Austral Entomology最新文献

An identification guide is provided for female adults of the mosquito groups, complexes or species that can be morphologically differentiated and that are likely to transmit arboviruses (e.g., dengue, Zika, chikungunya, Ross River and Japanese encephalitis) or parasites (e.g., Plasmodium spp. and Wuchereria bancrofti) in the Pacific Islands, countries and territories. This dichotomous key is adapted, with permissions, from a variety of text and image sources to facilitate the identification of disease vectors by individuals with limited taxonomic training including Pacific island country Vector Surveillance and Environmental Health officers, other public health officials and students.

Ceratitis capitata (Diptera: Tephritidae) is a highly polyphagous species and a seriously pest with a significant economic importance, having a great number of studies focused in its management. Recently, there has been a surge of interest in the symbiotic relationship between gut bacteria and their insect hosts. In this context, the objective of this work was to evaluate the role of gut microbiota on symbiotic and aposymbiotic wild medfly adult sexual behaviour, especially on mate choice and mating success. We also evaluate latency and mating time, sperm transference, testes and ovarian sizes and female fecundity. Finally, we compared cuticular hydrocarbon profiles to explore other possible mechanisms that mediate medfly mating success. For this purpose, teneral wild medfly adults were separated into two groups, symbiotic and aposymbiotic. Aposymbiotic adults were treated with an antibiotic mixture (tetracycline plus ciprofloxacin) until sexual maturity. Results of sexual behaviour assays showed that symbiotic males were more successful in mating in comparison with aposymbiotic males, and female preference could be related with a greater sexual organ development of symbiotic females and differences in male hydrocarbon cuticular profiles. Results support the hypothesis that the presence of gut bacteria can play a beneficial role on the sexual behaviour. Knowledge about the importance of cuticular hydrocarbons acting in mating recognition was obtained. This work is the first to report the influence of gut microbiota on this component of the exoskeleton for wild medfly and might be useful for the improvement of sustainable strategies for pest management such as the sterile insect technique.

Bacillus thuringiensis (Bt) endotoxins are often considered environmentally friendly pest control tools. However, the development of resistance to Bt toxins and emergence of exotic pests necessitate the characterisation of new Bt isolates. This study aims to identify and characterise novel Bt toxins and bioactive compounds that may be utilised to mitigate the impact of Spodoptera frugiperda (fall armyworm, FAW), a polyphagous agricultural pest species that has recently established populations in over 80 countries including Australia. Eight Bt isolates were used in bioassays to ascertain toxicity to FAW neonates. Six Bt isolates (Bt_01-02 and Bt_05-08) exhibited potential insecticidal activities. Three isolates including Bt_01 and Bt_07-08 caused 100% mortality, while Bt_02, Bt_05, and Bt_06 induced 71.27 ± 21.17, 98.44 ± 2.21 and 92.19 ± 11.05% mortality, respectively. Genome analysis was conducted to characterise the toxins and secondary metabolite gene clusters of each isolate. Four isolates (Bt_01, Bt_06, Bt_07, Bt_08) contained the Cry1Na-partial and Cry1I toxins, while Bt_05 contained Cry2A, Cry1H and Cry1-like amino acid sequences. In addition, the gene cluster for zwittermicin A, a crystal toxin enhancer, was present in all isolates. However, no known toxins or insecticidal compounds were identified in Bt_02 despite inducing high mortality. The pathogenicity of Bt_02 was also tested against two Australian native pest species: Helicoverpa armigera conferta and H. punctigera. This includes both the susceptible and Cry1Ac-resistant (Hp9-3784) lines of H. punctigera. Bt_02 caused 74.88 ± 19.82% mortality in H. armigera, 95.65 ± 6.15% mortality in H. punctigera and 90.91 ± 12.86% mortality in Hp9-3784. This suggests that Bt_02 may possess unknown toxins or bioactive compounds responsible for its effectiveness against three species of lepidopteran pests including those that exhibited Cry1Ac resistance.

Despite their striking appearance and abundance, the diversity and life-histories of cup moths and their relatives (Lepidoptera: Limacodidae) in Australia are not well known. An example is a caterpillar commonly known as the rainbow battleship, or rainbow school bus. This caterpillar has been claimed to be the larva of Calcarifera ordinata (Butler, 1886), a wattle cup moth, but rearing experiments have recently shown that caterpillars of C. ordinata are not rainbow battleships. Here, we use DNA barcoding to identify the rainbow battleship by comparing the mitochondrial gene COI to sequences obtained from a DNA-barcoding blitz at the Australian National Insect Collection. We positively identify the rainbow battleship caterpillar as the larva of Comana albibasis (Walker, 1862), an association not previously hypothesised. The COI barcode region appears to be a useful tool for identifying limacodids, including matching larval and adult forms. Divergence within some currently recognised species highlights the presence of potentially undescribed species diversity in Limacodidae.

In October 2020, Liriomyza huidobrensis (serpentine leafminer [SLM]) was first detected in Western Sydney, New South Wales (NSW), and subsequently Southern Queensland (QLD). Control failures were reported, and insecticide resistance was confirmed via bioassay, but mechanisms causing resistance remained unknown. We characterised the complete mRNA sequence of eight insecticide target genes of L. huidobrensis using RNA sequencing. We found that the Australian SLM carries three mutations (I129V, G227A and F331W) of the acetylcholinesterase (AChE) gene, causing resistance to mode of action (MOA) 1 chemicals; one mutation (A301S) of the gamma-aminobutyric acid receptor subunit beta (GABAR), causing resistance to MOA 2 chemicals; and two mutations (M918T and L1014L) of the voltage-gated sodium channel (VGSC) gene, causing resistance to MOA 3 chemicals. We consequently developed a multiamplicon-sequencing panel to screen 234 Australian field-collected SLM samples using next-generation sequencing. The multiplex panel includes mitochondrial cytochrome oxidase subunit 1 (COI) for species identification and AChE, VGSC, glutamate-gated chloride channel (GluCl) and chitin synthase 1 (CHS1) gene mutations. We confirm that all the individuals carry the multi-resistance alleles in a homozygous and fixed state. This is a rare phenomenon for a single individual to be homozygous for multiple resistance mutations, with only a few studies documenting such multi-resistance at the population level. Such resistance mechanism detection raises concern that there are limited chemical options for the control of invasive SLM in Australia.

Understanding the movement dynamics of fruit flies is critical to both surveillance and control strategies with much of what is known coming from mark–release–recapture or flight mill studies. However, recent studies have demonstrated the feasibility of field-tracking fruit flies using harmonic radar (HR). In this study, the effects of attaching HR tags to Bactrocera tryoni and Bactrocera jarvisi were assessed in large indoor cages with both cultured and wild flies. The Queensland fruit fly, B. tryoni, is a major horticultural pest in the Northern Territory and east coast of Australia. Jarvis' fruit fly, B. jarvisi, is one of the lesser Australian fruit fly species, with a distribution in northern and eastern Australia. Three flight-associated behavioural parameters were recorded: (1) flight success (proportion of flies that flew), (2) time to flight (period from release to take-off) and (3) flight duration (period from take-off to landing). Untagged flies were more likely to fly and also took flight more quickly than tagged flies with this result holding across fly species and fly origin (wild or cultured). Similarly, wild flies were more likely to fly than cultured flies, but no differences were observed between the flight successes of the two fruit fly species. For all tagged flies, mean time to flight increased with successive flight trials, while untagged flies mean time to flight over time varied with species and fly origin. The effect of tagging on flight duration varied by species (tagged > untagged for B. tryoni, tagged < untagged for B. jarvisi) but not by fly origin with species. Together, these results quantify the negative effects of HR tagging on B. tryoni and B. jarvisi flight behaviours that should be taken into account when interpreting the biological relevance of HR tracking studies. These results also suggest that HR tracking of fruit flies would benefit from the further development of smaller and lighter tags.

Fagan-Jeffries, E.P., Miles, M.M., Atkin-Zaldivar, T.-C.C., Howe, A.G., Subramaniam, S., Chambers, D.M., Tadle, F.P.J., Adnan, S.M., Sivasubramaniam, V., Woodward, A. (2024) Hymenopteran parasitoids of fall armyworm (Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae)) in Australia, with the description of five new species in the families Braconidae and Eulophidae. Austral Entomology, 63(2), 136–174. Available from: https://doi.org/10.1111/aen.12682

There were some inaccurate methods given for the rearing of parasitoids from S. frugiperda in Western Australia and the Northern Territory in the original version of this manuscript. After publication, it also came to the attention of the lead author that two researchers involved in the collection of parasitoids in those states were not included on the author list, and that is also corrected in this corrigendum. A more accurate reporting of the collection and rearing methods are as follows.

S. frugiperda egg masses and larvae were collected from commercial crops, volunteer and cover crops and field trials in Queensland, New South Wales, Western Australia and the Northern Territory during several discrete time periods between January 2020 and April 2023 and reared in the laboratory. Typically, S. frugiperda material was collected without evidence of parasitism, and it was retained in the laboratory until either parasitoid emergence or S. frugiperda moth emergence. Specimens of any emergent adult parasitoids were provided for taxonomic examination dry or in 70% ethanol or collected live into 96% ethanol and stored at −18°C for molecular diagnostics.

Damage to the margin and surface of fossil leaves has been used to identify the likely insect groups involved and to track potential changes in insect communities through evolutionary time. The Anglesea fossil site in Victoria, Australia, has a rich array of fossil leaves preserved in clay and clay-sand through six fossil lenses dated at late middle Eocene, ~40 Ma. Examination of a large number of fossil leaves and comparison to Northern Hemisphere fossils and modern damage has resulted in 12 with unique margin excisions postulated to be caused by megachilid leaf-cutter bees. Such findings precede the current dated megachilid phylogeny by ~24 million years. This study aims to draw attention to this discrepancy which may have implications for the understanding of megachilid dispersal events into Australia.

Coprophagous dung beetles provide important ecosystem services in improving soil quality and plant development in agricultural environments due to the availability of nutrients from dung removal. The study aimed to compare the effect of dung removal performed by two functional groups, among themselves and with mineral fertiliser, on improving soil and forage grass characteristics. An experiment in mesocosms was conducted in Southern Brazil during the summer/autumn of 2021, sowing Urochloa brizantha in the treatments: (1) telecoprid species (Canthon rutilans cyanescens), (2) paracoprid species (Dichotomius sericeus), (3) both species together, (4) mineral fertiliser and control with cattle dung. Dung removal was quantified weekly. At the end of the experiment, the soil's physical, chemical and microbiological characteristics, dry biomass and macronutrients (N, P and K) of the leaves and roots, and photosynthetic pigments of grasses were analysed. The dung beetle species studied increased total nitrogen and organic matter contents and their particulate fractions of C and N. Paracoprids decreased the soil bulk density and improved its soil aggregation, influencing the pH and Mg contents, with a reduction in Al levels. They were as efficient as mineral fertiliser in incorporating K into the soil. Treatments with beetles had values similar to mineral fertiliser in the foliar concentrations of P, and paracoprids promoted increases in the K concentration in the leaves and roots of the grass. This functional group was also more efficient in removing cattle dung, which was positively related to the amounts of N, organic matter and its particulate fractions, P, macroaggregates and the cation exchange capacity (CEC_pH7.0) of the soil. Thus, dung removal was associated with improvement in the soil, mainly paracoprids, reinforcing the importance of the ecosystem functions performed by these organisms in agricultural environments, where they can contribute to the increase in nutrient cycling with a consequent decrease in the use of mineral fertilisers.

The life cycle, nesting behaviour and diet breadth of the resin bee Megachile (Hackeriapis) tosticauda (Cockerell) are described for the first time. Microscopic imaging of the larval provisions and pollen from the scopa showed that Megachile tosticauda from Adelaide, South Australia, is narrowly oligolectic and specialised on Eucalyptus pollen. Parasites of the nests were identified, and the developmental timeline was outlined. A comparison between behaviour in South Australia (SA) and Western Australia (WA) revealed similarities in nest architecture and parasitism but showed discrepancies in emergence times, nest substrate and potentially diet width. However, the diet analysis from WA was based on visual floral visitations and pollen metabarcoding, neither of which indicate active pollen collection. The difference in diet breadth of this species needs to be ascertained by assessing the larval provisions.