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Biogeographic influences on the evolution and historical dispersal of the Australo-Pacific Dacini fruit flies (Tephritidae: Dacinae)
Get PDFFruit flies (Tephritidae: Dacini) are a frugivorous insect group that exhibit high endemic diversity in the rainforests of Australia and the western Pacific. In this region, biogeography has been influenced by tectonic plate movements and cycles of isolation and re-connection of landmasses and rainforest habitats during glacial periods. However, how such factors have influenced the speciation and historical dispersal of the regional Dacini is largely unknown. To address this, we use a dated phylogeny to reconstruct the biogeographical history of the tribe. We found the Dacini radiated eastward into the Pacific islands largely from sources in New Guinea. We also found evidence for historical dispersal from both Australia and New Guinea into New Caledonia, a pathway unique to this island compared with neighbouring islands. There was also evidence for multiple, bidirectional dispersal events between Papua New Guinea and Australia, likely facilitated by the cyclically exposed Torres Strait land bridge. Cape York in far northern Australia was likely the only entry point for species dispersing into Australia; there was no evidence for entry of flies into Australia directly from West Papua or Wallacea. Several lineages radiated after entering Australia, such as members of the Bactrocera dorsalis species group. Within Australia, speciation was not associated with the biogeographic barriers known to have impacted other rainforest fauna in eastern Australia. Overall, we demonstrate that isolation between islands and large landmasses is important in the evolution of the Australo-Pacific Dacini, but the reason for their extensive radiation within Australia and Papua New Guinea remains unclear
Impact of Fruit Maturity on Internal Disorders in Vapor Heat Treated Mango Cv. ‘B74’
Get PDFUN Sustainable Development Goal 12 (SDG 12) aims to reduce food losses in production and postharvest stages within supply chains. Identifying and addressing contributors to such losses is crucial to their reduction and to overall supply chain sustainability. Internal disorders (IDs) often contribute to postharvest losses and waste of highly perishable fruits like mangoes. Understanding and addressing influencers of susceptibility is limited but essential. Factors potentially associated with the expression of IDs in ‘B74’ mango commercial supply chains were investigated. Over three fruiting seasons (2020/21, 2021/22, and 2022/23), 43 export supply chains in Australia were monitored from two major production regions, the Northern Territory and North Queensland. Prior to export, the mangoes were subject to a mandatory phytosanitary vapor heat treatment (VHT) in which they were heated with saturated water vapor to a core temperature 46 °C maintained for 15 min and were then assessed for IDs at the end of their shelf life. The predominant IDs observed in the ‘B74’ fruit were flesh cavity with white patches (FCWP) and flesh browning (FB). VHT-induced FCWP, but not FB. Harvest maturity was identified as a predisposing factor. FB was generally positively correlated and FCWP was typically negatively correlated with fruit maturity at harvest. Relatively more-mature fruit was prone to FB irrespective of VHT, and relatively less-mature fruit was susceptible to FCWP post-VHT. Therefore, selective harvesting and/or sorting for optimum maturity after harvest can be practiced minimizing the incidence and severity of these two IDs in ‘B74’ fruit. Thus, dry matter (DM) sorting can contribute to postharvest loss reduction and the general sustainability of mango supply chains
An annotated checklist with a key to the genera of Australian psyllids (Hemiptera: Sternorrhyncha: Psylloidea)
No full textThe diversity of the psyllids of Australia reflects that of the plants of this country, with large radiations and ecological dominance of Myrtaceae (e.g., Eucalyptus), Fabaceae (e.g., Acacia), Casuarinaceae (e.g., Allocasuarina, Casuarina) and Scrophulariaceae (e.g., Eremophila, Myoporum). within Australian ecosystems, psyllids are critical components of food webs, especially with respect to providing energy-rich resources for many species of birds and insects and, historically, humans. Furthermore, in horticulture, agriculture and forestry, some Australian psyllid species are considered pests, causing leaf senescence and ‘dieback’, leaf deformation and inducing growth of sooty mould, with some adventive species capable of acting as vectors of plant pathogens. Several species are considered beneficial, having been introduced as biological control agents of weeds. Additionally, some Australian psyllids have established in other countries, or in regions within Australia that are not within their natural range; while others have such limited geographical ranges that they are of conservation concern. Here we provide an updated checklist of the species of Psylloidea present in Australia and updated a previous key to their genera based on adult morphology. This is the first checklist of the Australian psyllids compiled since the most recent global taxonomic classification, and provides detailed information on biogeographical, ecological and anthropogenic aspects, including global distribution, host plant data, pest status, conservation status, parasitoids, predators, and biological control programs. Our checklist includes information on 66 genera and 450 species, 414 formally described and 36 awaiting descriptions. This represents an increase of almost 20% of species since the last published checklist of 2004, which reported 354 described and 21 undescribed taxa. Additionally, we summarise the available information on more than 150 undescribed taxa. Finally, we reported here more than 60 new records, between distributions and host plant associations. Copyright © 2024 Magnolia Press
Image-based mesh generation for constructing a virtual representation of engineered wood product samples
Get PDFThe complex structure of timber has traditionally been difficult to model as it is a highly heterogeneous material. The density and material properties for structural species such as Pinus radiata (radiata pine) can vary greatly across the growth rings. Numerical simulation methods are becoming more prevalent as a method of predicting moisture migration, stress and strain distributions, and fungal/rot intrusion in engineered wood products (EWPs). All these applications require a computational mesh that captures the growth ring structure to facilitate an accurate assessment of the performance of EWPs. In this work, a low-cost image-based algorithm is developed for generating a virtual representation of a small cross laminated timber panel sample. Specifically, the proposed method results in a virtual description of an EWP sample comprised of a triangular prismatic mesh where the nodes are aligned on the growth rings of each individual timber component of the EWP, with specific wood material properties allocated to each mesh element. Each small component is treated individually and we assume there is no longitudinal variation in the density, pith location, and pith angle within the mesh structure. The initial step involves analysing an image of the end grain pattern of a single clear wood sample to identify the growth rings using a spectral clustering algorithm. Next, the centre of the tree (pith) is located through an iterative constrained least-squares algorithm to determine the pith angle. Image analysis of an anatomical image combined with the pith location allows for a constant density value to be assigned to each mesh element. The capability of this framework is then demonstrated by simulating the moisture migration and heat transfer throughout a CLT sample under atmospheric and saturating boundary conditions. Furthermore, the virtual representation provides the basis for simulating additional physical and biological phenomena, such as moisture-induced swelling, decay and fungal growth
Potential of flavesone as a grain protectant: Long-term efficacy and residues for controlling the lesser grain borer, Rhyzopertha dominica (F.), in stored wheat
No full textA study was undertaken to evaluate the synthetic biopesticide, flavesone, as a potential grain protectant for the lesser grain borer, Rhyzopertha dominica (F.), in wheat. The search for new grain protectants is critical because of the propensity of R. dominica to develop genetic resistance to various insecticides such as organophosphates (OPs), carbamates, synthetic pyrethroids and juvenile hormone analogues. Wheat was treated with 0, 60, 90 or 120 ppm of flavesone as it passed through an auger into large (1 tonne) storage bags. The treated wheat was stored for 13 months under sheltered ambient conditions in southeast Queensland, and samples were also collected 1 week after treatment and stored for 13 months in the laboratory at 30 °C and 55% RH for comparative purposes. Bioassays of wheat stored under laboratory and ambient conditions, showed that an application rate of 60 ppm provided protection for at least 13 months from a susceptible strain, based on high levels of suppression of the F1 generation. Untreated wheat stored under ambient conditions became heavily infested with R. dominica, while none were detected in any of the treatments, thus further confirming the potential of flavesone as an effective grain protectant. However, bioassays showed that the 60-ppm rate only provided 3 months protection from a strain that was resistant to OPs and pyrethroids, indicating potential non-target site resistance present in this strain. Higher application rates of 90 and 120 ppm were required for 13 months protection. As reported in some other grain protectant studies, initial flavesone residues were lower than the targeted rates, suggesting potential for improving formulation and application methods. Flavesone residues remained relatively stable throughout the study period. We believe that the data generated through this study will provide foundation in establishing field application rate for this new molecule and its possible registration for use by industry to mitigate resistance problems
A rust pathogen affecting the invasive Navua sedge (Cyperus aromaticus) in Australia – A fortuitous biocontrol agent?
No full textNavua sedge (Cyperus aromaticus), a perennial invasive sedge affecting beef, dairy and sugarcane industries in the Queensland wet tropics, is a target for biocontrol in Australia. Host specificity tests for a floret-infecting smut fungus Cintractia kyllingae and a leaf and stem infecting rust fungus Puccinia kyllingae-erectae, both native to Africa, are in progress at CABI, UK. In 2023, a rust fungus on leaves and stems of Navua sedge was reported from a grazing property in Topaz, northern Queensland. The rust was morphologically and genetically identical to P. kyllingae-erectae from Africa. Puccinia kyllingae-erectae was found to be widespread in the Atherton Tablelands, and in the coastal lowlands, from Innisfail in the south to Cape Tribulation in the north. Puccinia kyllingae-erectae killed 80–95% of the above ground foliage, although Navua sedge resprouts from underground rhizomes. The rust was not found on pasture species or other native sedge species indicating that it is host specific. Future studies will focus on determining the distribution, impact and host range of P. kyllingae-erectae in the field
Controlling Cabomba caroliniana with different flumioxazin application strategies
No full textCabomba caroliniana, a fully submerged aquatic plant originating from South America, has become highly invasive outside of its native range. It impacts native aquatic ecosystems, reduces biodiversity, affects public safety and economy. Flumioxazin is an efficient herbicide for managing cabomba while being environmentally safe. However, a single application is often insufficient to completely control cabomba. Consequently, follow-up applications become necessary to completely remove cabomba. We carried out a mesocosm study, replicated in winter and summer, to find the optimum dose and frequency of flumioxazin applications for effectively controlling cabomba. Single, or multiple low doses of flumioxazin spaced over time, were injected directly into outdoor mesocosms with a high density of cabomba. In the winter trial, the control efficacy of four application strategies (50 + 50 ppb, 50 + 50 + 50 ppb, 100 + 100 ppb and 200 ppb) on cabomba biomass reduction ranged from 86.3% to 95.5%. Meanwhile, in the summer trial, the biomass reduction of cabomba caused by the four strategies ranged from 98.1% to 100%. However, the differences between the four strategies were not significant both in summer and in winter. In conclusion, all four application strategies of flumioxazin have high efficacies on cabomba biomass reduction. A single high application (200 ppb) of flumioxazin can achieve a rapid biomass reduction of cabomba. The strategy of split applications of low dose can be used when there are other flumioxazin-sensitive native aquatic plants, which can achieve the same efficacy of flumioxazin with much less non-target damage. Further research will now investigate the efficacy of flumioxazin application strategies in the field
Adaptation to host plants modulates the dependence of tephritid fruit flies on their gut bacterial communities
No full textInsect gut microbial communities are recognized as important factors facilitating insect adaptation to host plant defenses. However, the impact of co-evolution with host plants on insects’ reliance on their gut bacterial communities remains poorly understood. In this study, we first showed a decrease in fitness for Bactrocera dorsalis, Zeugodacus cucurbitae, Zeugodacus tau, and Bactrocera correcta after eliminating their gut microbes, but only when they were fed on non-preferred hosts; no significant fitness changes were observed on preferred hosts. Furthermore, after a simulated adaptation period with bitter melon feeding, Z. cucurbitae larvae, whether axenic, symbiotic, or gnotobiotic, exhibited comparable fitness levels. In contrast, axenic larvae of B. dorsalis continued to display reduced fitness compared to their symbiotic and gnotobiotic counterparts. Our findings also revealed that bacterial removal altered gene expression patterns in B. dorsalis, indicating deficiencies in nutrient acquisition, assimilation, immunity, and detoxification processes, whereas these changes were less pronounced in Z. cucurbitae. Additionally, our experiments demonstrated that, unlike Z. cucurbitae, B. dorsalis relies on its intestinal flora to significantly detoxify bitter melon toxins. These results suggest that Z. cucurbitae may have developed microbe-independent strategies, such as genetically encoded detoxification or tolerance mechanisms, to cope with toxic host challenges
An investigation into methods to calculate effort controls in a multi-species fishery: northern and central Queensland otter trawl case study using data from 2017 to 2021
No full textThis report investigated how to combine multiple species, with and without stock assessments, into regional trawl effort caps. This was in the form of effort units (EU) for the northern and central regions of the Queensland east coast otter trawl fishery.
Variations in methods (detailed or ratio), spatial inshore and offshore stratifications (filtered or allocated divisions within a region), co-caught adjustments (species proportions from effort or catch data) and different species inclusions were investigated. These comparisons resulted in 64 different effort cap calculations per region. The calculations used data from 2017 to 2021 and stock assessment results from 2023 (Lovett et al. (2023), Fox et al. (2023) and Wickens et al. (2023)).
Some of the 64 effort cap calculations were above, and some were below, the current 2024 effort caps. Considerations are needed to mitigate exceeding species-specific target reference points, to maintain or improve average catch rates per boat-day for economic profit, and to limit bycatch
Talcarpones A and B: bisnaphthazarin-derived metabolites from the Australian fungus Talaromyces johnpittii sp. nov. MST-FP2594
No full textTalcarpones A (1) and B (2) are rare bisnaphthazarin derivatives produced by Talaromyces johnpittii (ex-type strain MST-FP2594), a newly discovered Australian fungus, which is formally described and named herein. The talcarpones were isolated along with the previously reported monomeric naphthoquinone, aureoquinone (3), suggesting a biosynthetic link between these metabolites. Talcarpone A is a lower homologue of hybocarpone (4), which was first isolated from a mycobiont of the lichen Lecanora hybocarpa. The structures of 1 and 2 were elucidated by detailed spectroscopic analysis, molecular modelling and comparison with literature data. Talcarpones 1 and 2 exhibited moderate antifungal activity (MIC 0.78–3.1 µg ml−1) and weak activity against Gram-positive bacteria (MIC 13–25 µg ml−1). The talcarpones also demonstrated noteworthy chemical reactivities, with 2 converting rapidly to 1, which in turn converted slowly to the highly coloured 3. These post-biosynthetic reactions point to a potential ecological role for the talcarpones in providing ongoing (slow-release) physicochemical protection for T. johnpittii against solar irradiation