Daddies in good shape: effect of body condition on male attractiveness in a harvestman with exclusive paternal care (Arachnida: Opiliones)

• Grant number: 14/21069-1
• Support type: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): February 01, 2015
• Effective date (End): December 31, 2015
• Field of knowledge: Biological Sciences - Zoology - Animal Behavior
• Principal researcher: Glauco Machado
• Grantee: Louise Alissa de Morais
• Home Institution: Instituto de Biociências (IB). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

In species with exclusive paternal care, caring males may provide direct benefit to the females, allowing them to forage and to invest in additional offspring, while the current offspring is protected by the males. By selecting caring males as preferential mating partners, females may also acquire indirect benefits, producing sons that are good care-givers. Although female preference for caring males has already been demonstrated for some species of fish and arthropods, a fundamental question remains unanswered: what is the criterion used by females in the beginning of the breeding season, when no male is caring for eggs? Our hypothesis is that females use body condition to evaluate their mating partners because paternal care is costly and only males in good body condition can pay for these costs. Moreover, considering that male body condition deteriorates during the caring period, males should be unable to care for eggs indefinitely throughout the breeding season. In this project, we will use the harvestman Iporangaia pustulosa (Gonyleptidae) to test two predictions: (1) males in good body condition in the beginning of the breeding season will acquire a first clutch faster than males in poor body condition; (2) males that regularly receive food during the caring period will sustain good body condition and will accumulate more eggs in their clutches when compared with caring males naturally deprived from food. These two predictions will be experimentally tested in the field throughout the breeding season of I. pustulosa. The results obtained here will shed light on the criteria used by females to select mating partners in species with exclusive paternal care, and more particularly on the role of body condition for male attractiveness and reproductive success.