Adaptations of Arthropod Predators to Agricultural Systems

Agricultural systems are habitat islands that are colonized by generalist arthropod predators. How predators find prey and apportion captured prey energy into competing physiologic demands are central adaptations that provide for the subsistence of predator populations. We have found that predators in soybeans maintain a low, consistent rate of predation, and compensate for changes in leaf area, the searching universe of predators in soybeans. Predators maintain survivorship but not reproductive effort at low prey inputs suggesting physiologic trade-offs at low prey densities. We find a major discrepancy between functional response theory and our field results, and suggest an alternative framework for study of predation under field-realistic conditions.