How do I identify earthworms?
A vital part of recording earthworms is to know how to tell each species from another. Earthworms have a number of characters that allow us to tell the difference between the species. As earthworms in general are not very large, some of these characters are require a microscope to investigate the characters in detail, but if you don't have a microscope a strong hand lens can work ok on larger species. An identification key can then be used to determine which species an earthworm is based on the characters that are present. The picture below, taken from Key to the Earthworms of the UK & Ireland by Sherlock (2012), shows some of the main characters that are used in identifying earthworms.
Key to the Earthworms of the UK & Ireland by Sherlock (2012) is part of the FSC AIDGAP series. The aim of AIDGAP series is to produce accessible keys suitable for non-specialists from sixth-form age upwards. This key provides a basic background in earthworm biology as well as information on sampling, recording and preserving earthworms. In addition to a dichotomous key, there is a quick earthworm comparison chart and species accounts.
The FSC Tomorrow's Biodiversity project have created an online multi-access key based on the content of the FSC AIDGAP key (the printed key is often still required to verify identification).
Earthworms by Sims & Gerard (1999) is part of the Synopses of the British Fauna and provides a much more detailed account of UK earthworm biology and taxonomy. The technical detail contained within the dichotomous key and diagrams make this key suitable for more experienced users. It is also available from the FSC.
OPAL Earthworm Guide is a key to the common species of UK earthworms only and covers less than half of UK earthworm species. It is a fantastic resource for looking at earthworms in more depth with children and individuals not experienced in biological recording. However, it is not a sufficiently detailed identification key for the purpose of the National Earthworm Recording Scheme. Few British species can be reliably identified from live specimens in the field.
The Earthworm Society of Britain (ESB) runs earthworm identification workshops where you can learn how to identify British earthworms. These are suitable for anyone interested in learning how to identify earthworms using a microscope and identification key. Identification workshops are available to all ESB members and will be advertised in advance in our members newsletter: Earthworm News. Please check out our upcoming events and our Facebook Page for more details.