Imidacloprid seed treatments affect individual ant behavior and community structure but not egg predation, pest abundance or soybean yield

• Published in: Pest management science Vol. 73; no. 8; pp. 1625 - 1632
• Main Authors: Penn, Hannah J, Dale, Andrew M
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.08.2017; Wiley Subscription Services, Inc
• Subjects: Abundance; Animals; ant predation; Ants; Ants - drug effects; Ants - physiology; Biodiversity; Biological control; Coating effects; Communities; Community composition; Community structure; Composition effects; Crop yield; Crops; Ecosystems; Eggs; Exposure; food web; Forage; Glycine max - drug effects; Glycine max - growth & development; Imidacloprid; Incidence; Indicators; Insecticides; Insecticides - pharmacology; Locomotion; Locomotion - drug effects; Morbidity; neonicotinoid; Neonicotinoids - pharmacology; Nitro Compounds - pharmacology; non‐target effect; Ovum - drug effects; Ovum - physiology; Pest Control; Pests; Predation; Predatory Behavior - drug effects; Seed coats; Seed treatments; Seeds; Seeds - drug effects; Seeds - growth & development; Soybeans; Species diversity; Species richness; Sublethal effects; Survival; non-target effect; neonicotinoid; species diversity; ant predation; food web
• ISSN: 1526-498X; 1526-4998
• DOI: 10.1002/ps.4499

BACKGROUND Neonicotinoid seed treatments are under scrutiny because of their variable efficacy against crop pests and for their potential negative impacts on non‐target organisms. Ants provide important biocontrol services in agroecosystems and can be indicators of ecosystem health. This study tested for effects of exposure to imidacloprid plus fungicide or fungicide‐treated seeds on individual ant survival, locomotion and foraging capabilities and on field ant community structure, pest abundance, ant predation and yield. RESULTS Cohorts of ants exposed to either type of treated seed had impaired locomotion and a higher incidence of morbidity and mortality but no loss of foraging capacity. In the field, we saw no difference in ant species richness, regardless of seed treatment. Blocks with imidacloprid did have higher species evenness and diversity, probably owing to variable effects of the insecticide on different ant species, particularly Tetramorium caespitum. Ant predation on sentinel eggs, pest abundance and soybean growth and yield were similar in the two treatments. CONCLUSION Both seed treatments had lethal and sublethal effects on ant individuals, and the influence of imidacloprid seed coating in the field was manifested in altered ant community composition. Those effects, however, were not strong enough to affect egg predation, pest abundance or soybean yield in field blocks. © 2016 Society of Chemical Industry