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 ever-wet forests of Southeast Asia. The coccid specimens clustered into ten 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 hollowed naturally.

本研究通过对核DNA（nuclear DNA）进行系统发育分析（phylogenetic analysis），旨在明确与东南亚常绿湿润森林中互利共生的举腹蚁属（Crematogaster）蚂蚁、血桐属（Macaranga）植物共生的球蚧属（Coccus）介壳虫的物种边界。该介壳虫标本可被聚类为10个支系，每个支系均对应一个形态种的鉴定结果。经鉴定为C. secretus的支系由外类群（outgroup）与主支系（Main Clade）相互分隔。本研究同时对三类共生体功能群（symbiont guilds）间的所有两两关联展开分析，以探究共生关联模式的构建机制。分析结果显示，每一种蚂蚁、植物或介壳虫的操作分类单元（operational taxonomic unit，OTU）往往会与另外两类共生体功能群中的多个O(T)U发生关联。不过，在测试可行的场景中，研究人员常观测到各类群对对应共生体功能群中的1个（有时为2个）伙伴O(T)U存在"偏好性"。共生体间相互的"偏好"或"规避"行为相对常见，且未发现明显的利益冲突。三类共生体功能群间的偏好伴侣网络呈现出基于植物表皮蜡质（epicuticular wax）有无的分区结构，这表明该特征在共生体选择最能满足自身需求的伴侣过程中发挥着基础性作用。在较低程度上，该网络的结构还受宿主植物茎干是由蚂蚁挖掘形成还是自然中空所影响。