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5 December 2013 11:26 am ,
Vol. 342 ,
An animal rights group known as the Nonhuman Rights Project filed lawsuits in three New York courts this week in an...
Researchers have been hot on the trail of the elusive Denisovans, a type of ancient human known only by their DNA and...
Thousands of scientists in the Russian Academy of Sciences (RAS) are about to lose their jobs as a result of the...
Dyslexia, a learning disability that hinders reading, hasn't been associated with deficits in vision, hearing, or...
Exotic, elusive, and dangerous, snakes have fascinated humankind for millennia. They can be hard to find, yet their...
Researchers have sequenced and analyzed the first two snake genomes, which represent two evolutionary extremes. The...
Snake venoms are remarkably complex mixtures that can stun or kill prey within minutes. But more and more researchers...
At age 30, Dutch biologist Freek Vonk has built up a respectable career as a snake scientist. But in his home country,...
- 5 December 2013 11:26 am , Vol. 342 , #6163
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Biological Control Backfires
4 December 2000 7:00 pm
North America's largest, most spectacular moths are being decimated by a foreign fly introduced to control gypsy moths, according to a report in the December issue of Conservation Biology. The researchers urge extreme caution when introducing new species to control pests, as they can easily have undesired side effects.
With a wingspan of up to 15 centimeters, the cecropia moth (Hyalophora cecropia) is North America's largest moth. It dwells in the forests of central and eastern North America, along with other members of the silk moth family. At the turn of the century, people reportedly gathered cocoons of silk moths by the bushel, just to watch them hatch in the parlor. Now trained entomologists are hard-pressed to find silk moths in the Northeast, and at least four species of silk moths are listed as threatened by the state of Massachusetts.
George Boettner, a wildlife biologist at the University of Massachusetts in Amherst, and his colleagues suspected that the culprit might be a European fly (Compsilura concinnata), introduced as a biological control for gypsy moths--a species introduced from Europe whose caterpillars have long been wreaking havoc in U.S. forests. Up to 1986, the fly was released in 30 states with gypsy moth problems. But the fly doesn't just kill gypsy moths; it's a generalist that attacks at least 180 species of insects, Boettner says. As early as 1919, scientists noted that another silk moth, the promethea moth, seemed to become rare in the areas where the fly had been loosed.
To test their hypothesis, the team put out promethea moth caterpillars at densities varying from one to 100 per tree. Flies killed between 52% to 100% of the promethea caterpillars. In another series of experiments, the team reared cecropia moth caterpillars and placed 300 of them, five per tree, in several spots in the Cadwell Memorial Forest in Massachusetts. After a week, the caterpillars were recaptured and reared further in the lab. Eventually, 81% of them had alien flies bursting from their bodies. "When you see that kind of mortality, it's a wake-up call," Boettner says, adding that it was unwise to release a predator with such a broad host range in the first place.
"It's a wonderful study," says Francis Howarth, an entomologist at the Bernice P. Bishop Museum in Honolulu, Hawaii. "I think it's the first that uses experimental techniques to figure out, in hindsight," what unintended consequences can occur during a biological control campaign.