Foraging niche partitioning of threeMyotisbat species and marine fish consumption byMyotis pilosusin a subtropical East Asian region

Abstract

AbstractMost bats are insectivorous, but some species have evolved the ability to prey on fish. Although piscivory has been confirmed in the Rickett’s big-footed myotis (Myotis pilosus), the extent of piscivory of other cohabitingMyotisspecies is uncertain. This study aims to explore the dietary niches and fish consumption of threeMyotisspecies in a subtropical East Asian region, and specifically the fish diet ofM. pilosus. Our findings reveal, for the first time, thatM. pilosusconsumes marine fishes, in contrast to previous research conducted in inland regions that suggested year-round consumption of cyprinids in freshwater habitats. We also observed seasonal variation in the diets ofM. pilosus. It predominately hunted wide-banded hardyhead silverside, sailfin flying fish, and shorthead anchovy during the wet season, while mainly preying upon mullets during the dry months. In more inland areas,M. pilosuswas found to primarily feed on invasive freshwater poeciliids. Furthermore,M. pilosusconsumed more fish during the dry season, while there was a greater consumption of insects during the wet months. Most notably among our findings is the consumption of fish by one individual of Chinese myotis (M. chinensis) and two individuals of Horsfield’s myotis (M. horsfieldii), indicating that they are potentially piscivorous. We revealed that bothM. horsfieldiiandM. pilosusconsumed water striders, suggesting that foraging of aquatic insects could be driving the evolution of fishing behavior. Our findings have also shed light on the flexibility of foraging behavior in piscivorous bats.