Three Types of Earthworm Assist Gardeners. Living In The Leaf Litter, Top Soil Or Burrowing Deep They All Contribute To Soil Health & Fertility.

The Three Types of Earthworm inhabit three distinct ecological niches as described below. They are made up of the 31 species of earthworm found in the British Isles. Worldwide there are at least 5000 species with science recognising more, as DNA profiling recognises more species and sub species.

Of the 31 species in the British Isles 16 are most likely to be found in gardens with the others filling specialist niches outside.

The Three Types Of Earthworms

The three basic types of worm are ….

Leaf litter / composting (epigeic) worms

Topsoil dwelling (endogeic) worms

Deep burrowing (anecic) worms.

More details on the three types of earthworms below

What Is An Earthworm?

It might seem quite a basic question but we need to be careful not to confuse earthworms with other types of worm. We aren’t talking here about the wide range of worms that include flatworms, segmented worms, ribbon worms, roundworms, pinworms,  peanutworms,  spoonworms, spiny-headed worms,  beardworms and arrowworms, this article is about earthworms with emphasis on the earth.

Worm compost can replace peat - there are three types of earthworms, this one is a compost worm.
Worm compost can replace peat

Earthworms are terrestrial invertebrates that breathe through their skin, so don’t posses lungs. To be able to “breathe” in this way their skin needs to remain moist. By breathe we mean oxygen is able to pass through the skin to reach the haemoglobin in the blood and CO2 is able to leave in the same way. Ditto, water is able to pass though the skin which means an earthworm doesn’t need to drink in the same way as we do.

Earthworms don’t have limbs of any kind and have two simple circulatory systems. They are also hermaphodites so posses both male and female sex organs. Some worms don’t even need to mate but can produce young by parthenogenesis.

More Details On the Three Types of Earthworm

Leaf litter / composting (epigeic) worms

These are the worms we see in compost heaps. But in nature, where compost heaps aren’t a natural feature, they live in the leaf litter under trees, in woods and forests.

Leave a compost heap for long after it cools down and it wil eventually attract compost worms which will happily breed and break down the compost even further. Compost worms don’t normally go deep into the soil but prefer to stay in the leaf litter, except in very cold weather when they will need to shelter or aestivate (go into a torpor).

These compost worms, of which Eisenia fetida (fetida refers to the fetid liquid this worm can give off if handled), is a typical species, are often called brandling worms, red wrigglers etc.

Some sources call compost worms as a distinct fourth type of worm, distinct from epidemic worms.

Topsoil dwelling (endogeic) worms

Typical top soil dwelling worm include Allolobophora chloroticaApporectodea roseaMurchieona muldali and Octolasion lacteum . These are the worms that form horizontal burrows in the top soil.

Deep burrowing (anecic) worms

Lumbricus terrestris or the common earthworm. It’s a large, reddish species that is now found world wide, but is thought to have originated in western Europe.

Anecic worms form deep vertical burrows and are able to take compost and leaf litter deep into the soil.

Anecic means to reach up.

This is one of the worms, alongside the top soil worms, beloved by birds when gardens are dug or fields ploughed.

Colin Kinnear / Tractor and Gulls
Gulls hunt earthworms behind the plough –
Colin Kinnear / Tractor and Gulls

As a young man I ploughed many many acres of land and, as I ploughed, the gulls came behind the plough to take worms. And behind the worms came the occasional buzzard to scavenge for any left over worms. In those distant days the buzzard was still only found in Devon and was not that common even there. Today it is found in most of the country which is a testament to its recovery powers once poisoning of birds of prey was outlawed.

Four Types of Earthworm

As mentioned above some authorities recognise four, not three, types of earthworm. Earthworms however, don’t categorise themselves as we categorise them. And in certain circumstances top soil earthworms go deeper and anecic earthworms spend more time in the top soil. Much depends on weather and soil conditions. The main thing to remember is that earthworms create ideal soil conditions for plants. The burrows they form aid drainage and air penetration. The organic material they move improves the soil and the casts they secrete are full of plant nutrients made more accessible for the plants.

Earthworms don’t eat living plants, they favour dead organic material. So they are a true gardeners’ friend.

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