Daily and Seasonal Variation in Non-Acoustic Communicative Behaviors of Male Greater Short-Nosed Fruit Bats (Cynopterus sphinx)

This is the authors' abstract. We don't add key points for this paper.

Monthly observations were made at a natural roosting site of Cynopterus sphinx, with a view to the behavior of males being observed over a period of one year. Here, we report seasonal, daily and inter-individual variation in three communicative behaviors engaged in by male bats. The frequency of male behaviors identified as scent-marking, vigorous wing-flapping and the making of an openwing gesture were found to vary seasonally, depending on the reproductive status of conspecific females in the study colony. The duration of scent-marking was markedly high during mating seasons, in comparison with wing-flapping and wing-gesturing. In mating seasons, the pattern to the daily variation in behavior correlated strongly with the gender of the responder present in the diurnal roost and/or colony. For instance, scent-marking and vigorous wing-flapping were more frequent during late-evening and early-morning hours, mostly when females were absent from the day roost, while male-male encounters were possible. In contrast, wing-gesturing was more frequent during morning and early-evening hours, when females were present in the day roost. The results from our study suggest that male scent-marking and wing-flapping are directed towards competitor males in the colony, with a view to resource-defense behavior being manifested. Furthermore, male wing-gesturing is predicted to be directed towards co-roosting females, with the aim in this case being for some form of social information to be communicated, particularly during the mating season. However, marginal inter-individual variation in the frequency of occurrence of behaviors between seasons was apparent, suggesting that these communicative behaviors could be tied to male-male competition in this species.