One fig to bind them all: host conservatism in a fig wasp community unraveled by cospeciation analyses among pollinating and nonpollinating fig wasps.
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.
Jousselin
Emmanuelle
E
Institut National de la Recherche Agronomique, Centre de Biologie et de Gestion des Populations, Campus International de Baillarguet, CS-30 016, 34 988 Montferrier sur Lez, France.|E-mail: jousseli@supagro.inra.fr.
Van Noort
Simon
S
Natural History Division, South African Museum, Iziko Museums of Cape Town, PO Box 61, Cape Town 8000, South Africa.
Berry
Vincent
V
Département Informatique, LIRMM- CNRS, 161, rue Ada 34392 Montpellier Cedex 5, France.
Rasplus
Jean-Yves
JY
Institut National de la Recherche Agronomique, Centre de Biologie et de Gestion des Populations, Campus International de Baillarguet, CS-30 016, 34 988 Montferrier sur Lez, France.
Rønsted
Nina
N
Jodrell Laboratory, Royal Botanic Gardens, Kew, TW9 3DS Richmond, Surrey, United Kingdom.
Erasmus
J Christoff
JC
Department of Genetics, University of Pretoria, Pretoria 0002, South Africa.
Greeff
Jaco M
JM
Department of Genetics, University of Pretoria, Pretoria 0002, South Africa.
D000818:Animals; D030681:Ficus / Q000235:genetics*; D049810:Genetic Speciation; D010802:Phylogeny; D054817:Pollination; D013559:Symbiosis; D014863:Wasps / Q000235:genetics*