Arthropod Energy and Nutrient Analysis

The lesser hairy­footed dunnart (<i>Sminthopsis youngsoni, Dasyuridae</i>) is a generalist marsupial insectivore in arid Australia, but consumes wolf spiders (<i>Lycosa spp., Lycosidae</i>) disproportionately often relative to their availability. Here, we tested whether lycosids have relatively high energy or nutrient contents compared to other invertebrates, and hence whether these aspects of food quality can explain selective predation of lycosids by <i>S.youngsoni</i>. Energy, lipid and protein composition of representatives of 10 arthropod families that are eaten by <i>S. youngsoni</i> in the Simpson Desert were ascertained using microbomb calorimetry, chloroform-methanol extraction and Dumas combustion. Differences between invertebrate groups were assessed using separate analyses of variance (ANOVAs) and appropriate post-hoc tests. These analyses were performed using this data.