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Hoverflies (Diptera : Syrphidae) as pollinators of sunflowers in the Waterberg region of Limpopo province, South Africa
Dissertation (MSc (Entomology))--University of Pretoria, 2023.
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| Format: | Thesis |
| Language: | English |
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University of Pretoria
2023
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| _version_ | 1867613498477903872 |
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| access_status_str | Open Access |
| author2 | Weldon, Christopher W. |
| author_browse | Weldon, Christopher W. |
| author_facet | Weldon, Christopher W. |
| collection | Thesis |
| dc_rights_str_mv | © 2022 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Dissertation (MSc (Entomology))--University of Pretoria, 2023. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/90367 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:37:06.348Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2023 |
| publishDateRange | 2023 |
| publishDateSort | 2023 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/90367 Hoverflies (Diptera : Syrphidae) as pollinators of sunflowers in the Waterberg region of Limpopo province, South Africa Weldon, Christopher W. xavierbrits@gmail.com Midgley, John Human, Hannelie Brits, Xavier UCTD Entomology Syrphidae Sunflower Agricultural sector Pollinators Dissertation (MSc (Entomology))--University of Pretoria, 2023. Pressure is being placed on the agricultural sector to supply an ever-growing demand for food as the population continues to increase globally. This is further complicated by a continues decrease in pollinators needed for fruit or seed yield due to human activity. One such crop is the economically important sunflower (Helianthus annuus L.), prised for its oil and use in animal feed production. Sunflowers are self-pollinated, however, result in a reduced yield without the interaction of pollinators. Most sunflower farms in South Africa rely on wild pollinators or managed honey bees for this service, but the dynamics of these pollinators is poorly known. This study aimed to create a better understanding of the role hover flies have in the pollination of sunflowers, focussing the study on the Lehau, South Africa, sunflower producing region. The two main objectives were (i) to determine hover fly assemblage in and around sunflowers fields during the growing season and (ii) to evaluate their sunflower visitation based on pollen load as well as to quantify their contribution to seed set. Hover fly assemblage was determined sweep net sampling on five sunflower fields and species identification based on taxonomic guides. This showed eleven species present in the area with Ischiodon aegyptius being the most abundant species throughout the growing season. Hover flies followed an edge effect with most of the sampled individuals being close to edge of the fields. Pollen load on the hover fly bodies was determined by comparing them to a pre-created pollen atlas from wildflowers found within a 100m radius of sample fields. This revealed that Asteraceae and Solanaceae were the two most prominent wildflowers interactions, with the sunflower containing Asteraceae pollen group being present on almost all of the sampled species. Contribution to seed set was established be enclosing pollinators (Syrphinae, Eristalinae, Muscidae and Apis mellifera) in voile bags on sunflower heads for 24 hours and comparing that to heads were pollinators were excluded and heads that was open to all pollinators for 24 hours. This resulted in Muscidae interaction showing the largest contribution to the proportion of pollinated seeds with Syrphinae interaction showing the second highest contribution. This showed that not only do a diverse assemblage of hover flies interact with sunflowers, but they do also contribute to the seed set. Ischiodon aegyptius is the most likely candidate for mass rearing as it is a generalist pollinator present throughout the growing season and can interact with a diverse assemblage of wildflowers as alternative food source when sunflower heads are not yet present. Zoology and Entomology MSc (Entomology) Unrestricted 2023-04-05T08:36:56Z 2023-04-05T08:36:56Z 2023 2023 Dissertation * S2023 http://hdl.handle.net/2263/90367 10.25403/UPresearchdata.22352968 en © 2022 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria |
| spellingShingle | UCTD Entomology Syrphidae Sunflower Agricultural sector Pollinators Hoverflies (Diptera : Syrphidae) as pollinators of sunflowers in the Waterberg region of Limpopo province, South Africa |
| title | Hoverflies (Diptera : Syrphidae) as pollinators of sunflowers in the Waterberg region of Limpopo province, South Africa |
| title_full | Hoverflies (Diptera : Syrphidae) as pollinators of sunflowers in the Waterberg region of Limpopo province, South Africa |
| title_fullStr | Hoverflies (Diptera : Syrphidae) as pollinators of sunflowers in the Waterberg region of Limpopo province, South Africa |
| title_full_unstemmed | Hoverflies (Diptera : Syrphidae) as pollinators of sunflowers in the Waterberg region of Limpopo province, South Africa |
| title_short | Hoverflies (Diptera : Syrphidae) as pollinators of sunflowers in the Waterberg region of Limpopo province, South Africa |
| title_sort | hoverflies diptera syrphidae as pollinators of sunflowers in the waterberg region of limpopo province south africa |
| topic | UCTD Entomology Syrphidae Sunflower Agricultural sector Pollinators |
| url | http://hdl.handle.net/2263/90367 |