Molecular phylogenies of fig pollinating and non-pollinating wasps and the implications for the origin and evolution of the fig-fig wasp mutualism

Figs host three ecologically distinct groups of wasps: pollinators, non-pollinators (parasitic wasps) and parasitoids. Both pollinators and non-pollinators complete their life cycles using fig tissue, while parasitoids appear to attack some groups of non-pollinators. We used nucleotide sequence data to address a series of questions concerning genealogical associations, host specificities and degree of strict-sense co-evolution exhibited by members of these groups. We used the relatively conserved 12S rRNA gene of the mitochondria to estimate high level relationships among pollinator, parasitic and parasitoid taxa by sampling species collected from host figs representing five sections (three subgenera) from Asia, Africa, Europe and Central America. We found that all pollinators formed a clear monophyletic group. However, we could not resolve whether or not all of the non-parasitoid wasps associated with figs (Agaonidae, sensu Boucek) formed a single monophyletic group. Further, we used the more variable COII mitochondrial gene to attempt to determine relationships among closely related species of pollinators within two New World genera. Using sequences from the same gene we estimated the phylogenetic relationships among the parasites collected from the same New World host fig species and compared them with those of the pollinators. At fine taxonomic scale, we found that for both pollinator and parasites, species were generally specific to a given fig host. Moreover, the phylogenies of the non-pollinators are largely congruent with those of the pollinators, suggesting the predominance of strict-sense co-evolution on shared host fig species. The implications of these findings and opportunities for future research are discussed.