Behaviour 2019
Bd infection affects call traits but not female choice in Pacific treefrogs (Pseudacris regilla)
Julia F Messersmith, Alejandro Vélez. San Francisco State University, San Francisco, CA, United States

Why females prefer elaborate mating displays is a central topic of sexual selection. In its simplest form, the Hamilton-Zuk hypothesis poses that females prefer showy males because mating displays are honest indicators of parasite resistance. In frogs, female choice is primarily based on the energetically costly mating calls produced by males. Here, we tested the effects of infection by the chytrid fungus, Batrachochytrium dendrobatidis (Bd), on Pacific treefrog mating behavior. We predicted that Bd infection would affect the pulsatile mating call produced males, and that females would prefer males of low infection based on their calls. First, we analyzed the calls of males and assayed their Bd infection. Males with high levels of Bd infection produce shorter calls with pulses delivered at faster rates than those with low infection levels. We then tested female choice using synthetic calls characteristic of males with high or low infection levels. Females did not show a preference between these calls. Our results underscore the importance of considering signals and signal preferences to understand how parasitism may affect reproductive success and the evolution of mating displays.