Seasonal changes in the testis, accessory glands and ejaculate characteristics of the southern hairy‐nosed wombat, Lasiorhinus latifrons (Marsupialia: Vombatidae)

Abstract

AbstractMost mammals exhibit seasonal variation in the reproductive capacity of one or both sexes. While the female southern hairy‐nosed wombat Lasiorhinus latifrons is a known seasonal breeder, the extent of seasonality in the male has not been documented. To examine this, gross body measurements including scrotal diameter and the dimensions of the accessory gland bulge were recorded and male reproductive tracts were examined between 1993 and 2000. Testes, epididymides and accessory glands from all males were dissected free of connective tissue and weighed. In addition, matched semen samples were collected over four time points in 2000 corresponding to the breeding season (September), immediately post‐breeding season (November), during the non‐breeding season (January), and immediately before the onset of the next breeding season (June) as determined from female reproductive status. Semen was collected by electro‐ejaculation and analysed for volume, sperm number and motility characteristics. Ejaculate volume, total ejaculate sperm number, percentage motile sperm, and the sperm motility rating and index were all significantly elevated in September and significantly lower in November and January. This correlated with a significant increase in body weight, peri‐cloacal gland width, and the weights of the prostate, Cowper's glands, urethral bulb and crus penis. The data confirm that male reproduction in the southern hairy‐nosed wombat, like that of the female, is highly seasonal with a peak in reproductive capacity occurring in August–September and a reduction by November.