Biology subjects

Carretero, M. A.

Publications and source records attributed to Carretero, M. A..

7 recordsLinked to original sources

bioRxiv2026

Resolution of multi-receiver trade-offs in wall lizard colouration

Animal colouration evolves under multiple, often conflicting, selective pressures. Conspicuous, non-aposematic colour-patterns that enhance conspecific communication may simultaneously increase detectability by predators. Such trade-offs can be resolved by optimising colour-patterns to match the perceptual abilities of different receivers. We tested whether dorsal colour-patterns of the Lusitanian wall lizard (Podarcis lusitanicus) are optimised for ecologically relevant receivers across relevant viewing distances, while accounting for the visual acuity of conspecifics and predators. Conspecifics and snakes detected chromatic information at shorter distances, whereas achromatic and luminance information were detected at longer distances. Birds showed a uniform decline in detectability across the colour-pattern components with increasing viewing distance. Larger males retained high chromatic detectability across all receivers despite the general distance-related decline, whereas females and smaller individuals exhibited less salient colour patterns, consistent with predator avoidance strategy. Our results show that lizards resolve the trade-off between conspecific communication and predator detection through distance-dependent colour-pattern perceptibility across receivers. This resolution breaks down in large males, for whom the benefits of salient chromatic patterns for intraspecific communication may outweigh increased detectability to predators.

evolutionary biology↗

bioRxiv2024

Climate drives long-term landscape and rapid short-term promoter evolution in the Western Canaries lizard, Gallotia galloti

Climate adaptation is caused by multiple mechanisms, including evolution of regulatory promoter sequences under broad environmental pressures, however, little is known about these processes in response to climate pressures in animals. Here, we examined spatial and temporal evolution of climate-related gene promoters in an insular species, the Western-Canaries lizard Gallotia galloti, across diverse environmental conditions over nine years. Outlier SNPs linked to elevation-sensitive environmental factors identified adaptively significant loci, including in aquaporin and Electron Transfer Flavoprotein Subunit Alpha (ETFA) gene promoters, demonstrating roles in local climate adaptation. Adaptive indexing mapped climate-driven genetic differentiation across the landscape, revealing local adaptation along an elevational gradient. Signatures of climate-related selection at the temporal scale showed specific promoters shaped by balancing selection supporting survival across environments, while others experienced positive selection, revealing a selective sweep of beneficial alleles. In addition, elevation-based ancestry groups of climate loci differed from the pattern observed in neutral loci, and temporal shifts in ancestry composition responded to preceding extreme weather events over the span of a single generation. Selection on specific promoter regions indicated adaptive evolution in transcription factor binding sites with the potential to enhance transcriptional flexibility, resulting in increased cellular stress tolerance. Our findings open new avenues into genomic mechanisms of resilience across spatially heterogeneous environments and how rapid evolution correlates with extreme weather events associated with climate change.

evolutionary biology↗

bioRxiv2024

Does hybridisation with an invasive species threaten Europe's most endangered reptile? Genomic assessment of Aeolian lizards on Vulcano island

Interspecific hybridisation can be consequential for rare and insular endemic species. The Critically Endangered Aeolian wall lizard, Podarcis raffonei, severely declined due to interactions with the invasive Italian wall lizard, Podarcis siculus. The largest population of P. raffonei survives on a narrow peninsula (Capo Grosso) that is mildly connected to the island of Vulcano, which has been entirely invaded by P. siculus. Recent observation of individuals with an intermediate phenotype raised concern over the risk that hybridisation might swamp this last stronghold. We genetically characterised lizards from Vulcano using genome-wide SNPs, considering individuals showing multiple phenotypes (native, invasive, and "intermediate"). Hybridisation rate was low ([~]3%), with just two F1 hybrids and two backcrosses. However, pure P. raffonei showed extremely low genetic diversity, a very small effective population size, and a low NE/NC ratio. Management strategies are urgently needed to control invasive species and maintain the genetic diversity of P. raffonei.

evolutionary biology↗

bioRxiv2023

On the role of melanistic coloration on thermoregulation in the crepuscular gecko Eublepharis macularius

Body coloration in ectotherms serves multiple biological functions, including avoiding predators, communicating with conspecific individuals, and involvement in thermoregulation. As ectotherms rely on environmental sources of heat to regulate their internal body temperature, stable melanistic body coloration or color change can be used to increase or decrease heat absorption and heat exchange with the environment. While the function of melanistic coloration for thermoregulation has been found to increase solar radiation absorption for heating in many diurnal ectotherms, research on crepuscular and nocturnal ectotherms is lacking. Since crepuscular and nocturnal ectotherms generally absorb heat from the substrate, coloration is likely under different selective pressures than in diurnal ectotherms. We tested if the proportion of dorsal melanistic body coloration is related to differences in body temperature heating and cooling rates in the crepuscular gecko Eublepharis macularius and whether changes in environmental temperature trigger color changes in this species. Temperature measurements of the geckos and of the environment were taken using infrared thermography and temperature loggers. Color data were obtained using objective photography and a newly developed custom software package. We found that body temperature reflected substrate temperatures, and that the proportion of melanistic coloration has no influence on heating or cooling rates or on color changes. These findings suggest that, in E. macularius, melanistic coloration may not be used for thermoregulation. Future research should further test the function of melanistic coloration in other crepuscular and nocturnal vertebrates to understand the evolution of melanistic pattern in animals active in low light conditions.

zoology↗

bioRxiv2021

Does heat tolerance actually predict geographic thermal limits of animal species?

To understand species' climatic vulnerability, our measures of species thermal tolerance should predict their geographic thermal limits. Yet, this assumption is ungranted. We tested if animals' heat tolerance restrict the warmest temperatures they can live at (Tmax), distinguishing among species differently challenged by their thermal environment. For that, we compiled 2350 measurements of species heat tolerance indexes and corresponding Tmax, measured at different microhabitats. We show that reptiles, a flagship for climatic vulnerability studies, are particularly unbounded by their heat tolerance. Contrarily, tolerance restricted marine fish geography in a non-linear fashion which contrasts with terrestrial taxa. Behavioral tolerance indexes, widely used to predict vulnerability, predicted Tmax inconsistently across Tmax indexes, or were inversely related to it. Animals heat tolerance restricts geographic limits more strongly for more thermally challenged species. In turn, factors uncoupling heat tolerance and Tmax (plasticity, thermoregulation, adaptation) should be more important for less thermally challenged species. Significance StatementTo identify climatic vulnerability, heat tolerance indices need to predict species' thermal limits to geographic distribution. Yet, we show that heat tolerance predicts geographic limits quite heterogeneously, depending on taxa, the type of measure of heat tolerance and how challenged are species at their hottest known location. Particularly, reptiles, a flagship of vulnerability studies, were less bounded by tolerance than taxa regarded as more capable to evade high temperatures, due to their capacity to evaporate water, find refuge, or migrate (Ex. amphibians, arthropods, birds and mammals). Measures of species behavioral heat tolerance may still need to improve. Factors thought to uncouple thermal tolerance and geographic limits should be stronger for less thermally challenged species.

ecology↗

bioRxiv2021

Population genomics of wall lizards reflects the dynamic history of the Mediterranean Basin

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 flow 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.

evolutionary biology↗

bioRxiv2018

Regulatory changes in pterin and carotenoid genes underlie balanced color polymorphisms in the wall lizard

Reptiles use pterin and carotenoid pigments to produce yellow, orange, and red colors. These conspicuous colors serve a diversity of signaling functions, but their molecular basis remains unresolved. Here, we show that the genomes of sympatric color morphs of the European common wall lizard, which differ in orange and yellow pigmentation and in their ecology and behavior, are virtually undifferentiated. Genetic differences are restricted to two small regulatory regions, near genes associated with pterin (SPR) and carotenoid metabolism (BCO2), demonstrating that a core gene in the housekeeping pathway of pterin biosynthesis has been co-opted for bright coloration in reptiles and indicating that these loci exert pleiotropic effects on other aspects of physiology. Pigmentation differences are explained by extremely divergent alleles and haplotype analysis revealed abundant trans-specific allele sharing with other lacertids exhibiting color polymorphisms. The evolution of these conspicuous color ornaments is the result of ancient genetic variation and cross-species hybridization.

evolutionary biology↗