At a glance
Essentials
- Size
- Can reach approximately 25 cm in length. The range may vary with age, sex and population.
- Distribution
- In the eastern United States, Lumbricus terrestris is identified as the most common earthworm species; this regional information does not, by itself, define its full distribution.
- Habitat
- Lives and burrows in soils with sufficient moisture and organic content; moist skin is necessary for gas exchange.
- Activity
- Burrows and moves through the soil by means of muscular contractions, using its bristles to anchor itself.
- Diet
- Consumes plants and other decomposing organisms, and also ingests soil, sand, and small mineral particles.
Observation guide
What to look for
- 01
Reddish-brown color: the body of Lumbricus terrestris has this hue, which is related to the hemoglobin in its blood.
- 02
Segmented body: it can have up to about 150 visible segments along its elongated body.
- 03
Identifiable clitellum: a somewhat swollen, discolored area occurs between segments 32 and 37.
- 04
Unequal ends: the body tapers toward both ends, and the posterior end is blunter.
Lighting, age and viewing angle can hide features. If identification affects consumption, handling or conservation, consult specialist sources.
Ecology
Description and characteristics
Appearance and structure. Lumbricus terrestris is a terrestrial annelid with an elongated body divided into rings or segments, with up to about 150 segments. Its coloration is reddish brown, associated with the hemoglobin pigment present in its blood. The body tapers toward both ends, although the posterior end is blunter. Between segments 32 and 37 is the clitellum, a somewhat swollen area of a different color that takes part in forming the cocoon in which the eggs are enclosed. Like other annelids, it has small bristles set into the body wall; these help it anchor itself as muscular contractions move the body. It has no lungs: it exchanges oxygen through its moist skin, so it needs conditions that allow the skin to remain moist.
Life in the soil. This earthworm burrows and moves through the soil. Contractions of the circular and longitudinal muscles generate waves of movement that can propel it forwards or backwards; the bristles help prevent it from slipping as it moves forward. It is associated with soils that have sufficient moisture and organic matter. While feeding on plant remains and other decomposing organisms, it also ingests soil, sand, and small mineral particles. In this process it consumes leaf litter: in experiments conducted in acidified forest soils in the western Adirondacks, individuals that survived in limed soils rapidly consumed the leaf litter. That result applies to the conditions studied and does not, by itself, describe all populations.
Reproduction. Lumbricus terrestris is hermaphroditic: each individual has male and female reproductive organs, but fertilization of the eggs requires sperm from another individual. During mating, two earthworms exchange sperm; afterward, the clitellum produces a cocoon containing the eggs. Thus, cocoon formation is a visible part of its reproductive cycle, although the available sources do not specify here the duration of development or the time until hatching. Its burrowing and feeding activity helps incorporate organic matter into the soil; experimental evidence also shows that its survival can vary markedly according to soil acidity conditions.