Science 336, 1028–1030 (2012)

A key challenge in understanding and predicting ecological response to climate change relates to the way that different species interact. Changes in the nature of current interactions have the potential to strongly amplify or attenuate direct climate effects on individual species.

Rachel Pateman, from the Department of Biology, University of York, UK, and co-workers documented changes in the range of the butterfly Aricia agestisover in the United Kingdom over the past ∼30 years, and found that the species has expanded northwards by 79 kilometres.

The rapid rate of range expansion was explained by the ability of the butterflies to use different plants as hosts for their caterpillars. Historically, the butterfly was largely restricted to a single plant species, but recent warmer conditions have enabled the butterfly to increasingly use a more widespread plant species, substantially increasing available habitat. This is a particularly interesting case, because interactions among species are often seen as constraints on species' responses to climate change, but these data show that temperature-dependent changes in species interactions can also help to facilitate change.