The Diets of Sminthopsis Murina and Antechinus Stuartii (Marsupialia: Dasyuridae) in Sympatry.

Abstract

In its diet, S. murina is similar to other small dasyurids that have been studied, being qualitatively opportunistic in that it feeds on a wide range of the arthropod prey available to it. Quantitatively, however, S, murina ingests significantly more Scarabaeidae, Blattodea, Coleoptera, Lepidoptera and larvae, and fewer Formicidae, Orthoptera and Isopoda than are available in pitfall traps during spring-summer, and so cannot be considered opportunistic in this sense. In autumn-winter it also takes significantly more Araneida and fewer Diptera, while Lepidoptera, Orthoptera and larvae are consumed only in the proportions in which they occur. A. stuartii consumes significantly more Coleoptera, Araneida and larvae than expected during the spring-summer season. In autumn-winter, it consumes significantly more Blattodea, Orthoptera and Arthropoda as well, but significantly fewer Formicidae and Diptera. Quantitatively, the two species differ significantly in the distribution of prey items for the spring-summer diet, and also differ in the individual diet categories of Scarabaeidae and larva during winter and for Arthropoda as well, in the total diet. The diet overlap is high (0.94) and there are significant rank correlation coefficients for diet categories, indicating no difference in the order of prey items in a qualitative sense. When the diets are analysed on the basis of habitat-season groups for each 'species' (including pitfall traps), neither habitat nor season is significant, but some of the samples are quite small. The 'species' effect is significant but largely reflects a difference between the diet items available (in pitfall traps) and those actually eaten by these two dasyurids. S. murina utilizes a wider range of prey than A. stuurtii and has a greater niche breadth; however, neither species could be called a diet specialist except in the broad sense ofinsectivores. Diet does not seem to be a significant component of the strong, microhabitat-based, ecological separation of these species.