Measuring biological control using surrogate prey items in winter wheat
Surrogate prey (insects or seeds) forming sentinels were used to measure the effects of semi-natural habitats at field to landscape scales on levels of biological control in winter wheat in the UK. Sentinels were located adjacent to three boundary types: grassy margin, hedgerows and woodland in landscapes of varying heterogeneity. The mean levels of predation were higher for most insect prey (up to 57%) compared to seeds (up to 8%). Seminatural habitats had both positive and negative effects at field and landscape scales but the response varied with the sentinel type.