Reproduction in the Angolan free-tailed bat Tadarida condylura in the Eastern Transvaal

Abstract

The reproductive patterns of the male and female Angolan free-tailed bat, T. condylura, were investigated at two localities in the Eastern Transvaal. Reproductive tracts were examined histologically. Female T. condylura were seasonal bimodally polyoestrus breeders with the breeding season extending from early spring (September) to late autumn (May). Parturition of the first offspring in early December was followed by a post-partum oestrus with females becoming pregnant within two weeks after first parturitions. Gestation and lactation periods were approximately 85 and 50 days, respectively. Ovarian follicle and endometrium development closely followed the breeding season, both displaying a bimodal pattern. The reproductive tract displayed dextral dominance typical of molossids. Prior to implantation, both uterine cornu were characterised by a decidual reaction. Implantation of the bilaminar blastocyst was mesometrial with the embryonic disc oriented antimesometrially. At the site of first attachment, a pre-placental pad of trophoblast cells was formed. Development of the placenta occurred in the abembryonic hemisphere. Male T. condylura displayed a bimodally seasonal breeding pattern extending from early June to February which closely parallelled the female reproductive pattern. Spermatogenic and accessory gland activities were synchronised. The testes never regressed to prepubertal conditions, but maintained baseline spermatogenic activity during reproductive quiescence. Reproductive recrudescence began during June and maximum testes and epididymides size coincided with the onset of copulation and conception in females. Leydig cell morphology and nucleus diameter closely parallelled spermatogenic activity. The germinal epithelium displayed an eleven stage spermatogenic cycle.