Butterfly heads north as temperatures rise

The Brown Argus is heading north as global temperatures rise, new research suggests

The study, published in the journal Molecular Ecology, reveals that climate change is causing certain species to move and adapt to a range of new habitats.

The study, led by academics at the universities of Bristol and Sheffield, aimed to understand the role of evolution in helping a species to successfully track ongoing climate change.

With temperatures rising, many species are moving further north in the UK but this may mean crossing a landscape with increasingly less of their preferred habitat, academics said.

Evolutionary change in the ability to use geographically widespread habitats or increased ability to move longer distances can help species to track the warming climate and move northwards.

The Brown Argus butterfly is successfully expanding its distribution northwards in the UK and uses a range of distinct habitats. Using genetic techniques to detect evolutionary change, the researchers were able to show that the colonisation of new sites further north by the Brown Argus had involved significant adaptation during or following colonisation.

Researcher James Buckley said: "These findings are important as understanding the likelihood and speed of such adaptive change is important in determining the rate of species extinction with ongoing climate change."

Butterfly Conservation surveys manager Richard Fox said: "The spread of the Brown Argus in Britain has been dramatic over the past 30 years and we knew that the butterfly was using different habitats and foodplants for its caterpillars in the areas that it has colonised.

"However, the mechanisms underlying these changes are much less clear. This new research provides good evidence of evolutionary changes within this butterfly.

"The next, and most interesting, question is why the expansion and associated habitat and evolutionary changes have taken place. This work shows, once again, the important role of British butterflies as the subjects of pioneering research across many different aspects of ecology."