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Earthworms are shifting their ranges northwards into forests between 45° and 69° latitude in North America that have lacked native earthworms since the last ice age. [3] Of the 182 taxa of earthworms found in the United States and Canada, 60 (33%) are introduced species, these earthworm species are primarily from Europe and Asia.
The Lumbricidae are a family of earthworms.About 33 lumbricid species have become naturalized around the world, [1] but the bulk of the species are in the Holarctic region: from Canada (e.g. Bimastos lawrenceae on Vancouver Island) and the United States (e.g. Eisenoides carolinensis, Eisenoides lonnbergi and most Bimastos spp.) and throughout Eurasia to Japan (e.g. Eisenia japonica, E. koreana ...
Megascolecidae is a family of earthworms native to Madagascar, Australia, New Zealand, Asia, and North America. [2] At up to 2 meters in length, [ 3 ] their large size distinguishes the Megascolecidae from other earthworm families.
Oligochaetes are well-segmented worms and most have a spacious body cavity (coelom) used as a hydroskeleton.They range in length from less than 0.5 mm (0.02 in) up to 2 to 3 metres (6.6 to 9.8 ft) in the 'giant' species such as the giant Gippsland earthworm (Megascolides australis) and the Mekong worm (Amynthas mekongianus).
However, 'earthworm' 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 colour to L. terrestris.
Approximately 182 earthworm taxa in twelve families are reported from the United States and Canada, of which sixty (about 33%) are introduced. [4] Only two genera of lumbricid earthworms are indigenous to North America while introduced genera have spread to areas without any native species, especially in the north where forest ecosystems rely on a large amount of undecayed leaf matter.
Earthworms store their partners' sperm in spermathecae ("sperm stores") and then the clitellum produces a cocoon that collects ova from the ovaries and then sperm from the spermathecae. Fertilization and development of earthworm eggs takes place in the cocoon. Leeches' eggs are fertilized in the ovaries, and then transferred to the cocoon.
Earthworms are environmental indicators of soil health. Earthworms feed on the decaying matter in the soil and analyzing the contents of their digestive tracts gives insight into the overall condition of the soil. The earthworm gut accumulates chemicals, including heavy metals such as cadmium, mercury, zinc, and copper. The population size of ...