Sexual selection in neotropical social wasps

Abstract

Sexual selection is the evolutionary mechanism by which certain characteristics are favored (sexually selected) when an individual's reproductive chances is increased. It has been extensively studied in a variety of organisms. Still, some groups have received relatively little attention. This is the case of social Hymenoptera (bees, ants and wasps). Mating systems such as leks and swarms typical of these insects are characterized by high variance in male reproductive success, promoting intense competition for reproductive opportunities in this sex and resulting in intrasexual selection. The variance in the reproductive quality of males and females regarding fertility, reproductive opportunities and genetic compatibility promotes the mate choice resulting in intersexual selection. Monandry is relatively common in social insects. In some lineages, a functional monandry is achieved by biasing the use of sperm from a particular male (when polyandrous females use sperm from only one male). In other lineages, females use sperm from several males, being functionally polyandrous. Polyandry can promote sperm competition and cryptic female choice. Research on sexual selection in social Hymenoptera has been driven by the success achieved with bees in recent decades, which has resulted in the expansion of research to include ants and, more recently, wasps. As for wasps, most studies have focused on the few species in the temperate region, while the high diversity of neotropical species remains poorly investigated. The neotropical region differs strongly from the temperate region in terms of temporal resource availability, climate and biological interactions, resulting in large differences in reproductive opportunities for organisms in general and possibly reflecting particular adaptations in their biology. In this sense, the diversity of species and the ecological peculiarities of the neotropical region result in great potential for the expansion of knowledge. Research with social insects is also marked by the scarcity of studies with males, which are considered the "neglected gender". Studying males of these insects can compensate for this bias, contributing to a better understanding of reproductive biology and its effects on the sociobiology of these species. This proposal aims to test hypotheses about sexual selection in neotropical social wasps (Hymenoptera:Vespidae:Polistinae). It is intended to investigate the role of different components related to this evolutionary mechanism: precopulatory (intrasexual and intersexual) and postcopulatory (sperm competition and cryptic female choice) sexual selection. Such goals will be achieved by integrating tools and methods from multiple disciplines such as natural history, ethology, behavioral ecology, chemical ecology, molecular genetics, animal physiology and cell biology. Observations and experiments will be carried out in the field and in the laboratory, and these will be applied both at an intraspecific and interspecific level. It is expected to identify new model species whose study can contribute to increase knowledge about sexual selection. This project also contemplates the training of several undergraduate and graduate students, as well as the collaboration between researchers from the department at USP and researchers from other institutions in the country and abroad. It is an opportunity to consolidate the applicant's line of research. (AU)