Grazing of goats on Mediterranean islets is a common practice. Its consequences on plant communities are well documented, although not on vertebrates. We aim to shed light on the effect of livestock farming on lizards by investigating five populations of the insular lizard, Podarcis gaigeae, differing in the duration and intensity of grazing. Data on grazing regime, invertebrate abundance, tick prevalence, infestation levels, gull nests and lizard densities were collected during a period of 6 consecutive years. Grazing had a negative impact on insect populations, thus decreasing food availability for lizards. Tick prevalence and infestation levels were higher in places of continuous grazing. Goat activity disturbed gulls, which avoid nesting, so depriving the islets of marine subsidies. As a consequence of all these factors, lizard densities were higher in ungrazed and lower in grazed biotopes. Grazing effects were more severe on islets communities than on the main island populations. Our data imply that management action should be taken to conserve the highly diverse islet populations.

Lacertid lizards are a widely radiated group of squamate reptiles with long-term stable ZZ/ZW sex chromosomes. Despite their family-wide homology of Z-specific gene content, previous cytogenetic studies revealed significant variability in the size, morphology, and heterochromatin distribution of their W chromosome. However, there is little evidence about the accumulation and distribution of repetitive content on lacertid chromosomes, especially on their W chromosome. In order to expand our knowledge of the evolution of sex chromosome repetitive content, we examined the topology of telomeric and microsatellite motifs that tend to often accumulate on the sex chromosomes of reptiles in the karyotypes of 15 species of lacertids by fluorescence in situ hybridization (FISH). The topology of the above-mentioned motifs was compared to the pattern of heterochromatin distribution, as revealed by C-banding. Our results show that the topologies of the examined motifs on the W chromosome do not seem to follow a strong phylogenetic signal, indicating independent and species-specific accumulations. In addition, the degeneration of the W chromosome can also affect the Z chromosome and potentially also other parts of the genome. Our study provides solid evidence that the repetitive content of the degenerated sex chromosomes is one of the most evolutionary dynamic parts of the genome.

Studies of animal communication have documented myriad rapid, context‐dependent changes in visual and acoustic signal design. In contrast, relatively little is known about the capacity of vertebrate chemical signals to rapidly respond, either plastically or deterministically, to changes in context. Four years following an experimental introduction of lizards to replicate experimental islets, we aimed to determine if chemical signal design of the experimental populations differed from that of the source population. In 2014, we translocated Podarcis erhardii lizards from a large, predator‐rich island to each of five replicate predator‐free islets. Mean population densities increased fivefold over the following 4 years and bite scars suggest significantly more intraspecific fighting among these experimental populations. In 2018, we analysed the chemical signal design of males in each of the experimental populations and compared it to the chemical signals of the source population. We found that males consistently presented a significantly more complex chemical signal compared to the source population. Moreover, their chemical signals were marked by high proportions of octadecanoic acid, oleic acid and α‐tocopherol, the three compounds that are known to be associated with lizard territoriality and mate choice. Our island introduction experiment thus suggests that the chemical signal design of animals can shift rapidly and predictably in novel ecological contexts.