UI researchers unearth live Giant Palouse Earthworms

A live adult Giant Palouse Earthworm stretches out in the hands of a UI researcher.

Our worm has once again been found.

Armed with a hi-tech worm shocking probe, a pair of researchers from the University of Idaho last month unearthed a pair of Giant Palouse Earthworms on Paradise Ridge, southeast of Moscow.

Shan Xu, a UI soil science student, and Karl Umiker, a senior scientific aid, found an adult worm and a juvenile worm on a research project March 27.

“And we managed not to cut them in half with the trowel,” Umiker told the Gazette Tuesday.

On Tuesday, the university announced the adult worm had been positively identified as a Driloleirus Americanus – the official name for the Giant Palouse Earthworm species - by Sam James, an earthworm expert at the University of Kansas.

“There’s only a couple people in the world that can positively ID the Giant Palouse Earthworm,” Umiker said.

Giant Palouse Earthworms move slower than European earthworms.

“When you pick up an exotic worm, they tend to squirm around in your hand. These worms are fine just laying around,” said Umiker. “They’re definitely quiet, country worms.”

While the near-foot-long worm was a translucent pinkish-white in color, it did not spit or smell like lilies, as has been stated in 19th Century reports of the worm.

“Maybe we just haven’t made it mad enough to spit yet,” Umiker speculated.

The search also turned up three worm cocoons that may also be the Palouse species. Those worms have since hatched and are being kept in soil at the UI. Those infant worms have not been identified as Palouse worms, but were found in the same site and are the same color as the confirmed Giant Palouse Earthworm.

DNA from the adult worm will be used to verify the other worms found at the site are indeed of the Giant Palouse variety.

The juvenile worm is being kept in a permeable sandwich bag in a cooler at the UI. Umiker said the bag is a good way to keep the worm in a moist environment and is thin enough to let enough oxygen through.

UI researchers have been scouring Paradise Ridge in search of the worm under a grant from the U.S. Fish and Wildlife Service.

“We are beginning to gain some understanding about where we are likely to find the giant Palouse Earthworm, and how much we have to learn about them,” said UI soil scientist Jodi Johnson-Maynard.

The last living Palouse worms were found by James (Ding) Johnson in 1988 in a second-growth forest near Moscow.

Another worm discovered on Paradise Ridge in 2008 appeared to be a Giant Palouse Earthworm, but was too damaged to positively identify.

In 2005, grad student Yaniria Sanchez-de Leon found the last verified Giant Palouse Earthworm. She cut the worm in half while digging a hole to sample worms and soil on WSU’s Smoot Hill.

Umiker has been digging for worms around the Palouse since 2001. Researchers have been experimenting with various techniques to bring the Palouse worm to the surface, ranging from an electro-shocker to hand sorting to pouring a liquid mustard extract on the ground which causes the worms to wriggle to the surface.

On March 27, Umiker and Xu took the UI-built electro-shocker to Paradise Ridge and stuck it in the ground. Minutes passed, and no worms appeared.

“I thought that was weird, because you usually get worms just crawling to the top,” said Umiker.

So they started digging up the soil. They found the juvenile worm about four inches deep, he said. They kept digging and found the adult worm “vertically oriented” in the soil.

Umiker explained most worms burrow horizontally within the upper foot of the soil. Giant Palouse Earthworms dig deep vertical tunnels.

They also noticed the worm was a pale pinkish color by the mouth and a translucent grayish white toward the tail.

Umiker next noticed the light-colored band around the worm was situated closer to the mouth than it would be in an exotic worm.

“I knew it was a native earthworm because of the position of the band, but I didn’t want to say it was a Giant Palouse Earthworm until we knew for sure,” said Umiker.

The land on which the worms were found is owned by Wayne and Jacie Jensen. The Jensens allow UI researchers to dig up their section of native prairie.

“There is a good science to be learned from the Giant Palouse Earthworm and its habitats, for non-farmland and farmland alike,” the Jensens said in a statement issued through the University.

Umiker said the worms can be viewed by anyone interested at the University’s College of Agricultural and Life Sciences building on the Moscow campus.