Response of natural enemies and their ecosystem services to wildflower planting size

Many arthropods provide valuable ecological services, such as natural pest suppression and pollination, which humans depend on because they support food production. An important means of conserving these beneficial insects so they provide services to food production is to meet their ecological requirements within or near crop fields. This can be achieved by providing a diverse assemblage of flowering plants that bloom throughout the season in agricultural landscapes. The importance of patch size for natural enemy abundance and diversity, and the services they provide, has not been studied in this context. In this project, the response of natural enemies and pest insects to wildflower planting size was measured by establishing twelve native Michigan flowering perennial plants in replicated plots ranging in size from 1 to 100m². These plots were sampled through the 2010 growing season by vacuum sampling of flowering portions of the plots, and through visual observations. To determine whether biological control services vary with patch size, the degree of suppression of soybean aphid (Aphis glycines) in each plot was measured by comparing the change in aphid abundance on open and covered soybean plants. The relationships between beneficial insects, the services they provide, and patch size will be discussed in the context of conservation biological control.