Reproduction of the dusky fruit bat Penthetor lucasi (Pteropodidae) in Brunei, Borneo

Abstract

The dusky fruit bat Penthetor lucasi is a small and poorly known species (Megachiroptera, Pteropodidae) inhabiting Southeast Asia. I studied its reproduction in Brunei, northern Borneo, where individuals were usually captured in rainforest. The climate of the study area is characterized by uniformly high temperatures and rainfall, but with two seasons of greater rainfall (April to July and October to December) and two of lesser rainfall. Based upon my data, I estimate the following regarding reproduction of P. lucasi. In general, reproduction of P. lucasi is characterized by a synchronized birth season around the month of October. Birth is followed by a postpartum estrus and mating; 2-4 months of lactation; a prolonged period of delayed embryonic development; and then relatively rapid embryonic development from July to September, with the subsequent birth likewise around October. In sum, the reproductive cycle is consistent with a pattern of seasonal monestry. The synchronized birth season of P. lucasi does not correspond to the season of abundant flowering/fruiting (April to June) at the study site; rather, the species was relatively absent during this time. Thus, reproduction of P. lucasi appears linked to the flowering/fruiting and availability of specific plant species. This conforms to the concept of a sequential food specialist in which a species uses only a small and select fraction of the plants that are flowering/fruiting at any period of time. Females become sexually mature when weighing approximately 33.0-34.0 g in body mass with forearms approximately 5.7-6.2 cm in length. Males attain sexual maturity at approximately 27.0-30.0 g body mass with forearms approximately 5.4-5.8 cm in length. Seasonal testis recrudescence was not observed.

Breeding and age-structure seasonality in Carollia brevicauda and other frugivorous bats (Phyllostomidae) in cloud forests in the Venezuelan Andes

“…Arguments against an endogenous component. Frugivorous and insectivorous phyllostomids, and frugivorous pteropids, are known to have a postpartum oestrus (e. g. Ramakrishna 1947;Fleming 1971;Laska 1990;Kofron 1997Kofron , 2007aDechmann et al 2005), and delayed development of the fetus (e. g. Bradshaw 1962;Fleming 1971;Burns and Easley 1977;Heideman 1989b;Kofron 1997Kofron , 2007aBadwaik and Rasweiler 2001;Meenakumari and Krishna 2005). Accordingly, a possible and most general explanation for the regulation of the annual breeding cycles of frugivorous phyllostomids (and pteropids) would involve a complete absence of an endogenous component (and therefore no need of an entraining time cue), with reproductively mature females being pregnant all year round.…”

Seasonal variation in the reproductive tract of the Indian flying fox, Pteropus giganteus (Brünnich, 1782)

“…The gestation period varies from four to six months. Polyovulation does not occur in flying foxes and birth of young usually takes place from February to April in northern latitudes (Nowak, 1999;Kretschmann & Hayes, 2004;Kofron, 2007;Fox & Gemma, 2008). The lactation period may extend from seven weeks to four months.…”