Lek promiscuity in a semelparous mammal, Antechinus stuartii (Marsupialia: Dasyuridae)?

Abstract

All male Antechinus stuartii die following a brief rut towards the end of their first year of life. Outside the rutting period, both males and females forage in clearly-defined invidual home ranges, but neither sex is territorial. As temperatures drop during the winter, both sexes may leave their foraging range each day to spend the latter part of the night and most of the daylight hours in communal nests which may be used by fifteen animals simultaneously, and over forty individuals during one winter. These temporary movements away from the foraging range cause an increase in the daily home range revealed by radiotelemetry. When the mating season commences, males abandon their foraging range and aggregate in a few of the communal nest trees, where they spend most of the night. There is some movement between aggregations, but the movement appears to be rapid and direct. Females continue to use their foraging area, and nest solitarily. However, they make excursions to the male aggregations, and spend time in the nests with the males. By the third week of the mating season, immediately prior to male mortality, males move frequently from one aggregation to another, but are still confined to the aggregations and direct movements between those nests. By this time some females have ceased visiting the aggregations and nest solitarily within their foraging range. These data suggest that the mating system of A. stuartii is lek promiscuity, and support the hypothesis that the abrupt mortality of males is a cost of endocrine changes which facilitate gluconeogenic mobilisation of body protein, allowing the males to sustain their vigil at the leks. Show more