The Lumbricus Rubellus

Earthworms are important components within ecosystem functionality and play a vital role in soil nutrition and fertility. (Edwards 2004). A prominent characteristic of earthworms is their ability to respire through diffusion of their skin (Bharambe et al 2008). As a direct result of this, earthworms are typically found in moist soils. (Roots 1956). The moist soil is vital in creating the ideal conditions for earthworms to maintain the hydrostatic pressure needed to respire (Laverack, 1963). Although moist soil is needed for this process, earthworms are generally absent from saturated soils as the oxygen levels of the soil are predominately limited this also limits earthworm populations in drier soils (Lee 1985).

The Lumbricus rubellus (L. rubellus) or red compost worm is a species of earthworm that has been introduced to many parts of the world (CABI 2014) and is now used in many recreational and commercial activities such as fishing and gardening. (Worm Affair 2014) The L.rubellus is typically found in nutrient rich soils, such as riparian environments (Sanchez et al 1982), the organic horizons of soil, while also being found in the humus level of soils (Blakemore 2006).

The purpose of this experiment was to test if L.rubellus have a soil moisture preference, and more specifically if there was a preference towards dry soil or moist soil. Investigating the soil preference of this particular earthworm would be significantly advantageous to agricultural needs and usage (Pacyna 2003). The knowledge of the preference would allow ideal environmental conditions to be established, this in effect would improve worm productivity (Pagad 2011) and the fertility of the soil.

Methods

Four treatment groups were selected to perform a manipul...

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Although the L. rubellus did migrate from the dry soil to the moist soil, other stressors such as nutrients and intra-competition could have pressured the earthworms to migrate. Dry soils won’t leach nutrients into the surrounding area, consequently there needs to be moisture for the nutrients to be released and consumed by the earthworms (Brix, 1979). It is also viable that intra-competition could have played a factor as it is likely that the earthworms migrated from a densely populated area to a less populated area to reduce competition for any nutrients and food available. Further

Despite these possibilities, it can be concluded that L. rubellus have a moist soil preference as described by the results, however further experiments could be conducted to further the knowledge regarding the other factors that may have had an influence on the migratory patterns.