Pollen DNA metabarcoding reveals cryptic diversity and high spatial turnover in alpine plant-pollinator networks.

Alpine plant-pollinator communities play an important role in the functioning of alpine ecosystems, which are highly threatened by climate change. However, we still have a poor understanding of how environmental factors and spatiotemporal variability shape these communities. Here, we investigate what drives structure and beta diversity in a plant-pollinator metacommunity from the Australian alpine region using two approaches: pollen DNA metabarcoding (MB) and observations. Individual pollinators often carry pollen from multiple plant species, and therefore we expected MB to reveal a more diverse and complex network structure. We used two gene regions (ITS2 and trnL) to identify plant species present in the pollen loads of 154 insect pollinator specimens from three alpine habitats and construct MB networks, and compared them to networks based on observations alone. We compared species and interaction turnover across space for both types of networks, and evaluated their differences for plant phylogenetic diversity and beta diversity. We found significant structural differences between the two types of networks; notably, MB networks were much less specialized but more diverse than observation networks, with MB detecting many cryptic plant species. Both approaches revealed that alpine pollination networks are very generalized, but we estimated a high spatial turnover of plant species (0.79) and interaction rewiring (0.6) as well as high plant phylogenetic diversity (0.68) driven by habitat differences based on the larger diversity of plant species and species interactions detected with MB. Overall, our findings show that habitat and microclimatic heterogeneity drives diversity and fine-scale spatial turnover of alpine plant-pollinator networks.

Phylogenomics reveals accelerated late Cretaceous diversification of bee flies (Diptera: Bombyliidae).

Bombyliidae is a very species-rich and widespread family of parasitoid flies with more than 250 genera classified into 17 extant subfamilies. However, little is known about their evolutionary history or how their present-day diversity was shaped. Transcriptomes of 15 species and anchored hybrid enrichment (AHE) sequence captures of 86 species, representing 94 bee fly species and 14 subfamilies, were used to reconstruct the phylogeny of Bombyliidae. We integrated data from transcriptomes across each of the main lineages in our AHE tree to build a data set with more genes (550 loci versus 216 loci) and higher support levels. Our overall results show strong congruence with the current classification of the family, with 11 out of 14 included subfamilies recovered as monophyletic. Heterotropinae and Mythicomyiinae are successive sister groups to the remainder of the family. We examined the evolution of key morphological characters through our phylogenetic hypotheses and show that neither the "sand chamber subfamilies" nor the "Tomophthalmae" are monophyletic in our phylogenomic analyses. Based on our results, we reinstate two tribes at the subfamily level (Phthiriinae stat. rev. and Ecliminae stat. rev.) and we include the genus Sericosoma Macquart (previously incertae sedis) in the subfamily Oniromyiinae, bringing the total number of bee fly subfamilies to 19. Our dating analyses indicate a Jurassic origin of the family (165-194 Ma), with the sand chamber evolving early in bee fly evolution, in the late Jurassic or mid-Cretaceous (100-165 Ma). We hypothesize that the angiosperm radiation and the hothouse climate established during the late Cretaceous accelerated the diversification of bee flies, by providing an expanded range of resources for the parasitoid larvae and nectarivorous adults.

Nocturnal oviposition behavior of blowflies (Diptera: Calliphoridae) in the southern hemisphere (South Africa and Australia) and its forensic implications.

Published research has offered contradictory evidence of the occurrence of nocturnal oviposition by carrion-breeding blowflies, a behavior that can affect the interpretation of forensic estimates of a minimum post mortem interval (minPMI) by up to 12 hours, depending on latitude and season. The majority of published studies are from the northern hemisphere. Field experiments were conducted in South Africa and Australia that extend observations to species of the southern hemisphere. Various vertebrate carrion was exposed at night in summer under different lunar phases and/or artificial lighting, and in woodland and pasture areas. Three laboratory experiments were also conducted. No nocturnal oviposition occurred outdoors in Berry, Australia, but Lucilia cuprina, Lucilia sericata and Chrysomya megacephala laid eggs outdoors at night in Grahamstown and Durban, South Africa. In laboratory experiments L. sericata, L. cuprina, Chrysomya chloropyga and Chrysomya putoria laid eggs and Calliphora augur deposited larvae under nocturnal conditions. Chrysomya albiceps and C. chloropyga laid eggs in darkness with increasing likelihood as ambient temperature increased. This study shows that nocturnal ovi/larviposition by carrion-breeding blowflies is possible in both South Africa and Australia. The forensic issue is therefore not whether nocturnal oviposition occurs, but rather whether the conditions of a particular case are more or less conducive to it. Circadian rhythms and physiological thresholds (particularly temperature and humidity) appear to act individually and in conjunction to stimulate or inhibit nocturnal laying. The significance of carcass size, freezing and handling of carcasses and comprehensive quantification for experimental design is discussed, and recommendations are made for future laboratory and case scene experiments.

Seven new Australian species of the southern hemisphere horse fly subgenus Scaptia (Pseudoscione) (Diptera: Tabanidae), including descriptions and a revised key.

Horse flies (Diptera: Tabanidae) are ecologically important pollinators and vectors of many disease-causing organisms, as adult females are known to mechanically transfer multiple disease agents during feeding affecting humans, livestock, and many native mammals. Scaptia (Pseudoscione) Lutz in Lutz, Araujo, & Fonseca 1918 has the widest distribution of all genera in the tribe Scionini, occurring in Australia, New Guinea, New Zealand, and South America. Seven new species of Australian S. (Pseudoscione) are described and included in an updated key to the subgenus. The new species are: S. (Pseudoscione) baylessi sp. nov. Lessard, S. (Pseudoscione) casseli sp. nov. Lessard, S. (Pseudoscione) mackerrasi sp. nov. Lessard, S. (Pseudoscione) moritae sp. nov. Lessard, S. (Pseudoscione) turcatelae sp. nov. Lessard, S. (Pseudoscione) turneri sp. nov. Lessard, and S. (Pseudoscione) wiegmanni sp. nov. Lessard. In addition, S. (Pseudoscione) occidentalis Mackerras, 1960, previously described as a subspecies, has been raised to species level. One new species significantly extends the known distribution of Scaptia into central Australia, >1,200 km NW from the nearest recorded species within the subgenus.

Detection of the Japanese encephalitis vector mosquito Culex tritaeniorhynchus in Australia using molecular diagnostics and morphology.

BACKGROUND: Culex (Culex) tritaeniorhynchus is an important vector of Japanese encephalitis virus (JEV) affecting feral pigs, native mammals and humans. The mosquito species is widely distributed throughout Southeast Asia, Africa and Europe, and thought to be absent in Australia. METHODS: In February and May, 2020 the Medical Entomology unit of the Northern Territory (NT) Top End Health Service collected Cx. tritaeniorhynchus female specimens (n = 19) from the Darwin and Katherine regions. Specimens were preliminarily identified morphologically as the Vishnui subgroup in subgenus Culex. Molecular identification was performed using cytochrome c oxidase subunit 1 (COI) barcoding, including sequence percentage identity using BLAST and tree-based identification using maximum likelihood analysis in the IQ-TREE software package. Once identified using COI, specimens were reanalysed for diagnostic morphological characters to inform a new taxonomic key to related species from the NT. RESULTS: Sequence percentage analysis of COI revealed that specimens from the NT shared 99.7% nucleotide identity to a haplotype of Cx. tritaeniorhynchus from Dili, Timor-Leste. The phylogenetic analysis showed that the NT specimens formed a monophyletic clade with other Cx. tritaeniorhynchus from Southeast Asia and the Middle East. We provide COI barcodes for most NT species from the Vishnui subgroup to aid future identifications, including the first genetic sequences for Culex (Culex) crinicauda and the undescribed species Culex (Culex) sp. No. 32 of Marks. Useful diagnostic morphological characters were identified and are presented in a taxonomic key to adult females to separate Cx. tritaeniorhynchus from other members of the Vishnui subgroup from the NT. CONCLUSIONS: We report the detection of Cx. tritaeniorhynchus in Australia from the Darwin and Katherine regions of the NT. The vector is likely to be already established in northern Australia, given the wide geographical spread throughout the Top End of the NT. The establishment of Cx. tritaeniorhynchus in Australia is a concern to health officials as the species is an important vector of JEV and is now the sixth species from the subgenus Culex capable of vectoring JEV in Australia. We suggest that the species must now be continuously monitored during routine mosquito surveillance programmes to determine its current geographical spread and prevent the potential transmission of exotic JEV throughout Australia.