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Anthropogenic climate change poses a significant threat to species on the brink of extinction. Many non-avian reptiles are endangered, but uncovering their vulnerability to climate warming is challenging, because this requires analyzing the climate sensitivity of different life stages and modeling population growth rates. Such efforts are currently hampered by a lack of long-term life-history data. In this study, we used over 3 decades of mark-recapture data from a natural population of the endangered meadow viper (Vipera ursinii ursinii) to unravel the patterns of temporal variation in reproductive traits, the local climatic determinants of inter-annual variation in reproduction, and the potential buffering effects of life cycle on population growth rate. We found significant inter-annual variation in body growth, gestation length, post-parturition body condition, clutch success, and offspring traits at birth, while reproductive effort showed little temporal variation. Temperature during gestation was the most critical factor, reducing gestation length and increasing both clutch success and post-parturition body condition. In contrast, neither air humidity nor global radiation affected reproductive outcomes. This population had a negative growth rate with minimal temporal variation, indicating a rapid decline largely independent of climatic conditions. Overall, the viper’s life-history traits appeared to be buffered against temporal variation in climatic conditions, with this declining population potentially benefiting on the short term from rising local temperatures. [ABSTRACT FROM AUTHOR]

Optimal regulation of body temperature and water balance is essential for the survival of terrestrial ectotherms in a changing world. A behavioural trade-off exists between these two constraints because maintaining a high body temperature usually increases evaporative water losses. In addition, the evaluation of predation risk is a key factor in behavioural decision for prey species, and predation threat can cause shift in individual behaviours due to the modification of the cost-benefit balance of thermo-hydroregulation. However, little is known on how prey integrate these different biotic and abiotic stressors when combined. Here, we performed an experimental study on the common lizard, a terrestrial ectotherm prey species, sensitive to water restriction and able to detect specialised predator scents in its environment. We analysed changes in thermo-hydroregulation behaviours, activity patterns and body temperature in response to a chronic water stress coupled with simulated punctual occurrences of predator scents. Water restriction and predator threat had mostly additive effects on lizard thermoregulation behaviour. They both reduced the time spent basking and thermoregulation precision. They also had opposite effects on the time spent active, water restriction reducing activity whereas the presence of predator scents increased it. Yet, we also found an interactive effect on hydroregulation behaviour, as water-restricted lizards showed a wet-shelter preference only in absence of predator odours. This study demonstrates the existence of some hydration state dependent behavioural responses to predator threat and suggests that fear of predators may compromise thermo-hydroregulation and thus prey performances. Significance statement: In this paper, we show that the fear of predators induces significant changes in the thermo-hydroregulation behaviours of a widespread terrestrial lizard species, some of which are influenced by a physiological increase in dehydration induced by an experimental restriction of water availability. There is a general lack of understanding about how prey respond to simultaneous changes in biotic and abiotic stressors; in particular, our comprehension of the non-energetic costs of thermoregulation caused by the presence of predators and the absence of water in the environment is extremely limited. Our findings indicate that predators have state-dependent effects on the behaviour of their prey and that joint changes in water availability and predation risks can compromise the thermo-hydroregulation strategies of their prey, potentially affecting their physiological performances. [ABSTRACT FROM AUTHOR]

During extreme climate events, behavioural thermoregulation may buffer ectotherms from thermal stress and overheating. However, heatwaves are also combined with dry spells and limited water availability, and how much individuals can behaviourally mitigate dehydration risks through microclimate selection remains largely unknown. Herein, we investigated the behavioural and physiological responses to changes in air and microhabitat humidity in a terrestrial ectotherm, the asp viper (Vipera aspis). We exposed individuals to a simulated heatwave together with water deprivation for 3 weeks, and manipulated air water vapour density (wet air vs. dry air) and microclimate (wet shelter vs. dry shelter) in a two-by-two factorial design. Dry air conditions led to substantial physiological dehydration and muscle wasting. Vipers exposed to dry air used more often a shelter that offered a moist microclimate, which reduced dehydration and muscle wasting at the individual level. These results provide the first experimental evidence that active behavioural hydroregulation can mitigate specific physiological stress responses caused by a dry spell in an ectotherm. Future studies investigating organismal responses to climate change should consider moisture gradient in the habitat and integrate both hydroregulation and thermoregulation behaviours. [ABSTRACT FROM AUTHOR]

Stress hormones and their impacts on whole organism metabolic rates are usually considered as appropriate proxies for animal energy budget that is the foundation of numerous concepts and models aiming at predicting individual and population responses to environmental stress. However, the dynamics of energy re-allocation under stress make the link between metabolism and corticosterone complex and still unclear. Using ectopic application of corticosterone for 3, 11 and 21 days, we estimated a time effect of stress in a lizard (Zootoca vivipara). We then investigated whole organism metabolism, muscle cellular O2 consumption and liver mitochondrial oxidative phosphorylation processes (O2 consumption and ATP production) and ROS production. The data showed that while skeletal muscle is not impacted, stress regulates the liver mitochondrial functionality in a time-dependent manner with opposing pictures between the different time expositions to corticosterone. While 3 days exposition is characterized by lower ATP synthesis rate and high H2O2 release with no change in the rate of oxygen consumption, the 11 days exposition reduced all three fluxes of about 50%. Oxidative phosphorylation capacities in liver mitochondria of lizard treated with corticosterone for 21 days was similar to the hepatic mitochondrial capacities in lizards that received no corticosterone treatment but with 40% decrease in H2O2 production. This new mitochondrial functioning allows a better capacity to respond to the energetic demands imposed by the environment but do not influence whole organism metabolism. In conclusion, global mitochondrial functioning has to be considered to better understand the proximal causes of the energy budget under stressful periods. [ABSTRACT FROM AUTHOR]

Stable differences in physiology among individuals may facilitate the evolution of consistent individual differences in behavior. In particular, according to the pace-of-life syndrome (POLS) hypothesis, individual variation in metabolic expenditure and stress physiology should be linked with exploration, aggression, or risk-taking behaviors. Previous studies have uncovered stable individual differences in metabolic expenditure and circulating glucorticoids in common lizards ( Zootoca vivipara). We tested the correlations between standard metabolic rates (SMR), glucorticoid stress response, and behavioral traits (activity, aggressiveness, risk taking, and sociability) in males. In ectotherms, the thermal dependence of SMR should be included in the POLS hypothesis; we therefore measured SMR at three temperatures from rest to preferred body temperature. Activity, aggressiveness, and risk taking, but not sociability, exhibited significant, short-term repeatability, and little correlation was found between behavioral traits. The SMR of lizards with a low metabolism at rest increased faster with body temperature. The SMR at rest was negatively correlated with behavioral variation in sociability and activity but not with risk-taking behavior. In addition, the plasma corticosterone level after an acute handling stress increased slightly but not significantly with aggressiveness. We discuss alternative interpretations for these relationships and conclude that the link between inter-individual variation in physiology and behavior is trait-dependent in the common lizard. Significance statement: Selection better promotes the evolution of consistent differences in behavior, or personalities, when they are coupled with differences in physiology. In adult common lizards, inter-individual differences in metabolic expenditure and glucocorticoid stress response are consistent and could play a crucial role in the maintenance of personalities. This study supported partially this hypothesis. We found that more sociable and active personality types had a lower metabolic expenditure, while more aggressive personality types tended to have a higher physiological stress response. At the same time, physiology was not correlated with individual differences in risk-taking behavior and drove little part of behavioral variation. The coupling between personalities and physiology appears to be trait-dependent, suggesting that behaviors may be relatively free to evolve independently from physiology. [ABSTRACT FROM AUTHOR]

The infrastructure for Analysis and Experimentation on Ecosystems (AnaEE-France) is an integrated network of the major French experimental, analytical, and modeling platforms dedicated to the biological study of continental ecosystems (aquatic and terrestrial). This infrastructure aims at understanding and predicting ecosystem dynamics under global change. AnaEE-France comprises complementary nodes offering access to the best experimental facilities and associated biological resources and data: Ecotrons, seminatural experimental platforms to manipulate terrestrial and aquatic ecosystems, in natura sites equipped for large-scale and long-term experiments. AnaEE-France also provides shared instruments and analytical platforms dedicated to environmental (micro) biology. Finally, AnaEE-France provides users with data bases and modeling tools designed to represent ecosystem dynamics and to go further in coupling ecological, agronomical, and evolutionary approaches. In particular, AnaEE-France offers adequate services to tackle the new challenges of research in ecotoxicology, positioning its various types of platforms in an ecologically advanced ecotoxicology approach. AnaEE-France is a leading international infrastructure, and it is pioneering the construction of AnaEE (Europe) infrastructure in the field of ecosystem research. AnaEE-France infrastructure is already open to the international community of scientists in the field of continental ecotoxicology. [ABSTRACT FROM AUTHOR]

Many scientific disciplines are currently experiencing a “reproducibility crisis” because numerous scientific findings cannot be repeated consistently. A novel but controversial hypothesis postulates that stringent levels of environmental and biotic standardization in experimental studies reduces reproducibility by amplifying impacts of lab-specific environmental factors not accounted for in study designs. A corollary to this hypothesis is that a deliberate introduction of controlled systematic variability (CSV) in experimental designs may lead to increased reproducibility. To test this hypothesis, we had 14 European laboratories run a simple microcosm experiment using grass (Brachypodium distachyon L.) monocultures and grass and legume (Medicago truncatula Gaertn.) mixtures. Each laboratory introduced environmental and genotypic CSV within and among replicated microcosms established in either growth chambers (with stringent control of environmental conditions) or glasshouses (with more variable environmental conditions). The introduction of genotypic CSV led to 18% lower among-laboratory variability in growth chambers, indicating increased reproducibility, but had no significant effect in glasshouses where reproducibility was generally lower. Environmental CSV had little effect on reproducibility. Although there are multiple causes for the “reproducibility crisis”, deliberately including genetic variation may be a simple solution for increasing the reproducibility of ecological studies performed under stringently controlled environmental conditions., Organismic and Evolutionary Biology

Dispersal of organisms generates gene flow between populations. Identifying factors that influence dispersal will help predict how species will cope with rapid environmental change. We developed an innovative infrastructure, the Metatron, composed of 48 interconnected patches, designed for the study of terrestrial organism movement as a model for dispersal. Corridors between patches can be flexibly open or closed. Temperature, humidity and illuminance can be independently controlled within each patch. The modularity and adaptability of the Metatron provide the opportunity for robust experimental design for the study of 'meta-systems'. We describe a pilot experiment on populations of the butterfly Pieris brassicae and the lizard Zootoca vivipara in the Metatron. Both species survived and showed both disperser and resident phenotypes. The Metatron offers the opportunity to test theoretical models in spatial ecology. [ABSTRACT FROM AUTHOR]

Strong evidence for a genetic basis of variation in physical performance has accumulated. Considering one of the basic tenets of evolutionary physiology-that physical performance and darwinian fitness are tightly linked-one may expect phenotypes with exceptional physiological capacities to be promoted by natural selection. Why then does physical performance remain considerably variable in human and other animal populations? Our analysis of locomotor performance in the common lizard (Lacerta vivipara) demonstrates that initial endurance (running time to exhaustion measured at birth) is indeed highly heritable, but natural selection in favour of this trait can be unexpectedly weak. A manipulation of dietary conditions unravels a proximate mechanism explaining this pattern. Fully fed individuals experience a marked reversal of performance within only one month after birth: juveniles with low endurance catch up, whereas individuals with high endurance lose their advantage. In contrast, dietary restriction allows highly endurant neonates to retain their locomotor superiority as they age. Thus, the expression of a genetic predisposition to high physical performance strongly depends on the environment experienced early in life. [ABSTRACT FROM AUTHOR]

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. Significance statement: Many animals use color to communicate. During intraspecific resource competition, some species use color signals as an assessment tool to determine if they should engage in or avoid conflicts. Studies have found that in non-mammalian vertebrates, UV coloration can be a good indicator of fighting ability or aggressiveness. We tested whether and how the UV-blue spots of common wall lizards play a role in male-male competition by studying the properties of their spots, and then used that information to design and conduct competition experiments between males involving spot manipulation. Both body size and spot manipulation influenced aggression and submission during encounters. In particular, results suggest that spot manipulation disrupted mutual assessment and thus that spots play a role in competition signaling in male common wall lizards. [ABSTRACT FROM AUTHOR]

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 statement: Water 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. [ABSTRACT FROM AUTHOR]