Marussich Wendy A, Machado Carlos A
Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721-0088, USA.
Mol Ecol. 2007 May;16(9):1925-46. doi: 10.1111/j.1365-294X.2007.03278.x.
Figs (Ficus spp., Moraceae) and their pollinating wasps (Hymenoptera, Agaonidae, Chalcidoidea) constitute a classic example of an obligate plant-pollinator mutualism, and have become an ideal system for addressing questions on coevolution, speciation, and the maintenance of mutualisms. In addition to pollinating wasps, figs host several types of nonpollinating, parasitic wasps from a diverse array of Chalcid subfamilies with varied natural histories and ecological strategies (e.g. competitors, gallers, and parasitoids). Although a few recent studies have addressed the question of codivergence between specific genera of pollinating and nonpollinating fig wasps, no study has addressed the history of divergence of a fig wasp community comprised of multiple genera of wasps associated with a large number of sympatric fig hosts. Here, we conduct phylogenetic analyses of mitochondrial DNA sequences (COI) using 411 individuals from 69 pollinating and nonpollinating fig wasp species to assess relationships within and between five genera of fig wasps (Pegoscapus, Idarnes, Heterandrium, Aepocerus, Physothorax) associated with 17 species of New World Urostigma figs from section Americana. We show that host-switching and multiple wasp species per host are ubiquitous across Neotropical nonpollinating wasp genera. In spite of these findings, cophylogenetic analyses (TREEMAP 1.0, TREEMAP 2.02beta, and parafit) reveal evidence of codivergence among fig wasps from different ecological guilds. Our findings further challenge the classical notion of strict-sense coevolution between figs and their associated wasps, and mirror conclusions from detailed molecular studies of other mutualisms that have revealed common patterns of diffuse coevolution and asymmetric specialization among the participants.
榕树（桑科榕属）及其传粉榕小蜂（膜翅目，榕小蜂科，小蜂总科）构成了专性植物 - 传粉者互利共生的经典例子，并已成为解决协同进化、物种形成和互利共生维持问题的理想系统。除了传粉榕小蜂外，榕树还寄生着几种非传粉寄生榕小蜂，它们来自不同的小蜂亚科，具有不同的自然历史和生态策略（如竞争者、造瘿者和寄生蜂）。尽管最近有一些研究探讨了传粉榕小蜂和非传粉榕小蜂特定属之间的共分化问题，但尚无研究涉及由与大量同域分布的榕树宿主相关的多个黄蜂属组成的榕小蜂群落的分化历史。在这里，我们使用来自69种传粉和非传粉榕小蜂物种的411个个体，对线粒体DNA序列（COI）进行系统发育分析，以评估与美洲榕组新世界Urostigma属17种榕树相关的五个榕小蜂属（Pegoscapus、Idarnes、Heterandrium、Aepocerus、Physothorax）内部和之间的关系。我们表明，宿主转换和每个宿主有多个黄蜂物种在新热带非传粉黄蜂属中普遍存在。尽管有这些发现，但协同系统发育分析（TREEMAP 1.0、TREEMAP 2.02beta和parafit）揭示了来自不同生态类群的榕小蜂之间共分化的证据。我们的发现进一步挑战了榕树与其相关黄蜂之间严格意义上协同进化的经典概念，并反映了其他互利共生详细分子研究的结论，这些研究揭示了参与者之间普遍存在的扩散协同进化和不对称特化模式。
