The Relationship Between Prey Size and Handling Time and Prey Size and Capture Success in 3 Sympatric Species of Dasyurid Marsupials

Abstract

Regressions of handling time on prey weight were determined for the dasyurids Srninthopsis hirtipes, S. ooldea and Ningaui spp. preying on grasshoppers and cockroaches in the laboratory. In all cases, a simple linear regression fitted the relationships better than logarithmic models. The slopes of the regression lines were steeper for grasshopper prey than for cockroach prey in all species, and for each prey type the slopes for the predators were ranked in order of predator weight. Capture efficiency, defined as the proportion of successful attacks, did not vary significantly between predator species and prey types, and all predators showed declining capture efficiencies with increasing prey size. Niche separation in these dasyurids does not appear to be based on different optimal prey sizes for each species.