Search results for "LIZARD"
showing 10 items of 106 documents
Sexual selection drives asymmetric introgression in wall lizards.
2015
Hybridisation is increasingly recognised as an important cause of diversification and adaptation. Here, we show how divergence in male secondary sexual characters between two lineages of the common wall lizard (Podarcis muralis) gives rise to strong asymmetries in male competitive ability and mating success, resulting in asymmetric hybridisation upon secondary contact. Combined with no negative effects of hybridisation on survival or reproductive characters in F1-hybrids, these results suggest that introgression should be asymmetric, resulting in the displacement of sexual characters of the sub-dominant lineage. This prediction was confirmed in two types of secondary contact, across a natur…
Learning outdoors: male lizards show flexible spatial learning under semi-natural conditions.
2012
Spatial cognition is predicted to be a fundamental component of fitness in many lizard species, and yet some studies suggest that it is relatively slow and inflexible. However, such claims are based on work conducted using experimental designs or in artificial contexts that may underestimate their cognitive abilities. We used a biologically realistic experimental procedure (using simulated predatory attacks) to study spatial learning and its flexibility in the lizard Eulamprus quoyii in semi-natural outdoor enclosures under similar conditions to those experienced by lizards in the wild. To evaluate the flexibility of spatial learning, we conducted a reversal spatial-learning task in which …
Relationship between diet and helminths in Gallotia caesaris (Sauria: Lacertidae)
2004
Diet and helminth fauna were analysed in Gallotia caesaris, a small lacertid lizard endemic to El Hierro (Canary Islands, Spain) in order to study the evolutionary and functional relationships between the two traits. This species is omnivorous but consumed a high proportion (82.13%) of plant matter including not only seeds but also leaves and other vegetative parts. Helminth fauna included many helminth species typical of herbivorous reptiles. Both herbivory and helminth presence were higher than expected for a lizard of its size. Comparison with other lacertids suggests that both traits result from an adaptation to insular conditions but that some "evolutionary time" to develop them is nee…
Ultraviolet vision in lacertid lizards: evidence from retinal structure, eye transmittance, SWS1 visual pigment genes, and behaviour
2014
Abstract Ultraviolet (UV) vision and UV colour patches have been reported in a wide range of taxa and are increasingly appreciated as an integral part of vertebrate visual perception and communication systems. Previous studies with Lacertidae, a lizard family with diverse and complex coloration, have revealed the existence of UV-reflecting patches that may function as social signals. However, confirmation of the signalling role of UV coloration requires demonstrating that the lizards are capable of vision in the UV waveband. Here we use a multidisciplinary approach to characterize the visual sensitivity of a diverse sample of lacertid species. Spectral transmission measurements of the ocula…
3-Acetylpyridine-induced degeneration and regeneration in the adult lizard brain: a qualitative and quantitative analysis
1997
Abstract The neurotoxin 3-acetylpyridine (3AP) produces highly selective neuronal damage in specific areas of the lizard brain. Following 3AP intoxication, proliferation and migration of replacement neurons born in the ventricular walls lead to regeneration of the lesioned areas. Earlier studies established the time course of 3AP-induced degeneration and subsequent regeneration in the medial cerebral cortex of adult lizards (Font, E., Garcia-Verdugo, J.M., Alcantara, S. and Lopez-Garcia, C., Neuron regeneration reverses 3-acetylpyridine-induced cell loss in the cerebral cortex of adult lizards, Brain Res. , 551 (1991) 230–235 [13] ). Complementary to our previous studies, we now provide a q…
Host-parasite relationships of Zootoca vivipara (Sauria: Lacertidae) in the Pyrenees (North Spain)
2000
The helminths infesting the common lizard, Zootoca vivipara (Jacquin, 1787), were studied with special attention to the relations between the number of nematodes, Oswaldocruzia filiformis (Goeze, 1782), and the size, sex and age class of the host. The possible seasonality of the parasite intensity and the relationship with the feeding habits of the host were also tested. Helminth infracommunities of Z. vivipara were depauperate with lizards harbouring only two species, the trematode Plagiorchis molini (Lent et Freitas, 1940) and the nematode O. filiformis. A positive correlation between host size and the number of O. filiformis was found for female Z. vivipara. However, no correlation was d…
Using visual modelling to study the evolution of lizard coloration: sexual selection drives the evolution of sexual dichromatism in lacertids
2012
Sexual selection has been invoked as a major force in the evolution of secondary sexual traits, including sexually dimorphic colorations. For example, previous studies have shown that display complexity and elaborate ornamentation in lizards are associated with variables that reflect the intensity of intrasexual selection. However, these studies have relied on techniques of colour analysis based on human – rather than lizard – visual perception. Here, we use reflectance spectrophotometry and visual modelling to quantify sexual dichromatism considering the overall colour patterns of lacertids, a lizard clade in which visual signalling has traditionally been underrated. These objective method…
Ascending projections from the optic tectum in the lizard Podarcis hispanica.
1998
The ascending projections of the optic tectum, including their cells of origin, have been studied in the lizard Podarcis hispanica by means of a two-step experimental procedure. First, tracers were injected in the tectum to study the anterograde labeling in the forebrain. Second, the cells of origin of these projections have been identified by analyzing the retrograde labeling after tracer injections in the thalamus, hypothalamus, and pretectum. Three main tectal ascending pathways have been described: the dorsal tecto-thalamic tract (dtt), the medial tecto-thalamic tract (mtt), and the ventral tecto-thalamic tract (vtt). The dtt originates in radial cells of layers 5 and 7 and bipolar cell…
Social behavior, chemical communication, and adult neurogenesis: Studies of scent mark function in Podarcis wall lizards
2011
Lacertid lizards have been hailed as a model system for the study of reptilian chemical communication. However, results obtained with the genus Podarcis, a diverse group of wall lizards with complex systematics, challenge emerging paradigms and caution against hasty generalizations. Here we review the available evidence on the role of chemical stimuli in male-female and male-male interactions in Iberian Podarcis. Males of several species can discriminate between chemicals left on substrates by females of their own or a different species, suggesting that differences in female chemical cues may underlie species recognition in this group. Females, on the other hand, do not respond differential…
Study of adult neurogenesis in the Gallotia galloti lizard during different seasons.
2011
In a previous study we found a seasonal distribution of cell proliferation (the first stage of adult neurogenesis) in the telencephalic ventricular walls of the adult Gallotia galloti lizard. The aim of the present work was to determine the influence of seasonality on the subsequent migration of the resulting immature neurons. We used wild animals injected with bromodeoxyuridine and kept in captivity within 30 days. To confirm the neuronal identity of these cells, we used double immunohistochemical 5-bromo-2'-deoxyuridine (BrdU) and doublecortin (DCX, an early neuronal marker) labeling, as well as autoradiography after the administration of methyl-[³H]thymidine ([³H]T). We found that: (1) t…