New Digs Many studies predict range alterations among species in response to climate change. Species, however, cannot be thought of as truly independent entities, because they all exist as a part of an interacting community. Most discussions of such interactions have focused on the potential restrictions they might place on range expansion; however, Pateman et al. (p. 1028 ) show that climate change has the potential to increase the number of species that can interact and thus facilitate expansion. British data collected by the general public on sightings of the Brown Argus butterfly and its host plants revealed an increased affiliation between the butterflies and a previously little-used group of plants. As summers warmed, populations associated with the new host were more productive than those associated with the more “traditional” host, which facilitated expansion of the butterflies into novel regions.