Egyptian fruit bats do not preferentially roost with their relatives

Roosts provide bats with place for daytime sheltering, protection from weather and predators, mating, and social interaction. Movements between multiple roosts are often necessary, either due to limited roost life, changes in roost conditions or demands at different times of the year. Information transfer is an important contributor to day-roosting behaviour and typically exhibits non-random social assortment dynamics. Some individuals appear to explore and share roost discoveries more often than others, though it remains unclear whether associations are stronger between close relatives than less related individuals. In the present study, network analysis, in combination with genetic and spatial data, was used to explore the roosting behaviour of Egyptian fruit bats (Rousettus aegyptiacus) within an isolated deme. Our results showed that the roosts had distinct core-periphery structure. The core of the winter roost network was represented by only two roosts, while in spring, the season of food scarcity, the core was represented by multiple roosts, suggesting their potential role as centres, where information about roosts and foraging sites is exchanged. We found no relationship between relatedness and roost sharing over two seasons. These results provide strong support that Egyptian fruit bats do not roost preferentially with relatives, in contrast to many animal populations where individuals preferentially associate with kin.