In the 1990s , the flyPhilornis downsiwas unintentionally introduced to the Galapagos Islands , probably in a lading of fruit . The grownup tent flap are harmless enough as invader go , but their kids are a substantial problem for the islands ’ native fowl , some of which are found nowhere else in the mankind and a few of which are peril .
The flies lie in their eggs in birds ’ nests just as the chick are issue from their own eggs , and once the larvae hatch , they begin to eat their hosts from both inside and out . No larger than grain of Elmer Leopold Rice , the maggots wriggle their way into the baby shuttlecock ’ nostrils and feed away at their rhinal cavity . As they get heavy , the parasite burst back out and retain to live in the nest , blot out by day and emerge each night to suck origin from the chicks . This is often too much for the birds to stand . In some years , the parasites have killed every unmarried bird in a given surface area and caused every nest to break . Even if the birds survive , they often have difficulty eat because their beaks are deform from the larva that crawl around inside .
Among the dame that the flies maim and kill are Darwin ’s finches , a chemical group of15related specie whose beak diverged in form as adaption to their affair and were a cardinal piece of grounds for Charles Darwin when he was developing his idea of development by natural selection . And even though they ’re textbook examples of adaptation , the skirt have n’t adapted to the parasite yet because they do n’t have a long evolutionary account with them . For now , it falls to scientist to protect them . preservation biologists have prove treat the nest with insecticide , which increases the number of bird that survive long enough to fly on their own , and also removing chicks of the most vulnerable species from their nests and raising them in incubators .
Neither of these strategies is cheap or easy . Treating the nest is particularly crafty because they ’re often knockout to determine or placed too gamey in the trees to arrive at . Now a squad of biologists thinks they ’ve find a fresh , more efficient direction to do it : bring the birdie the insecticides andlet them be their own exterminators .
The idea came to University of Utah doctoral bookman Sarah Knutie as she watched finches descend to the laundry lines outside her island dorm and pull threads from clothes and towels to tote up to their nests . She wondered if the birds would also take fiber that had been regale withpermethrin — an insecticide often used in flea collars and lice shampoos — and work them into the nest to “ ego - fumigate ” them .
To find out , Knutie , other students and their adviser Dale Clayton fashioned 30 dispensers out of telegram interlock , meet them with either permethrin- or water system - soaked cotton wool , and placed them along a road near nesting sites on Santa Cruz Island .
When the gentility season was over and the babe birds left home , the investigator collected and dissected 26 empty nest ramp up by four dissimilar finch metal money . Twenty - two of the nests bear cotton from the dispensers , and more than one-half of those turn back the insecticide - laced cotton fiber .
The birds were apparently glad to take the dosed cotton , and it paid off for them . The nests with the permethrin cotton plant in them contained about one-half as many parasites as the ones that had plain cotton plant or no cotton at all , and all but one of the nest with a least of a gram of treated cotton — about a thimble ’s Charles Frederick Worth — were leech - free .
If more cotton dispensers can be installed and maintained , they could make a Brobdingnagian difference for some of the island ’ boo . One of Darwin ’s finches , the Rhizophora mangle finch , has a population of less than 100 Bronx cheer confined to about a substantial kilometre of farming . It would only take 60 dispensers , Knutie says , to protect the whole population from the fly .
The researchers hope that the same method could be used to protect other birds and nest - building animal against sponger and pests , from Hawaiian honeycreepers dealing with feather lice to prairie dogs that are literally plagued byYersinia pestilence - stockpile fleas . Just a trivial quilt of cotton fiber could go a long way in help these animals help themselves .
