Data from: Nuclear-DNA-based species delineations of Coccus scale insects in symbiosis with plants and ants, and the role of plant epicuticular wax in structuring associations

We undertook phylogenetic analysis of nuclear DNA to elucidate species boundaries in the symbiotic Coccus scale insects associated with mutualistic Crematogaster ants and Macaranga plants occurring in the everwet forests of Southeast Asia. The coccid specimens clustered into 10 lineages, each corresponding to a morphospecies assignment. The lineage identified as C. secretus was separated from the Main Clade by an outgroup. We also examined all pairwise associations among the three symbiont guilds to understand how patterns of association were structured. The analyses revealed that each ant, plant or coccid operational (taxonomic) unit often associated with multiple O(T)Us of each of the other two guilds. However, where testing was feasible, a “preference” for one or sometimes two partner O(T)Us of each guild was often detected.
Mutual “preferences” or “avoidances” were relatively common among the symbionts, and no conflicts of interest were apparent. The network of preferred partners among all three guilds showed compartmentalization structured by the presence/absence of plant epicuticular wax, suggesting that this feature plays a fundamental role in how the symbionts select partners that best serve their needs. To a lesser degree, the network was also structured by whether the host plant stems were ant-excavated or naturally-hollowing.

本研究针对核DNA开展系统发育分析，以阐明与互利共生举腹蚁属（Crematogaster）昆虫、血桐属（Macaranga）植物形成共生关系的蚧属（Coccus）介壳虫的物种边界，该共生体系分布于东南亚的全年湿润常绿林中。介壳虫标本可聚类为10个演化支，每个演化支均对应一个形态种分类结果。经外类群界定，被鉴定为隐秘蚧（Coccus secretus，简称C. secretus）的演化支与主演化支相互分离。本研究同时对三类共生功能群间的所有两两关联进行了分析，以解析共生关联模式的构建机制。分析结果显示，每一类蚂蚁、植物或介壳虫的操作分类单元（operational taxonomic unit, OTU），往往会与另外两类功能群中的多个OTU形成关联。不过，在检测可行的情况下，研究常能观测到各功能群对另一类功能群中1个（有时为2个）搭档OTU的"偏好性"。
共生功能群间的双向"偏好"或"规避"行为相对普遍，且未观测到明显的利益冲突。三类功能群间的偏好性搭档网络呈现出以植物表皮蜡质有无为依据的分区结构，这表明该特征在共生体筛选最适配自身需求的搭档过程中发挥着基础性作用。在次要程度上，该网络的结构还取决于宿主植物茎干是经蚂蚁筑巢挖掘而成，还是天然中空的。