Interpopulational variation in mating system and reproductive success of Manogea porracea (Araneae, Araneidae), a spider with amphisexual care

Abstract

The first case of extended male care in solitary spiders was described to the spider Manogea porracea at the Fazenda Nova Monte Carmelo, Estrela do Sul, MG. Males can remove humidity from egg sacs after raining, repair webs when they are damaged by wind, rain or other stochastic factors, avoiding egg sacs to fall on the ground and to be attacked by predators, and protect offspring against araneophagic spiders. This Neotropical spider species occurs from Panama to Brazil. Although there is little evidence of inter-population variation in parental behaviors of animals, it is possible that species with a wide range geographical distribution, like M. porracea, could be subject to different conditions affecting male care (e.g., predation risk and mate availability). Preliminary observations suggest that some important parental traits vary between the population of Estrela do Sul and another population, located in Reserva Natural Vale, Linhares, ES. In the population of Linhares, males were also observed caring for offspring. They apparently offer food to females and spiderlings, although these behaviors were not observed in the population of Estrela do Sul. Males may become more selective and stay for longer on the web of a single partner, due to these additional investments. Consequently, mating system must be more strongly monogamous, and males may have greater reproductive success compared to males of the population of Estrela do Sul. In this project, we will describe male care in the M. porracea population of Linhares and its effects on offspring survival. We will also draw microsatellite markers to this spider aiming to compare mating system and the paternity percentage of males caring for offspring in both populations. Therefore, we intend to describe the inter-population variation in the recently discovered paternal behaviors of M. porracea and to evaluate its implications to mating system and male reproductive success of both population. To do these measures, we will apply genetic analysis to field observations and experimentations. These works, therefore, bring important innovations to studies about sexual selection and parental care in spiders and to my training as ecologist.