Evaluating Home Range, Foraging Behaviour, and Roost Loyalty of Greater Short-nosed Fruit Bats in Semi-Urban Areas Using Telemetry

The present study aims to document the emergence and return timings, night roost usage, foraging patterns, social interactions within the colony, alternate roost sites for females, and roost fidelity among both male and female bats. Radio telemetry is a crucial technique in wildlife ecology used to monitor animal movements and behaviours, helping to delineate their home ranges and habitat preferences. Bats, a highly diverse group of mammals, play vital roles in ecosystems through their foraging activities, such as seed dispersal, pollination, and pest control. This study employed radio telemetry to investigate the foraging behaviours, movement ranges, and roosting flexibility of the Greater Short-nosed Fruit Bat (Cynopterus sphinx) species.

In this research, a total of 15 bats were outfitted with compact, hand-wired, two-stage transmitter radio devices. The group included two harem males, nine harem females, and four non-harem males. To track these radio-tagged bats, three groups used TRX-1000S receivers paired with collapsible 5-element Yagi antennas. The findings revealed distinct patterns in emergence times and foraging behaviours. Female bats were the first to leave their roosts, with departure times ranging from 18:15 to 19:18 hours. Harem males, on the other hand, were the last to emerge, following the quicker departure of non-harem males. On average, harem males foraged within a distance of 2.4 km (±0.3 km), while non-harem males travelled further distances. Both male and female bats visited multiple feeding sites each night. Females travelled an average distance of 4.5 km (±0.9 km). The time spent at these foraging sites varied among individual bats. The study observation highlights the dynamic nature of roosting and social behaviour among Cynopterus sphinx, particularly females, who exhibit more fluidity in roosting preferences and social associations than males.

A notable difference was observed in roost fidelity; males exhibited higher roost fidelity than females, who frequently moved between harems and roost sites. The study highlighted gender-specific differences in emergence times and foraging behaviours. Understanding these patterns is essential for conservation and habitat management efforts, as it underscores the need to support bats in their roles as providers of crucial ecosystem services. Further, the immediate outcome of this study is tent construction, tent defence, and harem formation were strictly male-biased behaviours, and females contributed to parental care entirely. The evolution of sex-biased social behaviours has contributed to considerable variation in sex-biased dispersal patterns, foraging patterns, and spatial movement patterns.