Some aspects of female reproduction in the Grey-headed Flying-fox, Pteropus poliocephalus (Megachiroptera: Pteropodidae).

Abstract

Antral follicles are found in both ovaries of non-breeding females throughout the year, but not in pregnant bats after May, or in post-partum females until January. Follicle sizes increase in the breeding season, but plasma oestradiol concentrations do not change; significant increases occur only in the later stages of pregnancy. During early gestation corpora lutea appear secretory but plasma progesterone concentrations are low. Later in pregnancy progesterone concentrations rise although the CL appears to regress. The placenta is presumably responsible for the high hormone levels observed at this time. Possible factors regulating female receptivity and breeding season are discussed.