Constraints on Neltumius arizonensis (Coleoptera: Bruchidae) as a biocontrol agent of prosopis in South Africa : the role of parasitoids

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dc.contributor.advisor Hoffmann, John H en_ZA Roberts, Anthony en_ZA 2017-12-07T09:25:13Z 2017-12-07T09:25:13Z 2000 en_ZA
dc.description.abstract 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. en_ZA
dc.language.iso eng en_ZA
dc.subject.other Botany en_ZA
dc.subject.other Biological Conservation en_ZA
dc.title Constraints on Neltumius arizonensis (Coleoptera: Bruchidae) as a biocontrol agent of prosopis in South Africa : the role of parasitoids en_ZA
dc.type Thesis en_ZA 2017-02-03T12:44:26Z
uct.type.publication Research en_ZA
uct.type.resource Thesis en_ZA
dc.publisher.institution University of Cape Town
dc.publisher.faculty Faculty of Science en_ZA
dc.publisher.department Department of Biological Sciences en_ZA
dc.type.qualificationlevel Honours en_ZA
dc.type.qualificationname BSc (Hons) en_ZA
uct.type.filetype Text
uct.type.filetype Image

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