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Saturday, 5 June 2021

Slow

Dark-lipped Snail (Cepaea nemoralis)
While weeding one of the flowerbeds yesterday, Mike spotted this little mollusc curled up in its house among the mosses. It's a Dark-lipped Snail (Cepaea nemoralis), one of the most widespread and best-known snails in western Europe. That dark lip around the opening in its shell gives it one of its common names. I say "one" because it has a remarkable number of common names: Grove Snail, Banded Snail, Brown-lipped Snail and Lemon Snail among them. Some of that variety comes from the polymorphism the snail exhibits. It comes in a wide array of colours, from very pale yellow through orange and pink to very dark brown, and can be patterned with bands (like this one) and/or one to five stripes that follow the shell's spiral. Scientists think the variety of colours is the result of several intersecting selection pressures. The snails are found in a wide range of habits from woodland and gardens (where darker snails are common) to dunes and grassland (where paler ones are). Some birds (particularly Song Thrushes), mammals, and even some other invertebrates will happily gobble up any snail they find, so looking like the surroundings – and not like every other snail, so that predators can't form a consistent search image – can help a snail to avoid being eaten. These little molluscs are plant eaters, but prefer dead and decaying material, particularly that of nettles and buttercups, so are seldom a problem in the garden. They'll certainly find plenty to eat here! They grow to a reasonably large size, reaching up to 25 mm (about an inch) across. Though reasonably common across most of the UK, they don't quite reach northern Scotland.



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