The effects of moonlight on microhabitat use by Antechinus agilis (Marsupialia : Dasyuridae)

Abstract

This study investigates the effect of lunar illumination on microhabitat use of Antechinus agilis, an insectivorous, semi-arboreal species of dasyurid marsupial. The study was conducted in tall open forest near Melbourne, Australia, from April to August 1997. Microhabitat was investigated by use of live trapping and fluorescent pigment tracking. The influence of light on spatial and temporal activity was investigated by comparing microhabitat use in the field at two extremes of moonlight intensity, full and new moon, and by manipulating light intensity in the field. Antechinus agilis were trapped in and tracked through dense microhabitats in a greater proportion than was available, although this pattern was evident only in the vegetation stratum below one metre from the ground. Furthermore, animals did not respond to the microhabitat at the point of capture, but responded to a larger microhabitat scale radiating 10 m from the trap. However, light intensity appears to have little influence on the spatial or temporal activity of A. agilis at this site. Therefore A. agilis appear not to differentially use denser microhabitats in relation to light intensity. Habitat complexity, prey availability, interspecific competition and predation are discussed as possible reasons why A. agilis differentially use denser microhabitats.