Abstract: The study of chalcid wasps that live within syconia of fig trees (Moraceae, Ficus), provides a unique opportunity to investigate the evolution of specialized communities of insects. By conducting cospeciation analyses between figs of section Galoglychia and some of their associated fig wasps, we show that, although host switches and duplication have evidently played a role in the construction of the current associations, the global picture is one of significant cospeciation throughout the evolution of these communities. Contrary to common belief, nonpollinating wasps are at least as constrained as pollinators by their host association in their diversification in this section. By adapting a randomization test in a supertree context, we further confirm that wasp phylogenies are significantly congruent with each other, and build a "wasp community" supertree that retrieves Galoglychia taxonomic subdivisions. Altogether, these results probably reflect wasp host specialization but also, to some extent, they might indicate that niche saturation within the fig prevents recurrent intrahost speciation and host switching. Finally, a comparison of ITS2 sequence divergence of cospeciating pairs of wasps suggests that the diversification of some pollinating and nonpollinating wasps of Galoglychia figs has been synchronous but that pollinating wasps exhibit a higher rate of molecular evolution.
Abstract: The obligate mutualism between fig trees and their fig wasp pollinators, together with the general tendency for each host species to be pollinated by one fig wasp species, led to the hypothesis that these two lineages have cospeciated. The pollinators of African figs of section Galoglychia form a diverse group of genera whose species seem to be less constrained to a spe- cific host than other pollinating fig wasp genera. Various authors have suggested remarkably dif- ferent phylogenetic relationships between the seven genera associated with section Galoglychia . These uncertainties concerning the classification make it difficult to understand the his- torical patterns of association between these wasps and their hosts. The phylogenetic tree for the pollinators was reconstructed with 28S, COI and ITS2 DNA sequence data and compared with morphological classification of the hosts. Pollinator genera were monophyletic in all analyses. However, the relative position of some genera remains unresolved. Investigation of host − fig association suggests that there have been frequent host jumps between host sub- sections. This indicates that cospeciation between fig trees and fig wasps is not as stringent as pre- viously assumed. In addition, pollinators of the genus Alfonsiella associated with three host figs ( Ficus craterostoma , F. stuhlmannii and F. petersii ) are morphologically very similar in South Africa. We investigated the possibility that these pollinators form a complex of species with host-based genetic differentiation. Molecular analyses supported the distinction of the polli- nator of F. craterostoma as a good species, but the pollinators of F. stuhlmannii and F. petersii clustered within the same clade, suggesting that these two host species share a single pollina- tor, Alfonsiella binghami . Based on both molecular data and morphological re-evaluation, a new Alfonsiella species is described, Alfonsiella pipithiensis sp. nov., which is the pollinator of F. craterostoma in southern Africa. A key to both females and males of all described species of Alfonsiella is provided.
