Lopez-Vaamonde Carlos, Wikström Niklas, Kjer Karl M, Weiblen George D, Rasplus Jean Yves, Machado Carlos A, Cook James M
INRA, UR 633 Zoologie Forestière, F-45075 Orléans, France.
Mol Phylogenet Evol. 2009 Sep;52(3):715-26. doi: 10.1016/j.ympev.2009.05.028. Epub 2009 Jun 13.
Figs and fig-pollinating wasps are obligate mutualists that have coevolved for over 60 million years. But when and where did pollinating fig wasps (Agaonidae) originate? Some studies suggest that agaonids arose in the Late Cretaceous and the current distribution of fig-wasp faunas can be explained by the break-up of the Gondwanan landmass. However, recent molecular-dating studies suggest divergence time estimates that are inconsistent with the Gondwanan vicariance hypothesis and imply that long distance oceanic dispersal could have been an important process for explaining the current distribution of both figs and fig wasps. Here, we use a combination of phylogenetic and biogeographical data to infer the age, the major period of diversification, and the geographic origin of pollinating fig wasps. Age estimates ranged widely depending on the molecular-dating method used and even when using the same method but with slightly different constraints, making it difficult to assess with certainty a Gondwanan origin of agaonids. The reconstruction of ancestral areas suggests that the most recent common ancestor of all extant fig-pollinating wasps was most likely Asian, although a southern Gondwana origin cannot be rejected. Our analysis also suggests that dispersal has played a more important role in the development of the fig-wasp biota than previously assumed.
榕树和榕小蜂是专性互利共生者，它们已经共同进化了超过6000万年。但是传粉榕小蜂（榕小蜂科）起源于何时何地呢？一些研究表明榕小蜂科起源于白垩纪晚期，当前榕小蜂动物区系的分布可以用冈瓦纳大陆的分裂来解释。然而，最近的分子定年研究表明，分歧时间估计与冈瓦纳间断分布假说不一致，这意味着远距离海洋扩散可能是解释当前榕树和榕小蜂分布的一个重要过程。在这里，我们结合系统发育和生物地理数据来推断传粉榕小蜂的起源时间、主要多样化时期以及地理起源。根据所使用的分子定年方法，年龄估计范围差异很大，甚至当使用相同方法但约束条件略有不同时也是如此，这使得难以确定地评估榕小蜂科起源于冈瓦纳大陆。祖先区域的重建表明，所有现存传粉榕小蜂的最近共同祖先很可能是亚洲的，尽管不能排除起源于冈瓦纳大陆南部的可能性。我们的分析还表明，扩散在榕小蜂生物区系的发展中所起的作用比以前认为的更为重要。
