Earthworms belong to a class of creatures called annelids or “ringed” creatures. An annelid is a creature with a cylindrical body which is segmented both outside and inside. Earthworm anatomy is clearly illustrated by the diagrams below.
Types of Earthworms
There are approximately 4400 species of worms in the world, and researchers have broken them into three categories, largely descriptive of their habits in the soil. These three categories are endogeic, anecic and epigeic.
Endogeic worms build complex lateral burrow systems through all layers of the upper mineral soil. These worms rarely come to the surface; instead spending their lives in these burrow systems where they feed on decayed organic matter and bits of mineral soil. They are the only category of worm which actually eats SOIL. Endogeic worms tend to be medium sized and pale coloured.
Anecic worms build permanent, vertical burrows that extend from the soil surface down through the mineral soil layer. It is not unusual for these burrows to reach a depth of six feet or more. These worm species coat their burrows with mucous which stabilises the burrow so it does not collapse, and build little mounds (called middens) of stone and castings outside the burrow opening. Anecic worms are able to recognize their own burrows, even in an environment where there are hundred of other burrows present and return to these burrows each day.
The anecic species feed in decaying surface litter, so come to the soil surface regularly, which leaves them exposed to predators. They have developed a spoon shaped tale that bristles with little retractable hairs, called setae, with which to grip the burrow wall and avoid being easily pulled out. The anecic species also tend to be very large worms and have bellies with less pigmentation than their backs. These worms have a long generation time, do not do well in high density culture and require the stable burrow environment in order to thrive. In the absence of this burrow, anecic worms will neither breed nor grow.
The worms we use for composting systems are in the epigeic category. In nature the epigeic worms live in the top soil. These small, deeply pigmented worms have a poor burrowing ability, preferring instead an environment of loose organic litter or loose topsoil rich in organic matter. Epigeic species feed on organic surface debris and have adapted beautifully to the rapidly shifting, dynamic environment of the soil surface.
We use epigeic worms because a) we can duplicate their ideal environment in a bin or bed, b) they are voracious processors of organic debris, c) they do well in a high density culture and d) they are very tolerant of a wide range of environmental conditions and fluctuations.
Earthworms are an incredibly varied and adaptable group of animals that are so common in our world that they often go unnoticed and unsung. We are far more dependant on them than we realize, and are fortunate that they are so eager and able to rise to the challenges we pose them!
Some of these species and other species share similar common names even while their sizes, appearances, natural habitats, feeding and breeding habits, and temperature requirements, and behaviours are quite different.
Therefore, when buying earthworms be sure to request a species suitable for the intended use and conditions in which you will be storing them. Otherwise, your worms may end up fleeing or dying outright and you will be very disappointed.
At Westcountry worms we breed the Dendrobaena worm. The dendrobaena worm has been reclassified to the genus and species Eisenia Hortensis and is commonly call the European nightcrawler. We also have Tiger worms because it is almost impossible to keep them out when they are breeding outside. So we sell a mixture of these species.
Eisenia Hortensis
Reproductive rate:
1.6 cocoons per adult per week
81.2% hatching success rate
1.1 hatchlings per cocoon
Net reproduction of 1.4 young per adult per week
Growth rate
40-128 days to cocoon hatch
57-86 days to sexual maturity
97-214 days from egg to maturity
Temperature requirements:
Minimum tolerance 45°F
Maximum tolerance 88°F
Ideal 60-70°F
Wormeries 
Copyright Westcountry Worms 2006