One of the amazing things about working on earthworms is the fact that sooo little is known about them! This coupled with the fact that the more you discover about earthworms the more incredible they are, makes them, in my opinion, the best animals to work on. You can feel a little like the early explorers must have done when on fieldwork to countries with no species lists and real knowledge of their earthworm fauna; every stone you turn or every log you sort through can bring about the discovery of something new to science and certainly new for the country. Also everything is new for you. I felt like that on my fieldwork to Nicaragua, as a team (I worked with Frontier, the conservation group) we discovered 18 new species to Nicaragua and wrote a paper describing 3 new species to science. The highlight of trip being the discovery of a bright blue earthworm. We named it azul, meaning blue in Spanish. It was the first species of worm I described and I’ll never forget it!

There are, we think, roughly 5,000 species of earthworm described (with continual taxonomy changes we can never be too certain) however this is just a portion of the worms really out there. As I mentioned there are still a lot of countries with no real species lists and certainly not comprehensive. The figure should surely be over 10,000, so there is lots of work to be done!

One of the most exciting recent discoveries was made by Sam James in the Phillipines in 2011 called Archipheretima middeltoni. This worm was exciting for 2 reasons, for one its amazing colour… we all call it the fried egg worm! The other reason is it’s the only earthworm known to contain poison. Sam worked this out the hard way as he had collected these worms first off with other worms in his pot. One of the fried egg worms had got a bit damaged, as he walked and checked on his worms he realised some of the other worms were dying. He couldn’t understand why until he realised it was when they came in contact with the damaged worm that had some body fluid around it. I guess those fried eggs are really telling birds that they really don’t want to eat them!

Although earthworms have moved around the globe with Humans to some extent, and there are 18 different families of earthworm, there are certain generalisations of where families are mainly based or originate from. For example Lumbricidae (the family British earthworms are mainly in) is mainly found in Europe. One of the other biggest families, Megascolecidae is mainly found in Asia. I sampled a lot of worms in this family in Vietnam when I was on fieldwork but am also familiar with them from the tropical greenhouses in the UK. (They need warmer climates than those usually found in Europe). One thing I find very exciting about these worms is the beautiful iridescence they show, the more muscular bodies they have and the way they can curl themselves around and basically jump to avoid predation. Incredible!

However don’t forget the amazing diversity of worms here at home- there’s so much to explore under your lawn, in that compost bin and in the local forests!

Emma Sherlock is the Senior Curator of Free-Living Worms & Sponges at The Natural History Museum London which is a project partner of Earthworm Watch and Chair of the Earthworm Society of Britain.

Today’s blog is been created to celebrate World Earthworm Day, which you can follow using the #worldwormday on Twitter & Facebook. If this has inspired you to learn more about earthworms than why not take part in Earthworm Watch this autumn and also join the The Earthworm Society of Britain.

Earthworm Watch has been developed by Earthwatch (Europe)The Natural History Museum and the Earthworm Society of Britain to better understand the ecosystem benefits of earthworms. Earthworm Watch allows the public to help scientists map their abundance, better understand the human impact on their populations and with further research measure the services these ‘ecosystem engineers’ provide.