Arthropod community structure predicts natural pest control resilience to insecticide exposure

Greenop, Arran and Cook, Samantha and Wilby, Andy and Pywell, Richard F. and Woodcock, Ben A. (2020) Arthropod community structure predicts natural pest control resilience to insecticide exposure. Journal of Applied Ecology. ISSN 0021-8901 (In Press)

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Abstract

1. Biological pest control has become one of the central tenets of ecological intensification in agriculture. However, invertebrate natural enemies within agricultural ecosystems are exposed to a myriad of different pesticides at both lethal and sub-lethal doses, which can limit their capacity to carry out pest control. An important question is to understand how underlying diversity in invertebrate predator species, linked to their unique susceptibility to insecticides, can act to increase the resilience of natural pest control. 2. We explore this issue by assessing the effects of sub-lethal insecticide exposure on the predation rates of 12 generalist predators feeding on the aphid Sitobion avenae (Aphididae). Predation rates within a 24 hr period were assessed (predation assessment) for each species after receiving one of the following treatments: 1) no prior deltamethrin exposure before the predation assessment (control); 2) deltamethrin exposure immediately before the predation assessment (resistance); and 3) deltamethrin exposure five days before the predation assessment (recovery). Extrapolating from these species specific measures of resistance and recovery, we predicted the resilience of community level predation to insecticide exposure for predator communities associated with 256 arable fields in the UK. 3. There was large variation in sub-lethal effects of pesticide between even closely related species. This ranged from species showing no change in predation rates following sub-lethal insecticide exposure (high resistance), species showing only immediate depressed feeding rates after 24hrs (high recovery), or those with depressed feeding rates after five days (low resistance and recovery). 4. The community level analysis showed that resistance and recovery of natural pest control was predicted by both community phylogenetic diversity (positively) and weighted mean body mass (negatively). However, the removal of numerically dominant species from the analysis modified these effects. 5. Synthesis and applications. Our results highlight the importance of community diversity in maintaining the resilience of natural pest control following insecticide use. This suggests that while individual predator species may be the most efficacious in supporting pest control, communities dominated by such species may be more susceptible to depressed pest control than diverse assemblages exposed to typical insecticide based farmland management. However, the susceptibility of numerically dominant species is likely to alter diversity effects.

Item Type:
Journal Article
Journal or Publication Title:
Journal of Applied Ecology
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/2300/2303
Subjects:
ID Code:
147360
Deposited By:
Deposited On:
25 Sep 2020 10:30
Refereed?:
Yes
Published?:
In Press
Last Modified:
25 Sep 2020 10:30