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We report the first confirmed occurrence of Anatololacerta pelasgiana on Chalki Island (Dodecanese, Greece). The species was detected exclusively in and around the main settlement and port, within an area of ~0.9 km², consistent with an established population likely originating from recent human-mediated introduction. To infer source affinity, we sequenced mitochondrial cytochrome b from two individuals and compared the data with published Aegean and adjacent Anatolian datasets. The Chalki specimens share a widespread haplotype previously recorded on Rhodes, Kastellorizo and Athens (Greece), as well as in southwestern Turkey. These results suggest repeated, transport-mediated introductions from Rhodes as a recurrent driver of secondary colonization in the southeastern Aegean, and underscore local trade links as key pathways for small-island translocations, potentially relevant to other reptiles in the region.

Color polymorphism—two or more heritable color phenotypes maintained within a single breeding population—is an extreme type of intraspecific diversity widespread across the tree of life. Color polymorphism is hypothesized to be an engine for speciation, where morph loss or divergence between distinct color morphs within a species results in the rapid evolution of new lineages, and thus, color polymorphic lineages are expected to display elevated diversification rates. Multiple species in the lizard family Lacertidae are color polymorphic, making them an ideal group to investigate the evolutionary history of this trait and its influence on macroevolution. Here, we produce a comprehensive species-level phylogeny of the lizard family Lacertidae to reconstruct the evolutionary history of color polymorphism and test if color polymorphism has been a driver of diversification. Accounting for phylogenetic uncertainty with multiple phylogenies and simulation studies, we estimate an ancient origin of color polymorphism (111 Ma) within the Lacertini tribe (subfamily Lacertinae). Color polymorphism most likely evolved few times in the Lacertidae and has been lost at a much faster rate than gained. Evolutionary transitions to color polymorphism are associated with shifts in increased net diversification rate in this family of lizards. Taken together, our empirical results support long-standing theoretical expectations that color polymorphism is a driver of diversification.

Heat tolerance at the immobile embryonic stage is expected to be critical in determining species vulnerability to climate change. However, how the mean and developmental plasticity of embryonic heat tolerance vary geographically, and how these geographic variations affect species' vulnerability under climate change remain unknown. We experimentally determined the mean and developmental plasticity of embryonic acute heat tolerance (EAHT, i.e., heat shock temperature at which embryonic heartbeats ceased) for three latitudinally distributed populations of an oviparous lacertid lizard. The experimental results suggested that the mean EAHT decreased with decreasing latitude and that the reaction norms of EAHT in relation to developmental temperatures showed \"flat,\" \"bell-shaped,\" and \"decreasing\" patterns at high, medium, and low latitudes, respectively. Based on the means and plasticity of EAHT and weather data across China, we project that the heat stress frequency would increase from the present to the future and increase toward low latitudes. Furthermore, heat stress becomes more extensive with the incorporation of developmental plasticity. Incorporating the mean EAHT during the embryonic development season, heat stress frequency, and climate variables in a species distribution model projects that suitable habitats could move northward in response to ongoing climate change and shrink due to the loss of southern habitat. More-over, even lizards within the areas that are predicted to remain highly suitable are expected to experience increases in heat stress over time, particularly at medium and low latitudes. Our study reveals geographic variation in the mean and developmental plasticity of EAHT and highlights its importance for predicting species vulnerability and range shifts in response to climate change.

Despite it is widely accepted that intrapopulation variation is fundamental to ecological and evolutionary processes, this level of information has only recently been included into network analysis of species/population interactions. When done, it has revealed non-random patterns in the distribution of trophic resources. Nestedness in resource use among individuals is the most recurrent observed pattern, often accompanied by an absence of modularity, but no previous studies examine bipartite modularity. We use network analysis to describe the diet composition of the Balearic endemic lizard Podarcis lilfordi in 2 islets at population and individual levels, based on the occurrence of food items in fecal samples. Our objectives are to 1) compare niche structure at both levels, 2) characterize niche partition using nestedness and modularity, and 3) assess how size, sex, season, and spatial location influence niche structure. At population-level niche width was wide, but narrow at the level of the individual. Both islet networks were nested, indicating similar ranking of the food preferences among individuals, but also modular, which was partially explained by seasonality. Sex and body size did not notably affect diet composition. Large niche overlap and therefore possibly relaxed competition were observed among females in one of the islets and during spring on both islets. Likewise, higher modularity in autumn suggests that higher competition could lead to specialization in both populations, because resources are usually scarce in this season. The absence of spatial location influence on niche might respond to fine-grained spatio-temporally distribution of food resources. Behavioral traits, not included in this study, could also influence resource partitioning.

How does ecology influence cognitive evolution in lizards? Taking a comparative approach, De Meester et al. (2022) discovered that species living in temporally fluctuating environments tend to perform relatively poorly on cognitive tasks associated with behavioral flexibility compared to species living in more climatically stable environments. The negative association between environmental variability and cognitive performance suggests that stochastic environments can hamper, rather than stimulate, the evolution of cognitive ability.

Ectotherms are vulnerable to environmental changes and their parasites are biological health indicators. Thus, parasite load in ectotherms is expected to show a marked phenology. This study investigates temporal host–parasite dynamics in a lizard community in Eastern Spain during an entire annual activity period. The hosts investigated were Acanthodactylus erythrurus, Psammodromus algirus and Psammodromus edwardsianus, three lizard species coexisting in a mixed habitat of forests and dunes, providing a range of body sizes, ecological requirements and life history traits. Habitat and climate were considered as potential environmental predictors of parasite abundance, while size, body condition and sex as intrinsic predictors. Linear models based on robust estimates were fitted to analyse parasite abundance and prevalence. Ectoparasitic mites and blood parasites from two haemococcidian genera were found: Lankesterella spp. and Schellackia spp. Habitat type was the only predictor explaining the abundance of all parasites, being mostly higher in the forest than in the dunes. The results suggest that particularities in each host–parasite relationship should be accounted even when parasites infect close-related hosts under the same environmental pressures. They also support that lizard parasites can be biomarkers of environmental perturbation, but the relationships need to be carefully interpreted for each host–parasite assemblage.

Variation in life histories influences demographic processes, from adaptive changes to population declines leading to extinction. Among life history traits, generation length offers a critical feature to forecast species' demographic trajectories such as population declines (widely used by the IUCN Red List) and adaptability to environmental change over time. Therefore, estimates of generation length are crucial to monitor demographic stability or predict future changes in highly threatened organisms, particularly amphibians and reptiles, which are particularly threatened among vertebrates and for which uncertainty in future impacts remains high. Despite its importance, generation length for amphibians and reptiles is largely missing. Here, we aim to fill in this gap by modeling generation lengths for amphibians, squamates and testudines as a function of species size, climate, life history and phylogeny using generalized additive models and phylogenetic generalized least squares. We estimated generation lengths for 5059 (57%) amphibians, 8722 (73%) squamates and 117 (32%) testudines. Our models performed well for most families (e.g. Bufonidae among amphibians, Lacertidae and Colubridae among squamates, and Geoemydidae among testudines) while we found high uncertainty around the prediction of a few families, notably Chamaeleonidae. Species' body size and mean temperature were the main predictors of generation length in all groups. Although our estimates are not meant to substitute robust and validated measurements from field studies or natural history museums, they can help reduce existing biases in conservation assessments until field data is comprehensively available.

Lizard populations have been traditionally considered unusually stable. However, there are very few examples to verify this hypothesis on long-term studied populations. Over almost four decades, we have obtained long time series of the abundance of Lilford’s Wall Lizard, Podarcis lilfordi, from all known populations of Menorca (Balearic Islands, Spain). Lizard densities were estimated from line transects data using N-mixture models. Irregular time series were then checked for the presence or absence of a monotonic trend and for density dependence of each population. With multiple regression models we studied the relationship between weather events and the annual abundance of lizards. Density dependence was detected only in two populations: Addaia Petita and Binicodrell Gros. The analysis with EGSS and OUSS models, as well as the results with a Bayesian analysis, showed that most populations seem stable over the years, with a positive and statistically significant trend in five of the 17 populations under study. Only on Sanitja Island the population of lizards exhibits a significantly negative trend. Weather events have a very variable influence on each of these populations. In two small islets, Mel and Ses Mones, the annual number of cloudy days have a negative effect on the abundance of lizards. In Bledas Island, with an exposed geographical situation, we observe a significantly negative effect of all three weather events considered: storms, cloudy days and strong winds. Surprisingly, in Aire and Addaia Gran islands, the annual number of days with storms had a significantly positive effect, probably because the marine subsidies contributed to trophic availability of these two islands by the storms. This work is a first attempt to establish the real abundance of this species, its long-term trend and the influence of weather events on densities of a large set of populations. The relevance of weather events is strongly different on each population and depends on environmental conditions of each population, especially lizard abundance itself, the island surface, geographical location and degree of exposure to weather events.

Organisms generally have many defenses against predation, yet may lack effective defenses if from populations without predators. Evolutionary theory predicts that \"costly\" antipredator behaviors will be selected against when predation risk diminishes. We examined antipredator behaviors in Aegean wall lizards, Podarcis erhardii, across an archipelago of land-bridge islands that vary in predator diversity and period of isolation. We examined two defenses, flight initiation distance and tail autotomy. Flight initiation distance generally decreased with declining predator diversity. All predator types had distinctive effects on flight initiation distance with mammals and birds having the largest estimated effects. Rates of autotomy observed in the field were highest on predator-free islands, yet laboratory-induced autotomy increased linearly with overall predator diversity. Against expectation from previous work, tail autotomy was not explained solely by the presence of vipers. Analyses of populations directly isolated from rich predator communities revealed that flight initiation distance decreased with increased duration of isolation in addition to the effects of current predator diversity, whereas tail autotomy could be explained simply by current predator diversity. Although selection against costly defenses should depend on time with reduced threats, different defenses may diminish along different trajectories even within the same predator–prey system.

Coloration plays a crucial role in sexual selection. Stejneger's grass lizard ( Takydromus stejnegeri ) exhibits a diverse range of body colorations, including complex combinations of green or brown and striped or non-striped patterns in both sexes. In order to clarify the relationships among the variation of body coloration, body condition, and mate preference, we conducted a capture-mark-recapture survey in the wild and mate choice experiments in the laboratory. Analysis of data from 2,497 marked individuals revealed that adult females typically exhibit green patches on their sides, whereas adult males tend to display white stripes on their backs during the breeding season. These colorations did not correlate with their body condition. In the mate choice experiments, we found that green females preferred green males, while brown females preferred brown males. Conversely, males did not demonstrate a significant preference for both colors. Our findings suggest that the varied colorations of T. stejnegeri are influenced by life stage, sexual maturity, and potentially linked to assortative female choice. Significance Statement The maintenance of color variation is a fascinating subject in evolutionary biology, with sexual selection and mimicry often cited as two of the primary underlying mechanisms. However, long-term population monitoring and studies involving large sample sizes are rare, especially in reptiles—a group with elusive habits—where research is particularly scarce. This study has gathered an extensive collection of research samples to monitor seasonal variation in body color among individuals within the population and has conducted experiments on sexual selection to substantiate the maintenance of variation. We believe this research approach offers a compelling case study for investigating color variation.