Tiny and black parasitic invasive fly Philornis downsi is a threat to 21 species of endemic and native Galapagos birds, including 12 of the 17 finches from the Ecuadorian archipelago, where it arrived by accident in the 1960s.
The small insect saves the finches from islands as far away as Darwin, Wolf, Española and Genovesa, but in “all the rest the birds are being attacked and parasitized by this fly,” Paola Lahuatte, a researcher at the Charles Darwin Foundation, told Efe. (CDF).
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Also known as the “avian vampire fly,” the insect lays its eggs in the nests of birds and when the larvae hatch, they feed on the blood of the chicks “to the point that it often kills them,” he lamented.
The larva remains in the nest for regarding eight days before encapsulating itself to become an adult fly, at which stage it is no longer a threat to birds as it feeds on fruits, nectar and flowers.
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“The impact that has been seen in recent years is so great that there are species that are regarding to become extinct, such as the mangrove finch”, of which there are only regarding a hundred individuals, and whose chicks die in the nests because of Philornis downyes, he said.
But also endangered is the little witch bird, whose birds cannot reproduce successfully because of the insect infestation.
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Similar to the common fly, the Philornis downsi measures one centimeter and has a map of veins on the wing, which makes it unique at the taxonomic level.
Genetic analyzes determined that the fly arrived in the archipelago from the mainland, probably on ships or planes in which colonizers traveled in the 1960s, when there was no biosafety agency to control entry to the islands, as it is now.
The fly, which lives regarding seven months, “it might easily colonize all the islands and the parasitism was so great because there was no natural controller”, Lahuatte added.
Scientists are now embarking on the great challenge of finding means of control in the short and long term, and for this they have set up a laboratory where they breed and study the biological and ecological behavior of the insect.
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At the moment, and thanks to laboratory and field tests in continental Ecuador, at the University of Minnesota (USA) and the Escuela Politécnica del Litoral (ESPOL), they know that there are natural controls of the fly that are micro wasps native to South America.
“These microwasps parasitize when the fly has already encapsulated itself to become an adult. They lay their eggs inside this capsule and their larvae feed on the fly,” he explained.
But since the aforementioned microwasps do not live in Galapagos, experts need to study them to determine if they are specialists in feeding on Philornis and to ensure that they do not represent a risk to the archipelago’s ecosystems, before using them in a possible biological control program once morest the fly.
