COS 54-9
Linking habitat management with predator-prey interactions through molecular gut-content analysis
Enhancing the habitat diversity of agroecosystems can promote biological control by encouraging colonization and population growth of natural enemies. However, few studies have taken the next step to estimate the corresponding effects of habitat management on biological control services and trophic structure of the resulting natural enemy communities. We examined the effects of habitat management on the pest and predator populations, and trophic links between pests and predators using molecular gut-content analysis in an experimental cabbage field. In response to a factorial design of cover crop mulch and herbicide treatments, we counted the numbers of two pests, Plutella xylostella Linnaeus (Lepidoptera: Plutellidae) and Pieris rapae Linnaeus (Lepidoptera: Pieridae), and predators. To measure predation, we designed P. xylostella and P. rapae DNA primers.
Results/Conclusions
Pieris rapae were significantly more abundant in plots where cover crops were killed early in the season and predator communities were different between low versus high weed management plots. The molecular gut-content analysis revealed that 35% of predators tested positive for prey DNA, and habitat management influenced predation of P. xylostella. Combined we found complex effects of habitat management on both community structure of the natural enemies and that molecular diagnostics improves analysis of the effects of proposed habitat management strategies on natural enemy-pest systems.