1. ¹School of Biological Sciences, Washington State University, Pullman, WA, USA
2. ²Department of Mathematics, Washington State University, Pullman, WA, USA
3. ³Department of Biology, University of Idaho, Moscow, ID, USA

Correspondence: Dr R Gomulkiewicz, School of Biological Sciences, Washington State University, PO Box 644236, Pullman, WA 99164-4236, USA. E-mail: gomulki@wsu.edu

⁴Current address: Department of Biology, New Mexico State University, Las Cruces, NM 88003-8001, USA.

Received 1 August 2006; Revised 30 November 2006; Accepted 26 January 2007; Published online 7 March 2007.

Abstract

The geographic mosaic theory of coevolution is stimulating much new research on interspecific interactions. We provide a guide to the fundamental components of the theory, its processes and main predictions. Our primary objectives are to clarify misconceptions regarding the geographic mosaic theory of coevolution and to describe how empiricists can test the theory rigorously. In particular, we explain why confirming the three main predicted empirical patterns (spatial variation in traits mediating interactions among species, trait mismatching among interacting species and few species-level coevolved traits) does not provide unequivocal support for the theory. We suggest that strong empirical tests of the geographic mosaic theory of coevolution should focus on its underlying processes: coevolutionary hot and cold spots, selection mosaics and trait remixing. We describe these processes and discuss potential ways each can be tested.