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Scientists may have found a way to save the finches of the Galápagos Islands from a parasitic fly that threatens the small birds’ lives.
Charles Darwin studied the Galápagos finches (among other small birds) to prove evolution by natural selection. The finches from the Galápagos helped Darwin learn more about speciation, an evolutionary process by which new biological species appear.
According to researchers, the parasitic fly that appeared on the Galápagos Islands just a few decades ago, could wipe out the finch populations.
Dr. Dale Clayton, a parasitologist at the University of Utah, said that reducing the infested nests by 40 percent could diminish the risk of extinction.
In the new study – published December 18 in the Journal of Applied Ecology – the researchers looked at how the flies affected the medium ground finch (Geospiza fortis), which is one o the most common of more than 14 species of finches.
To calculate the birds’ extinction risk, the researchers used a mathematical model in which they entered five years worth of data.
The adult parasitic flies called Philornis downsi feed on fruit. However, when they lay their eggs in the birds’ nests, the parasitic larvae will feed on the blood and flesh of developing nestlings, causing significant mortality in newborn medium ground finches. Because these nestling are extremely small (the size of an M&M) it is very difficult for them to survive the fly larvae. When infected, they normally die a week after hatching.
Dr. Clayton said that – although risky – a possible solution to stop the parasitic fly would be the introduction of a parasitoid wasp. However, a host-specific parasitoid wasp is needed, to make sure that the wasps will not be flying around killing other species of insects on the islands.
Another solution would be ‘self-fumigation’, according to Dr. Clayton. Scientists could leave cotton balls sprayed with a safe insecticide for the birds to line their nests with. Nests lined with just one gram of fumigated cotton would be protected from the parasitic flies.
A third approach would be introducing sterile male parasitic flies. That way, females that mate with infertile males would not produce offspring and the populations would decline.
Reducing infestation by 40 could save the birds from going extinct, Dr. Clayton said. Since the numbers are based on the mathematical models, they may be somewhat erroneous or imprecise, he added.
Image Source: bugbog
