Roosting patterns and fur color variation in adult male Asian parti-colored bat (Vespertilio sinensis)

Abstract

Female Asian parti-colored bat (Vespertilio sinensis) are known to form nursery colonies exclusively comprised of pregnant individuals from May to August; however, there exists fragmented information regarding male roosting behavior during this period. In this study, we investigated the roosting patterns and fur color variation in adult male Asian parti-colored bats using bat boxes. Six adult males utilized bat boxes a total of 14 times during the maternity period. Male bats were observed roosting either individually or in groups of up to three individuals, and notably, never alongside females. These findings indicate sexual roost segregation and suggest the presence of a fission-fusion social system among these bats. Furthermore, the fur color of adult males remained relatively stable from April to August, contrasting with the observable light brown (reddish-brown) coloration adopted by adult females during the maternity season, accompanied by shedding of back hair. Our findings suggest the potential for distinguishing between sexes based on fur color observation during the maternity period.