SEASONAL-CHANGES IN THE REPRODUCTIVE ANATOMY OF MALE ANTECHINUS-STUARTII (MARSUPIALIA, DASYURIDAE)

Male Antechinus stuartii (Marsupialia: Dasyuridae) undergo significant endocrinological changes during their life history. The endocrine cha nges are associated with complete male mortality. The accessory reprod uctive tract of males is important for seminal plasma production, and changes associated with the reproductive cycle were not described in d etail by earlier studies. The present study sought to describe some of the seasonal changes in structure of the male accessory reproductive tract in relation to the known hormonal changes. The epididymis, prost ate, and bulbourethral glands are relatively undifferentiated in Febru ary and May, a time when plasma concentrations of testosterone are kno wn to be low. By July, considerable hypertrophy and differentiation of the accessory reproductive tract are observed. This is most obvious i n the bulbourethral glands, which change from being indistinguishable from one another in February and May to being three large morphologica lly and histologically distinct glands in July. The hypertrophy and se cretory activity continue into August, the breeding season. These find ings correlate with the hormonal profiles found in other studies of A. stuartii. (C) 1997 Wiley-Liss, Inc.