Negative impacts from intensifying agriculture have generated concerns that pollinator-dependent crop species, such as courgette Cucurbita pepo L., may be experiencing a pollination deficit. This thesis explores the extent to which pollination influences fruit set; how pollination could be improved; and how in doing so growers’ profits and agricultural resilience could increase, using UK field-grown courgettes as a model system. Inspired by evidence of parthenocarpy (fruit set in the absence of fertilisation) in courgette, a systematic review showed extensive use of parthenocarpy to circumvent the need for pollination in other ‘pollinator-dependent’ crop species across the globe. Nonetheless, pollination significantly increased yield and pollinators were abundant enough to fulfil the pollination requirements of courgette, which if extrapolated to the rest of the UK, equates to pollinators contributing approximately £2.7 million to annual UK courgette production. Furthermore, wild flowers within fields were shown to be effective at increasing the abundance of bumblebees and solitary bees. Further exploration of the mutualistic relationship between courgettes and pollinators showed that courgette can improve populations of Bombus terrestris (using the Bumble-BEEHAVE model), an important pollinator of courgette. This thesis concludes that pollination is a vital mechanism for ensuring optimal courgette yields and that whilst pollination levels were maximal at study sites, simple management, such as encouraging wild flowers within courgette fields could help to attract pollinators to courgette flowers and support bees’ nutritional requirements beyond the extensive, yet transient, resource provided by courgette. Understanding a crop’s requirement for pollinators can also aid growers in their decision making about what varieties and sites should be used which could increase their agricultural resilience and further their economic advantage. Further work is needed to understand how other environmental factors interact with pollination to influence fruit set so that growers can prioritise key regulating services in their management for optimal crop yields.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:754267 |
| Date | January 2018 |
| Creators | Knapp, Jessica Louise |
| Contributors | Osborne, Juliet |
| Publisher | University of Exeter |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/10871/33914 |
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