28 Apr 2011

Citizen science project reveals unexpected evolutionary change in snails

Thousands of members of the public across Europe have taken part in one of the largest evolutionary studies by observing banded snails in their gardens and open public spaces.
More than 6,000 people in 15 European countries took part in The Open University’s citizen science project to observe the evolutionary change in snails and the results have been published in the scientific journal PLoS ONE.
The seven-month project, Evolution MegaLab, is an online mass public experiment aimed at bringing Darwinian theory to life. It was launched in April 2009 to mark the 200th anniversary of Charles Darwin’s birth.
People were invited to report their sightings of banded snails to the MegaLab project via a website at and they received personalised interpretations of their observations in their own language.
Supported by the Royal Society and the British Council, the project team digitised more than 8,000 historical samples from the British Isles and continental Europe. More than 7,600 new observations were made in 2009.
The aim of the research was to find out whether the creatures have evolved in the past 40 years in response to known changes in temperature. It involved comparing samples collected by the general public with data collected between 1950 and 1990.
The research found two unexpected results. The expectation was that snail shells would have become lighter as a way of offering them protection from overheating in sunlight. This was only found to be the case for snails sampled in sand dune habitat, where it is harder for the snails to seek shelter from the heat of the sun. The possible explanation for no general increase in the frequency of lighter shells could be due to snails adapting to a warmer climate through behavioural thermoregulation.
However, the evolutionary change seen right across Europe was an unexpected increase in the percentage of snails with a single dark spiral band around the shell. There was also an unexpected decrease in the frequency of unbanded shells.
Open University Professor of Ecology Jonathan Silvertown, who devised the Evolution MegaLab, said: “This is one of the largest evolutionary studies ever undertaken. Through mass observation we wanted to give the general public, including families and school children, the opportunity to do real science and to experience the fun and excitement of discovery for themselves. Finding unexpected results is what science is all about.
“Exactly what caused the change in bandedness is still a mystery. It does not appear to be related to climate change and researchers suspect it may be due to a decrease in bird predation or some small-scale environmental change. But exactly what has gone on is food for thought.”
Professor Silvertown authored the article in PLoS ONE in collaboration with authors from the project’s partner institutions. He added: “The findings show the power of getting lots of people to help out. The data will set a benchmark for future studies of evolutionary change.”
Evolution MegaLab is one of a number of citizen science projects being run by the Open University. In 2009, the OU launched Creative Climate which is a global diary to show how human beings respond to climate change. It invites members of the public to post a diary and already the project has received hundreds of diary entries from across the world.
More recently the OU has created iSpot, which is an award-winning social network for natural history where people can share their observations of wildlife and get help identifying what they have seen. Ten thousand people have joined to date and made more than 43,000 observations of around 4,500 species.
The research paper is available online in PLoS ONE, click here.

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