SCIENCE
Notebook

Monday, March 26, 2007

Ladybug Taint: Not Fine in Wine

Ladybugs are well known to gardeners as a great natural tool to control aphids and other pests. But a new study has shown that the spotted insects have a less-appealing side: They produce a foul-smelling liquid that is increasingly being found in wines. There's even a name for it -- "ladybug taint."

The smell, which connotes green bell peppers or roasted peanuts, is produced by ladybugs as a defense mechanism. The chemicals they release, in a class of compounds called methoxypyrazines, are found in other animals and plants, but Jacek Koziel of Iowa State University said ladybugs are loaded with them. "Even tiny amounts can be detected by the human nose," he said.

His team used a gas chromatograph and a panel of volunteer "sniffers" to identify the odors from about 300 ladybugs of the species Harmonia axyridis. Batches of five bugs were sealed in test tubes and the odors were analyzed, revealing 28 distinct smells. Four chemicals were found to be associated with the ladybug odor.

This type of ladybug has been spreading rapidly across the Midwest because some tasty new prey -- the invasive soybean aphid -- has also become widespread. Winemakers report greater concentrations of ladybugs in their vineyards and on harvested grapes. Apparently the bugs are being mixed into the fermenting grape juice by accident.

Koziel's study was presented at last week's national meeting of the American Chemical Society.

-- Marc Kaufman

Pocket-Size Owl Appears in Peru

It has been more than 30 years since conservationists in Peru first caught a long-whiskered owlet in their nighttime bird nets, introducing to the birding world one of the smallest, and cutest, owls on the planet. Since then, just a handful of the wide-eyed, wispy-browed mini-owls have been trapped by researchers working in that country's mountainous frontier, and none had been seen flying in the wild -- until now.

In February, the intensely private and presumably threatened bird got over its shyness and made multiple appearances before birders working to preserve its remote habitat, which is among the richest areas of avian biodiversity in the world.

Birders hope that the owlet's recent appearances will bolster efforts to expand a recently created 4,000-acre private sanctuary there, which is home to hundreds of rare and endangered bird species.

Researchers with the Asociación Ecosistemas Andinos and the American Bird Conservancy, who are leading conservation efforts there, believe there are fewer than 1,000 of the owls, and perhaps as few as 250. With the help of foundation grants, the organizations have been buying tracts of land in a wooded region that abuts a much larger government preserve.

Last month, rangers spotted the owlet three times during daylight hours and recorded its calls. They also took the first pictures of the bird in the wild. More pictures can be seen at http://www.abcbirds.org/whiskeredowlpic.htm.

-- Rick Weiss

In Greenland, the Earth Moved

Greenland is not only a great place for ice, it is also a great place for rocks.

The world's largest island has long been a favorite place for geologists to study rocks that are older and of deeper origin than most of Earth's surface.

Now it appears that Greenland is home to the oldest evidence of tectonic movement, the shifting of plates of Earth's crust that is responsible for most of the planet's surface architecture.

Harald Furnes, of the University of Bergen in Norway, and an international group of collaborators, report in the journal Science on finding a 3.8-billion-year-old ophiolite, a section of oceanic crust that has ended up high and dry in a section of continental crust. Previously, the oldest ophiolite was from northern China and dated to 2.5 billion years ago.

Various lines of evidence suggest the Greenland rock was formed at a mid-oceanic ridge, where molten rock from below rises to the surface. It then moved away from the ridge as part of a newly formed oceanic plate.

-- David Brown