Diet of the eastern chestnut mouse (Pseudomys gracilicaudatus). I Composition, diversity and individual variation.

Abstract

Little is known about the biology and ecology of the eastern chestnut mouse (Pseudomys gracilicaudatus), let alone the details of its diet. In this paper, we examined the dietary composition, diversity and variation among individuals of this species in a coastal heathland of New South Wales, by means of microscopic examination of its faecal pellets. From 200 faecal samples, P. gracilicaudatus was found to consume considerable amounts of fungi (20% overall) and insects (over 10% on average). Seed was the most abundant food in its diet from August to February, accounting for 39%, with stem contributing 28% of the diet. Stem was dominant at other times, accounting for 34%, with seed contributing 24%. Although cohort-dependent foraging strategies have been reported in many small mammals, age-dependent foraging only occurred in autumn; sex-dependent foraging was not observed in P. gracilicaudatus. Analysis of dietary diversity (H') and among-individual variation (CVp,) showed that there were significant variations in the diet of P. gracilicaudatus in different seasons and successional stages. Negative association between H' and CVp, for seasons and vegetation succession suggested that individuals of P. gracilicaudatus consumed a range of food items, producing maximum dietary diversity. These results indicate that P. gracilicaudatus is a generalist herbivore, opportunistic in foraging and less specialised in food selection than any other Pseudomys species reported so far.