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Pinworm nematodes of the genus Syphacia (Nemata : Oxyurida : Oxyuridae) have a global distribution, and infect the caecum of rodents. Within the Australian Bioregion, 17 species of Syphacia infect a range of rodent hosts. Pinworms are traditionally thought to have coevolutionary relationships with their hosts, but the evolution and dispersal of Australian rodents and their helminths remains unclear. This combination of factors allowed us to investigate the likely relationships of Australian Syphacia species based on phylogenetic analysis, overlaid with the ecology and relationships of host species. We conducted a phylogenetic analysis using morphological characters of the species of Syphacia from the Australian Bioregion in order to examine the relationships between species, and to investigate how host evolution and phylogeny could inform (or be informed) by parasite phylogeny. Application of the taxon pulse theory of parasite speciation by matching host species to parasites shed some light on the timing of speciation of rodent hosts. We found that species of Syphacia had reasonably close host–parasite relationships, with additional evidence for ecological fitting or host switching occurring. Evidence provided here suggests strongly that most elements of the Stockholm Paradigm are at play in structuring the relationships we observe in this pinworm–mammal system.
Many theories attempt to explain patterns of community organisation among large herbivores. We explored the role of body size, diet type and residence time on habitat use in a community comprising four metatherians (western grey kangaroo, Macropus fuliginosus; eastern grey kangaroo, M. giganteus; red-necked wallaby, Notamacropus rufogriseus; swamp wallaby, Wallabia bicolor) and two eutherians (red deer, Cervus elaphus; European rabbit, Oryctolagus cuniculus) in south-eastern Australia. We used camera traps to estimate habitat occupancy, quantified habitat specialisation using relative entropy, and ran regressions using percentage grass consumed, log(mass) and log(time at site) as predictor variables and relative entropy as the response. If body size influenced habitat use, we predicted smaller species would occupy fewer habitats. If diet type influenced habitat use, we predicted intermediate feeders would use more habitats. If the time that a species had been present at a site predicted community organisation, newer species would use more habitats. None of these theories explained habitat use in our community. Red deer used a narrower range of habitats than expected, perhaps due to the poor suitability of habitats available in the Grampians. While interactions between our hypotheses are likely to be important, the body size model deserves further attention in this community.
Blood-sucking fly larvae are widespread parasites of nestling birds, but in many systems we lack knowledge of their basic biology. This study reports the first observation of an endemic Tasmanian fly species, Passeromyia longicornis (Diptera : Muscidae), parasitising the forty-spotted pardalote (Pardalotus quadragintus), another Tasmanian endemic. Because the forty-spotted pardalote is an endangered and declining songbird, P. longicornis is a species of interest to conservation biologists. Its larval form is an obligate, subcutaneous parasite of nestling birds, but before this study, there were just two published records of the species infesting avian hosts, and little known about its ecology or life cycle. This study documented hosts, prevalence, and larval life history of P. longicornis by locating and monitoring nests and ectoparasites of the forest bird community in south-eastern Tasmania. I also reared P. longicornis larvae in captivity to determine the length of the pupal stage in relationship to ambient temperature. Hosts of P. longicornis included forty-spotted pardalotes (87% prevalence across nests), striated pardalotes (Pardalotus striatus) (88% prevalence), and New Holland honeyeaters (Phylidonyris novaehollandiae) (11% prevalence). Both pardalote species were new host records. P. longicornis larvae burrowed under the skin of nestlings where they developed for 4–7 days, feeding on nestling blood. When fully grown, larvae dropped into the surrounding nest material and formed pupae. Length of the pupal stage was 14–21 days, and declined with increasing ambient temperature. Median parasite abundance was 15 larvae in infested forty-spotted pardalote nests and 11 larvae in infested striated pardalote nests. Nestling mortality was frequently associated with ectoparasite presence. This study provides the first survey of P. longicornis hosts, prevalence and life cycle, and shows that this species is likely a major player in the ecology of pardalotes, and possibly other forest bird species in Tasmania.
The Indian peafowl (Pavo cristatus) is a declared alien pest species on Kangaroo Island, South Australia, where it is implicated in a range of social problems and potential ecological impacts. To inform the management of feral peafowl, we aimed to (1) provide an estimate of peafowl distribution and abundance; (2) measure peafowl home ranges; (3) calculate the area of suitable peafowl habitat; and (4) estimate how the population could change under various culling scenarios. Using expert and landholder surveys, we estimated that ∼380 individuals (range 330–428) were distributed among 21 separate groups on Kangaroo Island. Habitat suitability modelling identified native vegetation near agriculture as the preferred peafowl habitat and indicated that substantial unoccupied suitable habitat is available. The mean home range of eight peafowl was 52 ha and one dispersal event of 4.5 km demonstrated that unoccupied suitable habitat could feasibly be colonised. Demographic models indicated that, if unmanaged, the peafowl population could exceed 2000 individuals after 10 years, but that culling ∼85 individuals annually could maintain the current population size. We therefore suggest that control of the Kangaroo Island peafowl population is warranted while the current distribution of peafowl is well understood.
Elusor macrurus is an endangered short-necked turtle restricted to the Mary River catchment in south-eastern Queensland. Shotgun sequencing of genomic DNA was used to generate a complete mitochondrial genome sequence for E. macrurus using the Illumina MiSeq platform. The mitogenome is 16 499 base pairs (bp) long with 37 genes arranged in the typical vertebrate order and a relatively short 918-bp control region, which does not feature extensive tandem repeats as observed in some turtles. Primers were designed to amplify a 1270-bp region that includes 81% of the typically hypervariable control region. Two haplotypes were detected in a sample of 22 wild-caught individuals from eight sites across its natural range. The Mary River turtle is a species with low mtDNA nucleotide variability relative to other Chelidae. The combination of a very restricted distribution and dramatic reduction in population size due to exploitation for the pet trade are the conditions likely to have led to very low mtDNA variability in this endangered species.
Introduced plant pathogens can devastate susceptible plant communities, and consequently impact on animal communities reliant on plants for food and habitat. Specifically, plant pathogens change the floristic diversity of vegetation communities, thereby reducing availability of food sources for fauna (e.g. pollen and nectar) and result in major changes to habitat structure when canopy and understorey plant species succumb to disease. Phytophthora cinnamomi poses a threat to flowering plant species (e.g. Banksia species) which are important food sources for nectarivorous fauna. The honey possum (Tarsipes rostratus) is the only obligate nectarivorous non-flying mammal living on a restrictive diet of nectar and pollen; consequently, these tiny mammals are likely to be particularly vulnerable to the landscape-wide devastation caused by P. cinnamomi. We investigated habitat selection by honey possums in a vegetation community infested with P. cinnamomi to determine how these mammals respond to habitat affected by this pathogen. Over four seasons, 18 honey possums were fitted with radio-transmitters and tracked to identify habitat preferences. Vegetation surveys were compared for locations selected by honey possums (as determined from tracking) and randomly selected sites. Radio-tracking revealed that sites selected by honey possums were significantly taller, denser, and more floristically diverse than their paired random locations. The presence of P. cinnamomi influences habitat use by honey possums, but animals show resilience in terms of using the best of what is available in both P. cinnamomi–affected and unaffected locations. Habitat patches comprising less susceptible species, or plants that have yet to succumb to infection, provide refuge and food resources for honey possums. Management to reduce the spread of existing P. cinnamomi infestations and prevent contamination of new locations will benefit vegetation communities and associated faunal communities, while identifying honey possum food plant species that are resilient to the pathogen may support revegetation attempts.
Gould’s wattled bat (Chalinolobus gouldii) is one of only three native Australian mammals with an Australia-wide distribution. However, currently no data are available on the thermal physiology of free-ranging C. gouldii. Therefore, we aimed to quantify the effect of roost choice on daily skin temperature fluctuations during winter in C. gouldii living in an agricultural landscape in a temperate region. Ambient conditions consisted of long periods below 0°C and snow. Some individuals roosted high in dead branches whereas one individual roosted in a large cavity located low in a live tree. Torpor was employed on every day of the study period by all bats, with bouts lasting for over five days. The skin temperature of individuals in the dead branches tracked ambient temperature, with skin temperatures below 3°C on 67% of bat-days (lowest recorded –0.2°C). In contrast, the individual in the tree cavity maintained a larger skin-ambient temperature differential, likely influenced by the internal cavity temperature. Our study presents the lowest skin temperature recorded for a free-ranging Australian microbat and reveals that roost choice affects the thermal physiology of C. gouldii, ensuring survival during periods of cold weather and limited food supply.
Lophoproctid and synxenid millipede species observed in this study showed clear differences in their sexual reproduction, including sperm web structure, egg morphology and development compared with species from Polyxenidae. Male Lophoturus queenslandicus (Lophoproctidae) produce a single spermatophore on a sperm web without signal threads due to their lack of silk-producing coxal glands. Females of this species lay fewer eggs and differ in their egg cluster arrangement, which includes nest trichomes for protection. Lophoproctid chorion has a thin protective membrane and the pupoid has fused papillae covering the entire anterior region and an aperture bordered by protective papillate sensilla is present at the apex of the pupoid. Lophoproctid millipedes have a comparatively short intermoult period between stadia. In contrast, male Phryssonotus novaehollandiae (Synxenidae) produce two spermatophores separated by a large gap on their sperm web, with signal threads that are less obvious. Synxenid chorion and pupoid stages were unique; the chorion was tough and thick and the pupoid had anterior projections without an aperture bordered by sensilla, unlike those observed in lophoproctid and polyxenid millipedes. This study extends knowledge of the reproduction of species from three major millipede families from the Suborder Polyxenida (Penicillata: Diplopoda). Additionally, the results indicate that the reproductive strategies of Australian lophoproctid and synxenid species are adapted to their harsh environment.
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