Evolution, 60(2), 2006, pp. 315±327 DO ANTS ENHANCE DIVERSIFICATION IN LYCAENID BUTTERFLIES? PHYLOGEOGRAPHIC EVIDENCE FROM A MODEL MYRMECOPHILE, JALMENUS EVAGORAS ROD EASTWOOD,1,2 NAOMI E. PIERCE,3,4 R. L. KITCHING,1,5 AND JANE M. HUGHES1,6 1Australian School of Environmental Studies, Grif®th University, Nathan 4111, Queensland, Australia 2E-mail: r.eastwood@grif®th.edu.au 3Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, Massachusetts 02138 4E-mail:
[email protected] 5E-mail: r.kitching@grif®th.edu.au 6E-mail: jane.hughes@grif®th.edu.au Abstract. The ant-tended Australian butter¯y, Jalmenus evagoras, has been a model system for studying the ecology and evolution of mutualism. A phylogeographic analysis of mitochondrial DNA cytochrome oxidase I sequences from 242 butter¯ies (615 bp) and 66 attendant ants (585 bp) from 22 populations was carried out to explore the relationship between ant association and butter¯y population structure. This analysis revealed 12 closely related butter¯y haplotypes in three distinct clades roughly corresponding to three allopatric subpopulations of the butter¯ies. Minimal genetic diversity and widespread haplotypes within biogeographical regions suggest high levels of matrilineal gene ¯ow. Attendant ants are signi®cantly more diverse than was previously thought, with at least seven well-de®ned clades corresponding to independent morphological determinations, distributed throughout the range of the butter¯ies. Nested analysis of molecular variance showed that biogeography, host plant, and ant associate all contribute signi®cantly in explaining variation in butter¯y genetic diversity, but these variables are not independent of one another.