Controlling Philornis downsi
The introduced parasitic fly, Philornis downsi, is believed to be the main cause of decline of landbird species on the Galapagos Islands. Philornis downsi lays its eggs in nests with incubating birds and its larvae feed on the blood of the nestlings, sometimes causing up to 100% chick mortality in a nest. At least 16 of 20 “song”” bird species only found in Galapagos are now threatened by P. downsi, including the iconic “Darwin’s finches”. In the case of the critically endangered Mangrove Finch, only 80 individuals remain in the wild.
Members of an international workshop in the Galapagos Islands developed a strategic plan for researching methods in 2012, to reduce the impact of Philornis downsi. Our Philornis project team are now working with local and international collaborators from eight countries. Together, we are studying the biology and behavior of Philornis and investigating potential control options, such as trapping using attractants and biological control using natural enemies. A two-year monitoring program has just been completed and data is being analyzed to understand the behavior of the fly in relation to bird breeding activity. In the laboratory, our team has also managed to develop methods for rearing Philornis downsi in captivity, to support our research into control methods.
Collaborators: Galapagos National Park Directorate, Galapagos Biosecurity Agency (ABG), University of Vienna, St Louis Zoo, Missouri, SUNY-ESF, University Minnesota, Hebrew University (Israel), LECEN - ICIVET LITORAL (Argentina), Flinders University, University of Utah, University of West Indies, FUNDAR, University of Guayaquil.
Funders: Galapagos Conservancy, International Community Foundation (with a grant awarded by The Leona M. and Harry B. Helmsley Charitable Trust), Galapagos Conservation Trust and Saint Louis Zoo Wildcare.
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