Reproductive biology of the long-eared kultarr Antechinomys auritus (Marsupialia: Dasyuridae): field and laboratory observations of the male

The breeding season of Antechinomys from Mileura Station, Western Australia, extends from August to February, which is 6 weeks later than for individuals that have originated from south-western Queensland. Field and laboratory observations indicated that males from Mileura Station are capable of breeding for extended periods during the breeding season and for more than one consecutive season. Males do not reach sexual maturity until the season following that in which they are born. Spermatorrhoea can commence in June, but not all males are producing spermatorrhoea until August. Scrotal width progressively increases in size with the approach of the winter solstice, reaching a peak in August, after which it undergoes a slow decline. The size of the accessory glands (epididymis, prostate and Cowper’s glands) also greatly increases in size during this period. The disparity in the timing of breeding of Antechinomys in different geographical locations is further explored and is probably due to a complex interaction of different environmental factors, including photoperiod, specific to each region.