Earthworm

=(European) Earthworm (//Lumbricus rubellus)//=

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__General Information__
The European earthworm has a long, tube shaped body that can reach anywhere between 60 and 150mm in length, and from 4 to 6mm in width. They have very pale bellies, and their back is usually a darker red or purple-brown color. (2)

__Detailed Description__
The earthworm is a hermaphrodite. Two worms will both impregnate each other, and long after they separate, each of them will leave behind a small cocoon. The offspring emerge from the cocoon, small but fully functional, only missing their reproductive organs which will develop over the following months. (1)

The earthworms eat up the leaf litter in wooded areas, a very important layer form many decomposers to thrive from, this can create competition between the worms and certain decomposers. (3)

An ability that helps the earthworm to survive, is its astounding ability to regenerate. Depending on the seriousness of an injury, an earthworm is able to repair or even regrow many parts of it's body, and it is even thought to be possible to create two separate worms from cutting one in half. (1)

__Habitat and Distribution__
Many different species of earthworm live in different types of soil. Specifically, the Lumbricus rubellus lives in areas with great amounts of organic material, and so are usually found closer to the surface than other types of earthworm, which can burrow deep down into the earth. Colonies of earthworms take time to grow, but though it may take years for a colony to move out even a small distance, this gradual change allows them to move in almost undetected. (3)

The European earthworm can now be found in many parts of the U.S., Canada, New Zealand, Australia, and of course all over it's native land of Europe. (2)

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__Impacts__
The introduction of this type of earthworm can greatly alter their new environments ecosystem. They greatly increase the rate at which organic matter in the soil is decomposed, and so help minerals to more quickly become available resources for many different species. The earthworm can also serve as an excellent food source for many species of birds and other animals (see right). (2)

On the other hand, the earthworm can also be harmful to its environment. For one, it is a carrier species for certain plant and animal pathogens. They can increase the rate of erosion due to their activity in the soil, removing certain materials that would normally help to halt the process of erosion. (2)

This specific type of earthworm is also very commonly used as bait for fishers, and so are often bred and sold in many different stores. (3)

__History__
The European earthworm came to the United States during colonial times. People moved trees, along with them came their soil, home to the European earthworm. Their natural environment is very similar to their current home here, making it a very easy change for them. (3)

__Control Measures__
Very little is done as far as controlling this species, as they can be quite useful to their environment. (3)

__Works Cited__
1. Butt, Kevin. "Earthworms.(biological research)." Biological Sciences Review. 18. 3 (Feb 2006): 14(4). Student Resource Center - Gold. Gale. Stroudsburg High School. 12 Nov. 2008 <http://find.galegroup.com/srcx/infomark.do?&contentSet=IAC-Documents&type=retrieve& tabID=T002&prodId=SRC-1&docId=A142058286&source=gale&srcprod=SRCG&userGroupName=stro53037&version=1.0>.

2. Pacyna, Sarah. __Columbia University__. 18 Feb. 2003. 20 Nov. 2008 <http://www.columbia.edu/itc/cerc/danoff-burg/invasion_bio/inv_spp_summ/ Lumbricus_rubellus.html>.

3. Samuels, Sam Hooper. "Alien earthworms' offspring thrive, and alter soil, in U.S.(Science Times Pages)(encroachment of nonnative species)." The New York Times. (August 29, 2000 pD1(N) pF1(L) col 2 (35 col): D1(N) pF1(L). Student Resource Center - Gold. Gale. Stroudsburg High School. 12 Nov. 2008 <http://find.galegroup.com/srcx/infomark.do?&contentSet=IAC-Documents&type=retrieve& tabID=T004&prodId=SRC-1&docId=A64714439&source=gale&srcprod=SRCG&userGroupName=stro53037&version=1.0 >.