The influence of prey availability on predator-prey food webs in high tunnels

High tunnels, a form of protected agriculture for growing specialty crops, are a cost-effective way to protect crops from adverse weather conditions and expand the growing season.  Unlike greenhouses, high tunnels have open sides to control temperature, allowing the immigration of pests and natural enemies from the adjacent open fields. Pest populations and predator-prey relationships are understudied in high tunnels, and high tunnels may be excellent environments for implementing conservation biological control. High tunnels are on a continuum from strict monocultures to polycultures. Monoculture growing practices can reduce arthropod biodiversity and abundance, changing predator-prey interactions and potentially reducing effective conservation biological control from occurring. For this experiment, predatory arthropods were collected monthly from three monoculture and seven polyculture high tunnels throughout Illinois in 2023 and 2024. Yellow sticky cards were collected and replaced weekly to monitor pest pressure in each tunnel. Molecular gut-content analysis was used to determine trophic linkages between predators and pests. Using a generalized linear model, the relationship between prey availability and average prey consumption was compared. The results were compared between monoculture and polyculture tunnels to determine how crop diversity affects predator-prey interactions. Pinpointing the trophic linkages between resident predators and pest insects is an initial step in implementing a successful conservation biological control program.