Parasites of the predator, Liasis fuscus, and its prey, Rattus colletti, on the Adelaide River floodplain, Northern Territory, Australia

A comprehensive survey of the parasites of the water python, Liasis fuscus, and the dusky rat, Rattus colletti, on the Adelaide River floodplain, Northern Territory, Australia, was undertaken. Sampling of sympatric hosts was also undertaken, however only six water rats, Hydromys chrysogaster, were collected. Influences of seasonal and host ecology on parasite community structure was then examined. The L. fuscus and R. colletti populations were sampled six times each, encompassing three wet seasons and three dry seasons. Endoparasites, ectoparasites, blood smears, faecal and tissue samples were collected. Ten species of endoparasite, namely the nematodes Dracunculus mulbus, Dioctowittus hughjonesi, Ophidascaris robertsi, Pseudabbreviata sp., Pseudostrongyluris polychrus, Eustrongylides acrochordus, the cestode Bothridium pithonis and Bothridium ornatum, diphyllobothriid spargana, and the pentastome Raillietiella sp. were collected from L. fuscus. Two ectoparasite species, Aponomma fimbriatum and Amblyomma limbatum were also collected. Faecal egg counts revealed cestode eggs but no protozoa were found in faecal or tissue samples. The intra-erythocytic protozoan Hepatozoon sp. was found in blood smears. Six species of endoparasite, namely the nematodes Nippostrongylus typicus, Mastophorus muris and Peramelistrongylus sp., the cestodes Hymenolepis diminuta and Raillietina celebensis and the trematode Echinoparyphium hydromyos were recorded from R. colletti. Four ectoparasite species, Haemaphysalis ratti, Peramelaelaps bandicoota, Hoplopleura sp. and fleas from the family Pulicidae were also found. No helminth eggs or protozoan oocysts were found in faecal samples, nor protozoa in tissue or blood samples. From the six water rats collected, three endoparasite species, Uncinaria hydromyidis, Hymenolepis australiensis and Echinoparyphium hydromyos, were recovered. The protozoan Klossiella sp. was found in kidney tubules. The parasite community within L. fuscus was found to be an isolationist community of endoparasites, characterised by low colonising ability, reproductive isolation, small population sizes and vacant niches, in combination with an 'insulating' effect from seasonal changes in community structure caused by the specialised diet of L. fuscus. In the parasite community of R. colletti, seasonal influences appear to be reducing the survival and maintenance of parasite populations producing a depauperate community, mainly caused by the annual habitat shift, unlike that found in other Australian species of Rattus species.</p

Dusky rat, Rattus colletti (Muridae), a new host for Echinoparyphium hydromyos (Trematoda: Digenea) in the Northern Territory, Australia

The digenean trematode Echinoparyphium hydromyos was recorded from the dusky rat, Rattus colletti, and the water rat, Hydromys chrysogaster, from the Adelaide River floodplain, Northern Territory, Australia. The dusky rat represents a new host for E. hydromyos and the Adelaide River floodplain is a new locality. This echinostome has previously been reported only from the water rat in southern and eastern Australia

The endoparasites of Liasis fuscus (Serpentes : Boidae) from the Adelaide River floodplain, Northern Territory, Australia

This study documents the parasite assemblage of Liasis fuscus Peters, 1873 from the Adelaide River flood plain, Northern Territory, Australia. In total, nine species of helminth (comprising three cestodes and six nematodes), onepentastome and one protozoan were found in 180 water pythons, with the Nematoda being the dominant and most diverse group, and a cestode, Bothridium omatum Maplestone & Southwell, 1923, the most prevalent species. In spite of the hosts being present in high numbers the helminth assemblage was depauperate, characterised by low prevalence, intensity, frequency and abundance of species, with neither season nor sex of host affecting abundance. There were, however, significant differences between ages of hosts, juveniles having fewer parasites, and seasonal diversity, with the wet season of 2004 and the dry of 2005 the most similar. Of the Australian python species analysed Morelia spilota (Lacepede, 1804) had the highest species richness. The lower species richness found in L. fuscus was possibly due to its unusual biology. Biogeographic relationships of the parasite fauna of L. fuscus are diverse, connections wi1h Africa, Asia, and South America being noted

The effects of early and late-season fires on mortality, dispersal, physiology and breeding of red-backed fairy-wrens ( Malurus melanocephalus )

Context. Mismanaged fire is one of the main processes threatening biodiversity in northern Australian savannas. While the suite of species adversely affected by fire has been quite well documented, empirical studies that seek to identify the ecological mechanisms that underpin these declines are rare. This dearth of mechanistic knowledge is hindering the refinement and development of conservation management practices and policy, such as early dry-season prescribed burning programmes. Aims. Our aim was to describe why red-backed fairy-wrens (RBWs; Malurus melanocephalus) decline after fire, as shown by previous studies. Methods. We examined the effects of early and late dry-season fire (and an unburnt control) on the mortality, dispersal, physiology and breeding of colour-marked RBWs. We also tested whether the early fire area became an important refuge after the late fire. Key results. Neither fire treatment caused a detectable increase in mortality. Individuals relocated short distances to unburnt habitat following both fires. Some individuals used the early fire area after the late fire, but only if they were already living nearby and most also relied on adjacent unburnt habitat. Blood-parasite infection and pectoral-muscle attrition were unaffected by the treatments. The early fire caused loss of body mass at a time when the control population gained mass after breeding, whereas the late fire had no effect on mass. Blood haemoglobin concentrations in birds affected by the late fire deviated from the levels observed in the control population, presumably because of disruption of behaviours associated with the onset of the breeding season. Mayfield estimations of daily egg-survival probability showed no difference among the treatments, whereas the daily probability of nestling survival was significantly lower in the late fire area. Pairs affected by the late fire also had a shorter breeding season and none attempted multiple broods after earlier successes. Conclusions. Our results suggest that the reproductive output of RBWs is low following late dry-season fire, and that this is the main mechanism that explains their decline. Implications. This study provides support for the value of using early dry-season prescribed burning to limit the effects of late dry-season wildfire. However, there are important caveats to this, such as the retention of near-by unburnt habitat, and the consideration of variable regeneration rates for different vegetation types

The endoparasites of Liasis fuscus (Serpentes : Boidae) from the Adelaide River floodplain, Northern Territory, Australia

This study documents the parasite assemblage of Liasis fuscus Peters, 1873 from the Adelaide River flood plain, Northern Territory, Australia. In total, nine species of helminth (comprising three cestodes and six nematodes), onepentastome and one protozoan were found in 180 water pythons, with the Nematoda being the dominant and most diverse group, and a cestode, Bothridium omatum Maplestone & Southwell, 1923, the most prevalent species. In spite of the hosts being present in high numbers the helminth assemblage was depauperate, characterised by low prevalence, intensity, frequency and abundance of species, with neither season nor sex of host affecting abundance. There were, however, significant differences between ages of hosts, juveniles having fewer parasites, and seasonal diversity, with the wet season of 2004 and the dry of 2005 the most similar. Of the Australian python species analysed Morelia spilota (Lacepede, 1804) had the highest species richness. The lower species richness found in L. fuscus was possibly due to its unusual biology. Biogeographic relationships of the parasite fauna of L. fuscus are diverse, connections wi1h Africa, Asia, and South America being noted

Dusky rat, Rattus colletti (Muridae), a new host for Echinoparyphium hydromyos (Trematoda: Digenea) in the Northern Territory, Australia

The digenean trematode Echinoparyphium hydromyos was recorded from the dusky rat, Rattus colletti, and the water rat, Hydromys chrysogaster, from the Adelaide River floodplain, Northern Territory, Australia. The dusky rat represents a new host for E. hydromyos and the Adelaide River floodplain is a new locality. This echinostome has previously been reported only from the water rat in southern and eastern Australia

Dioctowittus hughjonesi sp. n. (Nematoda: Cystoopsidae) from Liasis fuscus (Peters, 1873) (Serpentes: Boidae) from the Northern Territory and Morelia amethistina (Schneider, 1802) from Queensland, Australia

Dioctowittus hughjonesi sp n. (Nematoda: Cystoopsidae) is described from the peritoneal cavity of Liasis fuscus (Peters, 1873) from the Adelaide River floodplain, Northern Territory and from Morelia amethistina (Schneider, 1801) from Cape York Peninsula, Queensland. Dioctowittus hughjonesi is distinguished from others members of the genus by the presence of lateral lobes at both anterior and posterior ends, size of worms, size of eggs and presence of paired ventral papillae in males. The genus Dioctowittus is found only in tropical regions with high seasonal rainfall. A possible link in the life cycle between aquatic intermediate hosts and the presence of polar filaments in the egg remains problematic, requiring further study

The effects of early and late-season fires on mortality, dispersal, physiology and breeding of red-backed fairy-wrens (Malurus melanocephalus)

Context. Mismanaged fire is one of the main processes threatening biodiversity in northern Australian savannas. While the suite of species adversely affected by fire has been quite well documented, empirical studies that seek to identify the ecological mechanisms that underpin these declines are rare. This dearth of mechanistic knowledge is hindering the refinement and development of conservation management practices and policy, such as early dry-season prescribed burning programmes. Aims. Our aim was to describe why red-backed fairy-wrens (RBWs; Malurus melanocephalus) decline after fire, as shown by previous studies. Methods. We examined the effects of early and late dry-season fire (and an unburnt control) on the mortality, dispersal, physiology and breeding of colour-marked RBWs. We also tested whether the early fire area became an important refuge after the late fire. Key results. Neither fire treatment caused a detectable increase in mortality. Individuals relocated short distances to unburnt habitat following both fires. Some individuals used the early fire area after the late fire, but only if they were already living nearby and most also relied on adjacent unburnt habitat. Blood-parasite infection and pectoral-muscle attrition were unaffected by the treatments. The early fire caused loss of body mass at a time when the control population gained mass after breeding, whereas the late fire had no effect on mass. Blood haemoglobin concentrations in birds affected by the late fire deviated from the levels observed in the control population, presumably because of disruption of behaviours associated with the onset of the breeding season. Mayfield estimations of daily egg-survival probability showed no difference among the treatments, whereas the daily probability of nestling survival was significantly lower in the late fire area. Pairs affected by the late fire also had a shorter breeding season and none attempted multiple broods after earlier successes. Conclusions. Our results suggest that the reproductive output of RBWs is low following late dry-season fire, and that this is the main mechanism that explains their decline. Implications. This study provides support for the value of using early dry-season prescribed burning to limit the effects of late dry-season wildfire. However, there are important caveats to this, such as the retention of near-by unburnt habitat, and the consideration of variable regeneration rates for different vegetation types