Synchronization of oestrus, ovulation and birth in female Antechinus stuartii (Marsupialia: Dasyuridae).

Abstract

Reproduction and development were studied during six annual breeding seasons in 80 female Antechinus stuartii in laboratory colonies and in 34 females which were pregnant when trapped. Oestrus, ovulation and births were each highly synchronized within any one population from a specific locality in Victoria. Before ovulation, epithelial cells were present in the urine of the females for a mean of 20.0 clays ± 4.0 (S.D.) (N=72). Matings occurred in this period. In the colonies of animals from Kinglake, the first females came into oestrus over a 4-clay period in mid-July of 1976, 1982 and 1983. In laboratory colonies, ovulations in each year occurred over a 9 to 22-day period in the first half of August for Kinglake and Cement Creek and at later dates in August and September for animals from higher altitudes. In these colonies, half the animals or more ovulated within one week. Births were also synchronized. A similar pattern was found for field animals. Synchronization of breeding and the rate of development in A. stuartii were related to events in the life history.