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The semiochemistry of fruits as seen through the lens of Tephritid fruit flies and their parasitoids
Dissertation (PhD (Chemistry))--University of Pretoria, 2024.
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| Format: | Thesis |
| Language: | English |
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University of Pretoria
2024
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| _version_ | 1867613506634776576 |
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| access_status_str | Open Access |
| author2 | Rohwer, Egmont Richard |
| author_browse | Rohwer, Egmont Richard |
| author_facet | Rohwer, Egmont Richard |
| collection | Thesis |
| dc_rights_str_mv | © 2023 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 (PhD (Chemistry))--University of Pretoria, 2024. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/94664 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:37:14.131Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2024 |
| publishDateRange | 2024 |
| publishDateSort | 2024 |
| 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:2263/94664 The semiochemistry of fruits as seen through the lens of Tephritid fruit flies and their parasitoids Rohwer, Egmont Richard mianorn@gmail.com Ahmed Yusuf, Abdullahi Mohamed, Samira A Dekker, Teun Njurai Miano, Raphael Fruit Fruit fly Parasitoid GC-MS/GC-EAD Semiochemicals UCTD Dissertation (PhD (Chemistry))--University of Pretoria, 2024. The tephritid fruit fly is a term well-known in fruit and vegetable production. Several techniques including the use of parasitoids have been deployed for fruit fly control. In Sub-Saharan Africa, Fopius arisanus (Sonan) and Diachasmimorpha longicaudata (Ashmead) (Hymenoptera: Braconidae) have been introduced to supplement the existing native parasitoids. Although the effectiveness of parasitoids is known, there is a knowledge gap in the semiochemical-mediated interactions among tree-attached fruits, fruit flies, and parasitoids. Here, I aimed to compare the attraction of fruit flies and parasitoids to different fruits, evaluate fruit fly performances, in terms of recovered puparia, in these fruits and elucidate the fruits’ headspace volatile compounds. First, the attraction of Bactrocera dorsalis (Hendel), F. arisanus and D. longicaudata to the headspace volatiles of different treatments of three varieties of mangoes were compared. B. dorsalis and the two parasitoids were differentially attracted to the mango headspace volatiles compared to the control, clean air. A higher number of B. dorsalis puparia was recovered in the Apple mango variety (81.7%) but none from the Kent variety. Gas chromatography- mass spectrometry revealed several organic compounds with qualitative and quantitative differences. The majority of tentatively identified compounds were esters (33.8%). Most compounds were produced at higher concentrations by fruit fly-infested mangoes than non-infested ones. A similar approach to B. dorsalis' was followed on Ceratitis cosyra, the two parasitoids and its native Psyttalia cosyrae (Wilkinson). C. cosyra and the parasitoids differentially responded to the treatments of the three mango varieties. Ceratitis cosyra performed better in Kent mango (72.1% of the 287 puparia recovered) compared to Apple and Haden varieties. Esters were the main components of the non-infested ripe and the late post-oviposition larval stages of the three mango varieties. At the same time, monoterpenes and sesquiterpenes were dominant in the other mango treatments. The performances of B. dorsalis, C. cosyra, Zeugodacus cucurbitae and B. latifrons on different species of fruits (mango cv. Haden, banana cv. Fhia-17, and tomato cv. Improved Nouvelle F1) were investigated and the headspace volatiles of different treatments of the three mango varieties, ripe bananas and tomatoes analyzed using GC-MS and GC-electroantennographic detection (EAD). The fruit fly species performed differentially in the different fruits. There were overlapping detections of most EAD-active compounds across the four fruit fly species and parasitoids with esters being the most prevalent class of compounds. This study represents the first report of the interactions of different fruit fly species and their parasitoids to in situ headspace volatiles of different treatments of mangoes and the subsequent changes in the headspace components of these mango treatments. Results obtained not only provide a better understanding and add new knowledge to science on the dynamic interactions of the selected tephritid fruit fly species and their parasitoids to a variety of hosts with different physiological states but also show a convergence of fruit fly and parasitoid antennal-active compounds hence presenting an informed foundation for future reference in developing sound Integrated Pest Management (IPM) strategies for managing fruit flies without harming parasitoids. The Norwegian Agency for Development Cooperation (NORAD), the Section for Research, innovation, and higher education for the project “Combatting Arthropod Pests for Better Health, Food and Climate Resilience (grant number RAF-3058 KEN-18/0005); Swedish Research Links grant 2020-05344 Chemistry PhD (Chemistry) Unrestricted Faculty of Natural and Agricultural Sciences SDG-15:Life on land 2024-02-16T07:34:31Z 2024-02-16T07:34:31Z 2024-04-22 2024-02 Dissertation * http://hdl.handle.net/2263/94664 https://doi.org/10.25403/UPresearchdata.25223741 en © 2023 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 | Fruit Fruit fly Parasitoid GC-MS/GC-EAD Semiochemicals UCTD The semiochemistry of fruits as seen through the lens of Tephritid fruit flies and their parasitoids |
| title | The semiochemistry of fruits as seen through the lens of Tephritid fruit flies and their parasitoids |
| title_full | The semiochemistry of fruits as seen through the lens of Tephritid fruit flies and their parasitoids |
| title_fullStr | The semiochemistry of fruits as seen through the lens of Tephritid fruit flies and their parasitoids |
| title_full_unstemmed | The semiochemistry of fruits as seen through the lens of Tephritid fruit flies and their parasitoids |
| title_short | The semiochemistry of fruits as seen through the lens of Tephritid fruit flies and their parasitoids |
| title_sort | semiochemistry of fruits as seen through the lens of tephritid fruit flies and their parasitoids |
| topic | Fruit Fruit fly Parasitoid GC-MS/GC-EAD Semiochemicals UCTD |
| url | http://hdl.handle.net/2263/94664 https://doi.org/10.25403/UPresearchdata.25223741 |