Controlling Parasitic Flies

Controlling Parasitic Flies


Chemical Attractants of Philornis downsi, an Avian Parasite of the Galapagos Islands


SUNY-ESF and the Galapagos National Park Directorate


Funded in 2013; ongoing



Mockingbird © Jenny Howard.



Philornis downsi is a blood-feeding, parasitic fly that was introduced to Galapagos (first discovered there in 1997) and is causing substantial levels of mortality in several species of endemic birds, including the critically endangered medium ground finch, mangrove Finch, and Floreana mockingbird.

Mortality is caused by blood loss to nestlings, and the presence of Philornis in a nest often causes 100% brood failure. The proposed research builds on the past two and one-half years of unsupported research at SUNY-ESF with the primary objective of identifying chemical attractants that can serve as a cornerstone of a future pest management effort. Insect chemical attractants may be food odors or pheromones, and combinations of them can be used to monitor pest populations or to suppress populations through a variety of strategies that are well established in agricultural and forestry pest management.

This study utilizes established methods of field observation, trapping, chemical sampling, and analysis to identify the most effective combination of chemical attractants for P. downsi. Potential, specific uses of chemical attractants against P. downsi include population monitoring, detection, mass trapping, and mating disruption; any or all of these may be combined with other pest management strategies such as the sterile insect technique to enhance efficacy and reduce or eliminate nestling mortality.

Note: Another GC-funded complimentary project currently run by CDF adjunct scientist, Charlotte Causton, specifically examines the threat of Philornis downsi to Darwin’s finches and seeks to define solutions and control methods for this very serious threat to Galapagos bird nestlings.

Read the May 2015 journal publication: Philornis downsi, An Avian Nest Parasite Invasive to the Galapagos Islands, in Mainland Ecuador by Bulgarella et. al, Annals of the Entomological Society of America.

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