Identifying Earthworms

If you did not find any earthworms include that information on your data sheets, this is important information too!!!

Only try to identify reproductive adults: those earthworms which have a well defined clitellum which is usually a different colour than the earthworm’s body. Follow through the illustrations on the Taxonomic Key until you have identified each adult. A detailed illustration showing all the external features of the earthworm, including a size chart, can be found on the General Earthworm Diagram. Patterns are the key to identification! When identifying an earthworm, it is important to look at the patterns on its clitellum. The fine details are not as important, or even as clear, as stepping back to observe the general patterns.

Record the number of adults of each species at each site (for all sampling Protocols) on the Observation Form! Please be sure to indicate which protocol(s) you used.

If you are using Protocol 3 (Quantitative Hand-Sort), record the number of adults of each species at each soil depth.

How to use the Earthworm Taxonomic Key

1. Group adult earthworms together according to their size and colour. Size can be established by using the size chart on the General Earthworm Diagram to decide whether you have a small, medium or large adult. To determine the length of your earthworm, allow the worm to freely extend itself as if it was crawling. Measure the maximum distance the earthworm covers when completely stretched out. At no time should you manually stretch an earthworm - this kind of stress can severely damage an earthworm. Once size is established decide on the colour of the earthworm. Next, flip the worm over to expose its underside (ventral view). Look for the position of the clitellum to the head (some species have the clitellum very close to their heads) then examine the clitellum for genital tumescence (see figure 1) (GT) and the general pattern of the tubercula pubertatis (see figure 1) (TP) patterns.Be sure to use the on-line Taxonomic Key, Field Guide and Anatomy pages for more detailed information and instructions on how to identify your earthworms.
    
   
2. Examining fine details is not necessary when using the key. Instead, use the Taxonomic Key to examine the pattern on the clitellum. For example: suppose you have a greenish tinged earthworm that you have collected from a muddy garden. You’ve checked its size by using the size chart on the General Earthworm Diagram to find that it is small or medium (as size of this species depends on habitat). You look on the underside of the clitellum and you see 3 pairs of small button-like (or sucker-like) GT along the fringe of the clitellum. You also notice that these button-like GT are arranged on alternating segments. On the Taxonomic Key, a greenish earthworm, with button-like GT, on alternating segments is an Allobophora chlorotica.
    
   
3. Follow down the key as far as you can. Write the information (species name) on the Observation Form. After you have identified your adults, put one representative adult from each species you identified and any unknown species you found into separate containers or vials for preservation. When you have an earthworm you cannot identify, set aside one representative adult specimen in a vial supplied by Worm Watch, add some soil and put the lid on. Label the container as UNKNOWN #1 and fill in the Observation Form with the same information.
    
   
4. Return all the other earthworms to the soil in which you found them. You may find other earthworms that look the same as UNKNOWN #1 at other locations. Remember to always call this adult UNKNOWN #1 on the Observation Forms and the bottle. Make sure you also record the site location on the container or vial too. Do not put earthworms from more than one site in the same vial or container.When you are done sampling, bring your representative specimens back to your home, lab or school, to be preserved. Do not leave earthworms in the containers or vials overnight without preserving them!!!