Subject: Australian Earthworms

From: "Lawrence F. London, Jr." <[email-masked]>
Date: Fri, 21 Feb 1997 11:24:16 -0500

http://www.nectar.com.au/~stylesie/worms.html

-- 
Lawrence F. London, Jr.
mailto:[email-masked]  
http://sunSITE.unc.edu/InterGarden
mailto:[email-masked]
Earthworms

This page is an on-going project and will be updated and improved as I find the time. Any comments and critiques about content are most welcome. Email Colin Styles .

Contents

Australian Earthworms
Worms effects on soil
Breeding habits
Anatomy
Locomotion
Commercial (Composting) earthworms
Garden earthworms
Earthworm behaviour and Habitat
Lumbricus rubellus
Eisenia fetida
Eisenia andrei
Perionyx excavatus
Spenceriella spp
Eudrilus eugeniae
Bibliography
Hot worm links

Australian Earthworms

Australia has one of the most ancient and poor soil structures of any country on earth. Australia's earthworm population is small when compared to places like Europe. Our worms are generally poor soil builders and unused to improved pastures and composting situations. Many European and Asian worms have been accidently introduced to Australian soil over the centuries and it is these varieties that you will find in farmland and compost heaps the native types generally sticking to unimproved land.

Of the 3000 or so earthworm species identified worldwide, about 300 are native to Australia

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Worms effects on soil

Soil Earthworms will have biota (associated life forms) six times that of the worms. Good soil, with a density of five thousand worms per meter, can have 5 tonnes of worms per hectare and thirty tonnes of associated biota, all under the soils surface. This amount of life will aerate and fertilise more than 900 tonnes of soil per hectare each year.

In Europe Earthworms can build up the surface layer of topsoil at a rate of two milimeters per year. In Australia the rate is closer to half a milimeter per year.

Worms help to break down water resistant root mats that form underneath the surface and open up channels to aerate the soil and make it more water penetrable. Worm populated soil bacomes wet faster and deeper and holds the moisture longer. The worm burrows are coated in a nitrate rich mucous which helps to shore them against damage and provides plants with an easily digestible nitrate supply.

Nitrogen and carbon are separated in the worms gut and the nitrogen is deposited in the worms casting in a plant soluble form.

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Breeding habits

Worms are Hermaphrodites, they have both male and female sexual organs. One worm has two pairs of testes and two ovaries. Mating worms move together head to head and overlap thier bodies until they are nose to clitellum. A thick layer of mucous is excreted which wraps the worms tightly together. Sperm is ejected by both worms and collected and stored by the worms partner in special ducts. After the worms separate the clitellum quickly exudes an albuminous ring. The worm begins to wriggle out of this ring which slide forward over the worms head. On its way it passes over the ovary ducts of the worm and then the sperm storage ducts. After the worm finally wriggles out of the ring it closes and forms a capsule containing fertilised eggs. A capsule contains between 1 and 20 baby worms but usually averages out at 4 per capsule. Not all of the sperm is used each time a capsule is formed, so each worm might produce several capsules from one mating.

Worms do not mate between species, there are no worm hybrids. This is because besides any genetic incompatibilities the sex organs of different species do not correspond. Worms need to be of equivalent size and the same species in order to produce offspring.

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Anatomy

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Locomotion

Worms are extremely well muscled, they have longitudinal muscles and encircling muscles which cause the worm to stretch and contract its body in a co-ordinated fashion. When the worm is fully extended the worm will anchor its anterior (front) end to the soil and pull its posterior (rear) end up. The worm can also do this in reverse in a very graceful fashion. The worm anchors itself to the soil by using retractable spines calles Setae. These Setae are in pairs on each worm segment.

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Commercial (Composting) earthworms

Manure worms can be used for composting and are generally NOT very good in the garden (they need nutrient rich bedding, manure or food scraps). They are the ones that you can buy in bait shops and worm farms. Two types, Reds (Lumbricus rubellus) and Blues (Perionix excavatus) can survive and even thrive in well mulched soil but never introduce adult Reds or Blues to the garden, they will die. Introduce worm capsules (eggs) to the soil and the young worms will adapt more readily to the new environment. Commercial worms have a very high breeding rate and eat thier own weight in bedding and food per day. They will eat anything that was once alive but not while it is alive so are perfect for home and indoor composting.

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Garden earthworms

These worms do more for soil building. They burrow in relatively nutrient poor soil and clay, mix it with mulch and excrete it onto the surface as castings. Their burrows aerate the soil and make it more water retentive, microbe rich and because they are lined with mucous bind plant usable nitrogen to the soil. They are much harder (read expensive) to cultivate commercially than composting worms.

The best way to attract worms into your garden is to mulch it. Create plenty of worm food and worms will flock to you. This does take time though especially if you only have Australian native earthworms in your garden, they breed slowly and are poor performers compared to the European imported worms.

Next time you mow the lawn, leave the catcher behind and leave the grass clippings on the lawn. Within 12 month you could have worm densities of 5000 per square meter (under ideal conditions). At this density they can build your soil up by cm per year. Worms prefer a soil PH on the acidic side of neutral, but not too acidic. As they work they reduce soil acidity via a Calciferous gland, this combined with a light dusting of garden lime (or crushed egg shells) is great for soil PH.

Worms are probably the best thing you can do for your garden, they've been building and fixing the soil for 600 million years long before we came along and started introducing chemicals.

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Earthworm behaviour and Habitat

A useful earthworm classification method is based on feeding behaviour and habitat. All worms fall into these categories somewhere. Generally, the nearer the base of the triangle the more useful the worm for soil building and the nearer the peak are manure (Commercial) worms.

Epigeic
/\
/ <--------------- Eisenia fetida (Tiger or Red Tiger)
/ \
/ <---------------- Perionyx excavatus (Blue or Indian Blue)
/ \
/ <------------ Lumbricus rubellus (Red or Blood worm)
/ \
/ \
/ \
/ \
/ \
/ \
/ \
/ \
/ <---- Lumbricus terrestris
/ \
Endogeic ---------------------------------- Anecic

Epigeic: Surface dwelling worms that ingest freshly decaying plant or animal residues.

Endogeic: Soil dwelling worms that ingest soil and extract nutrition from degraded organic matter.

Anecic: Burrow deep into the soil but forage at night on the surface for freshly decaying plant or animal residues.

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Lumbricus rubellus

Common names: Red Worm, Blood Worm, Red Wiggler.
Colour: Deep red to purple on top, pale yellow on bottom
Length: 75mm full grown
Clitellum: Segments 27 - 32, raised on top, flush on bottom.
Habitat: Top 150mm of soil, under mulch.
Feeding habits: Rich, compost, decaying plant or animal matter.
Preferred temperature: 18 - 23 oC

Comments: Very active wigglers when exposed to sunlight. Worms exude amino acids that are lacking in fish which makes them almost irresistible to fishes and great bait. Prolific breeders

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Eisenia fetida

Common names: Tiger Worm, Garlic Worm.
Colour: Rusty brown with each segment clearly defined by a yellow band.
Length: 75mm full grown
Clitellum: Segments 26 - 32, raised all round.
Habitat: Under mulch and on the surface of soil.
Feeding habits: Rich, compost, decaying plant or animal matter.
Preferred temperature: 18 - 23 oC

Comments: Very active wigglers when exposed to sunlight. Worms exude coelemic fluid which smells unpleasant and are therefore not suitable for fishing bait.

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Eisenia andrei

Common names: Tiger Worm, Red Tiger Worm, Red and Tiger crossbreed.
Colour: Deep red or purple with each segment lightly defined by a yellow band.
Length: 75mm full grown
Clitellum: Segments 26 - 32, raised all round.
Habitat: Under mulch and on the surface of soil.
Feeding habits: Rich, compost, decaying plant or animal matter.
Preferred temperature: 18 - 23 oC

Comments: Very active wigglers when exposed to sunlight. Worms exude coelemic fluid which smells unpleasant and are therefore not suitable for fishing bait.

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Perionyx excavatus

Common names: Blue Worm, Indian Blue, Malaysian Blue.
Colour: Royal purple anterior with a deep red to brown posterior. The Clitellum and belly are a light yellow.
Length: 150mm full grown
Clitellum: Segments 7 - 10, flush, or depressed.
Habitat: Under mulch and on the surface of soil.
Feeding habits: Rich, compost, decaying plant or animal matter.
Preferred temperature: 20 - 27 oC

Comments: Very active wigglers, they also fluoresce when exposed to sunlight. They make good fishing bait and fetch a better price than Lumbricus rubellus. Thier breeding habits are prolific.

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Spenceriella spp

Common names: Blue Worm, Indian Blue, Malaysian Blue.
Colour: Royal purple anterior with a deep red to brown posterior. The Clitellum and belly are a light yellow.
Length: 150mm full grown
Clitellum: Segments 7 - 10, flush, or depressed.
Habitat: Under mulch and on the surface of soil.
Feeding habits: Rich, compost, decaying plant or animal matter.
Preferred temperature: 20 - 27 oC

Comments: Externally identical to Perionyx excavatus with which they are often confused. Very active wigglers, they also fluoresce when exposed to sunlight. They make good fishing bait and fetch a better price than Lumbricus rubellus. Thier breeding habits are prolific and this Australian native worm is Parthenogenetic, ie self fertilising.

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Eudrilus eugeniae

Common names: African night crawler.

Comments: More information when I get it.

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Bibliography

Earthworms in Australia

David Murphy
ISBN: 1 875657 09 6

Worms Downunder Downunder

Allan Windust

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Hot worm links

The Burrow
Rot Web Home Composting Information Site
New Jersey Online's Yucky Site: Worm World
City Farmer

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Designed by Colin Styles ©1996 S t y l e s i e Productions