Aerobic performance does not affect social rank in female Red Jungle Fowl

1. Exercise capacity ultimately constrains behaviour, and therefore may influence social interactions. The hypothesis was tested that individual differences in maximal rates of oxygen consumption (V·_O2max) – a primary determinant of sustainable exercise capacity – affect dominance hierarchies in experimental all-female flocks of the highly social Red Jungle Fowl (Gallus gallus). It was also examined whether social rank could in turn influence V·_O2max (which is quite plastic in most vertebrates), and whether these relationships were influenced by a common and relatively benign parasite, the intestinal nematode Ascaridia galli.

2. Substantial between-individual variation was found in V·_O2max that was significantly repeatable over time, but there was no indication that V·_O2max was affected by A. galli infection. Stable social hierarchies were quickly established in 26 of 28 experimental flocks (each contained three females previously isolated from each other). Infection status affected social rank, but there was no consistent pattern between rank and infection.

3. No indication was found that individual differences in V·_O2max either predicted the social rank in newly formed flocks, or were affected by social status in established flocks.