D3148: Identification of male-produced pheromone from Philornis downsi, an invasive avian parasite of Galápagos

The invasive fly Philornis downsi (Diptera, Muscidae) was introduced to the Galápagos archipelago by the 1960s and quickly became established due to its broad host range, absence of predators, and low resistance to parasitism among native Galápagos avian hosts. Nestling mortality from parasitism is a threat to endemic passerine species in the Galápagos archipelago, and there is a concerted effort to develop diverse management strategies for this invasive parasite. The development of a species-specific chemical lure for P. downsi is a high priority for the conservation of declining endemic bird species. Body wash extracts of P. downsi were analyzed using GC-EAG to determine if there were potentially attractant components. Three compounds were identified as potential attractants to female P. downsi. One of these compounds, 9-methyl heneicosane, was confirmed in previous work (n.p.) to be a male-produced cuticular hydrocarbon and was thus selected for synthesis. The compound was synthesized in a two-step, one pot Nickel-catalyzed Suzuki cross-coupling reaction from commercially available starting materials. Ongoing work includes assessing the behavioral activity of this compound for attraction by female P. downsi using Y-tube olfactometer bioassays. Outcomes of this work include the development of chemical lures for monitoring and an understanding of the roles of chemical cues in the mating system of P. downsi.