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.

Body Size‐Prey Relationships in Insectivorous Marsupials: Tests of Three Hypotheses

“…Fisher and C. R. Dickman, personal observations). Dasyurids are generally opportunistic predators that take prey in proportion to their availability; diet may follow seasonal changes in prey availability (Statham 1982, Fox and Archer 1984, Dickman 1986b, Green 1989.…”

“…Past studies have obtained close correlations between the sizes of invertebrates caught in pitfalls and those found in the diets of Antechinus stuartii and A. flavipes (Dickman 1 986b, Green 1989). In addition, it is unlikely that prey along trails were depleted by foraging and not renewed before sampling; almost all potential prey of dasyurids on or above ground or on tree surfaces are highly mobile (Hall 1980, Fox and Archer 1984, Dickman 1986a, b, 1988a, Read 1987, Fisher and Dickman 1993, while dasyurids move quickly through foraging areas.…”

“…and the Tasmanian devil Sarcophilus harrisii due to the partly carnivorous habits of these species (Green 1967, Blackhall 1980. Small dasyurids are particularly suitable study animals because mobile, ground-dwelling invertebrates comprise the bulk of the diet (Hall 1980, Fox and Archer 1984, Dickman 1986a, b, Read 1987, their foraging behavior is easy to observe, and their prey are particulate and readily measured.…”

Ecology and Conservation of a New Carnivorous Marsupial Species: the Silver-Headed Antechinus (Antechinus argentus)

“…Antechinus, and more broadly many dasyurids (e.g., Fox and Archer, 1984, Read, 1987, Fisher and Dickman, 1993. Although it was sometimes possible to identify prey items at lower taxonomic levels (such as the genus Laxta within Blattodea, the suborders Heteroptera and Auchennoryncha within Hemiptera, and eight ant genera: see Table 2.2), in general the degree of fragmentation of prey in faecal matter meant that identification only to order was possible, which is typical of diet studies in small dasyurids (e.g., Lunney et al, 2001, Burwell et al, 2005.…”

“…are known to primarily consume vertebrate prey (Jones and Barmuta, 1998), smaller species including Antechinus (e.g., A. agilis, A. minimus, A. stuartii, and A. swainsonii) feed on a variety of predominantly invertebrate prey (see Allison et al, 2006, Fox and Archer, 1984, Green, 1989, Hall, 1980, Lunney et al, 2001, Statham, 1982. These Antechinus species are regarded as dietary generalists, in that they consume prey opportunistically, differing from specialists that seek out a specific type of food (see Fisher and Dickman, 1993, Lunney et al, 2001, Read, 1987.…”