Browsing by Author "Tshililo, Precious"

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    Integrative taxonomy of the endemic Karoo agile grasshoppers, the Euryphyminae
    (Stellenbosch : Stellenbosch University, 2018-03) Tshililo, Precious; Bazelet, Corinna S.; Addison, Pia; Karsten, Minette; Stellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.
    ENGLISH ABSTRACT: The Euryphyminae are a small, African subfamily of grasshoppers which are not very well known. They are endemic to sub-Saharan Africa and consist of 23 genera, 16 of which have records of occurrence in South Africa. They are extremely agile and difficult to either catch or spot. Morphologically they are adapted to arid regions. The aim of this study was to use an integrative taxonomy approach to fill gaps in knowledge relating to Euryphyminae taxonomy and diversity in the Karoo biome. I collected all Euryphyminae information from literature and digitized 626 museum specimens which had been positively identified. I also conducted two month-long sampling trips and collected 624 specimens of Euryphyminae in thirty sites across the southern Karoo biome. Utilizing all data at my disposal, I conducted the first taxonomic review of South African Euryphyminae, investigated morphological and molecular variation within one speciose genus, Euryphymus, and analysed the ecology and diversity of Euryphyminae across space and time in the Karoo. In Chapter 2, I investigate the relationships among Euryphyminae genera by comparing morphological characters and molecular markers from three genes. I find that while most Eurphyminae genera are monophyletic and well-resolved, the evolutionary history does not comply with easily visible morphological traits. I provide an updated key to males of the Euryphyminae genera. In Chapter 3, I first classify various individual of genus Euryphymus on the basis of their morphology. I then use DNA barcoding to determine the relationship between individuals with various polymorphism. Results show that individuals group into five valid species using the 3% species divergence cutoff which is most commonly used for insect phylogenetics. Of these five species, some may be new to science and may require species description. This study shows that variation among and within Eurypyhminae genera is very high and that morphology alone may not be sufficient to differentiate among species. Finally, in Chapter 4, I investigate species richness, abundance and species composition of the Euryphyminae across space and time. I find that there are at least two distinct peaks of Euryphyminae abundance containing different species. Futhermore, most Euryphyminae species seem to be localized to a particular place and time, as most Karoo sites were dominated by one Euryphyminae species at a particular time, but this species composition turned over with the different seasons. This ecology seems to be closely tied to the arid ecosystem which Euryphyminae is specially adapted to utilize. As the first ever in-depth study on Euryphyminae, this study reveals that Euryphyminae are diverse and abundant in the Karoo biome. There may be many more as yet undiscovered species, and many of the known genera require taxonomic revision. Taxonomic revision will benefit from utilization of genetic traits. Furthermore, the evolutionary history of the Euryphyminae is not straight-forward and requires investigation to better understand how and when the Euryphyminae became specially adapted to utilize the arid and sparsely inhabited Karoo biome. Results from this study will be analysed in conjunction with results from ten other plant and animal taxa sampled in the same sites through SANBI’s Karoo BioGaps project. As a whole, these data will be used to aid in government decision making for the management and conservation planning of the Karoo, especially as it relates to shale gas exploration or fracking.