Thylogale Thetis Research Articles

Inhibition of Ageratina riparia (Asteraceae) by native Australian flora and fauna

We investigated the influence of native flora and fauna on the establishment and persistence of the exotic weed Ageratina riparia (Asteraceae) in disturbed and regenerating rainforests on the Springbrook plateau of south-eastern Queensland. The height and ground cover of A. riparia was positively associated with light availability beneath the rainforest canopy and negatively associated with forest leaf litter biomass. Regenerating rainforest with the associated increases in litter and decrease in light availability could therefore inhibit the establishment and density of A. riparia. The red-necked pademelon, Thylogale thetis, browsed extensively on A. riparia, but the pattern of browsing was not associated with light availability, forest leaf litter biomass or density of A. riparia. Browsing and incidental damage by T. thetis breaks up the broad stands of A. riparia. The physical damage caused by T. thetis, and the inhibition to establishment and density of A. riparia by native plant species, combine to reduce the environmental threat associated with A. riparia.

Selective herbivory by red‐necked pademelon Thylogale thetis at rainforest margins: factors affecting predation rates

AbstractWe examined browsing by red‐necked pademelons (Thylogale thetis) on shoots of rainforest plants at areas of rainforest–grassland interface in the Lamington Plateau of southeast Queensland. Terminal shoots from nine species (three each of vines, trees and shrubs) were compared. The effects of five factors (plant species, site, distance from forest edge, habitat (grassland or forest) and time (trip) at two levels of exposure (caged or uncaged)) were also compared. Among the uncaged shoots, 98% showed signs of damage compared with 18% of the caged shoots. In general, shoot predation was higher in the grassland than in the forest and decreased with increasing distance away from the forest edge in both habitats. The three vine species were more heavily browsed than all other species. Browsing by red‐necked pademelons is likely to influence regeneration near forest edges through direct death of seedlings as a result of predation and through altered competitive interactions resulting from selective herbivory. This effect, however, would be lower on seedlings within the forest habitat and would also reduce as seedlings establish themselves further from the forest edge into grassland habitat.

Mate Choice in Female Red‐necked Pademelons, Thylogale thetis (Marsupialia: Macropodoidea)

AbstractChanges in the behaviour of captive female red‐necked pademelons, Thylogale thetis, before, during and after oestrus were observed relative to the location of potential male mates. A penned female was presented with four adjacent, individually caged males representing the size classes large, medium, small and subadult. The female's behaviour was videotaped for 8–9 d spanning oestrous (3 d), post‐oestrous (3 d) and normal (3 d) sessions of time. Changes in the activity, orientation and location of six penned females, relative to the caged males, were transcribed from videotape. A model of female pademelon behaviour pattern was developed. Results suggest that the females spent a significantly greater amount of time directly in front of the largest available male, relative to the other three smaller males during the oestrous period only, and that a significant proportion of this time was spent involved in active behaviours (grooming and locomotion, compared with inactive behaviours of sitting and scan/sniffing). Although there was a significant preference for females to orientate their bodies away from the location of the males, they faced the males significantly more during oestrus than any other session. Furthermore, the females faced the large male significantly more frequently than any other male. This study provides evidence for mate choice by female red‐necked pademelons.

Corollonema thylogale n. g., n. sp. (Nematoda: Strongyloidea), parasitic in the pademelons Thylogale thetis and T. stigmatica (Marsupialia: Macropodidae) from Queensland, Australia

Corollonema thylogale n. g., n. sp. is described from the stomachs of Thylogale thetis and T. stigmatica from south-eastern Queensland. The new genus is characterised by four branches to the dorsal ray, a J-shaped ovejector, a cylindrical buccal capsule reduced to a posterior, thickened annulus and a leaf-crown of eight elements originating from the base of the buccal capsule. On the basis of these features, the new genus is placed in the subfamily Cloacininae Stossich, 1899 and the tribe Coronostrongylinea Beveridge, 1986. The presence of an internal leaf crown is unique within the tribe and the new genus is erected on this basis.

A Comparative-Study of Macroscopic and Microscopic Dimensions of the Intestine in 5 Macropods (Marsupialia, Macropodidae) .2. Relationship With Feeding-Habits and Fiber Content of the Diet

A comparative study of macroscopic and microscopic dimensions of the intestines in five macropod species indicated that the grazing macropods (the red kangaroo, Macropus rufus, and the eastern grey kangaroo, Macropus giganteus) had significantly longer caeca and large intestines than those of the browsing macropods (the swamp wallaby, Wallabia bicolor, and the red-necked pademelon, Thylogale thetis). This trend was not observed in the small intestine. The arid-adapted M. rufus also had a significantly longer large intestine than M. giganteus, which may be a water-conservation feature. Intestinal villi were tall in T. thetis, which consumed a less fibrous diet, whereas the agile wallaby, Macropus agilis, on a highly fibrous diet, had short villi; other macropods, on diets of medium fibre content, had villi of intermediate height. Thus, the size of the hindgut (i.e. caecum and large intestine) may provide an index of the specific feeding habit of a species (browsing or grazing), whilst parameters of the villi of the small intestine may reflect the quality of the animals' current diet.

A comparative study of macroscopic and microscopic dimensions of the intensine in five macropods (Marsupialia: Macropodidae). I. Allometric relationships.

Macroscopic and microscopic dimensions of the intestines in five macropod species (the red kangaroo, Macropus rufus; the eastern grey kangaroo, M. giganteus; the agile wallaby, M. agilis; the swamp wallaby, Wallabia bicolor; and the red-necked pademelon, Thylogale thetis) were investigated allometrically in relation to body mass. In general, the length of the small intestine changed in an area : volume (A:V) compensating manner, but the circumference showed negative allometry such that the overall change in surface areas, both ground and mucosal (including the contribution of villi), were isometric but also included the coefficient derived from 'Kleiber's Law' (0.75) in their 95 and 99% confidence limits, respectively. Villous height and width generally showed no significant correlations with body size, but villous density was lower in large individuals. The allometry coefficient for the length of the large intestine was generally near the A:V compensating value (0.5) in most intraspecific analyses but much higher in the interspecific analysis, suggesting that some factor other than body size might be important (possibly dietary fibre). Caecal length was significantly correlated with body size only in two largest species (M. rufus and M. giganteus) and the interspecific analysis gave a value near A:V compensation).

1H NMR spectroscopic survey of plasma and erythrocytes from selected marsupials and domestic animals of Australia

1. 1. 1H NMR spectra were acquired from whole plasma, intact erythrocytes, and ultrafiltrates of erythrocytes from nine native and eight introduced (domestic) Australian animals; single-pulse, spin-echo and 2-dimensional spectra were obtained. The aim was to detect and at least semi-quantify metabolites in the samples and compare the profiles amongst the species. 2. 2. The Australian natives that were studied were all marsupials: greater brown bandicoot; bettong; eastern grey kangaroo; red kangaroo; koala; possum; red necked pademelon; Tammar wallaby; and wombat. The introduced mammals that were studied were: cat; cattle; dog; goat; horse; pig; rabbit; and sheep. 3. 3. Because of the range of habitats and diets amongst the animals, it was postulated that the concentrations of the common metabolites in the blood would show marked differences and that there would also be some metabolites that were peculiar to a given animal. There were several major differences in the spectra: in the spectra of plasma, the glycoprotein and lipoprotein resonances showed the largest inter-species variation, whereas the most dramatic finding from the spectra of erythrocytes was a very high concentration of lysine in the cells from the Tammar wallaby.

Microbial Activity in the Forestomach of Free-Living Macropodid Marsupials - Comparisons With Laboratory Studies

Parameters of fermentative digestion were measured in five species of macropodid marsupials shot while feeding in the wild. These included details of microbiota, fermentation products (volatile fatty acids, gas, ammonia) and forestomach digesta pH. Ciliate protozoa and fungi, similar to anaerobic rumen fungi, were present in the forestomach of all species except Thylogale thetis. The bacterial flora was complex and numbers were similar to those in the ruminant forestomach. The forestomach gas contained more methane than found previously in captive macropodids, and in Wallabia bicolor hydrogen was present at 10- 11% of total gas. The pH of forestomach digesta was 5.7-6.7, indicative of animals actively feeding. Comparisons of stomach fill, ammonia and volatile fatty acid (VFA) concentrations and molar proportions, and rates of VFA production in the forestomach and hindgut, indicated that conclusions on digestive function in macropodids derived from studies on captive animals are generally applicable to free-living macropodids. The main differences probably lie in greater levels of feed intake in the field, and in greater opportunity for free-living macropodids to select from a more heterogeneous diet.

Nitrogen-Metabolism in the Parma Wallaby, Macropus-Parma

The maintenance nitrogen requirement of the parma wallaby, Macropus parma, was found to be 566 mg per kg W*0.75 per day on a dietary basis, and 477 mg per kg W*0.75 per day on a truly digestible basis. This is similar to that of the red-necked pademelon, Thylogale thetis, another small wallaby which occupies a similar moist forest habitat, but much higher than (at least double) those of four other macropodid marsupials, all of which are from less mesic environments, that have been studied. Urea recycling decreased in response to water restriction in M. parma; in other published reports urea recycling did not change in T. thetis when water intake was restricted, but in three arid-adapted eutherian herbivores it increased. Voluntary intakes of dry matter and water by M. parma wefe also similar to those published for T. thetis, but higher than those of other macropodid species. These results support the hypothesis that within the Macropodidae nutrient requirements are linked closely with preferred habitat, regardless of phylogeny.

Studies on the Nutrition of Macropodine Marsupials. 5.microbial Fermentation in the Forestomach of Thylogale Thetis and Macropus Eugenii.

Rates of volatile fatty acid (VFA) and ammonia production at different sites along the forestomach of Thylogale thetis, the red-necked pademelon, and Macropus eugenii, the tammar wallaby, were estimated in vitro and in vivo. Estimates of the flow of microbial nitrogen from the stomach were also obtained in vivo. In both species VFA production was faster in vitro and in vivo in the sacciform forestomach than in the tubiform forestomach. The ratio of total VFA production to digestible organic matter (OM) intake was similar in the 2 species, and similar to published estimates for ruminants. Net production of ammonia in vivo was faster in the sacciform forestomach than in the tubiform forestomach of T. thetis but not of M. eugenii. The ratio of total net ammonia production to nitrogen intake was similar in the 2 species, and net synthesis of microbial protein per kilogram OM apparently fermented in the stomach of T. thetis and M. eugenii was similar to that in ruminants. The decrease in fermentation rate along the forestomach of both species was consistent with the previously reported pattern of apparent digestion of OM in the macropodine stomach. Although this pattern of microbial activity differs from that in ruminants, the overall fermentation is extensive. Thus the lower fibre digestibility often found in macropodines compared with sheep may be related to a faster rate of passage of particulate digesta through the macropodine forestomach, but it is not due to a less efficient microbial fermentation.

Studies on the Nutrition of Macropodine Marsupials. 3. The Flow of Digesta Through the Stomach and Intestine of Macropodines and Sheep.

3. The two markers 51chromium EDTA and 103ruthenium were used to examine and compare digesta flow in the eastern grey kangaroo (Macropus giganteus), the red-necked pademelon (Thylogale thetis), the tammar wallaby (M. eugenii), the eastern wallaroo (M. robustus robustus) and in sheep fed on chopped lucerne hay, and in T. thetis and M. eugenii fed on fresh grass (Phalaris aquatica). The markers were also used to define the kinetics of digesta flow in the intestine, and to estimate the flow of fluid and DM through defined regions of the stomach and intestines of T. thetis and M. eugenii fed on the lucerne diet. The pattern of digesta flow and the degree of differential flow of the 2 markers observed in the macropodines differed markedly from those in sheep and were attributed solely to the mode of transport through the elongated stomach. In the macropodines it was apparent that total mixing of forestomach contents did not occur; rather, digesta flowed slowly along the tubiform forestomach. The relationship of this mode of transport, defined as tubular flow, to stomach structure, and the possible effects on digestion in the forestomach, are discussed.

Studies on the Nutrition of Macropodine Marsupials. 4. Digestion in the Stomach and the Intestine of Macropus Giganteus, Thylogale Thetis and Macropus Eugenii.

4. Digestion in the stomach, small intestine and large intestine of the red-necked pademelon (Thylogale thetis), the tammar wallaby (Macropus eugenii) and the eastern grey kangaroo (M. giganteus) fed on chopped lucerne hay freely was estimated in a slaughter experiment by reference to chromic sesquioxide added to the diet. Concentrations of volatile fatty acids and ammonia, and pH, indicated that microbial activity in the forestomach and large intestine (caecum and proximal colon) was extensive. In all 3 species virtually all of the soluble carbohydrate, 17% of apparently digestible crude protein, 62 to 65% of apparently digestible organic matter and 82 to 85% of digestible acid-detergent fibre were digested in the forestomach. There was a progressive loss of dietary substrates along the length of the forestomach; readily fermentable carbohydrate was digested largely in the sacciform forestomach and cranial region of the tubiform forestomach, and the rate of apparent loss of organic matter decreased along the tubiform forestomach.

Studies on the Nutrition of Macropodine Marsupials. 1. Intake and Digestion of Lucerne Hay and Fresh Grass, Phalaris Aquatica.

Intake and digestion of chopped lucerne hay was studied in three macropodine species, eastern grey kangaroo Macropus giganteus. red-necked pademelon Thylogale thetis and tammar wallaby M. eugenii, and in sheep. The utilization of fresh Phalaris grass by the two wallaby species T. thetis and M. eugenii was also examined and compared. On the chopped lucerne hay diet, intake of organic matter (OM) was similar in sheep and M. giganteus, but sheep digested more (P<0.05) OM and thus consumed more (P<0.05) digestible energy (DE) than all three macropodine species. Among the macropodines. M. eugenii consumed the least (P<0.01) OM and DE but digested more (P<0.05) OM. However, acid detergent fibre (ADF) digestibility was similar in the three macropodine species and lower (P<0.05) than in sheep. On the fresh grass diet M. eugenii consumed less (P<0.05) OM and DE than T. thetis. ADF digestibility was similar in both species. Although ,M. eugenii consumed less nitrogen (N) than the other three species on the lucerne diet (P<0.01) and less N than T. thetis on the Phalaris diet (P<0.05), N balance was similar and positive in all species. Data from this and other published studies indicate that the maintenance requirements for energy and nitrogen of most macropodines are lower than for sheep, and appear to be lower in M, eugenii than in any other macropodine studied so far. It is also apparent that there are probably few real differences among the Macropodinae in efficiency of fibre digestion, at least on diets of adequate nitrogen and DE content.

Studies on the Nutrition of Macropodine Marsupials. 2. Urea and Water Metabolism in Thylogale Thetis and Macropus Eugenii; Two Wallabies From Divergent Habitats.

Urea and water metabolism were studied in the red-necked pademelon Thylogale thetis. and tammar wallaby Mucropus eugenii fed diets of chopped lucerne hay and fresh grass Phalaris aquatica ad libitum. On both diets T. thetis consumed more nitrogen (P<0.05), plasma urea levels were higher (P<0.05) and urea entry rate was greater (P<0.05) than in M. eugenii. Urea excretion rate was greater (P<0.05) in T. thetis than in M. eugenii on the lucerne diet, and urea degradation rate was greater (P<0.05) in T. thetis on the Phalaris diet. The proportion of urea synthesized that was recycled to and degraded in the digestive tract was similar (52-56%) in both species on both diets. T. thetis consumed more water (feed and drinking water) (P<0.05), and water turnover time was less (P<0.05) and turnover rate greater (P<0.05) than in M. eugenii, on both diets. At least on diets of adequate nitrogen and digestible energy content, it appears that differences in nitrogen metabolism between T. thetis and M. eugenii are not attributable to differences in gut microbial activity; rather, the results of this and other studies suggest that M. eugenii has a greater urine-concentrating ability and lower maintenance requirements than T. thetis.

Stomach Structure and Function in Three Species of Macropodine Marsupials.

The topographic anatomy and the histology of the stomach are described for three species of macropodines, Macropus eugenii, M. giganteus and Thylogale thetis. together with information on the movement of digesta through the stomach. The three regions of the macropodine stomach were defined as sacciform fore stomach, tubiform fore stomach, and hind stomach. In both species of Macropus the largest region was the tubiform fore stomach, but in T. thetis it was the sacciform fore stomach. The opening between sacciform and tubiform fore stomachs in all three species is wide, but the two gastric regions are delimited by a permanent ventral fold. The position of the cardia in relation to this fold differed among species, and together with the presence (M. eugenii). reduction (M. giganteus) or absence (T. thetis) of a gastric sulcus, could be correlated with the initial distribution and subsequent dispersion of barium sulphate in radiographic studies. The wall of the sacciform and tubiform fore stomachs is differentiated into taeniae and nonpermanent haustra and semilunar folds. From this and earlier studies it appears that these structures are mainly responsible for the separation within the macropodine stomach of particulate from liquid digesta.

Spatial and Temporal Use of Habitat by the Red-necked Pademelon, Thylogale thetis (Marsupialia : Macropodidae)

Use of habitat by 10 red-necked pademelons was studied by radio-tracking in an area of rain forest that adjoined pasture. They consistently moved at nightfall to pasture, where they grazed until their return to the rain forest shortly before daybreak. The time of movement between habitats was highly predictable and varied seasonally with changes in daylength. Nocturnal and diurnal range areas are described within the total area occupied by each individual. They rarely moved from the forest edge more than 70 m onto pasture or 500 m into rain forest. Animals were not nocturnal and travelled widely through the rain forest by day, seeking food and sites for basking. The nocturnal and diurnal partitioning of habitat is seen as a strategy for exploiting the rich food resource of pasture while maximizing the probability of avoiding predators.

A Review of the Globocephaloidinae Inglis (Nematoda: Amidostomatidae) From Macropodid Marsupials.

The subfamily Globocephaloidinae Inglis, 1968 (Nematoda : Amidostomatidae) is redescribed and redefined. Two genera are recognized, Globocephaloides Yorke & Maplestone, 1926, and Amphicephaloides, gen. nov. Hypodontus Monnig, 1929 is removed from the Globocephaloidinae. Globocephaloides macropodis Yorke & Maplestone, 1926, redescribed from specimens from the type host, Mmropus agilis, was also found in Macropus dorsalis, M. giganteus, Petrogale inornata, P. venutula and Thylogale thetis. Globocephaloides wallabiae Johnston & Mawson, 1939, G. affinis Johnston & Mawson, 1939, and G. thetidis Johnston & Mawson, 1939, are placed as synonyms of G. macropodis. Globocephaloides trijidospicularis Kung, 1948, is redescribed. This species was found in Macropus giganteus, M. fuliginosus, M. rufogriseus, M. parryi, M. eugenii and Wallabia bicolor. Life-cycle stages are described. Amphicephaloides thylogale, gen, et, sp. nov., which differs from Globocephaloides in having a subdivided buccal capsule, was found in Thylogale billardierii, T. stigmatica and T. thetis.

Nitrogen and electrolyte balance in the wallabies Thylogale thetis and Macropus eugenii when given saline drinking water

1. 1. Addition of sodium chloride to the drinking water of the red-necked pademelon, Thyloyale thetis. reduced feed intake, nitrogen balance and potassium balance, and increased water intake, water turnover and sodium balance. 2. 2. In the tammar wallaby, Macropus eugenii, water intake, water turnover and sodium balance also increased, but to a lesser extent; feed intake and nitrogen balance did not change. 3. 3. Thus the tammar, an arid zone species, appears better able to adapt to saline drinking water than the pademelon. a species found only in rain forest.

Maintenance nitrogen requirements of the macropod marsupials Thylogale thetis, red-necked pademelon, and Macropus eugenii, Tammar wallaby

The maintenance nitrogen (N) requirement of the tammar wallaby, Macropus eugenii, a specles adapted to semiarid habitats, was estimated to be 0.24 g per kg W*0.75 per day of dietary N, or 0.23 g per kg W*0.75 per day of truly digestible N. In contrast, the red-necked pademelon, Thylogale thetis, a wallaby restricted to subtropical rain forest, required 0.60 g per kg W*0.75 per day dietary N, or 0.53 g per kg W*0.75 per day of truly digestible N for mamtenance. Apparent digestibility of dry matter (DM) was lower (P < 0.001) by the pademelons (59%) than by the tammars (72%), and DM intake was higher (39 versus 25 g per kg W*0.75 per day) (P < 0.001). Intake of free water was also greater (P < 0.001) by the pademelons than by the tammars (169 versus 107 ml per 100 g DM intake). It is concluded that the red-necked pademelon is not as 'rummant-like' in its digestive physiology and metabolism as macropod species from more and environments.

Production of volatile fatty acids in two species of wallaby and in sheep

1. 1. The production of volatile fatty acids (VFA) was estimated in vitro in the stomach and hind gut of two species of wallaby ( Thylogale thetis and Macropus rufogriseus) and of sheep ( Ovis aries) fed chopped lucerne hay. 2. 2. VFA production (kcal/day) was greater in the stomach of M. rufogriseus (42% of digestible energy (DE) intake) than in the sheep (29%) ( P < 0.05) and in T. thetis (21%) ( P < 0.01). 3. 3. In the hind gut, VFA production was greater in the sheep (6.9% of DE intake) than in the wallabies (mean 1.6%) ( P < 0.001). 4. 4. The difference in total VFA production between M. rufogriseus (43% of DE intake) and T. thetis (22%) is probably related to the nutritional environment of their preferred habitats, and to their feeding behaviour.