Earthworm

Earthworm is the common reference for the larger members of the Oligochaeta (which is either a class or subclass depending on the author) in the phylum Annelida. In classical systems they were placed in the order Opisthopora, on the basis of the male pores opening to the outside of body posterior to the female pores, even though the male segments are anterior to the female. Cladistic studies have supported placing them instead in the Haplotaxida, which also includes the family Haplotaxidae. Folk names for earthworm include "dew-worm"?"night crawler" and "angleworm."

Behavior

One often sees earthworms come to the surface in large numbers after a rainstorm. There are three theories for this behavior. The first is that the waterlogged soil has insufficient oxygen for the worms, therefore, earthworms come to the surface to get the oxygen they need and breathe more easily. Secondly, some species (notably Lumbricus terrestris) come to the surface to mate. This behavior is, however, limited to a few species. Thirdly, the worms may be using the moist conditions on the surface to travel more quickly than they can underground, thus colonizing new areas more quickly. This is in any event a dangerous activity in the daytime, since earthworms die quickly when exposed to direct sunlight with its strong UV content.

Related Topics:
Lumbricus terrestris - UV

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Above; anatomy of the earthworm

~ ~ ~ ~ ~ ~ ~ ~ ~ ~