Coexistence of Rhinolophus affinis and Rhinolophus pearsoni revisited

The investigation of mechanism of species coexistence promotes understanding of the mechanistic processes behind community ecology and ecosystem functions. Niche theory declares that species coexistence within a community must partition the resources of their environment. Two sympatric and morphologically similar bat species, Rhinolophus affinis and Rhinolophus pearsoni, provided a unique opportunity to test the causal mechanism of coexistence. Previous study showed that their coexistence was promoted not by the trophic and spatial niche differentiation but the relatively high abundance of prey resources, which was not in accord with the prediction of niche theory. Here, therefore, we reanalyzed the dietary composition by fecal analysis and surveyed the feeding time of both species. Our results showed that R. affinis and R. pearsoni hunt mainly mostly on Coleoptera and Lepidoptera, and there was a very high overlap (0.84) of trophic niche between the two species. However, significant difference in the duration of the activity period between both species was detected, which illustrated that temporal partitioning of prey resource use facilitated their coexistence. Additionally, our work highlighted the importance of integration of the traditional methods and next-generation sequencing methods for identifying dietary composition of carnivores, and suggested that ongoing studies of species coexistence must consider simultaneously multiple niche axes.