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Constraints on Neltumius arizonensis (Coleoptera: Bruchidae) as a biocontrol agent of prosopis in South Africa : the role of parasitoids
1. Two species of seed feeding bruchid, Algarobius prosopis and A. bottimeri, were introduced to South Africa in 1987 and 1990 respectively, to curb the spread of the invasive weed Prosopis. Failure of A. bottimeri to establish and reduced effectiveness of A. prosopis due to interference by livestoc...
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| Format: | Thesis |
| Language: | English |
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Department of Biological Sciences
2017
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| _version_ | 1867613219947806721 |
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| access_status_str | Open Access |
| author | Roberts, Anthony |
| author2 | Hoffmann, John H |
| author_browse | Hoffmann, John H Roberts, Anthony |
| author_facet | Hoffmann, John H Roberts, Anthony |
| author_sort | Roberts, Anthony |
| collection | Thesis |
| description | 1. Two species of seed feeding bruchid, Algarobius prosopis and A. bottimeri, were introduced to South Africa in 1987 and 1990 respectively, to curb the spread of the invasive weed Prosopis. Failure of A. bottimeri to establish and reduced effectiveness of A. prosopis due to interference by livestock resulted in the release of a third species, Neltumius arizonensis in 1992. 2. Algarobius prosopis populations have remained high but N. arizonensis has not been as successful. 3. Populations ofboth bruchids showed similar emergence patterns through the sampling period hence there is no temporal partitioning of resources. 4. Percentage emergence of N. arizonensis was low at the start of the season but increased as the season progressed with higher proportions of N. arizonensis emerging from 'tree' pods than 'ground' pods. Regardless of the spatial partitioning of resources by the two bruchids, N. arizonensis emergence numbers are still far lower than those of A. prosopis (approximately 1:4 respectively). 5. Oviposition strategies of N. arizonensis results in high levels of egg parasitism by Uscana sp., Trichogrammatidae, that A. prosopis escapes by ovipositing in concealed places avoiding detection by parasitoids. 6. Egg parasitism is extremely high on N. arizonensis eggs (67%) and has resulted in failure by N. arizonensis to establish large populations and hence its effectiveness as a biocontrol agent is negligible. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/26489 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:32:39.476Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2017 |
| publishDateRange | 2017 |
| publishDateSort | 2017 |
| publisher | Department of Biological Sciences |
| publisherStr | Department of Biological Sciences |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/26489 Constraints on Neltumius arizonensis (Coleoptera: Bruchidae) as a biocontrol agent of prosopis in South Africa : the role of parasitoids Roberts, Anthony Hoffmann, John H Botany Biological Conservation 1. Two species of seed feeding bruchid, Algarobius prosopis and A. bottimeri, were introduced to South Africa in 1987 and 1990 respectively, to curb the spread of the invasive weed Prosopis. Failure of A. bottimeri to establish and reduced effectiveness of A. prosopis due to interference by livestock resulted in the release of a third species, Neltumius arizonensis in 1992. 2. Algarobius prosopis populations have remained high but N. arizonensis has not been as successful. 3. Populations ofboth bruchids showed similar emergence patterns through the sampling period hence there is no temporal partitioning of resources. 4. Percentage emergence of N. arizonensis was low at the start of the season but increased as the season progressed with higher proportions of N. arizonensis emerging from 'tree' pods than 'ground' pods. Regardless of the spatial partitioning of resources by the two bruchids, N. arizonensis emergence numbers are still far lower than those of A. prosopis (approximately 1:4 respectively). 5. Oviposition strategies of N. arizonensis results in high levels of egg parasitism by Uscana sp., Trichogrammatidae, that A. prosopis escapes by ovipositing in concealed places avoiding detection by parasitoids. 6. Egg parasitism is extremely high on N. arizonensis eggs (67%) and has resulted in failure by N. arizonensis to establish large populations and hence its effectiveness as a biocontrol agent is negligible. 2017-12-07T09:25:13Z 2017-12-07T09:25:13Z 2000 2017-02-03T12:44:26Z Bachelor Thesis Honours BSc (Hons) http://hdl.handle.net/11427/26489 eng application/pdf Department of Biological Sciences Faculty of Science University of Cape Town |
| spellingShingle | Botany Biological Conservation Roberts, Anthony Constraints on Neltumius arizonensis (Coleoptera: Bruchidae) as a biocontrol agent of prosopis in South Africa : the role of parasitoids |
| thesis_degree_str | Bachelor's / Honours |
| title | Constraints on Neltumius arizonensis (Coleoptera: Bruchidae) as a biocontrol agent of prosopis in South Africa : the role of parasitoids |
| title_full | Constraints on Neltumius arizonensis (Coleoptera: Bruchidae) as a biocontrol agent of prosopis in South Africa : the role of parasitoids |
| title_fullStr | Constraints on Neltumius arizonensis (Coleoptera: Bruchidae) as a biocontrol agent of prosopis in South Africa : the role of parasitoids |
| title_full_unstemmed | Constraints on Neltumius arizonensis (Coleoptera: Bruchidae) as a biocontrol agent of prosopis in South Africa : the role of parasitoids |
| title_short | Constraints on Neltumius arizonensis (Coleoptera: Bruchidae) as a biocontrol agent of prosopis in South Africa : the role of parasitoids |
| title_sort | constraints on neltumius arizonensis coleoptera bruchidae as a biocontrol agent of prosopis in south africa the role of parasitoids |
| topic | Botany Biological Conservation |
| url | http://hdl.handle.net/11427/26489 |
| work_keys_str_mv | AT robertsanthony constraintsonneltumiusarizonensiscoleopterabruchidaeasabiocontrolagentofprosopisinsouthafricatheroleofparasitoids |