ASPECTS OF THE ECOPHYSIOLOGY AND DIETARY STRATEGY OF THE GREATER BILBY MACROTIS LAGOTIS: A REVIEW

Since European settlement, the distribution of the greater bilby (Macrotis lagotis), an omnivorous peramelid marsupial, has contracted into the driest and least fertile parts of its former range. A review of the dietary, metabolic and digestive strategies used by M. lagotis provides the basis for an explanation of its ability to persist in the arid regions where it is now restricted. M. lagotis utilises an opportunistic feeding strategy, selecting dietary items in accordance with their abundance. Termites, ants and seeds, that form a concentrated food source, are prevalent in their diet. In captivity, M. lagotis exhibits a flexible digestive strategy that enables them to use diets of varying nutritional value. However, the absence of a colonic separation mechanism in the hindgut suggests that they are limited to relatively low-fibre diets, and this is reflected in their diet in the field. The low water and maintenance nitrogen requirements of M. lagotis are consistent with arid habitation, but the field metabolic rate is higher than expected for an arid-zone mammal, which suggests that water rather than energy conservation is a priority for this species