摘要
•Most natural enemies in crop systems are omnivorous, and availability of plants, prey, and structural habitat determines their recruitment and retention.•We manipulated weed seeds, fly pupae, and cover crops in the field and used protein-based gut content analyses to link resource-mediated changes in omnivore assembly with biocontrol services.•Cover crops increased the frequency of weed seed consumption by omnivorous predators by 73%.•Only plant-based resources (seeds and vegetated habitat) induced predictable effects on foraging behavior.