Lumbricidae

Lumbricus terrestris

Lumbricidae

Next up in line is Dr. Pascal Querner from the University of Applied Life Sciences Vienna (BOKU), Management Committee member.

 

Why is this organism particularly interesting?

Lumbricus terrestris is maybe the best known earthworm on our planet. Already Charles Drawin described in his book „The Formation of Vegetable Mould, through the Actions of Worms, With Observations on their Habits“, published 1881, the importance of this soil animal. Also today many farmers, especially in organic farming, are aware of the importance of this soil animal, that can grow around 20cm and can have populations of 500 ind. per m2. It is a reddish worm widely distributed around the world. Through much of Europe, it is the largest naturally occurring species of earthworm and belongs to the group of anecic worms (other earthworm species are epigeic –soil surface and litter living; or endogeic –living in deeper soil layers). They form temporary deep burrows and comes to the surface to feed. An unusual habit of this species is to pull leaves into its burrows. While they generally feed on plant material, they have been observed feeding on dead insects and faces also.

What are the main characteristics of these organisms?

A variety of common names are used: Common earthworm, lob worm, nightcrawler, dew worm or even "Grandaddy Earthworm". Although this is not the most abundant earthworm, even in its native range, it is a very conspicuous and familiar earthworm species in garden and agricultural soils of the temperate zone. It is frequently seen on the soil surface, unlike most other earthworms, during or after rain and at night. L. terrestris lives solitarily in vertical, aerated burrows that are 1 to 2 m deep. After heavy rainfall and inundation of the soil, the oxygen-dependent (aerobic) invertebrates escape from their anoxic burrows and creep over the moist soil. On the soil surface earthworms can be eaten by predators like birds or hedgehogs. Many also die as a result of heat and radiation caused by the sun. The natural lifespan of L. terrestris is unknown, though individuals have lived for six years in captivity.

Why are they important?

In our project the activity of earthworms in the ecosystem are very important, as they are considered a good example of “ecosystem engineers”, modifying the soil texture, mixing soil particles, dispersing seeds, burrowing deep horizontal tunnels that enhance water infiltration, gas exchange, activity of microorganisms around the burrows. The burrows are used by many other animals to move within soil pores. „Worm casts“ consist of soil excreted by earthworms can be found on the soil surface. Bioturbation „the biological reworking of soils and sediments by all kinds of organisms, including microbes, rooting plants and burrowing animals” is another term to describe the activity of the worms. In some areas where it is an introduced species, it is a considered as pest for outcompeting native worms.

Where and how can I see the earthworm L. terrestris?

There are different types of earthworms and the species richness in a European grassland can be as high as 10 different types. L. terrestris is often found in grasslands or on the border of forests and hedges. If the size of the animals is over 15 cm, the coloration dark red and deep borrows can be found, this is a good indication that L. terrestris is present. But to identify the species correctly, the number of segments, the location of the Clitellum, the type of bristles are used by the experts. But with some training, identification in the field is possible.