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Molecular ecology and management of Leptocybe invasa (Hymenoptera: Eulophidae) in South Africa
Thesis (PhD)--University of Pretoria, 2014.
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| Format: | Thesis |
| Language: | English |
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2026
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| _version_ | 1867613556913995776 |
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| access_status_str | Open Access |
| author2 | Slippers, Bernard |
| author_browse | Slippers, Bernard |
| author_facet | Slippers, Bernard |
| collection | Thesis |
| description | Thesis (PhD)--University of Pretoria, 2014. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/110045 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:38:02.052Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2026 |
| publishDateRange | 2026 |
| publishDateSort | 2026 |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/110045 Molecular ecology and management of Leptocybe invasa (Hymenoptera: Eulophidae) in South Africa Slippers, Bernard gudrun.dittrich@fabi.up.ac.za Wingfield, Michael J. Hurley, Brett P. Dittrich-Schröder, Gudrun Forest entomology Gall farmer Pest management Invasive pest Biological control. Thesis (PhD)--University of Pretoria, 2014. The hymenopteran, Leptocybe invasa, is an economically important pest in commercial and small scale Eucalyptus plantations. This gall-forming wasp has spread throughout the world in less than a decade, at least in part owing to its thelytokous mode of reproduction and development within the concealed environment of a gall. Leptocybe invasa has emerged as a significant constraint to the sustainability of Eucalyptus forestry in South Africa and studies in this thesis were undertaken to contribute towards solutions to this problem. The thesis is comprised of six chapters, of which Chapter 1 is a literature review that considers the different reproductive modes in Hymenoptera. This topic represents one of the key, but complex factors contributing to the success of L. invasa and which is important to consider in its management. The following five chapters represent individual research units related to aspects of the invasion and management of the wasp, as well as the development of tools to study these topics. Each research chapter covers its own background literature and is presented as “stand alone” units, albeit linked to the central topic of understanding and managing the global L. invasa invasion. DNA based molecular tools were used throughout the manuscript. In order to conduct any molecular analyses an important first step was to optimise DNA extraction. This is especially important when there is little starting material, such as with L. invasa wasps that are approximately 1.1 – 1.4 mm in size. The quality of the extracted product in many instances determines the type of downstream analyses possible. In Chapter 2 different commercial, as well as traditional DNA extraction techniques are compared on individual L. invasa specimens. Techniques that yielded the largest amount of DNA, the highest concentration of DNA, as well as the speed and the cost of each method are assessed. In order to control a pest it is important to understand its biology. The success of L. invasa as a global plantation forestry pest has in part been attributed to its reproductive mechanism. This wasp reproduces by thelytoky where offspring are all female and males are absent/very rare. Many invasive pests reproduce sexually in their native environment and asexually in their invaded range. In invasive populations it is important to know what mode of reproduction, sexual or asexual, is ocurring as this will influence the management and control options implemented. In Chapter 3 flow cytometric techniques that could be used to distinguish male and female specimens of L. invasa were considered. This technique has been used to distinguish male and female hymenopterans based on their ploidy. Application of this technique using hymenopterans was possible due to their haplodiploid nature, where females are diploid and males are haploid, thus distinguishing male and female specimens In Chapter 4 molecular tools to characterize the genetic diversity in global populations of L. invasa were developed and applied. These data can be used effectively to investigate invasion pathways of the wasp as well as to confirm the reproductive mode/s and give an indication of the genetic diversity present within regional populations. Understanding the genetic diversity of a pest population has relevance when evaluating the potential of biological control and breeding for resistance. Given that L. invasa is amongst the most damaging emerging insect pests in Eucalyptus forestry, much emphasis is placed on rapid development of management tools using biological control and breeding for resistance. In Chapters 5 and 6, both these control options are considered. Firstly in Chapter 5, the biology and host specificity of a newly described parasitic wasp species, Selitrichodes neseri was studied in order to consider its potential as a biological control agent. Finally, in Chapter 6, tools were developed and used to compare the susceptibility between Eucalyptus species, genotypes and clones towards L. invasa attack. Zoology and Entomology PhD 2026-05-15T17:26:09Z 2026-05-15T17:26:09Z 15/02/03 2014 Thesis http://hdl.handle.net/2263/110045 en application/pdf |
| spellingShingle | Forest entomology Gall farmer Pest management Invasive pest Biological control. Molecular ecology and management of Leptocybe invasa (Hymenoptera: Eulophidae) in South Africa |
| title | Molecular ecology and management of Leptocybe invasa (Hymenoptera: Eulophidae) in South Africa |
| title_full | Molecular ecology and management of Leptocybe invasa (Hymenoptera: Eulophidae) in South Africa |
| title_fullStr | Molecular ecology and management of Leptocybe invasa (Hymenoptera: Eulophidae) in South Africa |
| title_full_unstemmed | Molecular ecology and management of Leptocybe invasa (Hymenoptera: Eulophidae) in South Africa |
| title_short | Molecular ecology and management of Leptocybe invasa (Hymenoptera: Eulophidae) in South Africa |
| title_sort | molecular ecology and management of leptocybe invasa hymenoptera eulophidae in south africa |
| topic | Forest entomology Gall farmer Pest management Invasive pest Biological control. |
| url | http://hdl.handle.net/2263/110045 |