Haylee J. Weaver

Contrasting diversity dynamics of phoretic mites and beetles associated with vertebrate carrion

Carrion is an ephemeral and nutrient-rich resource that attracts a diverse array of arthropods as it decomposes. Carrion-associated mites often disperse between animal carcasses using phoresy, the transport of one species by another. Yet few studies have contrasted the dynamics of mite assemblages with other insect taxa present at carrion. We examined and compared the changes in abundance, species richness and composition of mite and beetle assemblages sampled at kangaroo carcasses in a grassy eucalypt woodland at four different times over a 6-month period. We found that the majority of mites were phoretic, with the mesostigmatid genera Uroseius (Uropodidae), Macrocheles (Macrochelidae) and Parasitus (Parasitidae) the most abundant taxa (excluding astigmatid mites). Abundance and richness patterns of mites and beetles were very different, with mites reaching peak abundance and richness at weeks 6 and 12, and beetles at weeks 1 and 6. Both mites and beetles showed clear successional patterns via changes in species presence and relative abundance. Our study shows that mesostigmatid mite assemblages have a delay in peak abundance and richness relative to beetle assemblages. This suggests that differences in dispersal and reproductive traits of arthropods may contribute to the contrasting diversity dynamics of carrion arthropod communities, and further highlights the role of carrion as a driver of diversity and heterogeneity in ecosystems.

Two Species of Acanthocephala (Rhadinorhynchidae and Transvenidae) from Elasmobranchs from Australia

ABSTRACT: Acanthocephalan parasites, Serrasentis sagittifer, from a shark, Carcharhinus sorrah, and a species of Pararhadinorhynchus from a ray, Himantura granulata, are reported from Queensland, Australia. The collection of acanthocephalans from cartilaginous fish (elasmobranchs) as either occasional or definitive hosts is unusual, but not unknown. In this instance, the finding of S. sagittifer is considered an occasional infection. The life cycle of Pararhadinorhynchus sp., 1 of 4 species known only from elasmobranch hosts, is equivocal, as putative bony fish hosts are unknown. Of the other 3 species, only Megapriapus ungriai has an elasmobranch acknowledged as the definitive host.

An annotated checklist of Acanthocephala from Australian fish

Thirty one genera, comprising 58 named species, 15 undetermined species and nine species known only as cystacanths from paratenic fish hosts were found infesting 144 marine, esturine and freshwater species of fish from Australian and Australian Antarctic waters. Host habitats are given and the distribution and records of the acanthocephalans are given. A key to these parasites at the generic level is provided.

Three new species of the sucking louse genus Hoplopleura (Phthiraptera: Anoplura: Hoplopleuridae) from rodents (Mammalia: Rodentia: Muridae) in northern Australia

Three new species of the rodent louse genus Hoplopleura (Anoplura: Hoplopleuridae) are described and illustrated from Australia: H. melomydis new species from Melomys burtoni (Muridae: Hydromyini, grassland melomys) and M. capensis (Muridae: Hydromyini, Cape York melomys) from Queensland; H. notomydis new species and H. setosa new species from Notomys alexis (Muridae: Hydromyini, spinifex hopping mouse) from the Northern Territory. These new louse species are the first lice recorded from each of the three host rodent species.

Mosquito (Diptera: Culicidae) and Rainfall Associations with Arbovirus Disease in Eastern Victoria

Abstract Associations between mosquito abundance and Ross River virus (RRV) and Barmah Forest virus (BFV) disease are demonstrated for the Gippsland Lakes region of eastern Victoria, Australia. Significant correlations were obtained between RRV and BFV disease notifications and mosquito counts after lag times ranging from 2–4 months for the dominant mosquito species Aedes camptorhynchus, and 0–3 months for the less abundant mosquitoes Anopheles annulipes, Culex australicus and Culex globocoxitus. Correlations between RRV and BFV disease notifications and rainfall were significant after lag times of 3–4 months. Monthly abundance of Ae. camptorhynchus was significantly higher during above-average years of RRV notifications, with higher mosquito abundance during November to January. Together, these results clarify some important timelines between rainfall, mosquito abundance and increased arbovirus activity in eastern Victoria.

Effects of a mulch layer on the assemblage and abundance of mesostigmatan mites and other arthropods in the soil of a sugarcane agro-ecosystem in Australia

Sugarcane farmers can utilise a soil conservation technique called green cane trash blanketing, a form of mulching that can increase plant productivity through a number of channels, e.g., via altering soil physical, chemical and biological characteristics, and influence soil arthropod assemblages. Predatory mites (Mesostigmata) are important components of soil communities because they can control populations of other soil-dwelling pest species. Our aim was to characterise mulch-influenced predatory Mesostigmata community assemblages in sugarcane soils in Queensland, Australia. We found that application of a mulch layer significantly increased the abundance of Mesostigmata, and oribatid mites and collembolans, in soils. Furthermore, we observed that the assemblages of Mesostigmata in soil covered by mulch were significantly different to those in bare soil; and the assemblages of Mesostigmata changed over time. The assemblages of Mesostigmata, but not Oribatida or collembolans, were significantly different in soil under mulch depending on whether the mulch was freshly laid, or decomposing. Our results show that the use of mulch, specifically the green cane trash blanket, can increase overall microarthropod abundance including Mesostigmata. This is likely due to increased habitat complexity and changing resource availability.

Transcriptome sequencing of the long-nosed bandicoot (Perameles nasuta) reveals conservation and innovation of immune genes in the marsupial order Peramelemorphia

Bandicoots are omnivorous marsupials of the order Peramelemorphia. Conservation concerns and their unique biological characteristics suggest peramelomorphs are worthy research subjects, but knowledge of their genetics and immunology has lagged behind that of other high-profile marsupials. Here, we characterise the transcriptome of the long-nose bandicoot (Perameles nasuta), the first high-throughput data set from any peramelomorph. We investigate the immune gene repertoire of the bandicoot, with a focus on key immune gene families, and compare to previously characterised marsupial and mammalian species. We find that the immune gene complement in bandicoot is often conserved with respect to other marsupials; however, the diversity of expressed transcripts in several key families, such as major histocompatibility complex, T cell receptor μ and natural killer cell receptors, appears greater in the bandicoot than other Australian marsupials, including devil and koala. This transcriptome is an important first step for future studies of bandicoots and the bilby, allowing for population level analysis and construction of bandicoot-specific immunological reagents and assays. Such studies will be critical to understanding the immunology and physiology of Peramelemorphia and to inform the conservation of these unique marsupials.

New host records for ticks (Ixodidae) from the northern quoll (Dasyurus hallucatus) in north Queensland

Abstract. Ticks (Ixodidae) were collected from northern quolls (Dasyurus hallucatus) from three sites on the Atherton Tableland, north Queensland. Four species of ticks (Haemaphysalis humerosa, Ixodes fecialis, I. holocyclus and I. tasmani) were collected from quolls. Prevalence of infestation of ticks varied from 44 to 92% across the three sites. The collection of the three species of Ixodes represents new host records for D. hallucatus, thus adding valuable new details to the ecology of the parasite fauna of an endangered marsupial.