Estimation of pollinating insect populations in agro-ecosystems : comparing oilseed-rape fields and AES flower-strips
(2018)
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- Authors
- Supervisors
- Jacquemart, Anne-Laure
- Abstract
- Since 2005, flower-strip Agri-Environment Schemes (AES) are subsidised in Wallonia to create insect friendly areas in fields. Flower-strips can benefit pollinator insects, which can be needed by entomophilous crops as Brassica napus. But insect diversity and abundance hosted by Walloon flower-strips and flower resources (pollen and nectar) they provide are not well known. And the exact insect pollination Brassica napus needs are still under debate. In this thesis, we investigated flower-visiting insect diversity and abundance in both B. napus fields and flower-strips. We assessed the dependency of new B. napus cultivars to insect pollination and the flower resources provided by flower-strips. We particularly focused on insect-flower interactions networks to understand which insect and plant species interacted. Apis mellifera was the only flower visitor in B. napus fields, visiting only 1% of the flowers. But the pollination deficit was low (0.1), studied cultivars were poorly impacted by insect pollination. In flower-strips we observed 85 morphotypes of flower visitors, dominated by few common polylectic species (Bombus lapidarius OTU, Apis mellifera, and Eristalis tenax). We found insects visiting 40 of the 78 sown and spontaneous plant species flowering on flower strips. Centaurea jacea (sown) provided most of the flower resources (31% of nectar, 53% of pollen) and received 44% of the insect visits, and Fabaceae species provided 52% of Bombus pollen diet. Nevertheless, flower-strips provided very few flower-resources in spring, and most of the insect species were poorly abundant.
- Affiliations
Citations
Ouvrard, P. (2018). Estimation of pollinating insect populations in agro-ecosystems : comparing oilseed-rape fields and AES flower-strips. https://hdl.handle.net/2078.5/46091