Parasites influence social rank and morphology, but not mate choice, in female red junglefowl, Gallus gallus

Parasites can profoundly affect host morphology and behaviour, but previous work has focused on the effects of parasites on males. In the present study, we assessed the effects of infection with the nematode Ascaridia galli on the morphology and behaviour, including mate choice, of female red junglefowl. Hens infected with A. galli had lower mass and smaller combs than unparasitized birds when sexually mature. Parasite status had a significant effect on social rank in all-female flocks, with high-ranking birds being less likely to be parasitized. Larger females had higher social rank, but comb size was unrelated to social status. Neither parasite status nor social rank had any effect on mate choice. These results differ from those found for male red junglefowl, and suggest that males and females may allocate resources differently to comb versus growth. The low cost of choice in the red junglefowl mating system may also contribute to the lack of an effect of parasites and social status on mate choice.