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17 April 2014 12:48 pm ,
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Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
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Weed-eating Insects Munch Wrong Plants
2 August 2001 7:00 pm
HILO, HAWAII--An nonnative insect released in Colorado in 1992 to control the weed Canada thistle has started munching on native thistles instead, researchers reported here 31 July at the Society of Conservation Biology meeting. The finding strengthens some ecologists' claims that the current screening process for insect releases doesn't protect native species.
Nonnative organisms have been introduced to combat another alien species in the United States for almost a century. Although the releases were not well-regulated in the early part of the 20th century, in recent years, such plans have been subject to more and more testing before insects are set free. Advocates of biological control have claimed that recent reports of released insects harming native species are the result of releases made 20 or more years ago.
However, in 1999, ecologist Svata Louda of the University of Nebraska, Lincoln, found the biocontrol weevil Larinus planus feeding on a native thistle in the Gunnison National Forest of Colorado. "First I was flabbergasted--and then I was upset," she says. By collecting and dissecting seed heads of native Tracy's thistle and nearby Canada thistles, she and her collaborators found the weevil on native plants more often than on the target. In fact, biocontrol agents are to blame for more than 50% of the insect damage to seeds of Tracy's thistle.
The weevil was evaluated for release in 1990 using contemporary protocols intended to prevent harm to native species. Finding the insect chowing down on native plants demonstrates that the current criteria are not stringent enough, says ecologist Daniel Simberloff of the University of Tennessee, Knoxville, who has been critical of biological control efforts. He says of Louda's discovery, "I'm not surprised."