Bridled Nailtail Research Articles

Home ranges and movement schedules of sympatric bridled nailtail and black-striped wallabies

Home ranges and movement schedules of sympatric bridled nailtail wallabies, Onychogalea fraenata, and black-striped wallabies, Macropus dorsalis, were studied during wet and dry seasons by radio-tracking. Home ranges of black-striped wallabies (91 ha) were much larger than those of bridled nailtail wallabies (40 ha). Home-range size differed between sexes for bridled nailtail wallabies (males, 59 ha; females, 26 ha), but not for black-striped wallabies. Intraspecific seasonal differences in home-range size were not significant. All home ranges included diurnal shelter habitat, although the preferred type of shelter habitat was different for each species. Movement schedules differed significantly between wet and dry seasons for black-striped wallabies (which made a higher frequency of longer-distance movements during the dry season than during the wet season), but not for bridled nailtail wallabies.

Role of Catalase in H2O2-induced oxidant stress in marsupial erythrocytes

We have examined the catalase activity and H2O2-induced oxidant stress on methaemoglobin formation and haemolysis in eight species of marsupials: the black striped wallaby (Macropus dorsalis), bridled nailtail wallaby (Onychogalea fraenata), proserpine rock wallaby (Petrogale persephone), red legged pademelon (Thylogale stigmatica), spectacled hare wallaby (Lagorchestes conspicillatus), whiptail wallaby (Macropus parryi), common brushtail possum (Trichosurus vulpecula), and the koala (Phascolarctos cinereus). The results indicate a significant relationship between the activity of catalase and methaemoglobin formation by H2O2.

Comparative erythrocyte metabolism in marsupials and monotremes

Concentrations of ATP and DPG, activities of 10 enzymes and the glycolytic rates were measured in the erythrocytes of 11 species of marsupials and two species of monotremes. Mean DPG concentrations were greater in the erythrocytes of marsupials than those of eutherian mammals. The opposite is true of ATP. Significant findings from the results of enzyme activities were: high activity of hexokinase (7.39 ± 0.82 EU/g Hb) in the short-beaked echidna, pyruvate kinase (37.49 ± 1.0 EU/g) Hb in bridled nailtail wallaby and glucose-6-phosphate dehydrogenase (G6PD; 41.66 ± 1.24 EU/g Hb) in black-striped wallaby. About 6- to 7-fold difference in the activity of G6PD levels between the two species of wombats was confirmed. Glucose phosphate isomerase activity was also shown to be twice as high in the red cells of the common wombat compared with those of the southern hairy nosed wombat. There were wide variations in the glycolytic rate among the species examined.

Modelling the impact of predation on reintroductions of bridled nailtail wallabies.

Predation by introduced foxes and cats is generally thought to be the main reason for the poor success rate of macropod reintroductions on the Australian mainland. Predator-prey theory suggests that predation may have particularly severe impacts on very small populations, especially if a more common primary prey species is present (such as the rabbit). Thus, a sufficiently large reintroduction may overcome predation and succeed where a smaller one would fail. The minimum viable population would, however, be much larger than that predicted by standard population-viability analysis. We use a simple stochastic model based upon the bridled nailtail wallaby to explore this possibility. Even very small amounts of predation (2-4 individuals per six months) can be sufficient to cause reintroductions of up to 50 animals to fail. No clear threshold population size beyond which reintroductions will succeed is evident and, for a given mean, the probability distribution of predation has a very limited impact on the success of reintroductions. In almost all circumstances, a single reintroduction of a given size is preferable to multiple reintroductions of the same total number of individuals.

The diet of the Bridled nailtail wallaby (Onychogalea fraenata). I Site and seasonal influences and dietry overlap with the black striped wallaby (Macropus dorsalis) and domestic Cattle

The bridled nailtail wallaby (Onychogalea fraenata) is one of Australia's rarest marsupials, persisting only in a small area in central Queensland. Its diet and those of two sympatric herbivores, the blackstriped wallaby (Macropus dorsalis) and domestic cattle (Bos taurus/indicus), were assessed by identifying plant fragments in their faeces. The diet of 0 . fraenata was diverse, consisting of herbaceous plants, grasses and browse. In good seasons the intake was biased towards forbs and other herbaceous plants. Browse was only important when vegetation availability was low. Grass could be a major part of the diet when forbs were scarse. Black-striped wallabies and cattle were largely grass eaters. When conditions were dry, browse contributed up to 16% of the diet of M. dorsalis and 10% of the diet of cattle. Dietary overlap with 0. fraenata was greatest at such times, being above 50% for both species. Potential for dietary competition was apparent and it is suggested that this may have been a factor in the decline of 0 . fraenata with the advancement of European settlement and spread of domestic stock.

The diet of the Bridled nailtail wallaby (Onychogalea fraenata). II Overlap in dietry niche breadth and plant preferences with the black-striped wallaby (Macropus dorsalis) and domestic cattle

Patterns of dietary selection were examined in the rare bridled nailtail wallaby (Onychogalea fraenata) and compared with those of the black-striped wallaby (Macropus dorsalis) and cattle on the Taunton Scientific Reserve in central Queensland. These two species were considered as possible competitors of 0, fraenata. The dietary niche breadth, the similarity of diet to resources, of 0. fraenata was always narrower than those of the larger species. However, the niche breadths of all species broadened significantly during the driest seasonal conditions, which accounts for the increased dietary overlaps previously reported in these conditions. An analysis of dietary preferences (electivities) showed that 0. fraenata had a high preference for herbaceous plants (forbs and malvaceous species), whereas M. dorsalis and cattle had high preference for grass. During dry conditions the preferred diet of 0. fraenata was considerably different to its actual diet, indicating that the diet was suboptimal. This pattern was not as pronounced in the other herbivores, suggesting that 0. fraenata could be at a competitive disadvantage during these conditions in its last refuge.

The Marsupial Blastocyst - a Study of the Blastocysts in the Hill Collection

Blastocysts in the Hill Collection from Trichosurus vulpecula, Pefrogale penicillata, Macropus ruficollis (= M. rufogriseus), Macropus parma, Onychogalea fraenata, Bettongia gaimardi, Perameles obesula (=lsoodon obesulus), Perameles nasuta, Dasyurus viverrinus, Didelphis aurita (=D. marsupialis) and Didelphis virginiana were examined. They ranged from incomplete unilaminar blastocysts to late bilaminar blastocysts. The mode of formation of the unilaminar blastocyst appeared to be influenced by the presence or absence of the yolk mass. A unilaminar blastocyst lined by uniform protoderm cells occurred in a wide variety of marsupials. Differentiation of the unilaminar blastocyst into embryonic and extra-embryonic areas occurred at different stages of development. In macropodids and Didelphis it was found in small blastocysts soon after blastocyst completion. In dasyurids, Perameles and some other groups it was found in larger blastocysts, at least four cell generations after blastocyst completion. The first histological signs of differentiation of the unilaminar blastocyst into embryonic and extra-embryonic areas varied between different marsupials. In Didelphis, enlarged endoderm mother cells developed from the protoderm cells of one hemisphere. The protoderm cells of this hemisphere later differentiated as embryonic ectoderm and the endoderm mother cells gave rise to the primary endoderm. In D. viverrinus, bandicoots and T. vulpecula, the protoderm cells of one hemisphere differentiated simultaneously into cuboidal embryonic ectoderm and endoderm mother cells. In P. penicillata, M. ruficollis and M. parma the protoderm cells of one hemisphere proliferated to form a multilayered embryonic area which later differentiated into embryonic ectoderm and primary endoderm.