Parasites and Bright Male Plumage in the Satin Bowerbird (Ptilonorhynchus violaceus)

Results from our field studies of the satin bowerbird (Ptilonorhynchus violaceus) suggest that females choose males as mates based on their level of infection with the ectoparasite (Myrsidea ptilonorhynchi: Menoponidae). We evaluated predictions from three hypotheses for why this pattern of choice might evolve. The bright male and correlated infection models both suggest that females choose parasite free males because these males are more likely to sire parasite resistant offspring. The bright male hypothesis suggests that females are able to gauge infection based on plumage brightness. The correlated infection hypothesis claims that females assess resistance to endoparasites through a correlated effect on ectoparasites. In the parasite avoidance model female choice is shaped by the proximate benefits of avoiding infection. Six predictions from these models were tested using information on patterns of infection in satin bowerbirds. Of these models the parasite avoidance model was best supported by the available data.