WORM BIOLOGY

Anatomy

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. Earthworm anatomy is clearly illustrated by the diagrams below (Click on either image to see a larger version).

More Info from MSN

Kids - Visit Squirmin' Herman the Worm Here

Types of Earthworms

There are approximately 4500 species of worms in the world. Of those about 2500 are earthworm species. Earthworms are either earthmovers or composters. Earthmovers tend to be solitary species which tunnel through the earth, aerating, decompacting, and mixing soil strata and thus making surface nutrients available to plant roots at lower levels. Composters live en masse in organic matter on the soil surface, where they consume bacteria present in dead vegetation, animals and manure, turning it into humus. Worm species commonly sold on the market include Eisenia fetida, Lumbricus rubellus, Lumbricus hortensis, Lumbricus terristris, Eudrilus engeniae, Eisenia andrei, and Perionyx excavatus. 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 behaviors 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 Wormpost Northeast we sell Eisenia fetida.

Eisenia fetida and Lumbricus rubellus

At Wormpost Northeast we exclusively sell Eisenia fetida (changed to fetida from foetida as of 2004). The issue of correct classification of earthworms is confusing and Eisenia fetida, like other worm species, has multiple common names. These include redworm, red wiggler, red wriggler, brandling worm, manure worm. Fishing suppliers may call them red hybrid, dungworm, or striped worm. Eisenia fetida technically belongs to the Redworm category, which it shares with Lumbricus rubellus. Lumbricus rubellus, however, is referred to by some sources, as Driftworms, Garden Worms, Angle Worms, Leaf Worms, Red March Worms or Red Wrigglers. Perionyx excavatus, known commonly as Blueworms, is referred to by some as Redworms. However, while Eisenia fetida and Lumbricus rubellus are composting worms, Perionyx excavatus is a soil worker. So there you go.

When ordering redworms, make sure you know if it is Eisenia fetida or Lumbricus rubellus. Some websites make no distinction, yet there are some important ones and those will be delineated below. Both species of Redworms are composters, living naturally in soils which contain a lot of organic matter. For this reason they are sometimes used together in vermicomposting systems, with Eisenia fetida at the surface and Lumbricus rubellus further down. Eisenia fetida evolved in natural habitats of leaves, manure, compost piles and in many other decaying organic materials where they developed their trademarks as voracious eaters and prolific breeders.

Due to the nature of their work and habitat, Eisenia fetida are able to tolerate a temperature range of 40 to 90 degrees Fahrenheit, with an ideal range of 70-75 degrees. This is slightly higher than that of Lumbricus rubellus. By contrast Lumbricus rubellus can survive lower temps than Eisenia fetida, but for both redworm species the most suitable range is 71-89. At 50 degrees and below the amount of food eaten by the worms will decrease. The worms will be less active, and possibly move a little lower into the bedding (unless it is a cold floor causing the problem, in which case they will move nearer the surface.) At 39-41 degrees, the adult worms may stop producing cocoons and the growth rate of the younger worms will diminish (D. Brian Paley “The Burrow Environmental requirements”, 1995) Outdoors Lumbricus rubellus and Eisenia fetida are surface dwellers, yet Lumbricus rubellus can tunnel into the soil more deeply than Eisenia fetida to survive a freezing winter. For overwintering Eisenia fetida outdoors, piles or bins must be heavily insulated. Worms will be dormant and composting and breeding activity will dramatically slow or cease during this time.

Woms as bait

Redworms are not just good composters. According to Recorp Inc., “Redworms are used to feed small herps, aquarium and small pond fish. In fact, many bird owners have chosen redworms to supplement traditional seed-based diets.”

In the world of fish bait European nightcrawlers (Lumbricus rubellus) are favorites next to Canadian nightcrawlers (Lumbricus terristris). With the average adult measuring 4.0 inches in length, Lumbricus rubellus are ordinarily used as bait for bass and large fish “many fishermen use them as salt-water bait” (Recorp., Inc). The fact that Lumbricus rubellus “may be kept in the fridge or in cups at room temperature for several weeks.” is also to their credit. Eisenia fetida are less popular as fish bait than Lumbricus rubellus due to their more slender girth and shorter length of 1.5-2.5 inches, but they are “ideal for trout and panfish. Adults can be threaded whole on a #6 or smaller hook and will tolerate temps of 38-40 degrees, which makes them reliable in all weather without refrigeration. “Those who swear by Eisenia Foetida as fish bait do so because it survives longer in water” and “will remain wiggling and triggering the eating response from your fish for longer than other species of worm.” [Redworms Technical. LarvaTech at http://members.aol.com/larval1/earth.htm]

No matter what worm species you choose for fishing, please check state regulations. When finished fishing, dump extra worms in the water or bring them home. Please do not dump extra worms on the ground. Some worm species are problematic in the forest.

A Note on Invasive Worm Species

Occasionally we are asked whether worms actually harm the environment. A quick survey of Google will show that specific earthworm species have been blamed with the disappearance of leaf litter in North American forest ecosystems, which have evolved without earthworms. The danger is to tree roots, rare plant species, and animals sheltered by the leaf litter. This concern is discussed in detail with regards to Minnesota forrests by the University of Minnesota Extension Service. At Wormpost Northeast we explored this issue with cooperative extension agents, worm farmers, and biologists and have concluded that there is much disagreement on to what degree these concerns are founded and that it is best to directly consult scientific studies rather than any other source of information. We encourage you to do your own research and to keep in mind several points:

• Vermicomposting is an environmentally beneficial means of recycling organic wastes and reducing soil, water, and air pollution.
• All earthworms in North Americal are invasive, brought over from Europe, Asia, and Africa since the last ice age. Some regions have adapted to the presence of certain species and not others, and thus the introduction of new species may be termed "invasive". It stands to reason that as the climate changes, certain worm species will be able to survive in ecosystems that previously were inhospitipal to them.
• The popular wisdom is that earthworms eat microorganisms and cellulose present in organic matter and have no reason to spread to or ability to survive in to soils not containing sufficient "food". However, good worm habitat depends on the species and on whether or not the worm is a surface dweller or an earth dweller. To avoid exacerbating any existing problem or creating a new one, know your worm species and avoid putting worms or worm castings in or near a forrested area.
• Consult your local university horticulture program or cooperative extension service to inquire about local issues.
• Please share any hard studies related to this topic by emailing us a link at worms@wormpost.com.

Possible Solutions

• Worm classification. Ordering the proper worm species by its Latin or Greek genus and species name, for example Eisenia fetida (See: http://www.urbanext.uiuc.edu/worms/familytree/genus.html), can help you to avoid a species you do not want, although it common for batches of worms to contain species other than the dominant one. This is particularly the case when outdoor worm bins are in contact with the ground.

  Questionable species can be identified by an earthworm taxonomist. Shipping live worms outside the United States is frought with regulations. For United States residents we recommend Sam James, the leading worm taxonomist in North America. His contact information is as follows:
  
  Postal Address: 1000 North Fourth St. FM 1056/Fairfield, Iowa 52557.
  E-mail address: massemaj@yahoo.com
  Phone: (641) 919-0275

Worm Reproduction

Earthworms have a lifestyle which to many people seems enviable: They meet, eat, procreate, sleep, and excrete.

Redworms are sexually mature at eight to 10 weeks. They mate at any time of year, in their bedding at different levels and even on the lid of their worm bin, if that is where they reside. A redworm is sexually mature and able to reproduce at around three months of age, when it has formed a thick band, or “clitellum” around its body about one-third of the way between its mouth and anus. Worms are hermaphrodites and contain both male and female sexual organs. As shown in the diagram below, two worms will nestle against one another in opposite directions so that their clitella are touching. Each worm will secrete mucus forming a band around both worms at the clitella. Sperm from each worm move down a groove into receiving pouches of the other worm. The sperm enters a storage sac. The worms slide apart, withdrawing backwards through the band and continue on their separate ways. After the worms have separated, their clitella secrete another substance called albumin. This material forms a cocoon in which the eggs are fertilized and baby worms hatch. Redworm cocoons, which are round and small, change color during their development. First they are white, become yellow, later brown and gradually enlarge. When the new worms are ready to emerge, the cocoons are turning red and are about the size of a grape seed.

Worm development within the cocoon takes at least three weeks. Temperature and other conditions are factors in the development of the hatchlings. A cocoon might hold as many as 10 eggs, but usually only three or four worms will emerge. The young hatchlings are whitish with a pink tinge showing their blood vessels. Redworms can lay 2 cocoons a week for six months to a year (Applehoff, Worms Eat My Garbage, 1982).