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Male lizards often display multiple pigment‐based and structural colour signals which may reflect various quality traits (e.g. performance, parasitism), with testosterone (T) often mediating these relationships. Furthermore, environmental conditions can explain colour signal variation by affecting processes such as signal efficacy, thermoregulation and camouflage. The relationships between colour signals, male quality traits and environmental factors have often been analysed in isolation, but simultaneous analyses are rare. Thus, the response of multiple colour signals to variation in all these factors in an integrative analysis remains to be investigated.Here, we investigated how multiple colour signals relate to their information content, examined the role of T as a potential mediator of these relationships and how environmental factors explain colour signal variation.We performed an integrative study to examine the covariation between three colour signals (melanin‐based black, carotenoid‐based yellow–orange and structural UV), physiological performance, parasitism, T levels and environmental factors (microclimate, forest cover) in male common lizards Zootoca vivipara from 13 populations.We found that the three colour signals conveyed information on different aspects of male condition, supporting a multiple message hypothesis. T influenced only parasitism, suggesting that T does not directly mediate the relationships between colour signals and their information content. Moreover, colour signals became more saturated in forested habitats, suggesting an adaptation to degraded light conditions, and became generally brighter in mesic conditions, in contradiction with the thermal melanism hypothesis.We show that distinct individual quality traits and environmental factors simultaneously explain variations of multiple colour signals with different production modes. Our study therefore highlights the complexity of colour signal evolution, involving various sets of selective pressures acting at the same time, but in different ways depending on colour production mechanism. [ABSTRACT FROM AUTHOR]

Aging is the price to pay for acquiring and processing energy through cellular activity and life history productivity. Climate warming can exacerbate the inherent pace of aging, as illustrated by a faster erosion of protective telomere DNA sequences. This biomarker integrates individual pace of life and parental effects through the germline, but whether intra- and intergenerational telomere dynamics underlies population trends remains an open question. Here, we investigated the covariation between life history, telomere length (TL), and extinction risk among three age classes in a cold-adapted ectotherm (Zootoca vivipara) facing warming-induced extirpations in its distribution limits. TL followed the same threshold relationships with population extinction risk at birth, maturity, and adulthood, suggesting intergenerational accumulation of accelerated aging rate in declining populations. In dwindling populations, most neonates inherited already short telomeres, suggesting they were born physiologically old and unlikely to reach recruitment. At adulthood, TL further explained females' reproductive performance, switching from an index of individual quality in stable populations to a biomarker of reproductive costs in those close to extirpation. We compiled these results to propose the aging loop hypothesis and conceptualize how climate-driven telomere shortening in ectotherms may accumulate across generations and generate tipping points before local extirpation. [ABSTRACT FROM AUTHOR]

The Mediterranean Basin has experienced extensive change in geology and climate over the past six million years. Yet, the relative importance of key geological events for the distribution and genetic structure of the Mediterranean fauna remains poorly understood. Here, we use population genomic and phylogenomic analyses to establish the evolutionary history and genetic structure of common wall lizards (Podarcis muralis). This species is particularly informative because, in contrast to other Mediterranean lizards, it is widespread across the Iberian, Italian, and Balkan Peninsulas, and in extra-Mediterranean regions. We found strong support for six major lineages within P. muralis , which were largely discordant with the phylogenetic relationship of mitochondrial DNA. The most recent common ancestor of extant P. muralis was likely distributed in the Italian Peninsula, and experienced an "Out-of-Italy" expansion following the Messinian salinity crisis (∼5 Mya), resulting in the differentiation into the extant lineages on the Iberian, Italian, and Balkan Peninsulas. Introgression analysis revealed that both inter- and intraspecific gene flows have been pervasive throughout the evolutionary history of P. muralis. For example, the Southern Italy lineage has a hybrid origin, formed through admixture between the Central Italy lineage and an ancient lineage that was the sister to all other P. muralis. More recent genetic differentiation is associated with the onset of the Quaternary glaciations, which influenced population dynamics and genetic diversity of contemporary lineages. These results demonstrate the pervasive role of Mediterranean geology and climate for the evolutionary history and population genetic structure of extant species. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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.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.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 5 weeks.Warmer nocturnal temperatures increased the prevalence of ectoparasitic infestation and altered allocation of resources towards 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.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. ​ [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Pre-copulatory female mate choice based on male ultraviolet (UV) coloration has been demonstrated in several vertebrate species; however, post-copulatory mechanisms have been largely overlooked. Here, we investigated female mate preference based on male UV coloration in the common lizard Zootoca vivipara , in which males display conspicuous UV coloration on their throat. During two successive years, we staged sequential mating trials between females and four different males with UV-reduced or control belly and throat coloration. We recorded pre-copulatory female behaviour, copulation behaviour and assigned paternity to all offspring. Females were more aggressive towards UV-reduced males and, during the second year, UV-reduced males had a lower probability of siring at least one egg (fertilization success) during the last mating trials. However, in the second year, copulation was shorter with control males. Altogether, our results suggest that females exert subtle pre-copulatory mate preference based on male UV ornaments and, conditional on the study year and female mating history, some degree of post-copulatory preference for UV-control males leading to differential male fertilization success. This study suggests that UV-based female mate choice may be more widespread than previously thought in vertebrates, and emphasizes the importance of using a study design well adapted to the species reproductive behaviour. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Swallowtail butterflies (Papilionidae) are among the most spectacular and well‐known Lepidoptera in the European fauna, but their systematics is not fully elucidated. A notable case is that of Iphiclides feisthamelii which, after more than 180 years since description, still has a debated status, being often considered as a subspecies of Iphiclides podalirius. To elucidate the relationship between the two taxa and the evolutionary processes that led to their separation, we combine mitochondrial and nuclear DNA (mtDNA and nDNA) data, Wolbachia screening, genitalia morphology and wing UV reflectance. Our results show that the two taxa clearly differ in male and female genital morphology, male wing UV reflectance and nDNA. Two Wolbachia strains were found to widely infect the studied samples, apparently explaining the phylogeographic pattern displayed by mtDNA. The available data point towards a historical Wolbachia infection that spread from I. podalirius to I. feisthamelii and produced a mitochondrial introgression. Currently, a new Wolbachia strain is spreading across mainland populations of I. podalirius, mediating once more a mitochondrial genetic sweep, which has already infected and introgressed I. feisthamelii populations in south‐eastern France. We conclude that, given the marked differences in morphology and nDNA between the two taxa, and the apparent restriction of hybridization to a narrow contact area where non‐hybrid specimens are common, the taxon feisthamelii should be considered as a separate species. Within this species, two well‐differentiated nDNA lineages that represent European and Maghrebian populations are documented, here proposed as subspecies. The case of, presumably, two consecutive Wolbachia‐mediated mitochondrial introgression events, further supports the view that infection by this endosymbiont may be frequently related to mito‐nuclear discordance in insects. [ABSTRACT FROM AUTHOR]

The blue-throated keeled lizard, Algyroides nigropunctatus, is distributed along the Adriatic coast from Italy to Greece and is sexually dichromatic. Males display a striking blue on their throat, an orange ventrum, and a dark brown dorsal colouration, but their colouration has never been objectively assessed. Here, we describe the colouration of 13 male blue-throated keeled lizards from Cres Island (Croatia) using spectrophotometry and ultraviolet (UV) photography, and show that the blue throat and the blue spots located on the flanks reflect in the UV part of the spectrum. We discuss the potential role of UV-blue colouration in social signalling. [ABSTRACT FROM AUTHOR]

Over the past 20 years, portable and relatively affordable spectrophotometers have greatly advanced the study of animal coloration. However, the small size of many colour patches poses methodological challenges that have not, to date, been assessed in the literature. Here, we tackle this issue for a reflectance spectrophotometry set-up widely used in ecology and evolution (the beam method)., We reviewed the literature on animal coloration reporting the use of reflectance spectrophotometry to explore how the minimum measurable size of a colour patch is determined. We then used coloured plastic sheets to create artificial colour patches, and quantify the relationship between colour patch size and distortions induced by resulting chimeric spectra (spectra contaminated by an adjacent colour patch). Finally, we assessed the generality of our findings using natural colour spots in the lizard Podarcis muralis, as a biologically realistic model., We found a lack of consensus in the literature, frequently resulting in the rejection of valid data or the potential inclusion of unreliable data. As expected, we show that decreasing colour patch size reduces the reliability of reflectance measurements, but also that spectral distortions resulting from chimeric spectra depend on patch/background colour combinations. We found similar results using natural colour spots in P. muralis., We propose a series of steps to avoid the pitfalls described above. First, we provide guidelines on how to identify chimeric spectra and estimate the minimum size of a measurable colour patch in order to avoid them. Second, we show that reducing the probe-to-surface distance allows for more accurate measurements and therefore improves the spectrophotometric assessment of small colour patches. Third, we suggest that, as a general rule of thumb, very small (< 2 mm) colour patches should be avoided when using traditional spectrophotometry methods. [ABSTRACT FROM AUTHOR]

Habitat destruction has resulted in the fragmented distribution of numerous terrestrial species, which poses a challenge for conservationists. Furthermore, species management can be further compounded by life history constraints such as low dispersal, hindering the ability of species to recolonize areas they formerly occupied. For these species, a thorough understanding of the local threats and factors that limit their distribution is crucial for effective management. We used occupancy models to examine which factors at landscape and habitat scales (i.e. land uses, fire history, and vegetation structure) explain the presence of terrestrial tortoises within the range of the westernmost isolated population of the endangered Testudo hermanni hermanni in the Albera Range (NE of the Iberian Peninsula). We randomly surveyed 25 sites (75% of the area known with presence of tortoises) of natural woodlands with 5 to 8 replicates per site in spring 2012-2014. From a sampling effort of 148 hours, we only detected 52 tortoises in 12 of 25 transects. These low numbers are evidence of low population densities. Sites with presence of tortoises were spatially aggregated although the species was absent from apparently adequate sites on the edges of its distribution range. Current and historic land-use primarily explained the presence of tortoises. Besides, wildfires and reduction of habitat complexity also participate to explain the distribution of Hermann's tortoises. We also discuss some aspects of the conservation of Testudo hermanni in relation to our results. [ABSTRACT FROM AUTHOR]