In the tropics, precipitation patterns result in seasonal fluctuations in the abundance and distribution of plant and animal species. Tropical predators and parasites are therefore faced with seasonal changes in prey and host availability.
2. This study investigates the seasonal interaction among a specialised ectoparasite, eavesdropping frog-biting midges (Corethrella spp.), and their anuran hosts, examining how the abundance and diversity of the frog-biting midge community fluctuate between the rainy (host abundant) and dry (host sparse) seasons.
3. Midges were captured in both the rainy and dry seasons using acoustic playbacks of calls from a common frog species that breeds during the rainy season, the túngara frog (Engystomops, Physalaemus, pustulosus). During the dry season túngara frog choruses are absent. To explore seasonal shifts in host preference or changes in the midge community due to host specificity, midges were also captured using playbacks of calls from a frog that breeds during the dry season, the pug-nosed tree frog (Smilisca sila).
4. While the overall abundance of midges decreased in the dry season, only slight differences in the relative abundance between midge species were found. These results suggest that midge populations can shift between hosts as they become available across seasons, allowing adult populations of frog-biting midges to persist year-round. To overcome the challenge of detecting and localising different host species, it is proposed that frog-biting midges have evolved a generalised acoustic template, allowing them to respond to a broad range of available hosts, regardless of seasonal host composition.