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High insect pest damage increases faba bean (Vicia faba) yield components but only in the absence of insect pollination
  • Laura Riggi,
  • Chloé Raderschall,
  • Ola Lundin
Laura Riggi
Swedish University of Agricultural Sciences

Corresponding Author:[email protected]

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Chloé Raderschall
Swedish University of Agricultural Sciences
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Ola Lundin
Swedish University of Agricultural Sciences
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Abstract

Identifying and quantifying crop stressors interactions in agroecosystems is necessary to guide sustainable crop management strategies. Over the last 50 years, faba bean cropping area has been declining, partly due to yield instabilities associated to uneven insect pollination and herbivory. Yet, interactions between pollinators and a key pest, Bruchus rufimanus (florivorous and seed predating herbivore), on faba bean yield have not been investigated. Using a factorial cage experiment in the field we investigated how interactions between two potential stressors, lack of pollination from Bombus terrestris and herbivory by B. rufimanus, affect faba bean yield. Lack of insect pollination reduced bean weight per plant by 15%. Effects of B. rufimanus herbivory differed between the individual plant and the plant-stand scale (i.e. when averaging individual plant scale responses), likely due to high variation in the level of herbivory among individual plants. At the individual plant scale, B. rufimanus herbivory increased yield but only in the absence of pollinators, possibly due to plant over-compensation and/or pollination by B. rufimanus. At the plant-stand scale, we found no effect of B. rufimanus on yield. However, there was a tendency for heavier individual bean weight with insect pollination, but only when B. rufimanus herbivory was absent, possibly due to a negative effect of B. rufimanus on the proportion of legitimate flower visits by B. terrestris. This is the first experimental evidence of interactive effects of B. terrestris and B. rufimanus on faba bean yield. Our preliminary findings of negative and indirect associations between B. rufimanus and individual bean weight call for a better acknowledgment of these interactions in the field in order to understand drivers of crop yield variability in faba bean. This study showed that herbivory can increase yield, but this effect is only detectable when investigated in combination with lack of pollination.
10 Aug 2021Submitted to Ecology and Evolution
11 Aug 2021Submission Checks Completed
11 Aug 2021Assigned to Editor
16 Aug 2021Reviewer(s) Assigned
20 Sep 2021Review(s) Completed, Editorial Evaluation Pending
29 Sep 2021Editorial Decision: Revise Minor
23 Nov 20211st Revision Received
24 Nov 2021Submission Checks Completed
24 Nov 2021Assigned to Editor
24 Nov 2021Review(s) Completed, Editorial Evaluation Pending
12 Dec 2021Editorial Decision: Revise Minor
12 Jan 20222nd Revision Received
12 Jan 2022Submission Checks Completed
12 Jan 2022Assigned to Editor
12 Jan 2022Review(s) Completed, Editorial Evaluation Pending
17 Jan 2022Editorial Decision: Accept
Mar 2022Published in Ecology and Evolution volume 12 issue 3. 10.1002/ece3.8686