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Rare Earthworm Discovery E-mail
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Thursday, 02 February 2006

Rare Earthworm Discovery


The Spokesman-Review (Spokane, Washington)
By James Hagengruber
Turn of Shovel Turns up Rare Giant Palouse Earthworm
It was at the end of a long day of worm research when University of Idaho graduate student Yaniria Sanchez-de Leon dug into the prairie soil and spotted the quick flash of white skin.

Her shovel came up with a small segment of the pale flesh. She took another scoop on that sunny May afternoon last year and retrieved the rest of the worm. Sanchez-de Leon immediately suspected she might have found a giant Palouse earthworm, an extremely rare worm that reportedly grows to 3 feet in length, is as thick as a pinky finger and spits a lily-scented saliva when frightened.
Nearly 20 years had passed since the last Driloleirus americanus was found. But this worm seemed to fit the bill: pale white and twice as long as the usual European wrigglers that have taken over the dirt world below the Palouse prairie.

After years of research, including a summer spent studying worms in a Costa Rican coffee plantation, Sanchez-de Leon knows a bit about worms. But she kept her discovery relatively hush-hush until it could be verified by Northwest worm expert William Fender.

On Monday, the discovery was confirmed. Sanchez-de Leon, originally from Puerto Rico, expressed dismay over accidentally chopping the worm in half, but she said the news is exciting.

"I've been trying to look for them," said Sanchez-de Leon, whose research focuses on earthworm populations and carbon dynamics in native prairie and retired farmland.

The 6-inch white wonder was found in one of Sanchez-de Leon's shoebox-sized test pits at Washington State University's Smoot Hill Ecological Preserve near Palouse, Wash. Even though the worm is much smaller than some adult specimens, it is believed to be an adult. Positive identification was made by comparing everything from external markings to the digestive tract and even by scrutinizing the tiny suckers used by worms to cling to mates during copulation.

The giant Palouse earthworm was first unearthed in 1897 by Frank Smith, who wrote, "this species is very abundant in that region of the country and that their burrows are sometime seen extending to a depth of over 15 feet," according to information on the Palouse Prairie Foundation Web site. Since then, there have been few sightings.

The last was recorded in 1988 near Moscow Mountain, and was made by University of Idaho graduate student Paul Johnson, along with James "Ding" Johnson, head of the university's plant, soil and entomological sciences department. There have been several worm expeditions in recent years, but none has been successful.

"This is exciting," James Johnson said of the discovery. "By earthworm standards they're pretty cool."

The giant Palouse earthworm is believed to be declining in numbers because of the loss of the Palouse prairie and the introduction of European worms, said Fender, a noted expert from McMinnville, Ore. Most of the garden-variety worms are exotic species, he noted.

Worms play a critical role in soil and plant health. The true impact of the loss of native species isn't known, but Fender thinks quick action is needed to save what's left.

"I'd like to see some efforts to restore some of the habitat and see if the native earthworm populations can recover," he said. "We really don't know if they can. It may be a one-way street."

Fender is now looking into mounting his own expedition to find additional specimens. "There's going to be more," he said.
The discovery also raises the potential for pursuing protections for the remaining worms, including a possible petition for listing under the Endangered Species Act.

"Frankly, we were hoping to find some to protect," Fender said. "With americanus, it's been quite a while since we've seen them."

Fender has spent years unsuccessfully searching for specimens of the giant Oregon earthworm a a close cousin of the Palouse worm. He has preserved bodies of both types of worms at his house and is one of the few people to have ever seen a living Palouse worm in the wild.

"They can move fairly quickly underground. They'll shorten up," Fender said. "They can get out of the way fairly quickly, but they're not as active as a night crawler."

The blind worms are believed to eat decaying grasses and leaves, but the occasional insect has turned up in a dissected worm's intestine. Like other worms, the giant Palouse earthworm lives most of its life underground, emerging only when the air is damp.

"They can get from one place to another much more rapidly over the ground than under," Fender explained. But staying topside is dangerous, not only because of predatory birds or curious children, but because of their lack of skin pigment. "They'll essentially get sunburned very, very quickly and die."

The worm's pale color, Fender said, is "quite striking." Another oddity of the native species is its ability to exude a lily-scented saliva. Sanchez-de Leon does not recall any flowery scent when she found her worm, but Fender said the odor is not always present.

"You've got to poke it on the nose to get any kind of odor," Fender said. The scent is believed to be a defense mechanism a one of many mysteries yet to be plumbed from the subterranean landscape of the Palouse.

Sanchez-de Leon said she plans to look for more worms at the test plots this spring. Fender cautioned against people doing their own digging, prodding and probing for the worms. The latest discovery shows that even an expert's touch does not ensure a happy ending for the worm.
"It's hard to collect them without injuring them," Fender said.

Last Updated ( Thursday, 02 February 2006 )
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