School of BioSciences - Theses
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ItemThe diversity and behaviour of Dermaptera (earwigs) in the southern Australian grain belt( 2018)Dermaptera (earwigs) are a cosmopolitan order of insects that have recently come to the attention of the Australian grain industry. Researchers have been sampling Dermapteran diversity and abundance across the southern Australian grain belt, but resolution of the sample is stifled by taxonomic impediment, particularly for specimens of the morphologically uniform Anisolabididae family. Molecular methods can provide much needed resolution to the study of Australian Dermaptera. I barcoded known Dermaptera species from across the southern Australian states to assess the utility of barcoding for Dermapteran biodiversity research. I also assessed the diversity of the Anisolabididae by combining morphological identification and DNA barcodes. I then estimated their phylogeny with a larger molecular dataset comprised of two mitochondrial and two nuclear gene fragments under a maximum-likelihood framework. Anisolabididae males were divided into seven morphospecies based on the shape of the forceps and parameres (a male genital structure), and these morphospecies were corroborated by barcodes (low within versus between-species genetic distance). Paramere shape distinguished two putative genera, Anisolabis Fieber and Gonolabis Burr. The molecular phylogeny did not support the monophyly of the genera, rather forming clades distinguished by the shape of the forceps. The evolutionary significance of paramere versus forceps morphology in Dermapteran taxonomy is discussed. Anisolabididae were only found in Western and South Australia and showed apparent endemism. Extending the study of Australian Anisolabididae beyond grains-producing regions may reveal a diverse endemic fauna, almost entirely unexplored heretofore.
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ItemDinoflagellate endosymbionts of corals (Symbiodiniaceae) closely associate with a diversity of bacteria( 2019)The ecological success of coral reef ecosystems is dependant on their obligate endosymbiosis with dinoflagellates in the family Symbiodiniaceae. This symbiosis does not occur in isolation; a diverse community of bacteria contribute to coral health and functioning. Though microbial-coral relationships are well studied, and dinoflagellate-bacterial associations are abundant in the marine environment, limited research focuses on Symbiodiniaceae-bacterial interactions. We combined autofluorescence quenching of Symbiodiniaceae with fluorescence in situ hybridisation to create three-dimensional reconstructions. These results present the first conclusive evidence that six species of Symbiodiniaceae harbour intracellular bacteria as well as cell surface associated extracellular bacteria. Hybridisation of class specific probes (Gammaproteobacteria, Alphaproteobacteria and Flavobacteriia) showed that taxonomic affiliation of intracellular bacteria differed between Symbiodiniaceae species. Furthermore, 147 members from the phyla Proteobacteria, Bacteroidetes and Firmicutes were isolated from ex hospite Symbiodiniaceae. Low diversity of cultured bacterial symbionts suggest that Symbiodiniaceae are selective in their association with bacteria. Based on the diversity and functional potential of Symbiodiniaceae-bacterial associations microbial interactions should no longer be ignored as potentially contributing to the coral holobiont health and functioning.