Browsing by Author "Hlaka, Vaylen"

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    Identification, distribution, and genetic diversity of olive lace bugs and olive flea beetles in the Western Cape province of South Africa
    (Stellenbosch : Stellenbosch University, 2021-12) Hlaka, Vaylen; Van Asch, Barbara; Stellenbosch University. Faculty of AgriSciences. Dept. of Genetics.
    ENGLISH ABSTRACT: South Africa is a minor contributor to the olive industry globally. However, that has not stopped the country from making a mark in the industry by achieving several awards for producing the world’s finest olive oil. Although the production of olives in South Africa is still new compared to Europe, it has created employment for many and has alleviated poverty in surrounding communities. The production of olives has its fair share of challenges, which include stress from insect pests and diseases. Olive lace bugs and olive flea beetles are considered pests of the olive industry in South Africa, but little is known about these pests and their impact on the production of olives. The similarity between wild African olive trees and cultivated olive suggests that these pests, along with other species associated with olives, jumped from wild olive trees to cultivated olive trees. The study aimed to contribute to the catalogue of entomofauna associated with wild and cultivated olives in South Africa by identifying olive lace bug and olive flea beetle species using morphological and DNA-based methods in which four olive lace bug species (Cysteochila lineata, Neoplerochila paliatseasi, Neoplerochila sp., and Plerochila australis) and two olive flea beetles (Argopistes capensis and Argopistes sexvitattus) were identified. Phylogenetic analyses and estimates of intra- and inter-specific genetic divergences were determined using novel and publicly available DNA barcodes for the family Tingidae for olive lace bugs, and the tribe Alticini for olive flea beetles. Novel mitochondrial genomes for olive lace bugs and olive flea beetles were generated and the phylogenetic position of olive lace bugs and olive flea beetles within their respective family or tribe. In addition, a survey was conducted for the purpose of identifying olive lace bug and olive flea beetle species distributed in olive orchards farms in the Western Cape. Phylogenetic analysis and genetic divergence supported the morphological identification of olive lace bugs and olive flea beetles. The complete mitogenomes of olive lace bugs and olive flea beetle species in South Africa were sequenced. The phylogenetic position of olive lace bugs and olive flea beetles was inferred in context of other complete and partial mitogenomes available within their family/tribe. The four olive lace bugs and two olive flea beetles formed clusters of closely related species in their respective phylogenetic trees. These results show that the group of olive lace bugs and the group of olive flea beetles have a recent common mitochondrial ancestor and indicate that adaptation to feeding on Olea may have a common ancestral evolutionary origin.