Molecular phylogeography of myrmecophyte-ant-scale insect tripartite symbiosis in Southeast Asian tropical forests

许多热带植物为蚂蚁提供住所，从而获得保护免受食草动物的侵害。这些蚁植-蚂蚁系统中的大多数包括介壳虫作为第三伴生种。介壳虫生活在植物中空的茎里，吸食植物的汁液，为蚂蚁提供蜜露。我们调查的三种方式之间的相互作用myrmecophytic血桐植物，他们的居民Crematogaster（Decacrema）蚂蚁，和滋养层Coccus规模昆虫的演变。以往的研究表明，这三个属之间有紧密的联系，虽然有时也会涉及到其他一些属。综合样本的蚂蚁和鳞片的mtDNA COI同源性分别揭示了10个和5个支持良好的谱系。两个物种的亲缘关系和Maearanga物种的亲缘关系的比较表明没有共同物种形成。而蚂蚁规模和植物规模的相互作用是分散的，蚂蚁-植物的一个是具体的意义上说，主机转移已受到植物茎性状，本身与血桐属植物的生长。应用COI分歧率为1.5%，每我，Decacrema蚂蚁和Coccus规模从Macaranga被推断为至少12，和10我的老，分别，表明他们一直在多样化的同时，自中新世中期以来，在东南亚的潮湿森林社区。

Many tropical plants house ants and thereby gain protection from herbivores. Most of these myrmecophyte-ant systems include scale insects as the third associate. Scale insects live inside the plant hollow stem, suck the plant sap, and provide honeydew to the ants. We investigate the evolution of the three-way interaction among myrmecophytic Macaranga plants, their inhabitant Crematogaster (Decacrema) ants, and the trophobiont Coccus scale insects. Previous studies show that these three genera have a tight association although a few other genera are sometimes involved.The mtDNA COI phylogenies of comprehensively-sampled ants and scales reveal ten and five well-supported lineages, respectively. Comparisons of the two phylogenies and a published Maearanga phylogeny indicate an absence of cospeciation. Whereas the ant-scale and plant-scale interactions are diffuse, the ant-plant one is specific in the sense that host shifts have been constrained by plant stem traits that are themselves correlated with Macaranga phylogeny. Applying COI divergence rates of 1.5% per My, the Decacrema ants and the Coccus scales from Macaranga are inferred to be at least 12, and 10 My old, respectively, indicating that they have been diversifying contemporaneously since the mid-Miocene in the wet forest community of Southeast Asia.