We have used molecular variation in microsatellite and mitochondrial DNA to throw light on the origins of enigmatic geographical patterns, known as 'area effects', in the shell polymorphisms of the land snail Cepaea nemoralis. Our aim was to assess the relative importance of recent selection and historical events in the formation of these patterns. On the Marlborough Downs in Wiltshire, England...

Biologists and philosophers have been extremely pessimistic about the possibility of demonstrating random drift in nature, particularly when it comes to distinguishing random drift from natural selection. However, examination of a historical case--Maxime Lamotte's study of natural populations of the land snail, Cepaea nemoralis in the 1950s--shows that while some pessimism is warranted, it has ...

Abstract Many parasites and hosts are embroiled in an on-going arms race that affects the evolution of each participant. One such battle is between parasitic nematodes terrestrial gastropods which have co-evolved for 90–130 MY. Recently, snails been shown to encase kill invading using their shell as a defence mechanism. However, there remarkably little known about this process terms understandi...