A Mechanistic Interpretation of Prey Selection by Anax junius Larvae (Odonata: Aeschnidae)

Abstract

Preferential orientation, pursuit, and capture by a predator have been proposed for the establishment of prey preference and prey switching; however, very little is known about which of these behaviors is actually involved in active prey selection. Based on laboratory arena experiments in which the proportions of two prey types were manipulated, I distinguished the specific foraging process underlying prey preference and prey switching in nymphs of the dragonfly Anax junius. Dragonfly nymphs showed a higher probability of pursuing the more abundant of two prey types than predicted from relative prey frequencies. An increase pursuit probability was correlated with an increased capture success on the abundant prey type. I hypothesize that prey selection in Anax junius nymphs results from a simple behavioral rule of thumb; Continue to pursue only those prey types you have successfully captured in the immediate past."