Search results for "Lizard"
showing 10 items of 106 documents
Natural History and impacts of an invasive snake: the horseshoe whip snake, Hemorrhois hippocrepis (Linnaeus, 1758), on Ibiza
2021
The island of Ibiza, located in the Balearic Islands (Western Mediterranean), has remained free of introduced snakes for millennia, unlike the majority of Mediterranean islands. But in 2003, with the Mediterranean garden fad, the entrance of old olive trees to the island became common, and three snake species appeared on Ibiza, traveling as stowaways inside the trunks of the olive trees. The most successful invader was the horseshoe whip snake (Hemorrhois hippocrepis). This PhD dissertation studies the natural history of the invasive population and compares it to the source population’s, in the southern Iberian Peninsula, in order to acquire knowledge that helps fighting against the invasio…
Epistatic interactions between pterin and carotenoid genes modulate intra-morph color variation in a lizard.
2021
Color polymorphisms have become a major topic in evolutionary biology and substantial efforts have been devoted to the understanding of the mechanisms responsible for originating such colorful systems. Within-morph continuous variation, on the other hand, has been neglected in most of the studies. Here, we combine spectrophotometric/visual modeling and genetic data to study the mechanisms promoting continuous variation within categorical color morphs of Podarcis muralis. Our results suggest that intra-morph variability in the pterin-based orange morph is greater compared to white and yellow morphs. We also show that continuous variation within the orange morph is partially discriminable by …
Regulatory changes in pterin and carotenoid genes underlie balanced color polymorphisms in the wall lizard
2019
Significance Reptiles show an amazing color diversity based on variation in melanins, carotenoids, and pterins. This study reveals genes controlling differences between three color morphs (white, orange, and yellow) in the common wall lizard. Orange pigmentation, due to high levels of orange/red pterins in skin, is caused by genetic changes in the sepiapterin reductase gene. Yellow skin, showing high levels of yellow carotenoids, is controlled by the beta-carotene oxygenase 2 locus. Thus, the color polymorphism in the common wall lizard is associated with changes in two small regions of the genome containing genes with crucial roles in pterin and carotenoid metabolism. These genes are likel…
Rapid learning of a spatial memory task in a lacertid lizard (Podarcis liolepis).
2018
Abstract Mammals and birds are capable of navigating to a goal using learned map-like representations of space (i.e. place learning), but research assessing this navigational strategy in reptiles has produced inconclusive results, in part due to the use of procedures that do not take account of the peculiarities of reptilian behavior and physiology. Here I present a procedure suitable for testing spatial cognition that exploits a naturally evolved, ethologically relevant ability common to many lizards (i.e. refuge seeking behavior). The procedure requires lizards to learn the location of an open refuge inside a rectangular arena containing artificial refuges in every corner, using distal ex…
Relationships between helminth communities and host traits inPodarcis bocageiandPodarcis carbonellifrom NW Portugal
2006
A parasitological survey was carried out to determine the relationships between helminth fauna and some biological traits of two host species of lacertid lizards. Size, sex, diet, and season of collection, as well as infracommunities and component communities of Podarcis bocagei and P. carbonelli from Douro litoral (northwest Portugal), have been analysed. In both host species, we found low values of parasite infection parameters and diversity. These findings were in accordance with their feeding habits, eating only animal prey and no plant matter. Evidences suggest a relationship between the presence of Brachylaima sp (Trematoda: Brachylaimidae) and the ingestion of snails by both lizard s…
Intestinal Helminth Parasites of Wall Lizards, Podarcis vaucheri Complex (Sauria: Lacertidae) from Algeria
2011
Abstract A parasitological survey was carried out to determine the relationships between the helminth fauna and biological traits of the hosts in three Algerian populations of Podarcis lizards belonging to two different evolutionary lineages. Size, sex, and locality of collection, as well as the infracommunities and component communities, were analyzed. Very low values of parasite infection parameters and diversity were found in all three populations. This is in accordance with the feeding habits of these lizard hosts, which only eat animal prey and no plant matter. Spauligodon saxicolae (Nematoda: Pharyngodonidae), a specialist in lizards, is reported here for the first time in Africa. Thi…
Activity and body orientation of Gallotia galloti in different habitats and daily times
2011
Abstract In lizards, site selection is related to the acquisition of resources such as refuges, mates or prey, but also to the exploitation of sites suitable for thermoregulation. The latter process may be affected by lizard posture and body axis orientation in relation to the sun as a way to optimize heat exchange throughout the day. Specific postures and body orientations could also contribute to more efficient signal transmission in social contexts. In this paper we analyze activity and body axis orientation of adult males and females of the lacertid Gallotia galloti in two localities of Tenerife with different structural habitats. We performed transects at both sampling localities in t…
Parasitic infracommunities of the Aegean wall lizard Podarcis erhardii (Lacertidae, Sauria): isolation and impoverishment in small island populations
2009
AbstractThe Aegean wall lizard Podarcis erhardii, is widely distributed across the islands of the Aegean Sea (Greece). While there exists a relatively substantial body of knowledge on the ecology and life history of the species, the parasite communities of the taxon remain almost completely unknown. Quantifying the composition of these communities in P. erhardii is not only important for autoecological reasons, but also because inter-island comparisons of this lizard's parasite communities can shed light on the factors that structure parasite diversity in general. Here we investigate the gastrointestinal parasite communities of P. erhardii populations occurring on 16 landbridge islands of t…
Color-assortative mating in a color-polymorphic lacertid lizard
2013
Color polymorphisms are common in lizards, which provide an excellent model system to study their evolution and adaptive function. The lacertid genus Podarcis is particularly interesting because it comprises several polymorphic species. Previous studies with lacertid lizards have tried to explain the maintenance of color polymorphisms by correlational selection between color morphs and several phenotypic traits. Particular attention has been paid to their putative role as signals reflecting alternative reproductive strategies under frequency-dependent selection, but the relationship between mating patterns and color polymorphism has not been previously considered. In this study, we use long…
Ultraviolet reflectance of male nuptial colouration in sand lizards (Lacerta agilis) from the Pyrenees
2007
Abstract The evolutionary significance of lacertid colourations is relatively unexplored. However, several studies have demonstrated signalling by means of bright green colouration in Swedish Lacerta agilis males during the breeding season. Unfortunately, most of these studies have been based on human colour perception that differs in several ways from that of lizard. An important difference between human and lizard colour vision is the presence of an ultraviolet (UV) sensitive cone in lizards. The available evidence suggests that male sand lizards colorations do not reflect UV wavelengths, at least in Swedish populations. However, this study, based on objective (spectrophotometric) measur…