Gourmet butterflies speed north

A new study has shown how a butterfly has changed its diet, and consequently has sped northwards in response to climate change. Researchers found that warmer summers have allowed the Brown Argus butterfly to complete its life cycle by eating wild Geranium plants. Because the Geraniums are widespread in the British countryside, this change in diet has allowed the butterfly to expand its range in Britain at a surprisingly rapid rate. Over the past 20 years, the Brown Argus has spread northwards by around 79 kilometres and has become common in the countryside in much of southern England.