Abstract
Since its discovery in 1997, Philornis downsi has been shown to reduce fledgling success and fitness in many bird species within the Galapagos, including the endemic and critically endangered Darwin’s finches. Despite its impact, there are currently no practical methods to control the nest parasite. This study investigated potential kairomones that adult P. downsi use to locate bird nests, with the goal of developing an efficient olfaction-based method to monitor and control the insect. Volatile organic compounds were collected from the feces, uropygial glands, and eggs of laboratory- reared zebra finches, as well as whole-nest headspace from zebra finches, central New York birds, and finches in the Galapagos. Selected compounds were then tested for electrophysiological and behavioral response using GC-EAD/EAG and laboratory/field bioassays with adult P. downsi. Acetone, collected from eggs, and uropygial gland extracts was shown to illicit electrophysiological responses in the adult fly, but no compounds tested demonstrated attractiveness.