Patterns of dispersal and sexual maturation in males of a neotropical paper wasp

• Grant number: 23/12334-2
• Support Opportunities: Research Grants - Visiting Researcher Grant - International
• Start date: April 20, 2024
• End date: May 19, 2024
• Field of knowledge: Biological Sciences - Zoology - Animal Behavior
• Principal Investigator: André Rodrigues de Souza
• Grantee: André Rodrigues de Souza
• Visiting researcher: Markus Rantala
• Visiting researcher institution: University of Turku, Finland
• Host Institution: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Associated research grant: 20/14464-2 - Sexual selection in neotropical social wasps, AP.JP

Abstract

To maximize fitness, males of social hymenopterans (ants, bees, and wasps) invest in direct reproduction rather than helping their kins. However, direct reproduction is constrained by sexual maturation. It takes a few days of adult life for sperm to migrate from the testes to the storage organs (seminal vesicles). It is only from the seminal vesicles that sperm can be mixed with accessory gland products and compose the ejaculate. Social wasp males spend early adulthood in their natal nest. They do not forage for themselves nor to their colony, instead, they receive food via trophallaxis from both adult females and larvae until they become sexually mature and leave the nest permanently to mate. The social environment of a colony can be quite variable in terms of the presence and number of adult females and larvae, which can have strong effects on the amount of food that sexually immature males will receive. The benefits of remaining in the natal nest during sexual maturation (delayed natal dispersal) may be higher for males who experience more favorable social environments (for example, nests with more adult females and larvae). Consequently, males living in less favorable social environments could disperse earlier. The reproductive biology of male social insects has often been studied at mating sites such as leks, swarms or even at the nest in some cases. Less attention has been paid to the behavior of males before arriving at mating sites, despite potential impacts on their competitive ability. To fill this knowledge gap, we will investigate dispersal and sexual maturation patterns in males from a wild population of the neotropical social wasp Mischocyttarus cerberus. First, we will test whether dispersion is age-dependent and associated with sexual maturation. These patterns are often assumed, but empirical evidence for them is scarce. Second, we will test whether delayed dispersal is predicted by the social environment. A variety of social environments (from just a few to dozens of adults and larvae) and male dispersal ages (5-23 days) occur in contemporary colonies of this species, but a link between these has never been addressed in social hymenopterans. Finally, since the social environment in a nest can ultimately affect food availability for males, we will experimentally test whether male dispersal is modulated by opportunities to obtain food in the nest. (AU)