Oregon giant earthworm
Encyclopedia
The Oregon giant earthworm (Driloleirus macelfreshi) is a species of invertebrate
in the Megascolecidae
family. This worm was first discovered in 1937, when a live specimen was unearthed in Salem. Very few other sightings of this species have been documented.
(Driloleirus americanus) of Washington, this species can grow to lengths in excess of 3 feet and up to an inch in width. When handled, the worms emit a peculiar aroma that is reminiscent of flower
s—hence their genus name Driloleirus, which means "lily-like worm." Oregon giant earthworms live in the deep, moist, undisturbed soils of riparian forests. These worms tunnel deeper into the soil than their smaller "garden-variety" counterparts, and are known to dig burrows as deep as fifteen feet to escape the summer drought
s. However during the wetter seasons, they are found closer to the soil surface, feeding on the rich layers of accumulated organic material.
of Oregon and has also been identified within the Oregon Coast Range
. Like Oregon’s other indigenous worms, this species has a narrow range of tolerance for soil conditions, favoring fine textured soils rich in clay (Fender 1995). It has been suggested that it prefers well drained soils (fine-grained, clay to silt loams) that are near subsurface water, often where the water table is reachable but the soil is not waterlogged. This species is associated with deep, little disturbed soils in moist mixed forest of Douglas firs, grand firs, and bigleaf maples and is also known from pure Douglas-fir woodlots and occasionally from oak-ash woods (Wells et al. 1983). It is apparently tolerant of the acidic soil found under coniferous forest
s.
Invertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
in the Megascolecidae
Megascolecidae
Megascolecidae is a large family of earthworms which has native representatives in Australia, New Zealand, Southeast and East Asia, and North America. The most ancient lineages of the family show a Gondwanan distribution and have been used as evidence of continental drift. Members of the Pheretima...
family. This worm was first discovered in 1937, when a live specimen was unearthed in Salem. Very few other sightings of this species have been documented.
Biology
Like its cousin, the giant Palouse earthwormGiant Palouse earthworm
The giant Palouse earthworm or Washington giant earthworm is a species of earthworm belonging to the genus Driloleirus found in the Palouse region of Eastern Washington state as well as parts of Idaho in the United States. The worm was discovered in 1897 by Frank Smith near Pullman, Washington...
(Driloleirus americanus) of Washington, this species can grow to lengths in excess of 3 feet and up to an inch in width. When handled, the worms emit a peculiar aroma that is reminiscent of flower
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...
s—hence their genus name Driloleirus, which means "lily-like worm." Oregon giant earthworms live in the deep, moist, undisturbed soils of riparian forests. These worms tunnel deeper into the soil than their smaller "garden-variety" counterparts, and are known to dig burrows as deep as fifteen feet to escape the summer drought
Drought
A drought is an extended period of months or years when a region notes a deficiency in its water supply. Generally, this occurs when a region receives consistently below average precipitation. It can have a substantial impact on the ecosystem and agriculture of the affected region...
s. However during the wetter seasons, they are found closer to the soil surface, feeding on the rich layers of accumulated organic material.
Distribution
The Oregon Giant earthworm is endemic to the Willamette ValleyWillamette Valley
The Willamette Valley is the most populated region in the state of Oregon of the United States. Located in the state's northwest, the region is surrounded by tall mountain ranges to the east, west and south and the valley's floor is broad, flat and fertile because of Ice Age conditions...
of Oregon and has also been identified within the Oregon Coast Range
Oregon Coast Range
The Oregon Coast Range, often called simply the Coast Range and sometimes the Pacific Coast Range, is a mountain range, in the Pacific Coast Ranges physiographic region, in the U.S. state of Oregon along the Pacific Ocean...
. Like Oregon’s other indigenous worms, this species has a narrow range of tolerance for soil conditions, favoring fine textured soils rich in clay (Fender 1995). It has been suggested that it prefers well drained soils (fine-grained, clay to silt loams) that are near subsurface water, often where the water table is reachable but the soil is not waterlogged. This species is associated with deep, little disturbed soils in moist mixed forest of Douglas firs, grand firs, and bigleaf maples and is also known from pure Douglas-fir woodlots and occasionally from oak-ash woods (Wells et al. 1983). It is apparently tolerant of the acidic soil found under coniferous forest
Forest
A forest, also referred to as a wood or the woods, is an area with a high density of trees. As with cities, depending where you are in the world, what is considered a forest may vary significantly in size and have various classification according to how and what of the forest is composed...
s.
Conservation Status
It has not been sighted since April 29, 1981 and feared extinct. The biggest threat to these elusive giants, if they still exist, is the destruction of their riparian habitat due to agricultural activity, logging and development and also competition from introduced European worms.External links
- Oregon giant earthworm from pacificbio.org