Lumbricus terrestris
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| Common Earthworm | ||||||||||||||||
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| Lumbricus terrestris Linnaeus, 1758 |
Lumbricus terrestris is a large reddish worm native to Europe. Through much of Europe it is the largest naturally occurring species of earthworm, typically reaching 20-25cm long when extended (though in parts of southern Europe there are native species which are much larger). It has an unusual habit of copulating on the surface at night, which makes it more visible than most other earthworms. It is now also widely distributed elsewhere around the world, along with several other lumbricids, due to human introductions. In some areas where it has been introduced, it is a serious pest species, out-competing locally native worms.
Common names
Being widely distributed, Lumbricus terrestris goes under a variety of common names. In the British Isles it is primarily called the Common Earthworm. In North America and New Zealand the term Nightcrawler (or Night Crawler) is more common. In Canada, it is also called the Dew Worm, and in Britain Lob Worm (though that, as lobworm is also applied to a marine polychaete). In the rest of the world most references are just to the scientific name, though with occasional reference to the above names.
Although not the numerically most abundant earthworm even in its native range, it gets called the Common Earthworm (or even just "the Earthworm") as it is a very conspicuous and familiar earthworm species in garden and agricultural soils of the temperate zone, and frequently being seen on the surface, unlike most other earthworms. It is also used as the example earthworm for millions of biology students around the world, even in areas where the species does not exist. However this name can be a source of confusion, since in most of the world other species are more typical. For example, through much of the unirrigated temperate areas of the world, the "common earthworm" is actually Aporrectodea (=Allolobophora) trapezoides which in those areas is a similar size and dark color to Lumbricus terrestris.
Biology
Lumbricus terrestris is an anecic worm, that is, it forms permanent deep burrows and comes to the surface to feed, as opposed to burrowing through the soil for its food as most other earthworms do. An unusual habit of this species is to pull leaves into the mouth of its burrow where they partially decay before being eaten. While they generally feed on plant material, they have been observed feeding on squashed insects and feces.
The potential life span of Lumbricus terrestris is unknown, though it has been kept in the laboratory for 6 years. Official estimates of 4 to 8 years for a general life span are probably reasonable.
In parts of Europe, notably the Atlantic fringe of northwestern Europe, it is now locally endangered due to predation by the New Zealand Flatworm (Arthurdendyus triangulatus) and the Australian Flatworm (Australoplana sanguinea), two predatory flatworms accidentally introduced from New Zealand and Australia. These predators are very efficient earthworm eaters, being able to survive for lengthy periods with no food, so therefore still persisting even when their prey has dropped to unsustainably low populations. In some areas, this is having a serious adverse effect on soil structure and quality, as the soil aeration and organic material mixing previously done by the earthworms ceases.
External links
- Types of Earthworms - New Zealand (http://www.crop.cri.nz/psp/articles/docs/worms/wormtype.htm)
- Earthworm Research Group (ERG):Frequently Asked Questions (http://www.uclan.ac.uk/facs/science/envman/cwm/erg/erg_faqs.htm)
- NNZ-Nightcrawler (http://www.naturenorth.com/fall/ncrawler/ncrawler2.html)
- The microfungal community of Lumbricus terrestris middens in a Linden (Tilia cordata) forest (PDF) (http://www.urbanfischer.de/journals/pedo/content/sample/2810166a.pdf)
- Exotic Earthworms in Minnesota Hardwood Forests (PDF) (http://files.dnr.state.mn.us/ecological_services/nongame/projects/consgrant_reports/2002_Frelich_sign2.pdf)