Prospects for biological control of the avian nest parasite Philornis downsi in the Galápagos Islands

BULGARELLA , M.; HEIMPEL, G.; BRITO VERA, G.; QUIROGA, M.

Minneapolis

Conferencia; Entomological Society of America Meeting; 2015

Entomological Society of America

Philornis downsi is a bird-parasitic muscid fly that is native to mainland South America but has recently invaded the Galápagos Islands, where it is parasitizing Darwin?s finches and other land birds. This parasite was previously known from Brazil, Argentina and Trinidad & Tobago. We provide here the first report of P. downsi from mainland Ecuador, supporting the hypothesis that the invasion route of P. downsi from its native range to the Galápagos Islands includes mainland Ecuador. Our collections also uncovered pupal remains of 3 other different morphologies of pupal exuvia that belong to different fly species. Dipteran nest parasites were found parasitizing 22% and 27% of naturally occurring nests at 2 sites in western Ecuador in 2013 and 2014, respectively. Philornis downsi was the species infesting 74% and 40% of the nests parasitized in 2013 and 2014, respectively. These records included new bird host species for the genus Philornis: the Streak-headed Woodcreeper (Lepidocolaptes souleyetii) and the Fasciated Wren (Campylorhynchus fasciatus). The levels of nest parasitism that we found are much lower than levels reported for the Galápagos Islands and are within the range of values in previous studies on mainland South and Central America. Finally, we found that one P. downsi pupa collected in 2013 had been attacked by a parasitoid in the genus Brachymeria (Hymenoptera, Chalcididae). Overall, 9% of fly pupae collected in 2013, and 14% of those collected in 2014, had emergence holes of unidentified parasitoid species.