Ecological Studies of a Population of Antechinus bellus (Marsupialia : Dasyuridae) in Troprical Northern Australia

Abstract

A population of the fawn antechinus, Antechinus bellus, was monitored in tropical open-forest of the Northern Territory between June 1980 and January 1983. Sixty males and 66 females were captured and marked over 9525 trap-nights. The species exhibits the typical Antechinus life-history strategy, characterized by a highly synchronized mating period after which all males die. This field evidence supports earlier speculation based on laboratory studies and limited museum collections. Mating occurs over 2 weeks in late August and parturitions about a month later. Young remain attached to the nipples for 4-5 weeks and are suckled in the nest until weaned in early January. Reproduction patterns, population dynamics and changes in relative abundance resemble those in A. stuartii from south-eastern Australia. The life-history strategy of A. bellus contrasts with that of the regionally sympatric Parantechinus bilarni, in which fecundity is lower and males may survive to breed a second time. The strategy exemplified by A. bellus does not seem optimal for the wet-dry tropics, given the erratic nature of rainfall in the early wet season, which may influence the relative abundance of the insect food resource available for lactating females and newly weaned juveniles. However the existence of patches of structurally diverse open-forest may moderate environmental fluctuations and enhance resource availability, and thus be of critical importance for the survival of local populations.