Their actions of consuming plant debris, mixing debris and soil layers, burrowing in the soil, nutrient release from decaying litter, stimulating microbial activity, providing channels for root growth, and deposition of fecal pellets, are known to drastically influence the properties of soils. We, however, often give them credit only under circumstances when they are the dominant organisms in an ecosystem. Pastures, turf grass, lawns, and undisturbed forests support large populations of earthworms and are places where we give them credit for these activities. Our agricultural systems usually support lower populations and therefore, they are ignored because their impact is not so visible. Earthworms are multi-segmented invertebrates and are both male and female.
Some species require mating while some reproduce without mating.
After mating, a cocoon is deposited enclosing eggs and sperm. The egg is fertilized within the cocoon. Cocoons later hatch into small fully developed, but not mature earthworms. As the young earthworms mature, a distinguishable swollen region behind the anterior end develops known as a clitellum. A fully developed clitellum is the sign of a mature earthworm.