Season's greetings: diet and its links to reproductive timing of the small-island endemic Christmas Island flying-fox (Pteropus natalis)

Knowledge of foraging resource utilization and its links to reproductive timing is important for resource management and species conservation. In this study, we examine the foraging resource utilization of the critically endangered Christmas Island flying-fox (Pteropus natalis) in relation to the timing of the species' reproductive events. To determine the diet of the species, we identified pollen and seeds collected from 608 individuals caught over 3 years, and combined these data with foraging observations. We then compared the temporal patterns in the use of diet plants to seasonal patterns in rainfall, and to the timing of reproductive events. We found that P. natalis foraged on the flowers, fruits, leaves, and stems of 57 plant species from 34 families, including most native tree species on Christmas Island, highlighting the importance of the pollination and seed dispersal services that P. natalis provides. The temporal occurrence of fruit and pollen in the diet of P. natalis correlated with changes in mean seasonal rainfall. The greatest mean proportion of fruit in the diet of P. natalis occurred during the wet season (December–March), coinciding with parturition and lactation, whereas the greatest mean proportion of pollen in the diet of P. natalis occurred during the dry season (August–November), coinciding with volancy. This research provides links between the foraging resource requirements and the timing of reproductive events in a small-island flying-fox and suggests strategies for management of important dietary resources to aid in the conservation of this threatened but ecologically important species.