寄生生物广泛存在于陆地生态系统中，是生物多样性的重要组成部分。寄生生物的进化多样化过程与其他营养级生物紧密相关，然而目前对于这一进化和分化的生态过程仍不清楚。不同类型榕小蜂之间专化并相互依存的特殊关系，为研究包括寄生关系在内的多层营养级系统的生态学提供了绝佳的实验材料。
中科院西双版纳热带植物园综合保护中心植物地理组副研究员Michael McLeish与南非斯特伦布什大学、Iziko南非博物馆以及开普敦大学合作，在南非乌干达森林斑块中研究寄生小蜂与其寄主传粉小蜂、非传粉小蜂间的关系，从而探讨寄生小蜂与其寄主植物物种专一性的问题。该研究利用单倍型网络检测种内线粒体DNA分化，以及系统发育的方法推断相应的物种关系。结果表明，在同一森林斑块中，寄生榕小蜂可以在至少四种不同榕树植物上繁殖，即相对于在榕果内产卵的榕小蜂来说，在榕果外产卵的寄生小蜂具有更广泛的寄主植物范围。
研究同时发现，在观察区域内，寄生小蜂并没有在所有可利用的寄主植物上繁殖产卵，暗示了寄生小蜂对榕属植物繁殖-传粉小蜂间权衡关系的调节作用。榕小蜂对传粉共生系统的影响程度必须考虑到榕树与榕小蜂不同表型相互作用能力所产生的后果，但是不仅仅等同于时间和空间上的差异。重建不同榕小蜂及其近缘类群在榕果内外产卵这一特征的进化路线，有助于提出关于榕小蜂功能类群和共生关系进化过程的新假说。
相关研究结果以Host-Plant Species Conservatism and Ecology of a Parasitoid Fig Wasp Genus (Chalcidoidea; Sycoryctinae; Arachonia)为题，发表在国际期刊PLoS ONE上。（生物谷Bioon.com）
doi:10.1371/journal.pone.0044804
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Host-Plant Species Conservatism and Ecology of a Parasitoid Fig Wasp Genus (Chalcidoidea; Sycoryctinae; Arachonia)
Michael J. McLeish, Gary Beukman, Simon van Noort, Theresa C. Wossler
Parasitoid diversity in terrestrial ecosystems is enormous. However, ecological processes underpinning their evolutionary diversification in association with other trophic groups are still unclear. Specialisation and interdependencies among chalcid wasps that reproduce on Ficus presents an opportunity to investigate the ecology of a multi-trophic system that includes parasitoids. Here we estimate the host-plant species specificity of a parasitoid fig wasp genus that attacks the galls of non-pollinating pteromalid and pollinating agaonid fig wasps. We discuss the interactions between parasitoids and the Ficus species present in a forest patch of Uganda in context with populations in Southern Africa. Haplotype networks are inferred to examine intraspecific mitochondrial DNA divergences and phylogenetic approaches used to infer putative species relationships. Taxonomic appraisal and putative species delimitation by molecular and morphological techniques are compared. Results demonstrate that a parasitoid fig wasp population is able to reproduce on at least four Ficus species present in a patch. This suggests that parasitoid fig wasps have relatively broad host-Ficus species ranges compared to fig wasps that oviposit internally. Parasitoid fig wasps did not recruit on all available host plants present in the forest census area and suggests an important ecological consequence in mitigating fitness trade-offs between pollinator and Ficus reproduction. The extent to which parasitoid fig wasps exert influence on the pollination mutualism must consider the fitness consequences imposed by the ability to interact with phenotypes of multiple Ficus and fig wasps species, but not equally across space and time.
