Our country needs you to count worms: Volunteers wanted to carry out first earthworm 'census'

They might be slimy, slithery and wriggly - but according to Darwin, worms are one of the most important creatures on earth.

And with their habitats increasingly under threat, volunteers are being asked to help with an earthworm 'census'.

The £500,000 project will see amateur scientists pouring mustard - a mild irritant to worms - on their flowerbeds. They can then identify any disgruntled (but otherwise unharmed) specimens which surface.

The collated results will be used to shed light on one of Britain's most common, but also most poorly understood, creatures.

Organisers also hope to identify rare species which could be on the brink of extinction.

David Jones, of the Natural History Museum, said that surprisingly little research has been done on earthworms since Darwin wrote in the 19th century: 'Worms have played a more important part in the history of the world than most persons would at first suppose.'

Mr Jones added: 'Darwin did a lot of work on earthworms at his home in Kent, but since then the research has been sporadic.
'We don't fully understand which earthworms live where - and which particular species like which types of soil.'

Although there are dozens of ways to encourage worms to the surface, including imitating rainfall or rubbing a metal pole in the ground to simulate the burrowing of a mole, rigorous research has shown that dousing soil in mustard is the most effective technique.

As long as the condiment is diluted enough, it irritates the worms without causing them long-term damage.

The worm count is part of a five-year community science project called Open Air Laboratories, or Opal.

It is being led by the Natural History Museum and funded by £11.7million of lottery money.

During the census, due to take place in the spring, volunteers will be sent free worm-watching packs.

These will contain a chart allowing them to identify 13 of the most common worms by colour, size, shape and pattern of rings. More sophisticated identification software will be available on the project's website.

The packs will also include a strip of litmus paper to help identify whether soil is acid or alkaline, and a questionnaire about its quality.

A future Opal project will ask volunteers to look out for tar spot fungus on tree leaves and lichen to help monitor air pollution. Other mass surveys will look at the wildlife in ponds, streams and rivers.