Love bites: males of lizards prefer to mate with conspecifics, but do not disdain parthenogens

Abstract

Abstract Parthenogenesis has been discovered in a great number of reptiles, indicating that parthenogens can outcompete bisexual species and hybridize with them. This raises intriguing questions: how do parthenogenetic species coexist with gonochoristic relatives, and what outcome does this coexistence produce? To answer these two questions, we studied relationships between male rock lizards, Darevskia valentini, and parthenogenetic Darevskia armeniaca. We compared social and sexual reactions of males to females of their own species and parthenogenetic D. armeniaca and vice versa. We found that females of both species basked together with males and demonstrated mostly submissive behaviour. Females of D. valentini were less aggressive towards males in the mixed-species population than in the single-species population, suggesting female competition for males. The proportion of successful and unsuccessful mating attempts with females of bisexual and unisexual species was equal, and we found no significant differences in male reactions to bisexual and unisexual females in sympatry. The proportion of females bearing mating scars on their venters and the number of these scars per female were greater in the bisexual species. This indicates that females of the bisexual species were more attractive than parthenogenetic females as mating partners to males. We found no triploid hybrids among the offspring of parthenogenetic females that mated with males in the mixed population. Our findings suggest that parthenogenetic species might outcompete bisexual species by mating with males and integrating into the social system.