Sexual selection and environmental change

CHIARAVIGLIO MARGARITA

Hangzhou

Simposio; WCH8; 2016

Sexual Selection and Environmental ChangeChiaraviglio Margarita, Naretto Sergio, Blengini Cecilia, Cardozo GabrielaInstituto de Diversidad y Ecología Animal (IDEA) CONICET. Biología del Comportamiento. Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba. Argentina. Contact zones have long been recognized as natural laboratories of evolution. In this work, we focused on two closely related lizard species. The contact zone of these lizards coincides principally with the arid South American Gran Chaco which is under strike environmental changes. The choice of a social context may depend on the relative quality of individuals, given by the phenotype of competitors or potential mates. Temporal variation in the presence of females and males might be associated with the variation in social and environmental context over the reproductive season. The reproductive traits are under influence of sexual pressures before and after copulation. Competition for mating can differ in species with different sex ratio and different degrees of sexual size dimorphism. The strength of sexual selection varies across populations because they undergo varying competition for mating opportunities. Besides intraspecific pressures, individuals seem to be subjected to pressures driven by interspecific interactions in sympatry. Lizards may vary their reproductive strategies through varying sexual characters, body size, gonadal investment, and sperm traits. We evaluated the reproductive traits, involved in pre- and postcopulatory competition, in allopatric and sympatric populations of Salvator lizards. We observed a spatial gradient of male competition among populations. Accordingly, variation in secondary sexual character, the relative testis mass, and the length of sperm component was observed between allopatry and sympatry in each species, suggesting differences in the investment of reproductive traits. Interestingly, the trade-off between testes and secondary sexual character varied differently from allopatry to sympatry between these Salvator species, suggesting that the influence of social context on reproductive traits investment would affect lizard species differently.