A GUERRA DOS SEXOS: DOS CONFLITOS SEXUAIS À EVOLUÇÃO DO CANIBALISMO SEXUAL PRÉ-COPULATÓRIO EM ARANHAS

Abstract

Spiders are known to have a relationship between males and females not so harmonic. Reproduction can be a risk for males. For females, reproduction can mean easy meal. On the males side, their interests are to survive and get a copulation. Females in turn want the best quality and viability of their offspring. In this context of sexual conflicts, cannibalism appears as the most extreme result of the clash of interests between males and females. We discuss here how much these conflicts may have influenced the stabilization of aggressive behavior in spider populations as a major focus on Dolomedes triton species. We tested this influence with an individual-based demographic model (IBM), simulating virtually the reproductive dynamics of D. triton with several scenarios in which they may influence the frequency of pre-copulatory cannibalism of this species. The target species is well known for cannibalizing a courting male even before the copulation takes place. It ends there with reproductive success and brings costs to fitness not only for males but also for females. The frequency of sexual cannibalism of this species may be associated not only with the level of aggressiveness of the female, but also with the interaction between the aggressive male phenotype and its strategies to avoid cannibalism. Males of various species of spiders are known to have reproductive strategies that decrease the rate of cannibalism and/or increase their survival. Therefore, unlike most of the work on sexual cannibalism, our model is considering how much males and their interactions with females affect the evolutionary and population dynamics of behavior over generations.