioral flexibility nor the behavior of yearlings. Behaviors were barely repeatable in juveniles and inconsistent through early life. Assuming that dry conditions may initiate flight responses, these results suggest complex relationships between the developmental timing of water stress, exploration and anxiety behaviors, and dispersal syndromes.Significance statementWater restriction should initiate a range of behaviors related to a flight response. However, there is little evidence that changes in water availability across development influence offspring behavior in wild animals. Experiments with lizards demonstrate that maternal water restriction increased the anxiety of their juveniles, whereas their exploration was higher in dry environments. Thus, water availability may be a critical determinant of space use behavior and dispersal syndromes.}, keywords = {maternal effect, squamate reptiles, stress, thigmotaxis, water availability}, pubstate = {published}, tppubtype = {article} } Behavioral plasticity induced by maternal effects is crucial in adjusting offspring phenotype to match the environment. In particular, changes in water availability during development may initiate a range of behavioral responses, such as natal dispersal, but the contribution of maternal effects from water stress in explaining behavioral variation has been overlooked so far. In this study, we examined behavioral plasticity of juvenile common lizards (Zootoca vivipara) in response to changes in pre-natal and post-natal hydric conditions. We exposed pregnant mothers either to a moderate water restriction or to ad libitum access to water. We used neutral arena tests to measure repeatedly activity and space use behaviors of their offspring, either in dry or wet soil conditions, at two distinct life stages (juveniles and yearlings) in order to quantify behavioral flexibility, age differences, and personalities (consistent inter-individual differences). Juveniles and yearlings had greater exploration scores in dry than wet conditions regardless of the pre-natal conditions. Pre-natal water restriction and dry post-natal conditions enhanced thigmotaxis (i.e., a behavior related to anxiety) in juveniles. Maternal environment did not influence behavioral flexibility nor the behavior of yearlings. Behaviors were barely repeatable in juveniles and inconsistent through early life. Assuming that dry conditions may initiate flight responses, these results suggest complex relationships between the developmental timing of water stress, exploration and anxiety behaviors, and dispersal syndromes.Significance statementWater restriction should initiate a range of behaviors related to a flight response. However, there is little evidence that changes in water availability across development influence offspring behavior in wild animals. Experiments with lizards demonstrate that maternal water restriction increased the anxiety of their juveniles, whereas their exploration was higher in dry environments. Thus, water availability may be a critical determinant of space use behavior and dispersal syndromes. | |
Alexandru Milcu; Ruben Puga-Freitas; Aaron M Ellison; Manuel Blouin; Stefan Scheu; Grégoire T Freschet; Laura Rose; Sebastien Barot; Simone Cesarz; Nico Eisenhauer; Thomas Girin; Davide Assandri; Michael Bonkowski; Nina Buchmann; Olaf Butenschoen; Sébastien Devidal; Gerd Gleixner; Arthur Gessler; Agnès Gigon; Anna Greiner; Carlo Grignani; Amandine Hansart; Zachary Kayler; Markus Lange; Jean-Christophe Lata; Jean-François Le Galliard; Martin Lukac; Neringa Mannerheim; Marina E. H. Müller; Anne Pando; Paula Rotter; Michael Scherer-Lorenzen; Rahme Seyhun; Katherine Urban-Mead; Alexandra Weigelt; Laura Zavattaro; Jacques Roy Genotypic variability enhances the reproducibility of an ecological study Journal Article Nature ecology & evolution, 2 (2), pp. 279, 2018. @article{milcu_genotypic_2018, title = {Genotypic variability enhances the reproducibility of an ecological study}, author = {Alexandru Milcu and Ruben Puga-Freitas and Aaron M Ellison and Manuel Blouin and Stefan Scheu and Grégoire T Freschet and Laura Rose and Sebastien Barot and Simone Cesarz and Nico Eisenhauer and Thomas Girin and Davide Assandri and Michael Bonkowski and Nina Buchmann and Olaf Butenschoen and Sébastien Devidal and Gerd Gleixner and Arthur Gessler and Agnès Gigon and Anna Greiner and Carlo Grignani and Amandine Hansart and Zachary Kayler and Markus Lange and Jean-Christophe Lata and Jean-François Le Galliard and Martin Lukac and Neringa Mannerheim and Marina E. H. Müller and Anne Pando and Paula Rotter and Michael Scherer-Lorenzen and Rahme Seyhun and Katherine Urban-Mead and Alexandra Weigelt and Laura Zavattaro and Jacques Roy}, url = {https://www.nature.com/articles/s41559-017-0434-x}, doi = {https://doi.org/10.1038/s41559-017-0434-x}, year = {2018}, date = {2018-01-01}, journal = {Nature ecology & evolution}, volume = {2}, number = {2}, pages = {279}, keywords = {}, pubstate = {published}, tppubtype = {article} } | |
Andréaz Dupoué; Jean-François Le Galliard; Rémy Josserand; Dale F DeNardo; Béatriz Decencière; Simon Agostini; Claudy Haussy; Sandrine Meylan Water restriction causes an intergenerational trade-off and delayed mother–offspring conflict in a viviparous lizard Journal Article Functional ecology, 32 (3), pp. 676–686, 2018. Links | BibTeX | Tags: corticosterone, dehydration, reproduction, survival, trade-off @article{dupoue_water_2018, title = {Water restriction causes an intergenerational trade-off and delayed mother–offspring conflict in a viviparous lizard}, author = {Andréaz Dupoué and Jean-François Le Galliard and Rémy Josserand and Dale F DeNardo and Béatriz Decencière and Simon Agostini and Claudy Haussy and Sandrine Meylan}, url = {https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2435.13009}, doi = {https://doi.org/10.1111/1365-2435.13009}, year = {2018}, date = {2018-01-01}, journal = {Functional ecology}, volume = {32}, number = {3}, pages = {676--686}, keywords = {corticosterone, dehydration, reproduction, survival, trade-off}, pubstate = {published}, tppubtype = {article} } | |
Andréaz Dupoué; Alexis Rutschmann; Jean-François Le Galliard; Jean Clobert; Pauline Blaimont; Barry Sinervo; Donald B Miles; Claudy Haussy; Sandrine Meylan Reduction in baseline corticosterone secretion correlates with climate warming and drying across wild lizard populations Journal Article Journal of Animal Ecology, 87 (5), pp. 1331–1341, 2018. @article{dupoue_reduction_2018, title = {Reduction in baseline corticosterone secretion correlates with climate warming and drying across wild lizard populations}, author = {Andréaz Dupoué and Alexis Rutschmann and Jean-François Le Galliard and Jean Clobert and Pauline Blaimont and Barry Sinervo and Donald B Miles and Claudy Haussy and Sandrine Meylan}, url = {https://besjournals.onlinelibrary.wiley.com/doi/abs/10.1111/1365-2656.12843}, doi = {https://doi.org/10.1111/1365-2656.12843}, year = {2018}, date = {2018-01-01}, journal = {Journal of Animal Ecology}, volume = {87}, number = {5}, pages = {1331--1341}, keywords = {}, pubstate = {published}, tppubtype = {article} } | |
Sarah Fiorini; Alexis Millot; Simon Chollet; Florent Massot; Jean-François Le Galliard; Emma Rochelle-Newall; Gerard Lacroix The PLANAQUA platform: a cutting-edge experimental infrastructure for multi-scale studies on aquatic ecosystems Conference EGUGA, 2018. BibTeX | Tags: @conference{fiorini_planaqua_2018, title = {The PLANAQUA platform: a cutting-edge experimental infrastructure for multi-scale studies on aquatic ecosystems}, author = {Sarah Fiorini and Alexis Millot and Simon Chollet and Florent Massot and Jean-François Le Galliard and Emma Rochelle-Newall and Gerard Lacroix}, year = {2018}, date = {2018-01-01}, booktitle = {EGUGA}, pages = {9724}, keywords = {}, pubstate = {published}, tppubtype = {conference} } | |
Yann Dusza; Sabrina Juarez; Simon Chollet; Régis Ferrière; Amandine Hansart; Florent Massol; Mathieu Llavata; Jean-François Le Galliard; Enrique Pérez Sánchez-Cañete; Greg Barron-Gafford Quantifying the importance of biotic and abiotic drivers in creating lags in soil CO2 efflux Conference EGUGA, 2018. BibTeX | Tags: @conference{dusza_quantifying_2018, title = {Quantifying the importance of biotic and abiotic drivers in creating lags in soil CO2 efflux}, author = {Yann Dusza and Sabrina Juarez and Simon Chollet and Régis Ferrière and Amandine Hansart and Florent Massol and Mathieu Llavata and Jean-François Le Galliard and Enrique Pérez Sánchez-Cañete and Greg Barron-Gafford}, year = {2018}, date = {2018-01-01}, booktitle = {EGUGA}, pages = {8461}, keywords = {}, pubstate = {published}, tppubtype = {conference} } | |
Willem Bonnaffé; Mélissa Martin; Marianne Mugabo; Sandrine Meylan; Jean-François Le Galliard Ontogenetic trajectories of body coloration reveal its function as a multicomponent nonsenescent signal Journal Article Ecology and evolution, 8 (24), pp. 12299–12307, 2018. @article{bonnaffe_ontogenetic_2018, title = {Ontogenetic trajectories of body coloration reveal its function as a multicomponent nonsenescent signal}, author = {Willem Bonnaffé and Mélissa Martin and Marianne Mugabo and Sandrine Meylan and Jean-François Le Galliard}, url = {https://onlinelibrary.wiley.com/doi/full/10.1002/ece3.4369}, doi = {https://doi.org/10.1002/ece3.4369}, year = {2018}, date = {2018-01-01}, journal = {Ecology and evolution}, volume = {8}, number = {24}, pages = {12299--12307}, keywords = {}, pubstate = {published}, tppubtype = {article} } | |
2017 |
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Andréaz Dupoué; Alexis Rutschmann; Jean-François Le Galliard; Jean Clobert; Frédéric Angelier; Coline Marciau; Stéphanie Ruault; Donald Miles; Sandrine Meylan Shorter telomeres precede population extinction in wild lizards Journal Article Scientific Reports, 7 (1), pp. 16976, 2017, ISSN: 2045-2322. Abstract | Links | BibTeX | Tags: @article{dupoue_shorter_2017, title = {Shorter telomeres precede population extinction in wild lizards}, author = {Andréaz Dupoué and Alexis Rutschmann and Jean-François Le Galliard and Jean Clobert and Frédéric Angelier and Coline Marciau and Stéphanie Ruault and Donald Miles and Sandrine Meylan}, url = {https://www.nature.com/articles/s41598-017-17323-z}, doi = {10.1038/s41598-017-17323-z}, issn = {2045-2322}, year = {2017}, date = {2017-12-01}, urldate = {2018-01-15}, journal = {Scientific Reports}, volume = {7}, number = {1}, pages = {16976}, abstract = {Identifying the early warning signals of catastrophic extinctions has recently become a central focus for ecologists, but species’ functional responses to environmental changes remain an untapped source for the sharpening of such warning signals. Telomere length (TL) analysis represents a promising molecular tool with which to raise the alarm regarding early population decline, since telomere attrition is associated with aging processes and accelerates after a recurrent exposure to environmental stressors. In the southern margin of their range, populations of the common lizard (Zootoca vivipara) recently became extinct at lowest elevations due to changes in climate conditions. However, the proximal signals involved in these demographic declines are still unknown. Here, we sampled 100 yearling lizards from 10 natural populations (n = 10 per population) along an extinction risk gradient. Relative lizard abundance dramatically dropped over 12 years in low-altitude populations characterized by warmer ambient temperatures and higher body growth of lizards early in life. A non-linear relationship was found between TL and population extinction risk, with shorter telomeres in populations facing high risk of extinction when compared to non-threatened ones. Our results identify TL as a promising biomarker and imply that population extinctions might be preceded by a loop of physiological aging.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Identifying the early warning signals of catastrophic extinctions has recently become a central focus for ecologists, but species’ functional responses to environmental changes remain an untapped source for the sharpening of such warning signals. Telomere length (TL) analysis represents a promising molecular tool with which to raise the alarm regarding early population decline, since telomere attrition is associated with aging processes and accelerates after a recurrent exposure to environmental stressors. In the southern margin of their range, populations of the common lizard (Zootoca vivipara) recently became extinct at lowest elevations due to changes in climate conditions. However, the proximal signals involved in these demographic declines are still unknown. Here, we sampled 100 yearling lizards from 10 natural populations (n = 10 per population) along an extinction risk gradient. Relative lizard abundance dramatically dropped over 12 years in low-altitude populations characterized by warmer ambient temperatures and higher body growth of lizards early in life. A non-linear relationship was found between TL and population extinction risk, with shorter telomeres in populations facing high risk of extinction when compared to non-threatened ones. Our results identify TL as a promising biomarker and imply that population extinctions might be preceded by a loop of physiological aging. | |
Paulina Artacho; Samuel Perret; Julia Saravia; Jose Luis Bartheld; Jean-François Le Galliard Geographic variation and acclimation effects on thermoregulation behavior in the widespread lizard Liolaemus pictus Journal Article Journal of Thermal Biology, 63 , pp. 78–87, 2017. Abstract | Links | BibTeX | Tags: @article{artacho_geographic_2017, title = {Geographic variation and acclimation effects on thermoregulation behavior in the widespread lizard Liolaemus pictus}, author = {Paulina Artacho and Samuel Perret and Julia Saravia and Jose Luis Bartheld and Jean-François Le Galliard}, url = {https://www.sciencedirect.com/science/article/abs/pii/S0306456516301097}, doi = {https://doi.org/10.1016/j.jtherbio.2016.11.001}, year = {2017}, date = {2017-01-01}, journal = {Journal of Thermal Biology}, volume = {63}, pages = {78--87}, abstract = {Populations at the warm range margins of the species distribution may be at the greatest risks of extinction from global warming unless they can tolerate extreme environmental conditions. Yet, some studies suggest that the thermal behavior of some lizard species is evolutionarily rigid. During two successive years, we compared the thermal biology of two populations of Liolaemus pictus living at the northern (warmer) and one population living at the southern (colder) range limits, thus spanning an 800 km latitudinal distance. Populations at the two range margins belong to two deeply divergent evolutionary clades. We quantified field body temperatures (Tb), laboratory preferred body temperatures (PBT), and used operative temperature data (Te) to calculate the effectiveness of thermoregulation (E). During one year in all populations, we further exposed half of the lizards to a cold or a hot acclimation treatment to test for plasticity in the thermal behavior. The environment at the southern range limit was characterized by cooler weather and lower Te. Despite that, females had higher Tb and both males and females had higher PBT in the southernmost population (or clade) than in the northernmost populations. Acclimation to cold conditions led to higher PBT in all populations suggesting that plastic responses to thermal conditions, instead of evolutionary history, may contribute to geographic variation. Lizards regulated moderately well their body temperature (E≈0.7): they avoided warm microhabitats in the northern range but capitalized on warm microhabitats in the southern range. We review literature data to show that Liolaemus species increase their thermoregulation efficiency in thermally challenging environments. Altogether, this indicates that habitats of low thermal quality generally select against thermoconformity in these lizards.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Populations at the warm range margins of the species distribution may be at the greatest risks of extinction from global warming unless they can tolerate extreme environmental conditions. Yet, some studies suggest that the thermal behavior of some lizard species is evolutionarily rigid. During two successive years, we compared the thermal biology of two populations of Liolaemus pictus living at the northern (warmer) and one population living at the southern (colder) range limits, thus spanning an 800 km latitudinal distance. Populations at the two range margins belong to two deeply divergent evolutionary clades. We quantified field body temperatures (Tb), laboratory preferred body temperatures (PBT), and used operative temperature data (Te) to calculate the effectiveness of thermoregulation (E). During one year in all populations, we further exposed half of the lizards to a cold or a hot acclimation treatment to test for plasticity in the thermal behavior. The environment at the southern range limit was characterized by cooler weather and lower Te. Despite that, females had higher Tb and both males and females had higher PBT in the southernmost population (or clade) than in the northernmost populations. Acclimation to cold conditions led to higher PBT in all populations suggesting that plastic responses to thermal conditions, instead of evolutionary history, may contribute to geographic variation. Lizards regulated moderately well their body temperature (E≈0.7): they avoided warm microhabitats in the northern range but capitalized on warm microhabitats in the southern range. We review literature data to show that Liolaemus species increase their thermoregulation efficiency in thermally challenging environments. Altogether, this indicates that habitats of low thermal quality generally select against thermoconformity in these lizards. | |
Andréaz Dupoué; Alexis Rutschmann; Jean-François Le Galliard; Donald B Miles; Jean Clobert; Dale F DeNardo; George A Brusch; Sandrine Meylan Water availability and environmental temperature correlate with geographic variation in water balance in common lizards Journal Article Oecologia, 185 (4), pp. 561–571, 2017, ISSN: 0029-8549, 1432-1939. Abstract | Links | BibTeX | Tags: @article{dupoue_water_2017, title = {Water availability and environmental temperature correlate with geographic variation in water balance in common lizards}, author = {Andréaz Dupoué and Alexis Rutschmann and Jean-François Le Galliard and Donald B Miles and Jean Clobert and Dale F DeNardo and George A Brusch and Sandrine Meylan}, url = {https://link.springer.com/article/10.1007/s00442-017-3973-6}, doi = {10.1007/s00442-017-3973-6}, issn = {0029-8549, 1432-1939}, year = {2017}, date = {2017-01-01}, urldate = {2018-01-04}, journal = {Oecologia}, volume = {185}, number = {4}, pages = {561--571}, abstract = {Water conservation strategies are well documented in species living in water-limited environments, but physiological adaptations to water availability in temperate climate environments are still relatively overlooked. Yet, temperate species are facing more frequent and intense droughts as a result of climate change. Here, we examined variation in field hydration state (plasma osmolality) and standardized evaporative water loss rate (SEWL) of adult male and pregnant female common lizards (Zootoca vivipara) from 13 natural populations with contrasting air temperature, air humidity, and access to water. We found different patterns of geographic variation between sexes. Overall, males were more dehydrated (i.e. higher osmolality) than pregnant females, which likely comes from differences in field behaviour and water intake since the rate of SEWL was similar between sexes. Plasma osmolality and SEWL rate were positively correlated with environmental temperature in males, while plasma osmolality in pregnant females did not correlate with environmental conditions, reproductive stage or reproductive effort. The SEWL rate was significantly lower in populations without access to free standing water, suggesting that lizards can adapt or adjust physiology to cope with habitat dryness. Environmental humidity did not explain variation in water balance. We suggest that geographic variation in water balance physiology and behaviour should be taken account to better understand species range limits and sensitivity to climate change.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Water conservation strategies are well documented in species living in water-limited environments, but physiological adaptations to water availability in temperate climate environments are still relatively overlooked. Yet, temperate species are facing more frequent and intense droughts as a result of climate change. Here, we examined variation in field hydration state (plasma osmolality) and standardized evaporative water loss rate (SEWL) of adult male and pregnant female common lizards (Zootoca vivipara) from 13 natural populations with contrasting air temperature, air humidity, and access to water. We found different patterns of geographic variation between sexes. Overall, males were more dehydrated (i.e. higher osmolality) than pregnant females, which likely comes from differences in field behaviour and water intake since the rate of SEWL was similar between sexes. Plasma osmolality and SEWL rate were positively correlated with environmental temperature in males, while plasma osmolality in pregnant females did not correlate with environmental conditions, reproductive stage or reproductive effort. The SEWL rate was significantly lower in populations without access to free standing water, suggesting that lizards can adapt or adjust physiology to cope with habitat dryness. Environmental humidity did not explain variation in water balance. We suggest that geographic variation in water balance physiology and behaviour should be taken account to better understand species range limits and sensitivity to climate change. | |
Marta Gallardo Ruiz; Jean-François Le Galliard; Thomas Tully Genetic variation in light vision and light-dependent movement behaviour in the eyeless Collembola Folsomia candida Journal Article Pedobiologia, 61 , pp. 33–41, 2017, ISSN: 0031-4056. Abstract | Links | BibTeX | Tags: dispersal, Folsomia candida, light sensitivity, phenotypic plasticity @article{gallardo_ruiz_genetic_2017, title = {Genetic variation in light vision and light-dependent movement behaviour in the eyeless Collembola Folsomia candida}, author = {Marta Gallardo Ruiz and Jean-François Le Galliard and Thomas Tully}, url = {https://www.sciencedirect.com/science/article/abs/pii/S003140561630138X}, doi = {https://doi.org/10.1016/j.pedobi.2016.12.001}, issn = {0031-4056}, year = {2017}, date = {2017-01-01}, journal = {Pedobiologia}, volume = {61}, pages = {33--41}, abstract = {Abstract Animals can cope with spatiotemporal variation in their environment through mobility and selective habitat choice. Intra-specific variation in habitat choice has been documented especially for host plant preferences and cryptic habitat selection in insects. Here, we investigated the genetic variation in light sensitivity and light-dependent habitat choice in the eyeless Collembola Folsomia candida with a choice test under four different lighting conditions (control dark condition, two simulations of undergrowth natural light conditions and red light). We tested twelve clonal strains from diverse geographical origins that are clustered in two evolutionary clades with contrasting fast or slow life-history strategies. The clones differed in their mean movement probabilities in the dark treatment. These differences were related to the two different phylogenetic clades, where fast-life history clones are on average more mobile than slow-life history counterparts as predicted by the ‘colonizer syndrome’ hypothesis. We found behavioural avoidance of light in the three light conditions. Moreover, photophobia was stronger when the simulated light spectrum was brighter and included non-red light. Photophobia was similar among all clonal lineages and between the two clades, which suggests that this behaviour is a shared behavioural trait in this species. We discuss the use of light as an environmental cue for orientation, displacement and habitat choice under natural conditions.}, keywords = {dispersal, Folsomia candida, light sensitivity, phenotypic plasticity}, pubstate = {published}, tppubtype = {article} } Abstract Animals can cope with spatiotemporal variation in their environment through mobility and selective habitat choice. Intra-specific variation in habitat choice has been documented especially for host plant preferences and cryptic habitat selection in insects. Here, we investigated the genetic variation in light sensitivity and light-dependent habitat choice in the eyeless Collembola Folsomia candida with a choice test under four different lighting conditions (control dark condition, two simulations of undergrowth natural light conditions and red light). We tested twelve clonal strains from diverse geographical origins that are clustered in two evolutionary clades with contrasting fast or slow life-history strategies. The clones differed in their mean movement probabilities in the dark treatment. These differences were related to the two different phylogenetic clades, where fast-life history clones are on average more mobile than slow-life history counterparts as predicted by the ‘colonizer syndrome’ hypothesis. We found behavioural avoidance of light in the three light conditions. Moreover, photophobia was stronger when the simulated light spectrum was brighter and included non-red light. Photophobia was similar among all clonal lineages and between the two clades, which suggests that this behaviour is a shared behavioural trait in this species. We discuss the use of light as an environmental cue for orientation, displacement and habitat choice under natural conditions. | |
Rémy Josserand; Andréaz Dupoué; Simon Agostini; Claudy Haussy; Jean-François Le Galliard; Sandrine Meylan Oecologia, 184 (1), pp. 75–86, 2017. @article{josserand_habitat_2017, title = {Habitat degradation increases stress-hormone levels during the breeding season and decreases survival and reproduction in adult common lizards. Oecologia. In press}, author = {Rémy Josserand and Andréaz Dupoué and Simon Agostini and Claudy Haussy and Jean-François Le Galliard and Sandrine Meylan}, url = {https://link.springer.com/article/10.1007%2Fs00442-017-3841-4}, doi = {https://doi.org/10.1007/s00442-017-3841-4}, year = {2017}, date = {2017-01-01}, journal = {Oecologia}, volume = {184}, number = {1}, pages = {75--86}, keywords = {}, pubstate = {published}, tppubtype = {article} } | |
Marianne Mugabo; Jean-François Le Galliard; Samuel Perret; Beatriz Decencière; Claudy Haussy; Sandrine Meylan Sex-specific density-dependent secretion of glucocorticoids in lizards: insights from laboratory and field experiments Journal Article Oikos, 126 (7), pp. 1051–1061, 2017, ISSN: 1600-0706. Abstract | Links | BibTeX | Tags: @article{mugabo_sex-specific_2017, title = {Sex-specific density-dependent secretion of glucocorticoids in lizards: insights from laboratory and field experiments}, author = {Marianne Mugabo and Jean-François Le Galliard and Samuel Perret and Beatriz Decencière and Claudy Haussy and Sandrine Meylan}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/oik.03701}, doi = {10.1111/oik.03701}, issn = {1600-0706}, year = {2017}, date = {2017-01-01}, urldate = {2020-04-09}, journal = {Oikos}, volume = {126}, number = {7}, pages = {1051--1061}, abstract = {Negative density feedbacks have been extensively described in animal species and involve both consumptive (i.e. trophic interactions) and non-consumptive (i.e. social interactions) mechanisms. Glucocorticoids are a major component of the physiological stress response and homeostasis, and therefore make a good candidate for proximate determinants of negative density feedbacks. Here, we combined laboratory and field experiments with enclosed populations to investigate the relationship between density, social stress and plasma corticosterone levels in the common lizard Zootoca vivipara. This species exhibits strong negative density feedbacks that affect females more than males, and its life history is sensitive to experimentally-induced chronic elevation of corticosterone plasma levels. We found that prolonged crowding in the laboratory can trigger a chronic secretion of corticosterone independent from food restriction. In the field experiments, corticosterone levels of females were not affected by population density. Corticosterone levels of males increased with population density but only during the late activity season in a first field experiment where we manipulated density. They also increased with density during the mating season but only in populations with a female-biased sex ratio in a second field experiment where we crossed manipulated density and adult sex ratio. Altogether, our results provide limited evidence for a role of basal corticosterone secretion in density feedbacks in this species. Context and density-dependent effects in males may arise from changes in behavior caused by competition for resources, male–male competition, and mating.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Negative density feedbacks have been extensively described in animal species and involve both consumptive (i.e. trophic interactions) and non-consumptive (i.e. social interactions) mechanisms. Glucocorticoids are a major component of the physiological stress response and homeostasis, and therefore make a good candidate for proximate determinants of negative density feedbacks. Here, we combined laboratory and field experiments with enclosed populations to investigate the relationship between density, social stress and plasma corticosterone levels in the common lizard Zootoca vivipara. This species exhibits strong negative density feedbacks that affect females more than males, and its life history is sensitive to experimentally-induced chronic elevation of corticosterone plasma levels. We found that prolonged crowding in the laboratory can trigger a chronic secretion of corticosterone independent from food restriction. In the field experiments, corticosterone levels of females were not affected by population density. Corticosterone levels of males increased with population density but only during the late activity season in a first field experiment where we manipulated density. They also increased with density during the mating season but only in populations with a female-biased sex ratio in a second field experiment where we crossed manipulated density and adult sex ratio. Altogether, our results provide limited evidence for a role of basal corticosterone secretion in density feedbacks in this species. Context and density-dependent effects in males may arise from changes in behavior caused by competition for resources, male–male competition, and mating. | |
Yann Voituron; Rémy Josserand; Jean-François Le Galliard; Claudy Haussy; Damien Roussel; Caroline Romestaing; Sandrine Meylan Chronic stress, energy transduction, and free-radical production in a reptile Journal Article Oecologia, 185 (2), pp. 195–203, 2017, ISSN: 1432-1939. Abstract | Links | BibTeX | Tags: @article{voituron_chronic_2017, title = {Chronic stress, energy transduction, and free-radical production in a reptile}, author = {Yann Voituron and Rémy Josserand and Jean-François Le Galliard and Claudy Haussy and Damien Roussel and Caroline Romestaing and Sandrine Meylan}, url = {https://link.springer.com/article/10.1007/s00442-017-3933-1}, doi = {https:doi.org10.1007s00442-017-3933-1}, issn = {1432-1939}, year = {2017}, date = {2017-01-01}, journal = {Oecologia}, volume = {185}, number = {2}, pages = {195--203}, abstract = {Stress hormones, such as corticosterone, play a crucial role in orchestrating physiological reaction patterns shaping adapted responses to stressful environments. Concepts aiming at predicting individual and population responses to environmental stress typically consider that stress hormones and their effects on metabolic rate provide appropriate proxies for the energy budget. However, uncoupling between the biochemical processes of respiration, ATP production, and free-radical production in mitochondria may play a fundamental role in the stress response and associated life histories. In this study, we aim at dissecting sub-cellular mechanisms that link these three processes by investigating both whole-organism metabolism, liver mitochondrial oxidative phosphorylation processes (O2 consumption and ATP production) and ROS emission in Zootoca vivipara individuals exposed 21Â days to corticosterone relative to a placebo. Corticosterone enhancement had no effect on mitochondrial activity and efficiency. In parallel, the corticosterone treatment increased liver mass and mitochondrial protein content suggesting a higher liver ATP production. We also found a negative correlation between mitochondrial ROS emission and plasma corticosterone level. These results provide a proximal explanation for enhanced survival after chronic exposure to corticosterone in this species. Importantly, none of these modifications affected resting whole-body metabolic rate. Oxygen consumption, ATP, and ROS emission were thus independently affected in responses to corticosterone increase suggesting that concepts and models aiming at linking environmental stress and individual responses may misestimate energy allocation possibilities.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Stress hormones, such as corticosterone, play a crucial role in orchestrating physiological reaction patterns shaping adapted responses to stressful environments. Concepts aiming at predicting individual and population responses to environmental stress typically consider that stress hormones and their effects on metabolic rate provide appropriate proxies for the energy budget. However, uncoupling between the biochemical processes of respiration, ATP production, and free-radical production in mitochondria may play a fundamental role in the stress response and associated life histories. In this study, we aim at dissecting sub-cellular mechanisms that link these three processes by investigating both whole-organism metabolism, liver mitochondrial oxidative phosphorylation processes (O2 consumption and ATP production) and ROS emission in Zootoca vivipara individuals exposed 21Â days to corticosterone relative to a placebo. Corticosterone enhancement had no effect on mitochondrial activity and efficiency. In parallel, the corticosterone treatment increased liver mass and mitochondrial protein content suggesting a higher liver ATP production. We also found a negative correlation between mitochondrial ROS emission and plasma corticosterone level. These results provide a proximal explanation for enhanced survival after chronic exposure to corticosterone in this species. Importantly, none of these modifications affected resting whole-body metabolic rate. Oxygen consumption, ATP, and ROS emission were thus independently affected in responses to corticosterone increase suggesting that concepts and models aiming at linking environmental stress and individual responses may misestimate energy allocation possibilities. | |
Jean-François Le Galliard; Andre Chanzy; Jean Clobert; Jacques Roy; Jean-Gabriel Valay; Christian Mougin; Christian Pichot AnaEE France - L'apport de l'expérimentation à l'étude de la biodiversité Conference Séminaire Ecoscope: Données et évaluation de la biodiversité. Quels enjeux, quels défis?, 2017. BibTeX | Tags: @conference{le_galliard_anaee_2017, title = {AnaEE France - L'apport de l'expérimentation à l'étude de la biodiversité}, author = {Jean-François Le Galliard and Andre Chanzy and Jean Clobert and Jacques Roy and Jean-Gabriel Valay and Christian Mougin and Christian Pichot}, year = {2017}, date = {2017-01-01}, booktitle = {Séminaire Ecoscope: Données et évaluation de la biodiversité. Quels enjeux, quels défis?}, pages = {np}, keywords = {}, pubstate = {published}, tppubtype = {conference} } | |
Eunice Iribe Villasenor; Katerina Dontsova; Sabrina Juarez; Jean-François Le Galliard; Simon Chollet; Mathieu Llavata; Florent Massol; Pierre Barré; Alexandre Gelabert; Damien Daval; Peter Troch; Greg Barron-Gafford; Joost Van Haren; Régis Ferrière The effect of elevated CO2 and temperature on nutrient uptake by plants grown in basaltic soil Conference AGUFM, 2017 , 2017. BibTeX | Tags: @conference{villasenor_iribe_effect_2017, title = {The effect of elevated CO2 and temperature on nutrient uptake by plants grown in basaltic soil}, author = {Eunice Iribe Villasenor and Katerina Dontsova and Sabrina Juarez and Jean-François Le Galliard and Simon Chollet and Mathieu Llavata and Florent Massol and Pierre Barré and Alexandre Gelabert and Damien Daval and Peter Troch and Greg Barron-Gafford and Joost Van Haren and Régis Ferrière}, year = {2017}, date = {2017-01-01}, booktitle = {AGUFM}, volume = {2017}, pages = {B51F--1876}, keywords = {}, pubstate = {published}, tppubtype = {conference} } | |
Joost LM Van Haren; Enrique P Sanchez-Canete; Sabrina Juarez; Elizabeth L Howard; Katerina Dontsova; Jean-François Le Galliard; Greg Barron-Gafford; Till Volkmann; Peter A Troch Projected effects of vegetation and organic matter on soil carbon dynamics after rainfall in a model basalt landscape. Conference AGUFM, 2017 , 2017. BibTeX | Tags: @conference{van_haren_projected_2017, title = {Projected effects of vegetation and organic matter on soil carbon dynamics after rainfall in a model basalt landscape.}, author = {Joost LM Van Haren and Enrique P Sanchez-Canete and Sabrina Juarez and Elizabeth L Howard and Katerina Dontsova and Jean-François Le Galliard and Greg Barron-Gafford and Till Volkmann and Peter A Troch}, year = {2017}, date = {2017-01-01}, booktitle = {AGUFM}, volume = {2017}, pages = {B43A--2113}, keywords = {}, pubstate = {published}, tppubtype = {conference} } | |
2016 |
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Malo Jaffré; Jean-François Le Galliard Population viability analysis of plant and animal populations with stochastic integral projection models Journal Article Oecologia, 182 (4), pp. 1031–1043, 2016, ISSN: 1432-1939. Abstract | Links | BibTeX | Tags: @article{jaffre_population_2016, title = {Population viability analysis of plant and animal populations with stochastic integral projection models}, author = {Malo Jaffré and Jean-François Le Galliard}, url = {http:dx.doi.org10.1007s00442-016-3704-4}, issn = {1432-1939}, year = {2016}, date = {2016-01-01}, journal = {Oecologia}, volume = {182}, number = {4}, pages = {1031--1043}, abstract = {Integral projection models (IPM) make it possible to study populations structured by continuous traits. Recently, Vindenes et al. (Ecology 92:1146–1156, 2011) proposed an extended IPM to analyse the dynamics of small populations in stochastic environments, but this model has not yet been used to conduct population viability analyses. Here, we used the extended IPM to analyse the stochastic dynamics of IPM of small size-structured populations in one plant and one animal species (evening primrose and common lizard) including demographic stochasticity in both cases and environmental stochasticity in the lizard model. We also tested the accuracy of a diffusion approximation of the IPM for the two empirical systems. In both species, the elasticity for λ was higher with respect to parameters linked to body growth and size-dependent reproduction rather than survival. An analytical approach made it possible to quantify demographic and environmental variance to calculate the average stochastic growth rate. Demographic variance was further decomposed to gain insights into the most important size classes and demographic components. A diffusion approximation provided a remarkable fit to the stochastic dynamics and cumulative extinction risk, except for very small populations where stochastic growth rate was biased upward or downward depending on the model. These results confirm that the extended IPM provides a powerful tool to assess the conservation status and compare the stochastic demography of size-structured species, but should be complemented with individual based models to obtain unbiased estimates for very small populations of conservation concern.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Integral projection models (IPM) make it possible to study populations structured by continuous traits. Recently, Vindenes et al. (Ecology 92:1146–1156, 2011) proposed an extended IPM to analyse the dynamics of small populations in stochastic environments, but this model has not yet been used to conduct population viability analyses. Here, we used the extended IPM to analyse the stochastic dynamics of IPM of small size-structured populations in one plant and one animal species (evening primrose and common lizard) including demographic stochasticity in both cases and environmental stochasticity in the lizard model. We also tested the accuracy of a diffusion approximation of the IPM for the two empirical systems. In both species, the elasticity for λ was higher with respect to parameters linked to body growth and size-dependent reproduction rather than survival. An analytical approach made it possible to quantify demographic and environmental variance to calculate the average stochastic growth rate. Demographic variance was further decomposed to gain insights into the most important size classes and demographic components. A diffusion approximation provided a remarkable fit to the stochastic dynamics and cumulative extinction risk, except for very small populations where stochastic growth rate was biased upward or downward depending on the model. These results confirm that the extended IPM provides a powerful tool to assess the conservation status and compare the stochastic demography of size-structured species, but should be complemented with individual based models to obtain unbiased estimates for very small populations of conservation concern. | |
Sabrina Juarez; Katerina Dontsova; Jean-François Le Galliard; Simon Chollet; Mathieu Llavata; Florent Massol; Alexis Cros; Pierre Barré; Alexandre Gelabert; Damien Daval Effect of elevated CO2 and temperature on abiotic and biologically-driven basalt weathering and C sequestration Conference EGU General Assembly Conference Abstracts, 18 , 2016. BibTeX | Tags: @conference{juarez_effect_2016, title = {Effect of elevated CO2 and temperature on abiotic and biologically-driven basalt weathering and C sequestration}, author = {Sabrina Juarez and Katerina Dontsova and Jean-François Le Galliard and Simon Chollet and Mathieu Llavata and Florent Massol and Alexis Cros and Pierre Barré and Alexandre Gelabert and Damien Daval}, year = {2016}, date = {2016-01-01}, booktitle = {EGU General Assembly Conference Abstracts}, volume = {18}, pages = {15196}, keywords = {}, pubstate = {published}, tppubtype = {conference} } | |
Mélissa Martin; Sandrine Meylan; Claudy Haussy; Beatriz Decencière; Samuel Perret; Jean-François Le Galliard UV color determines the issue of conflicts but does not covary with individual quality in a lizard Journal Article Behavioral Ecology, 27 (1), pp. 262–270, 2016. Abstract | Links | BibTeX | Tags: @article{martin_uv_2016, title = {UV color determines the issue of conflicts but does not covary with individual quality in a lizard}, author = {Mélissa Martin and Sandrine Meylan and Claudy Haussy and Beatriz Decencière and Samuel Perret and Jean-François Le Galliard}, url = {https://academic.oup.com/beheco/article/27/1/262/1744829}, doi = {https://doi.org/10.1093/beheco/arv149}, year = {2016}, date = {2016-01-01}, journal = {Behavioral Ecology}, volume = {27}, number = {1}, pages = {262--270}, abstract = {Ultraviolet (UV) colors are visual signals potentially involved in territorial conflicts. However, the role of UV signals remains unclear relative to the prior resident effect and familiarity with the opponent, and the reliability of UV signals is still controversial. Male common lizards Zootoca vivipara exhibit substantial variation in the reflectance of their throat UV color patch. We tested whether UV reflectance was correlated with indicators of individual condition. We further manipulated throat UV reflectance of resident and intruder lizards and staged repeated encounters in the laboratory during the mating season. We found no evidence of condition dependence of the UV colors expression. During the first encounter among unfamiliar males, a reduction of UV reflectance of 1 of the 2 opponents influenced agonistic behaviors and the contest outcome, such that there was a significant advantage for residents over intruders. This advantage disappeared when both opponents were UV reduced. During the subsequent encounters among familiar males, fighting was more aggressive when opponents displayed similar UV signals, but UV signals did not influence the contest outcome. These results demonstrate that UV reflectance acted as a badge of status in male common lizards whose effects on the behavioral response were modulated, but not overridden, by the prior resident effect and by the familiarity effect. Male–male interactions are therefore mediated by UV signaling and competition for mates should play a major role in the evolutionary maintenance of this ornament. We discuss putative functions and reliability of UV signals.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Ultraviolet (UV) colors are visual signals potentially involved in territorial conflicts. However, the role of UV signals remains unclear relative to the prior resident effect and familiarity with the opponent, and the reliability of UV signals is still controversial. Male common lizards Zootoca vivipara exhibit substantial variation in the reflectance of their throat UV color patch. We tested whether UV reflectance was correlated with indicators of individual condition. We further manipulated throat UV reflectance of resident and intruder lizards and staged repeated encounters in the laboratory during the mating season. We found no evidence of condition dependence of the UV colors expression. During the first encounter among unfamiliar males, a reduction of UV reflectance of 1 of the 2 opponents influenced agonistic behaviors and the contest outcome, such that there was a significant advantage for residents over intruders. This advantage disappeared when both opponents were UV reduced. During the subsequent encounters among familiar males, fighting was more aggressive when opponents displayed similar UV signals, but UV signals did not influence the contest outcome. These results demonstrate that UV reflectance acted as a badge of status in male common lizards whose effects on the behavioral response were modulated, but not overridden, by the prior resident effect and by the familiarity effect. Male–male interactions are therefore mediated by UV signaling and competition for mates should play a major role in the evolutionary maintenance of this ornament. We discuss putative functions and reliability of UV signals. | |
Hugo Mell; Rémy Josserand; Beatriz Decencière; Paulina Artacho; Sandrine Meylan; Jean-François Le Galliard Do personalities co-vary with metabolic expenditure and glucocorticoid stress response in adult lizards? Journal Article Behavioral Ecology and Sociobiology, 70 , pp. 951–961, 2016. @article{mell_personalities_2016, title = {Do personalities co-vary with metabolic expenditure and glucocorticoid stress response in adult lizards?}, author = {Hugo Mell and Rémy Josserand and Beatriz Decencière and Paulina Artacho and Sandrine Meylan and Jean-François Le Galliard}, url = {https://link.springer.com/article/10.1007/s00265-016-2117-z}, doi = {https://doi.org/10.1007/s00265-016-2117-z}, year = {2016}, date = {2016-01-01}, journal = {Behavioral Ecology and Sociobiology}, volume = {70}, pages = {951--961}, keywords = {}, pubstate = {published}, tppubtype = {article} } | |
Alexis Rutschmann; Donald B Miles; Jean-François Le Galliard; Murielle Richard; Sylvain Moulherat; Barry Sinervo; Jean Clobert Climate and habitat interact to shape the thermal reaction norms of breeding phenology across lizard populations Journal Article Journal of Animal Ecology, 85 (2), pp. 457–466, 2016, ISSN: 1365-2656. Abstract | Links | BibTeX | Tags: among-population variation, anthropogenic disturbance, phenology, phenology, phenotypic plasticity, phenotypic plasticity, thermal sensitivity, Zootoca vivipara @article{rutschmann_climate_2016, title = {Climate and habitat interact to shape the thermal reaction norms of breeding phenology across lizard populations}, author = {Alexis Rutschmann and Donald B Miles and Jean-François Le Galliard and Murielle Richard and Sylvain Moulherat and Barry Sinervo and Jean Clobert}, url = {https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2656.12473}, doi = {https://doi.org/10.1111/1365-2656.12473}, issn = {1365-2656}, year = {2016}, date = {2016-01-01}, journal = {Journal of Animal Ecology}, volume = {85}, number = {2}, pages = {457--466}, abstract = {* Substantial plastic variation in phenology in response to environmental heterogeneity through time in the same population has been uncovered in many species. However, our understanding of differences in reaction norms of phenology among populations from a given species remains limited. * As the plasticity of phenological traits is often influenced by local thermal conditions, we expect local temperature to generate variation in the reaction norms between populations. * Here, we explored temporal variation in parturition date across 11 populations of the common lizard (Zootoca vivipara) from four mountain chains as a function of air temperatures during mid-gestation. We characterized among-population variation to assess how local weather conditions (mean and variance of ambient temperatures during mid-gestation) and habitat openness (an index of anthropogenic disturbance) influence the thermal reaction norms of the parturition date. * Our results provide evidence of interactive effects of anthropogenic disturbance and thermal conditions, with earlier parturition dates in warmer years on average especially in closed habitats. * Variation in the reaction norms for parturition date was correlated with mean local thermal conditions at a broad geographical scale. However, populations exposed to variable thermal conditions had flatter thermal reaction norms. * Assessing whether environmental heterogeneity drives differentiation among reaction norms is crucial to estimate the capacity of different populations to contend with projected climatic and anthropogenic challenges.}, keywords = {among-population variation, anthropogenic disturbance, phenology, phenology, phenotypic plasticity, phenotypic plasticity, thermal sensitivity, Zootoca vivipara}, pubstate = {published}, tppubtype = {article} } * Substantial plastic variation in phenology in response to environmental heterogeneity through time in the same population has been uncovered in many species. However, our understanding of differences in reaction norms of phenology among populations from a given species remains limited. * As the plasticity of phenological traits is often influenced by local thermal conditions, we expect local temperature to generate variation in the reaction norms between populations. * Here, we explored temporal variation in parturition date across 11 populations of the common lizard (Zootoca vivipara) from four mountain chains as a function of air temperatures during mid-gestation. We characterized among-population variation to assess how local weather conditions (mean and variance of ambient temperatures during mid-gestation) and habitat openness (an index of anthropogenic disturbance) influence the thermal reaction norms of the parturition date. * Our results provide evidence of interactive effects of anthropogenic disturbance and thermal conditions, with earlier parturition dates in warmer years on average especially in closed habitats. * Variation in the reaction norms for parturition date was correlated with mean local thermal conditions at a broad geographical scale. However, populations exposed to variable thermal conditions had flatter thermal reaction norms. * Assessing whether environmental heterogeneity drives differentiation among reaction norms is crucial to estimate the capacity of different populations to contend with projected climatic and anthropogenic challenges. | |
Christian Mougin; Didier Azam; Thierry Caquet; Nathalie Cheviron; Samuel Dequiedt; Jean-François Le Galliard; Olivier Guillaume; Sabine Houot; Gérard Lacroix; Francois Lafolie; Pierre-Alain Maron; Radika Michniewicz; Christian Pichot; Lionel Ranjard; Jacques Roy; Bernhard Zeller; Jean Clobert; André Chanzy Un ensemble coordonné de plateformes ouvertes la recherche internationale en écotoxicologie: Analyse et Expérimentation sur les Ecosystèmes–France Inproceedings Colloque «Construire le réseau ANTIOPES 2.0-La toxicologie et l’écotoxicologie prédictives: de l’appliqué à l’opérationnel», pp. np, 2016. BibTeX | Tags: @inproceedings{mougin_ensemble_2016, title = {Un ensemble coordonné de plateformes ouvertes la recherche internationale en écotoxicologie: Analyse et Expérimentation sur les Ecosystèmes–France}, author = {Christian Mougin and Didier Azam and Thierry Caquet and Nathalie Cheviron and Samuel Dequiedt and Jean-François Le Galliard and Olivier Guillaume and Sabine Houot and Gérard Lacroix and Francois Lafolie and Pierre-Alain Maron and Radika Michniewicz and Christian Pichot and Lionel Ranjard and Jacques Roy and Bernhard Zeller and Jean Clobert and André Chanzy }, year = {2016}, date = {2016-01-01}, booktitle = {Colloque «Construire le réseau ANTIOPES 2.0-La toxicologie et l’écotoxicologie prédictives: de l’appliqué à l’opérationnel»}, pages = {np}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } | |
Rebecca Hingley; Sabrina Juarez; Katerina Dontsova; Edward Hunt; Jean-François Le Galliard; Simon Chollet; Alexis Cros; Mathieu Llavata; Florent Massol; P Barré; others Effects of Climate Change and Vegetation Type on Carbon and Nitrogen Accumulation during Incipient Soil Formation Conference AGUFM, 2016 , 2016. BibTeX | Tags: @conference{hingley_effects_2016, title = {Effects of Climate Change and Vegetation Type on Carbon and Nitrogen Accumulation during Incipient Soil Formation}, author = {Rebecca Hingley and Sabrina Juarez and Katerina Dontsova and Edward Hunt and Jean-François Le Galliard and Simon Chollet and Alexis Cros and Mathieu Llavata and Florent Massol and P Barré and others}, year = {2016}, date = {2016-01-01}, booktitle = {AGUFM}, volume = {2016}, pages = {B53F--0578}, keywords = {}, pubstate = {published}, tppubtype = {conference} } | |
Quintessence Consortium Networking our way to better ecosystem service provision Journal Article Trends in Ecology & Evolution, 31 (2), pp. 105–115, 2016. @article{consortium_networking_2016, title = {Networking our way to better ecosystem service provision}, author = {Quintessence Consortium}, url = {https://www.sciencedirect.com/science/article/pii/S0169534715003006}, doi = {https://doi.org/10.1016/j.tree.2015.12.003}, year = {2016}, date = {2016-01-01}, journal = {Trends in Ecology & Evolution}, volume = {31}, number = {2}, pages = {105--115}, keywords = {}, pubstate = {published}, tppubtype = {article} } | |
2015 |
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Paulina Artacho; Julia Saravia; Beatriz Decencière Ferrandière; Samuel Perret; Jean-François Le Galliard Quantification of correlational selection on thermal physiology, thermoregulatory behavior, and energy metabolism in lizards Journal Article Ecology and Evolution, 5 (17), pp. 3600–3609, 2015, ISSN: 2045-7758. Abstract | Links | BibTeX | Tags: metabolism, natural selection, performance, squamate reptiles, thermal coadaptation @article{artacho_quantification_2015, title = {Quantification of correlational selection on thermal physiology, thermoregulatory behavior, and energy metabolism in lizards}, author = {Paulina Artacho and Julia Saravia and Beatriz Decencière Ferrandière and Samuel Perret and Jean-François Le Galliard}, url = {https://onlinelibrary.wiley.com/doi/full/10.1002/ece3.1548}, doi = {https://doi.org/10.1002/ece3.1548}, issn = {2045-7758}, year = {2015}, date = {2015-01-01}, journal = {Ecology and Evolution}, volume = {5}, number = {17}, pages = {3600--3609}, abstract = {Phenotypic selection is widely accepted as the primary cause of adaptive evolution in natural populations, but selection on complex functional properties linking physiology, behavior, and morphology has been rarely quantified. In ectotherms, correlational selection on thermal physiology, thermoregulatory behavior, and energy metabolism is of special interest because of their potential coadaptation. We quantified phenotypic selection on thermal sensitivity of locomotor performance (sprint speed), thermal preferences, and resting metabolic rate in captive populations of an ectothermic vertebrate, the common lizard, Zootoca vivipara. No correlational selection between thermal sensitivity of performance, thermoregulatory behavior, and energy metabolism was found. A combination of high body mass and resting metabolic rate was positively correlated with survival and negatively correlated with fecundity. Thus, different mechanisms underlie selection on metabolism in lizards with small body mass than in lizards with high body mass. In addition, lizards that selected the near average preferred body temperature grew faster that their congeners. This is one of the few studies that quantifies significant correlational selection on a proxy of energy expenditure and stabilizing selection on thermoregulatory behavior.}, keywords = {metabolism, natural selection, performance, squamate reptiles, thermal coadaptation}, pubstate = {published}, tppubtype = {article} } Phenotypic selection is widely accepted as the primary cause of adaptive evolution in natural populations, but selection on complex functional properties linking physiology, behavior, and morphology has been rarely quantified. In ectotherms, correlational selection on thermal physiology, thermoregulatory behavior, and energy metabolism is of special interest because of their potential coadaptation. We quantified phenotypic selection on thermal sensitivity of locomotor performance (sprint speed), thermal preferences, and resting metabolic rate in captive populations of an ectothermic vertebrate, the common lizard, Zootoca vivipara. No correlational selection between thermal sensitivity of performance, thermoregulatory behavior, and energy metabolism was found. A combination of high body mass and resting metabolic rate was positively correlated with survival and negatively correlated with fecundity. Thus, different mechanisms underlie selection on metabolism in lizards with small body mass than in lizards with high body mass. In addition, lizards that selected the near average preferred body temperature grew faster that their congeners. This is one of the few studies that quantifies significant correlational selection on a proxy of energy expenditure and stabilizing selection on thermoregulatory behavior. | |
Jean-François Le Galliard; Mathieu Paquet; Marianne Mugabo An experimental test of density-dependent selection on temperament traits of activity, boldness and sociability Journal Article Journal of Evolutionary Biology, 28 (5), pp. 1144–1155, 2015, ISSN: 1420-9101. Abstract | Links | BibTeX | Tags: competition, correlational selection, natural selection, personality, trade-off @article{le_galliard_experimental_2015, title = {An experimental test of density-dependent selection on temperament traits of activity, boldness and sociability}, author = {Jean-François Le Galliard and Mathieu Paquet and Marianne Mugabo}, url = {https://onlinelibrary.wiley.com/doi/full/10.1111/jeb.12641}, doi = {https://doi.org/10.1111/jeb.12641}, issn = {1420-9101}, year = {2015}, date = {2015-01-01}, journal = {Journal of Evolutionary Biology}, volume = {28}, number = {5}, pages = {1144--1155}, abstract = {Temperament traits are seen in many animal species, and recent evolutionary models predict that they could be maintained by heterogeneous selection. We tested this prediction by examining density-dependent selection in juvenile common lizards Zootoca vivipara scored for activity, boldness and sociability at birth and at the age of 1 year. We measured three key life-history traits (juvenile survival, body growth rate and reproduction) and quantified selection in experimental populations at five density levels ranging from low to high values. We observed consistent individual differences for all behaviours on the short term, but only for activity and one boldness measure across the first year of life. At low density, growth selection favoured more sociable lizards, whereas viability selection favoured less active individuals. A significant negative correlational selection on activity and boldness existed for body growth rate irrespective of density. Thus, behavioural traits were characterized by limited ontogenic consistency, and natural selection was heterogeneous between density treatments and fitness traits. This confirms that density-dependent selection plays an important role in the maintenance of individual differences in exploration-activity and sociability.}, keywords = {competition, correlational selection, natural selection, personality, trade-off}, pubstate = {published}, tppubtype = {article} } Temperament traits are seen in many animal species, and recent evolutionary models predict that they could be maintained by heterogeneous selection. We tested this prediction by examining density-dependent selection in juvenile common lizards Zootoca vivipara scored for activity, boldness and sociability at birth and at the age of 1 year. We measured three key life-history traits (juvenile survival, body growth rate and reproduction) and quantified selection in experimental populations at five density levels ranging from low to high values. We observed consistent individual differences for all behaviours on the short term, but only for activity and one boldness measure across the first year of life. At low density, growth selection favoured more sociable lizards, whereas viability selection favoured less active individuals. A significant negative correlational selection on activity and boldness existed for body growth rate irrespective of density. Thus, behavioural traits were characterized by limited ontogenic consistency, and natural selection was heterogeneous between density treatments and fitness traits. This confirms that density-dependent selection plays an important role in the maintenance of individual differences in exploration-activity and sociability. | |
Mélissa Martin; Sandrine Meylan; Samuel Perret; Jean-François Le Galliard UV coloration influences spatial dominance but not agonistic behaviors in male wall lizards Journal Article Behavioral Ecology and Sociobiology, 69 (9), pp. 1483–1491, 2015, ISSN: 1432-0762. Abstract | Links | BibTeX | Tags: @article{martin_uv_2015, title = {UV coloration influences spatial dominance but not agonistic behaviors in male wall lizards}, author = {Mélissa Martin and Sandrine Meylan and Samuel Perret and Jean-François Le Galliard}, url = {https://link.springer.com/article/10.1007/s00265-015-1960-7}, doi = {https://doi.org/10.1007/s00265-015-1960-7}, issn = {1432-0762}, year = {2015}, date = {2015-01-01}, journal = {Behavioral Ecology and Sociobiology}, volume = {69}, number = {9}, pages = {1483--1491}, abstract = {A bright ultraviolet (UV) component in the coloration of males may signal individual quality and thus determine the outcome of male-male contests. Yet, the role of the UV component of coloration in resolving conflicts is still controversial relative to factors such as residency status and seasonality. Here, we investigated whether a reduction of UV reflectance of lateral blue spots in male wall lizards (Podarcis muralis) interacts with residency status (resident vs. intruder) to influence agonistic behaviors, the outcome of contests, and basking time (a measure of spatial dominance). We performed this experiment during one breeding and one non-breeding season. The UV manipulation did not predict the outcome of contests. During the breeding season, the agonistic behaviors and basking time depended on the residency status of males but not on their UV treatment. During the non-breeding season, experimental factors affected basking time only. For a given male, the time spent basking depended in a complex manner on its residency status, its UV treatment, and those of its rival. UV reflectance of blue spots thus influences the processes of mutual assessment and spatial dominance, but is not a critical determinant of fighting success. Altogether, these results evidence context-dependent effects of the UV reflectance of blue spots on territorial behaviors according to residency status and, potentially, season. They also suggest that UV signaling may be more important than expected for male-male interactions during the non-breeding season.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A bright ultraviolet (UV) component in the coloration of males may signal individual quality and thus determine the outcome of male-male contests. Yet, the role of the UV component of coloration in resolving conflicts is still controversial relative to factors such as residency status and seasonality. Here, we investigated whether a reduction of UV reflectance of lateral blue spots in male wall lizards (Podarcis muralis) interacts with residency status (resident vs. intruder) to influence agonistic behaviors, the outcome of contests, and basking time (a measure of spatial dominance). We performed this experiment during one breeding and one non-breeding season. The UV manipulation did not predict the outcome of contests. During the breeding season, the agonistic behaviors and basking time depended on the residency status of males but not on their UV treatment. During the non-breeding season, experimental factors affected basking time only. For a given male, the time spent basking depended in a complex manner on its residency status, its UV treatment, and those of its rival. UV reflectance of blue spots thus influences the processes of mutual assessment and spatial dominance, but is not a critical determinant of fighting success. Altogether, these results evidence context-dependent effects of the UV reflectance of blue spots on territorial behaviors according to residency status and, potentially, season. They also suggest that UV signaling may be more important than expected for male-male interactions during the non-breeding season. | |
Christian Mougin; Didier Azam; Thierry Caquet; Nathalie Cheviron; Samuel Dequiedt; Jean-François Le Galliard; Olivier Guillaume; Sabine Houot; Gérard Lacroix; François Lafolie; Pierre-Alain Maron; Radika Michniewicz; Christian Pichot; Lionel Ranjard; Jacques Roy; Bernd Zeller; Jean Clobert; André Chanzy A coordinated set of ecosystem research platforms open to international research in ecotoxicology, AnaEE-France Journal Article Environmental Science and Pollution Research, pp. 1–14, 2015, ISSN: 0944-1344. Links | BibTeX | Tags: ecotoxicology, Ecotrons, information system, mesocosms, modelling, stress @article{mougin_coordinated_2015, title = {A coordinated set of ecosystem research platforms open to international research in ecotoxicology, AnaEE-France}, author = {Christian Mougin and Didier Azam and Thierry Caquet and Nathalie Cheviron and Samuel Dequiedt and Jean-François Le Galliard and Olivier Guillaume and Sabine Houot and Gérard Lacroix and François Lafolie and Pierre-Alain Maron and Radika Michniewicz and Christian Pichot and Lionel Ranjard and Jacques Roy and Bernd Zeller and Jean Clobert and André Chanzy}, url = {https://link.springer.com/article/10.1007/s11356-015-5233-9}, doi = {https://doi.org/10.1007/s11356-015-5233-9}, issn = {0944-1344}, year = {2015}, date = {2015-01-01}, journal = {Environmental Science and Pollution Research}, pages = {1--14}, keywords = {ecotoxicology, Ecotrons, information system, mesocosms, modelling, stress}, pubstate = {published}, tppubtype = {article} } | |
Marianne Mugabo; Samuel Perret; Beatriz Decencière; Sandrine Meylan; Jean-François Le Galliard Density-dependent immunity and parasitism risk in experimental populations of lizards naturally infested by Ixodid ticks Journal Article Ecology, 96 (2), pp. 450–460, 2015, ISSN: 0012-9658. Abstract | Links | BibTeX | Tags: @article{mugabo_density-dependent_2015, title = {Density-dependent immunity and parasitism risk in experimental populations of lizards naturally infested by Ixodid ticks}, author = {Marianne Mugabo and Samuel Perret and Beatriz Decencière and Sandrine Meylan and Jean-François Le Galliard}, url = {https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1890/14-0524.1}, doi = {https://doi.org/10.1890/14-0524.1}, issn = {0012-9658}, year = {2015}, date = {2015-01-01}, journal = {Ecology}, volume = {96}, number = {2}, pages = {450--460}, abstract = {When effective immune defenses against parasites are costly and resources limited, individuals are expected to alter their investment in immunity in response to the risk of infection. As an ecological factor that can affect both food abundance and parasite exposure, host density can play an important role in host immunity and host-parasite interactions. High levels of intraspecific competition for food and social stress at high host density may diminish immune defenses and increase host susceptibility to parasites. At the same time, for contagious and environmentally transmitted parasites, parasite exposure often increases with host density whereas in mobile parasites which actively search for hosts, parasite exposure can decrease with host density due to the "encounter-dilution effect" (as defined by Mooring et Hart (1992) at the host intraspecific level). To unravel these multiple and potentially opposing effects of host density on immunity, we manipulated density of the common lizard Zootoca vivipara and measured local inflammation in response to PHA injection and levels of infestation by the tick Ixodes ricinus, a mobile ectoparasite for which we expected an encounter dilution effect to occur. Local inflammation strongly decreased with lizard density in adults but not in yearlings. Tick infestation (abundance and prevalence) was negatively correlated with lizard density in both age classes. Using path analyses, we found independent, direct negative density feedbacks on immunity and parasite exposure in adults, supporting the hypothesis of energetic constraints andtextbackslashor physiological stress acting on immunity at high density. In contrast, for yearlings, the best path model showed that density diluted exposure to parasites, which themselves down-regulated immune defenses in lizards. These results highlight the importance of investigating the pathways between host density, host immunity and parasite infestation, while accounting for relevant individual traits such as age.}, keywords = {}, pubstate = {published}, tppubtype = {article} } When effective immune defenses against parasites are costly and resources limited, individuals are expected to alter their investment in immunity in response to the risk of infection. As an ecological factor that can affect both food abundance and parasite exposure, host density can play an important role in host immunity and host-parasite interactions. High levels of intraspecific competition for food and social stress at high host density may diminish immune defenses and increase host susceptibility to parasites. At the same time, for contagious and environmentally transmitted parasites, parasite exposure often increases with host density whereas in mobile parasites which actively search for hosts, parasite exposure can decrease with host density due to the "encounter-dilution effect" (as defined by Mooring et Hart (1992) at the host intraspecific level). To unravel these multiple and potentially opposing effects of host density on immunity, we manipulated density of the common lizard Zootoca vivipara and measured local inflammation in response to PHA injection and levels of infestation by the tick Ixodes ricinus, a mobile ectoparasite for which we expected an encounter dilution effect to occur. Local inflammation strongly decreased with lizard density in adults but not in yearlings. Tick infestation (abundance and prevalence) was negatively correlated with lizard density in both age classes. Using path analyses, we found independent, direct negative density feedbacks on immunity and parasite exposure in adults, supporting the hypothesis of energetic constraints andtextbackslashor physiological stress acting on immunity at high density. In contrast, for yearlings, the best path model showed that density diluted exposure to parasites, which themselves down-regulated immune defenses in lizards. These results highlight the importance of investigating the pathways between host density, host immunity and parasite infestation, while accounting for relevant individual traits such as age. | |