Plant Tannins and Essential Oils Have an Additive Deterrent Effect on Diet Choice by Kangaroos

Tannins and essential oils are well recognised as antiherbivore compounds. We investigated the relative effectiveness of the polyphenol, tannin, and the essential oils, 1,8-cineole and pine oil, as feeding deterrents against western grey kangaroos. Both groups of secondary metabolites are naturally abundant in many Australian plants. These three metabolite groups were incorporated separately or together into standard pellets for presentation to kangaroos, and their behaviour (sequence of food choice and feeding time) and amounts consumed were observed. The control (with no secondary metabolites) was much preferred. There was a sharp reduction in the ingestion of pellets containing tannins, 1,8-cineole or pine oil. Combinations of the metabolites resulted in almost no consumption. In association with tannin, pellets containing either 1,8-cineole or pine oil were as effective deterrents as both combined. There was a strong correlation between time spent feeding on the different diets and the amount of food consumed, although the rate of intake was markedly slower when secondary metabolites were present. Behavioural observations showed that the amount of food ingested is initially guided by the presence/absence of essential oils, apparently detected by smell, and later by the presence/absence of tannins, by taste. Both groups of secondary metabolites work in concert by stimulating different senses that minimise herbivory by marsupials, such as the western grey kangaroo, and help to explain their abundance in the Australian flora.

Genetic Structure and Gene Flow in Eastern Grey Kangaroos in an Isolated Conservation Reserve

Dispersal is a key process for population persistence, particularly in fragmented landscapes. Connectivity between habitat fragments can be easily estimated by quantifying gene flow among subpopulations. However, the focus in ecological research has been on endangered species, typically excluding species that are not of current conservation concern. Consequently, our current understanding of the behaviour and persistence of many species is incomplete. A case in point is the eastern grey kangaroo (Macropus giganteus), an Australian herbivore that is subjected to considerable harvesting and population control efforts. In this study, we used non-invasive genetic sampling of eastern grey kangaroos within and outside of the Mourachan Conservation Property to assess functional connectivity. In total, we genotyped 232 samples collected from 17 locations at 20 microsatellite loci. The clustering algorithm indicated the presence of two clusters, with some overlap between the groups within and outside of the reserve. This genetic assessment should be repeated in 10–15 years to observe changes in population structure and gene flow over time, monitoring the potential impact of the planned exclusion fencing around the reserve.

Torquenema n. g., Wallabicola n. g., and Macropostrongyloides phascolomys n. sp.: New Genera and a New Species of Nematode (Strongylida: Phascolostrongylinae) Parasitic in Australian Macropodid and Vombatid Marsupials

The strongyloid nematodes belonging to the subfamily Phascolostrongylinae occur primarily in the large intestines of macropodid and vombatid marsupials. Current molecular evidence suggests that the two nematode species, Macropostrongyloides dissimilis and Paramacropostrongylus toraliformis, from macropodid marsupials are distant from their respective congeners. Furthermore, specimens of Macropostrongyloides lasiorhini from the large intestines of the southern hairy-nosed wombat (Lasiorhinus latifrons) and the common wombat (Vombatus ursinus) are genetically distinct. This study aimed to describe the new genera Torquenema n. g. (with T. toraliforme n. comb. as the type species) from the eastern grey kangaroo, Wallabicola n. g. (with W. dissimilis n. comb. as the type species) from the swamp wallaby and a new species Macropostrongyloides phascolomys n. sp. from the common wombat, using light and scanning electron microscopy.

Phylogenetic Relationships within the Nematode Subfamily Phascolostrongylinae (Nematoda: Strongyloidea) from Australian Macropodid and Vombatid Marsupials

The strongyloid nematode subfamily Phascolostrongylinae comprises parasites of the large intestine and stomach of Australian macropods and wombats. In this study, we tested the phylogenetic relationships among the genera of the Phascolostrongylinae using the first and second internal transcribed spacers of the nuclear ribosomal DNA. Monophyly was encountered in the tribe Phascolostrongylinea comprising two genera, Phascolostrongylus and Oesophagostomoides, found exclusively in the large intestine of wombats. The tribe Hypodontinea, represented by the genera Hypodontus and Macropicola from the ileum and large intestine of macropods, was also found to be monophyletic. The tribe Macropostrongyloidinea, comprising the genera Macropostrongyloides and Paramacropostrongylus, was paraphyletic with the species occurring in the stomach grouping separately from those found in the large intestines of their hosts. However, Macropostrongyloidesdissimilis from the stomach of the swamp wallaby and Paramacropostrongylus toraliformis from the large intestine of the eastern grey kangaroo were distinct from their respective congeners. This study provided strong support for the generic composition of the tribe Phascolostrongylinea. The unexpected finding of M. dissimilis and P. toraliformis being distantly related to their respective congeners suggests a requirement for future taxonomic revision that may warrant separation of these species at the generic level.