WinkleWatch: A Community Science Project on Snail Colour
An international group of snail scientists, including Prof. Roger Butlin’s team from the University of Sheffield, are trying to solve a long-standing “mystery” in evolutionary biology: Why do periwinkles - sea snails - have so much variation in colour? This work requires data from numerous geographical locations, and colour variation is a fascinating phenomenon that can easily spark curiosity in non-scientists. The researchers have therefore turned this project into a community science project, calling beachgoers from all over Europe and North America to submit pictures of periwinkles via the website here.
What are winkles?
Periwinkles are small sea snails found across the coasts of Europe and North America, mostly on stones and rocks. Their main predators are crabs. Studies at the University of Sheffield and elsewhere have already demonstrated that where crabs are common, snails have evolved thicker and larger shells as a protective mechanism. In contrast to shell size and shape, shell colour is less well understood. Periwinkles come in a rainbow of colours, including white, orange and purple, and show striking checkerboard and striped patterns. Often, many different colours can be found on a single beach. So far, nobody knows why the snails have not settled on a small number of “optimised” colours, and what benefits shiny colours could have for a species without good colour vision.
Colour as an adaptation
Many animals have evolved colours that match their environments. One reason is to avoid being obvious to predators. Other animals have colours that don’t match their environment and are useful e.g. for attracting mates. Have periwinkles evolved to blend in with their local environment? Are their colours affected by climate conditions, as lighter shells heat up less in the sun? The scientists will analyse the submitted images and apply statistical methods to compare the colour of the snails to that of their habitat. They will also test whether colour changes along a north-south gradient and thus potentially represents an adaptation to temperature variation.
Want to help?
Heading to the beach? Take your phone and spare a few minutes to help solve this scientific question! Visit the page below to find out exactly what the scientists need you to do and then submit your pictures.