Parasitized Male Field Crickets Exhibit Reduced Trilling Bout Rates and Durations

Abstract

AbstractThe reproductive compensation hypothesis suggests that recently parasitized animals could offset future reproductive losses by increasing their current reproductive effort. We test this hypothesis by determining how male Texas field crickets (Gryllus texensis) alter their mate attraction displays following parasitism by acoustically orienting female parasitoid flies Ormia ochracea (Diptera, Tachinidae, Ormiini). Larval tachinid parasitoids cause little damage in phase I of host infestation. However, substantial host damage occurs in phase II, which results in parasitoid emergence and host death. We predicted that recently parasitized crickets would increase their mate attraction behaviour over pre‐parasitism levels to enhance their abilities to attract a mate in phase I. Contrary to our prediction, during phase I neither total signalling time, trilling bout duration, trilling bout rate or amplitude changed from pre‐parasitism levels. During phase II male crickets had significantly reduced total signalling times, and produced calls of significantly shorter duration at significantly slower trilling bout rates. Our results suggest that male Texas field crickets do not compensate for their shortened lifespan by increasing their reproductive effort following parasitism.