Island bat diets: does it matter more who you are or where you live?

Abstract

Differences in body size, echolocation call frequency and location may result in diet partitioning among bat species. Comparisons between island populations are one way to evaluate these competing hypotheses. We conducted a species-level diet analysis of three Rhinolophus and one Hipposideros species on the Philippine islands of Cebu, Bohol and Siquijor. We identified 655 prey (MOTUs) in the guano from 77 individual bats. There was a high degree of overlap among species' diets despite differences in body size and call frequency. For example, the diet of the 3 g-Hipposideros pygmaeus (mean CF = 102 kHz) exhibited a diet overlap higher than expected by chance with all three Rhinolophus species, even the 13 g-Rhinolophus inops (mean CF = 54 kHz). We observed more convergence in diet between Rhinolophus species and H. pygmaeus than between Rhinolophus species themselves, which may be explained by the broad diet of H. pygmaeus. There was less dietary overlap between Rhinolophus virgo from two islands than between R. virgo and congeners from Cebu. These data suggest that location causes convergence in diet, but specific species characteristics may drive niche specialization. The complex interplay between location and the perceptual ability of each species leads to a situation where simple explanations, for example body size, do not translate into predictable prey partitioning. In particular, our observations raise interesting questions about the foraging strategy and adaptability of the tiny H. pygmaeus.

Dietary overlap and seasonality in three species of mormoopid bats from a tropical dry forest

“…Similarly, Sedlock et al . () also found interspecific dietary overlap and concluded that location determined what bats consume more effectively than their taxonomy or perceptual abilities. Here, we suggest that seasonal changes in food abundance have the same effect.…”

“…; Sedlock et al . ). However, we found no evidence that diet changes in the same direction as insect abundance/diversity.…”

“…; Sedlock et al . ) and there may be some technical biases in the detection of this order (Clare ), they are not always the most abundant order ( e.g. Eptesicus fuscus ; Clare et al .…”

“…Findley ; Sedlock et al . ). However, other studies have shown that sympatric species may partition resources in ways that impact diet ( e.g .…”

Prey preference of the common vampire bat (Desmodus rotundus, Chiroptera) using molecular analysis

“…DNA-based techniques have been used to identify prey species in the diet of insectivorous bats (Clare et al 2009(Clare et al , 2011Bohmann et al 2011;Razgour et al 2011;Zeale et al 2011;Dodd et al 2012;Burgar et al 2014;Sedlock et al 2014). Carter et al (2006) reported on techniques for isolation, amplification, and identification of avian DNA from fecal samples of Diaemus youngi, the white-winged vampire bat, a specialist avian sanguinivore (Greenhall et al 1983).…”