Estimations of Species Richness in The Complex Communities of Nematode Parasites Found in The Stomachs of Kangaroos and Wallabies (Family Macropodidae)

Abstract

Kangaroos and wallabies harbour a diverse array of strongyloid nematodes in their sacculated forestomachs. Determining the number of nematode species present in complex communities such as these can be technically difficult due to the large size of the host organ, the large numbers of nematodes and the large number of closely related nematode species. This problem was investigated using species accumulation methods in 16 eastern grey kangaroos (Macropus giganteus), 15 red-necked wallabies (Macropus rufogriseus) and 6 swamp wallabies (Wallabia bicolor). Nematodes from a subsample of known size were identified individually to species and the number of nematodes which needed to be examined before all of the species in the subsample were found was determined. In M. giganteus (mean worm burden 20,500), between 27 and 92 (mean 57) nematodes had to be examined before all (13) species were recovered. In M. rufogriseus (mean worm burden 60,600), an examination of between 16 and 178 (mean 57) nematodes recovered all (8) species while in W. bicolor (mean worm burden 16,300), 16–196 (mean 67) nematodes needed to be examined to recover all (15) species present. It was concluded that examination of samples of 200 nematodes from each animal would have been sufficient to identify all parasite species present.