Abstract

We compared morphological indices, flight behaviour, and foraging and habitat use in two sympatric species of flying foxes, the insular flying fox (Pteropus tonganus) and the Samoan flying fox (Pteropus samoensis), to test the prediction that morphologically similar species overlap in ecology. Both species are fruit and flower specialists, forage for patchily distributed food, fly with a foetus or young, and transport large-seeded fruits. Patterns of major foraging activity and foraging mode vary between species: P. samoensis is predominantly diurnal and uses soaring flight for commuting and assessing food resources, while P. tonganus is predominantly nocturnal and commutes extensive distances between roosts and foraging areas. Our results indicate that P. tonganus and P. samoensis are morphologically and ecologically similar, despite differences in flight behaviour. Differences in flight behaviour are attributable to the time of day when most extensive flying occurs for each species.