Predicting predation efficiency of biocontrol agents: linking behavior of individuals and population dynamics

Behavioral ecology and population ecology are two separate branches of ecology; studies linking the effect of individual behavior and population dynamics are rare. This paper connects a stochastic optimal foraging model of insect predators with an age structured population model of its prey. I modeled syrphid larvae feeding on cereal aphids, an interaction critical to cereal crops in Germany. The key stochastic element in this model is the foraging success of predators, which influences survival and developmental time of predators and mortality of the prey population. The model predicts that the level of control incurred by predators is highest if predators arrive when prey numbers are still small, the growth rate of prey population is small, and predator density is moderately high. If the number of predators per prey was high or prey distribution was much aggregated, predators were less successful in finding prey. As a result predation efficacy was reduced.