Effects of fly parasitoids on nightly calling duration in field crickets

Abstract

The song of male field crickets, Gryllus integer (Orthoptera: Gryllidae), attracts flies, Euphasiopteryx ochracea (Diptera; Tachinidae). Flies deposit larvae on male crickets and the larvae burrow in and consume the host. Effects of fly parasitism on duration of calling in G. integer were studied. Male crickets were collected at street lights and placed in jars and were electrically monitored for calling song. Calling duration was measured for 7 nights. Fly larvae were then placed on males and calling duration was measured for an additional 7 nights. In two replicates, males called significantly less following parasitism, and average calling duration declined gradually before death. Other males which remained free of fly larvae showed no reduction in calling. Field-collected males which subsequently died from fly parasitism called significantly less than non-parasitized males. Acoustically orienting flies reduce the ability of parasitized males to attract females acoustically.