Meeting Abstract
Introduced parasites are a threat to biodiversity when naïve hosts lack effective defenses against such parasites. Several parasites have recently colonized the Galápagos Islands, threatening native bird populations. For example, the introduced parasitic nest fly Philornis downsi has been implicated in the decline of endangered species of Darwin’s finches, such as the mangrove finch (Camarhynchus celibates). In our study, we show that Darwin’s finches can be encouraged to “self-fumigate” nests with cotton fibers that have been treated with a mild insecticide (1% permethrin solution). Nests with treated cotton had significantly fewer P. downsi than control nests, and nests containing at least one gram of treated cotton were virtually parasite-free. Nests directly fumigated with permethrin had fewer parasites and fledged more offspring than nests treated with water. The results from this study demonstrate that self-fumigation can be used to mitigate the effect of nest flies on Darwin’s finches and potentially in other systems.
