Codivergence and multiple host species use by fig wasp populations of the Ficus pollination mutualism

Statistical parsimony and AMOVA revealed deep divergences at the COI locus within several pollinating fig wasp species that persist on the same host Ficus species. Changes in branching patterns estimated using the generalized mixed Yule coalescent test indicated lineage duplication on the same Ficus species. Conversely, Elisabethiella and Alfonsiella fig wasp species are able to reproduce on multiple, but closely related host fig species. Tree reconciliation tests indicate significant codiversification as well as significant incongruence between fig wasp and Ficus phylogenies.The findings demonstrate more relaxed pollinating fig wasp host specificity than previously appreciated. Evolutionarily conservative host associations have been tempered by horizontal transfer and lineage duplication among closely related Ficus species. Independent and asynchronistic diversification of pollinating fig wasps is best explained by a combination of both sympatric and allopatric models of speciation. Pollinator host preference constraints permit reproduction on closely related Ficus species, but uncertainty of the frequency and duration of these associations requires better resolution.Several lines of theory have been proposed to account for the enormous diversity of phytophagous insects. Diversification conceivably ensues by ecological opportunity and adaptation to the exploitation of previously unattainable resources [1,2]; by restricted gene flow through allopatric means [3,4]; and disruptive selection and sympatric speciation [5,6]. In order to discern among potential mechanisms driving speciation, both historical pattern and ecological scale processes are important to consider [7-10]. Comparative phylogenetic approaches that test congruence between host and associate populations can contribute to greater resolution in unravelling ecological scale processes [11-14]. Here we interpret the codiversification between Ficus host species and populations of a group of African fig wasp