Data from: Expressed sequence tags reveal Proctotrupomorpha (minus Chalcidoidea) as sister to Aculeata (Hymenoptera: Insecta)

Hymenoptera is one of the most diverse groups of animals on the planet and have vital importance for ecosystem function as pollinators and parasitoids. Higher level relationships among Hymenoptera have been notoriously difficult to resolve with both morphological and traditional molecular approaches. Here we examined the utility of expressed sequence tags for resolving relationships among hymenopteran superfamilies. Transcripts were assembled for 6 disparate Hymenopteran taxa with additional sequences added from public databases for a final dataset of 24 genes for 16 taxa and over 10kb of sequence data. The concatenated dataset recovered a robust and well-supported topology demonstrating the monophyly of Holometabola, Hymenoptera, Apocrita, Aculeata, Ichneumonoidea, and a sister relationship between the two most closely related proctotrupomorphs in the dataset (Cynipoidea + Proctotrupoidea). The data strongly supported a sister relationship between Aculeata and Proctotrupomorpha, contrary to previously proposed hypotheses. Additionally there was strong evidence indicating Ichneumonoidea as sister to Aculeata + Proctotrupomorpha. These relationships were robust to missing data, nucleotide composition biases, low taxonomic sampling, and conflicting signal across gene trees. There was also strong evidence indicating that Chalcidoidea is not contained within Proctotrupomorpha.膜翅目（Hymenoptera）是地球上物种多样性最为丰富的动物类群之一，作为传粉昆虫与寄生性天敌，其对生态系统功能发挥着至关重要的作用。长期以来，研究者素来难以通过形态学与传统分子研究方法厘清膜翅目的高阶类群亲缘关系。本研究探讨了表达序列标签（expressed sequence tags）在解析膜翅目总科间亲缘关系中的应用潜力。研究对6个不同的膜翅目类群进行了转录本组装，并结合公共数据库中的额外序列，最终构建了涵盖16个类群、24个基因位点且总序列长度超过10千碱基对的数据集。串联后的数据集获得了稳健且高支持率的系统发育拓扑结构，证实了全变态类（Holometabola）、膜翅目、细腰亚目（Apocrita）、针尾亚目（Aculeata）以及姬蜂总科（Ichneumonoidea）的单系性，并明确了数据集内两个亲缘关系最近的后尾下目类群——瘿蜂总科（Cynipoidea）与肿腿蜂总科（Proctotrupoidea）互为姊妹群。该数据强烈支持针尾亚目与后尾下目（Proctotrupomorpha）互为姊妹群的结论，这与此前提出的相关假说相悖。此外，研究还获得了强有力的证据，表明姬蜂总科为针尾亚目+后尾下目这一支系的姊妹群。上述类群关系在存在数据缺失、核苷酸组成偏倚、类群采样不足以及基因树间存在冲突信号的情况下仍保持稳健。同时，研究也获得了充分证据，证明小蜂总科（Chalcidoidea）并不隶属于后尾下目范畴。