Abstract:
Gonipterus sp. n. 2 is an invasive pest of Eucalyptus spp. This pest is managed by Anaphes nitens, an egg parasitoid of Gonipterus spp. Despite Gonipterus sp. n. 2 being a major pest in Eucalyptus plantations, no studies have explored the population genetic diversity of this pest nor its biological control agent. The absence of previous studies from the scientific literature is due to the lack of molecular markers to study the population genetic diversity of these organisms.
The research presented in this dissertation reports the development of microsatellite markers for Gonipterus sp. n. 2 and its biological control agent A. nitens from genome sequence data. The genetic diversity of Gonipterus sp. n. 2 was assessed in five South African provinces using the developed microsatellite markers together with the cytochrome oxidase 1 (CO1) mitochondrial gene region. Analysis of the CO1 mitochondrial gene region revealed haplotypes with minor variations indicating moderate diversity in the South African Gonipterus sp. n. 2 population based on the gene sequence data. Genetic analysis based on the eight microsatellites developed for Gonipterus sp. n. 2 revealed multi genotypes and moderate genetic diversity in the South African population of this pest. The results therefore suggest that Gonipterus sp. n. 2 was introduced multiple times into the country. Seven microsatellite markers that were polymorphic were developed for A. nitens. These microsatellite markers will be used in future studies to investigate the population genetic diversity of A. nitens.
The research presented in this dissertation contributes critical molecular tools for population genetic diversity studies of Gonipterus sp. n. 2 and its biological control agent Anaphes nitens. Preliminary knowledge of the population genetic diversity of Gonipterus sp. n. 2 in South Africa is also provided in this dissertation. It is hoped that the knowledge gained from this study will stimulate further research on the population genetic diversity of Gonipterus sp. n. 2, other invasive Gonipterus species and A. nitens in other parts of the world, especially where they occur in native areas. Knowledge of the population genetic diversity of Gonipterus spp. and A. nitens in the native areas will help determine if there is a genetic divergence between invasive and native populations.
