The reproductive cycle of male tomb bats, Taphozous hildegardeae (Chiroptera: Emballonuridae), in a seasonal environment of the African tropics

Two cave populations of Hildegarde’s tomb bat had a reproductive cycle that corresponded closely to the rainfall-induced seasonality of coastal Kenya (4°S). Males had pronounced bimodal cycles of body weight due to the deposition of fat during periods of relative food abundance in both rainy seasons, and fat depletion during competitive mating and the dry seasons, when numbers of moths were lowest. The main period of sexual regeneration coincided with the increase in body weight experienced during the ’long rains’ (April-June) and led to mating. A secondary peak in the weights of male sexual glands, associated with the increase in body weight that occurred in the ’short rains’ (October-December), did not result in reproduction. It is suggested that this latter period of sexual activity was related to the maintenance of year-round harems, and may represent the male response to a vestigial, bimodally polyoestrous, reproductive cycle.