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Written by Administrator   
Sunday, 11 September 2005

by Kelly Slocum

It can, indeed, be confusing to determine which worm species is right for you, what with the multitude of varying opinions and experiences discussed on the internet. What follows is an excerpt of a worm growing manual I wrote based on verifiable, peer reviewed research conducted around the world. Please forgive its length, but hopefully it will provide you with enough information on which to base a decision.


Be aware, also, that it is extremely difficult and rare to come across a pure culture of only one worm species, particularly if the worm bed is in contact with the soil or if the system is fed materials that have been in contact with the soil. In most areas of North America beds in contact with the soil will become dominated with Eisenai fetida over time, regardless of the species with which it was started, because E. fetida is generally the most successful species and will tend to outcompete any others. Having said that, there are a few worm beds in the southeastern US that were started with E. fetida worms, but have become dominated by Perionyx excavatus. It just goes to show, the worm species best suited to any environment to which it has access is the one that will dominate. If the system is being operated for the purpose of vermicomposting then the species present is essentially irrelevant, as the one naturally selected for will thrive. If it is your intent to grow a particular species, however, then you'll want to ensure your beds are protected to prevent contamination by species which may be more successful than the one you choose to grow.

Eisenia fetida*/Eisenia andreii (common name, Red Worm). There are two worm species listed here because in virtually all cultures of E. fetida, E. andreii is present. E. andreii so closely resembles E. fetida in behavior, environmental requirements, reproductive and growth rate, and appearance that the only way to distinguish between the two is through molecular scanning. There is no external difference between the two species. For all intents and purposes these worms can be considered identical. Eisenia fetida is generally the only worm mentioned because the two are so closely associated and because fetida is typically the more populous of the two.

Eisenia fetida/Eisenia andreii are the worm species identified as the most useful in vermicomposting systems and are the easiest to grow in high-density culture because they tolerate the widest range of environmental conditions and fluctuations, and handling and disruption to their environment of all species identified for this purpose. E. fetida/E. andreii are also common to virtually every landmass on earth, meaning there is no concern over importing potentially alien species to an environment where they might cause damage. While this worm species is considered the premier worm for most applications, it is a small worm, not always suited for use as bait.

· Temperature range: Minimum; 38° F, maximum; 88° F, ideal range; 70° F-80° F.

· Reproductive rate: Approximately 10 young per worm per week under ideal conditions.

· Average number of young per cocoon: Approximately 3.

· Time to emergence from the cocoon: Approximately 30-75 days under ideal conditions.

· Time to sexual maturity: Approximately 85-150 days under ideal conditions.

*Note: The spelling ‘fetida’ was changed a few years ago to ‘foetida’ then subsequently changed back for reasons clear only to a few earthworm taxonomists. The different spellings do not denote different species. Information on this species can be found under both spellings, though the correct spelling is ‘fetida’.

Eudrilus eugeniae (common name, African nightcrawler)

This worm is a semi-tropical species, meaning it cannot easily tolerate cool temperatures and is usually grown indoors or under temperature controlled conditions in most areas of North America. E. eugeniae is a large species, well suited for use as a bait worm, but does not tolerate handling or disruption to its environment.

This species is used in some vermicomposting systems around the Mediterranean region and in some areas of eastern Asia.

· Temperature range: Minimum; 45° F, maximum; 90° F, ideal range; 70°-80° F.

· Reproductive rate: Approximately 7 young per worm per week under ideal conditions.

· Average number of young per cocoon: Approximately 2.

· Time to emergence from the cocoon: Approximately 15-30 days under ideal conditions.

· Time to sexual maturity: Approximately 30-95 days under ideal conditions.

Amynthas gracilus, also known as Pheretima hawayana(common name, Alabama or Georgia jumper)

A. gracilus is another large worm species well suited for use as bait. It is also a tropical species with a poor tolerance for cold temperatures. This worm tolerates handling and disruption to the worm bed as well as does E. fetida and is generally considered an easy worm to culture provided appropriate temperatures can be maintained.

A. gracilus is used in a few vermicomposting systems in Malaysia and the Philippines. · Temperature range: Minimum; 45° F, maximum; 90° F, ideal range; 70° F-80° F.

· Reproductive rate: Undetermined, though believed to be similar to E. eugeniae.

· Average number of young per cocoon: Undetermined, though believed to be similar to E. eugeniae.

· Time to emergence from the cocoon: Undetermined, though believed to be similar to E. eugeniae

· Time to sexual maturity: Undetermined, though believed to be similar to E. eugeniae

Perionyx excavatus (common name, Indian Blue worm)

Perionyx excavatus is a beautiful worm with an iridescent blue or violet sheen to its skin clearly visible under bright light. It is a very small worm, poorly suited as fishing bait, but has an impressive growth and reproductive rate far in excess of the other species grown in bin culture.

This is another tropical worm species with a very poor tolerance for low temperatures, fluctuations in the bin environment, handling or disruption to the system. P. excavatus is often referred to as “the Traveler” for its tendency to leave the bin en masse for no apparent reason.

Due to it’s temperamental nature this species is rarely used in vermicomposting systems in North America, though it is naturally occurring in systems in contact with the soil in the southeastern US and most tropical regions of the world. · Temperature range: Minimum; 45° F, maximum; 90° F, ideal range; 70° F-80° F.

· Reproductive rate: Approximately 19 young per worm per week under ideal conditions.

· Average number of young per cocoon: Approximately 1.

· Time to emergence from the cocoon: Approximately 15-21 days under ideal conditions.

· Time to sexual maturity: Approximately 30-55 days under ideal conditions.

Eisenia hortensis, also known as Dendrobaena veneta (European nightcrawler)

E. hortensis is a large worm species well suited for use as a bait worm. Its ideal temperature range is a bit cooler than is that of E. fetida and it requires higher moisture levels than do the other species tested for use in bin culture and vermicomposting, but the species tolerates handling and disruption to its environment, and environmental fluctuations very well. Because this worm has a very low reproductive and growth rate, relatively speaking, it is considered the least desirable species of those tested for either bin culture or vermicomposting systems. It is used in a few vermiprocessing systems in Europe for the remediation of very wet organic materials. · Temperature range: Minimum; 45° F, maximum; 85° F, ideal range; 55° F-65° F.

· Reproductive rate: Just under 2 young per worm per week under ideal conditions.

· Average number of young per cocoon: Approximately 1.

· Time to emergence from the cocoon: Approximately 40-125 days under ideal conditions.

· Time to sexual maturity: Approximately 55-85 days under ideal conditions.


Last Updated ( Monday, 12 June 2006 )
 
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