Predator functional responses and the biocontrol of aphids and mites

Biocontrol with predators is a key tool for controlling agricultural pests and preserving the productive efficiency of crops. Determining which predators to use for biocontrol often involves measuring their functional response-the relationship between foraging rate and prey abundance, yet comparisons of functional responses across predators are complicated by differences in experimental procedures. Here we use a compilation of functional responses standardized for time and space units to illustrate key sources of variation in functional responses for predators being tested for control of aphids and mites. Our results show that arena size (as a proxy for habitat structure) is a crucial predictor of predator performance, indicating that assessments of functional responses on the crops of interest may be necessary for accurate comparisons. Our results also suggest that larger predators may generally be more efficient, and that warming linked to climate change could make biocontrol using predators more effective when pests are abundant.