Leech vs Earth Worm
Leeches are hermaphrodites that belong to the subclass Hirundinea. Earthworms are also hermaphrodites but belong to Oligochaeta. Hermaphrodites are organisms with both female and male reproductive organs.
Contrary to popular belief only some leeches feed on blood. Most of the other types of leeches prey on small invertibrates which they eat whole. Some species of leeches that do feed on blood are extensively used for medical and therapy purposes. Earthworms on the other hand are mostly scavengers. They feed on dead organic matter. They pass the soil through their gut and the nutrients and nourishment is extracted from it and the rest of the soil is discarded. Discarded soil or droppings are called castings. This soil is rich in nutrients and minerals. It is said that the earthworms have played a vital role through the ages in keeping the soil aerated and fertile.
The natural habitat of leeches is very varied. They may be found in lakes, ponds, rivers, oceans, land, rocks, leaves, woods, on other animals just about anywhere where the humidity is high and the temperature is right. Earthworms are generally found just below the earth’s surface coming up only when there is rain. Although there are some species that may also be found in water.
Blood sucking Leeches would normally attach to their hosts and start sucking blood. They secrete an anticlogulant that prevent the blood from clotting. The bite itself would not spread an infection, however, the bacteria carried from the blood of previous hosts survive inside a leech for many months and may cause an infection. Care should be taken while removing a leech from the skin as it may regurgitate its stomach contents into the wound and detach. This would cause any viruses or bacteria in its stomach to spread the infection to the host. Earthworms on the other hand are not known to bite.
Summary
1.Leeches belong to the subclass Hirundinea while Earthworms belong to Oligochaeta.
2.Very few types of leeches feed on blood the rest prey on small invertibrates while earthworms pass the soil through their gut and extract nutrients from it.
3.Some types of leeches are used for medical purposes while earthworms perform their role in ecology by keeping the soil aerated and fertile.
4.Some leeches can bite feeding on blood while the earthworms are not known to bite.