Specificity within bird-parasite-parasitoid food webs: A novel approach for evaluating potential biological control agents of the avian vampire fly

Quantitative food web analyses can provide insights into the specificity of consumer species such as herbivores, parasites, and parasitoids. Understanding such specificity patterns can be useful in forecasting the potential benefits and risks of biological control agents being considered for introduction against invasive species.
The avian vampire fly, Philornis downsi (Diptera: Muscidae), is a neotropical bird parasite that is invasive in the Galapagos Islands, where it is causing substantial mortality of endemic bird species. We used a novel in-field experimental food web approach within the native range of P. downsi in western Ecuador to test the hypothesis that pupal parasitoids known to attack P. downsi specialize in members of the genus Philornis, which occur only in bird nests. Since other fly species are difficult to locate in the field, we developed a method to deploy puparia of non-Philornis fly species adjacent to bird nests to assess the specificity of the parasitoids more accurately. We used two complementary indices to assess the specificity of all the parasitoids found. Here we share information showing that two parasitoids, Conura annulifera, and Trichopria sp. were Philornis spp. specialists.
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