Pre and postcopulatory sexual selection in reproductive traits of Tupinambis lizards in allopatry and sympatry

BLENGINI, CECILIA; NARETTO, SERGIO; CARDOZO, GABRIELA; GIOJALAS, LAURA; CHIARAVIGLIO, MARGARITA

New York

Congreso; The 15 th Conference of International Society of Behavioural Ecology; 2014

International Soceity of Behavioral Ecology

The reproductive strategies of males are influenced by sexual pressures before and after copulation. Sex ratio and presence of related species may indicate different social contexts of selective pressures. The relative importance of pre-copulatory and post-copulatory pressures may vary in different social contexts. In males, morphological traits of robustness, secondary sexual characters, testis investment and sperm traits reveal the reproductive strategies. We evaluate the reproductive traits involved in pre- and post-copulatory mechanisms in wild populations of Tupinambis lizards in allopatry and sympatry. We observed a gradient from high to low competition among males, with the following order: allopatric zone of T. rufescens; sympatric zone for both species; and allopatric zone of T. merianae, showing scenarios with different levels of reproductive competition. Accordingly, variation in the relative pterygoideus muscle mass, the relative testis mass and the length of sperm component was observed between populations, suggesting differences in the investment of reproductive characters. Moreover, no barriers between species were observed in sympatry. Interactions between two closely related species could affect reproductive strategies in different ways. Then, the trade-off between testes and muscle varied differently fromallopatry to sympatry between these Tupinambis species. Here, we show the influence of intra- and interspecific competition on reproductive strategies, which suggests a trade-off between pre- and post-copulatory traits in Tupinambis lizards.