Earthworm Morphology

Earthworm Morphology

General Information

The main features of earthworms are that they are bilaterally symmetrical, externally segmented, with a corresponding internal segmentation. Earthworms do not have a skeleton. They have a thin layered cuticle, bearing setae on all segments except the first two; with an outer layer of circular muscles and an inner layer of longitudinal muscles. Earthworms are hermaphrodite – (definition: is an organism that has both reproductive organs associated with both male and female sexes) and have very few gonads, which are located in definite segmental positions. When earthworms become mature, a swollen area of the epidermis (Clitellum), located in particular segments, forms a cocoon in which the eggs or ova are

In lumbricid worms the male pores are situated ventro-laterally on the 15th, or occasionally on the 13th segment. Each pore lies in a slit-like depression, which in some species is bordered by raised lips or grandular papillae, which often extend onto the segments beside them. in other families, the male pores may be on quite different segments, and in some, particularly the Megascolecidae, the male pores may be associated with one of town pairs of prostatic pores. These are openings of the ducts of accessory reproductive bodies known as prostates, which are usually absent from lumbricid species. The male and prostatic pores are sometimes combined as one opening, but when separate they are usually joined by longitudinal seminal grooves, on either side of the ventral surface of the body. Earthworm –Advantages and disadvantages

Earthworms play a significant role in soils. Although they are seen as a major pest for turfgrass managers they are many benefits to be gained from having earthworms in the soil. Earthworms cause nutrients tried up in organic matter to be released back into the soil, creating a sticky organic molecule that will form a good crumb structure in the soil, which therefore prevents the leaching of nutrients (Ford

The result of this process is the production of earthworm castings. Earthworm castings produced as a result of vermicomposting contain beneficial nematodes, protozoa, fungi, organic matter, plant growth regulators, plant growth hormones (IAA and gibberellins), and soluble nutrients (N, P, K, Ca and Mg). The nutrients held within the organic matter and microbial bodies do not easily leach out. Fungus and other bacteria form part of an aggregate with the organic matter making it difficult for nutrient leaching from heavy water movement through the soil profile. Bacteria and fungi feed on organic matter in the soil. As they do this they store nutrients within their body while releasing others. The nematodes and protozoa in the castings turn prey on them and nutrients are released from the beneficial and fungal bodies into the soil in a plant available-form ready for root