Acoustic preferences and localization performance of blood-sucking flies (Corethrella Coquillett) to tungara frog calls

Mating signals that increase attractiveness of males to femalescan also increase conspicuousness of the signaler to predatorsand parasites. We investigated the acoustic preference of speciesof blood-sucking flies of the genus Corethrella (Diptera: Corethrellidae),which eavesdrop on the sexual advertisement signals of túngarafrogs (Physalaemus pustulosus). Male frogs of this species facultativelyproduce 2 types of mating calls: simple (whines alone) and complex(whines and chucks). We tested the acoustic preference of theflies and their ability to locate their host when the frogsproduce simple or complex calls. The flies exhibited phonotaxisto both types of calls but were preferentially attracted tocomplex calls. We show that acoustic information alone is sufficientfor the flies' accurate localization of calling frogs. Complexcalls, however, were not approached at closer distance or withdecreased landing error (i.e., proportion of landings outsidethe target) than simple calls, suggesting that call structuredoes not influence localization performance. Female túngarafrogs and frog-eating bats (Trachops cirrhosus) also prefercomplex to simple túngara frog calls. Thus, intendedand unintended receivers with different ear morphologies exhibitthe same preference for a specific túngara frog calltype. This result is discussed in the context of the evolutionof call attractiveness in a communication network.