Fig. 1

Diagrammatic representation of some of the major components of the geographic mosaic of coevolution between a pair of species. Interactions within local communities are shown as arrows within circles and indicate selection acting on either one or both species. Different arrow angles represent differences among communities in how selection acts on the species. Differences in arrow thickness and lines represent differences in the strength or form of natural selection. Arrows between communities indicate gene flow, with thicker arrows representing more gene flow. In this diagram, coevolutionary hotspots (i.e., communities in which selection is reciprocal on the interacting species) occur within a broader matrix of coevolutionary coldspots (i.e., communities in which selection either does not act on the interacting species or is not reciprocal). Modified from Thompson (2005)