Resource overlap and infrequent predation on key pests show vulnerability in cotton biological control services

Authors: SCHMIDT, JASON - University Of Georgia; RUSSELL, KATHERINE - University Of Georgia; BOWERS, CARSON - University Of Georgia; Coffin, Alisa; THOMPSON, MELISSA - University Of Georgia; Grabarczyk, Erin; Tillman, Patricia - Glynn; OLSON, DAWN - Retired ARS Employee

Submitted to: Agriculture, Ecosystems and Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/2/2024
Publication Date: 7/7/2024
Citation: Schmidt, J.M., Russell, K., Bowers, C., Coffin, A.W., Thompson, M., Grabarczyk, E.E., Tillman, P.G., Olson, D. 2024. Resource overlap and infrequent predation on key pests show vulnerability in cotton biological control services. Agriculture, Ecosystems and Environment. 374. Article 109164. https://doi.org/10.1016/j.agee.2024.109164.
DOI: https://doi.org/10.1016/j.agee.2024.109164

Interpretive Summary: Maintaining diverse arthropod communities, including insects, spiders, and others, in agricultural landscapes is important for resilient agriculture systems. However, the diversity of arthropods has declined in agricultural systems, and recent studies suggest that standard pesticide applications not only harm beneficial arthropods, like spiders and wasps, but also fail to provide long-term pest control solutions. Increasing the number of different types of arthropods in agricultural systems is a challenge because knowledge is limited about pest and predator communities, and how they interact. Additional studies are required that characterize pest and predator communities as well as their interactions in food web networks. We explored community interactions of predatory species that feed on key pests and alternative prey in cotton fields near Ashburn, Georgia, over a three-year period. We built graphs of food webs based on the analysis of gut contents of predators and counts of pests and predators in the environment. Overall, many predator diets overlapped, resulting in similar foraging patterns on groups of cotton pests. However, predation on key cotton pests, such as stink bugs and white flies, was low. A lack of predators in this community suggests that natural pest control could be improved and strengthened. Improving agricultural habitats in and around agricultural fields to increase predatory arthropods in cotton communities may be a path forward to diversify biological control services.

Technical Abstract: Promoting arthropod biodiversity to increase ecosystem services through ecological intensification is a challenge for agriculture. And recent evidence suggests that standard pesticide applications not only harm natural enemies but may also fail to deliver long-term pest control solutions. To better understand the dynamics of biodiversity and resulting services, linking estimates of pests, with predator species, and associated interactions will help build predictive frameworks to estimate effective arthropod natural enemy communities. We took a network-based approach to investigate community interactions of predatory arthropods that feed on key pests and alternative prey in cotton over a three-year period. We merged prey activity, generalist predator communities collected from cotton canopies, and reconstructed trophic interactions with DNA detection frequencies estimated from molecular gut content analysis. Overall, many predator diets overlap, resulting in similar foraging patterns on groups of cotton pests. Moreover, predation on key cotton pests, such as stink bugs and white flies, was low. Therefore, increasing specialized arthropod predators in this community should improve biological control service delivery.