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高的动物类群之一，作为传粉者与寄生性昆虫，其对生态系统功能具有至关重要的作用。长期以来，学界难以通过形态学与传统分子手段厘清膜翅目高级阶元的系统发育关系。本研究探讨了表达序列标签（expressed sequence tags, ESTs）在解析膜翅目总科间系统发育关系中的应用潜力。我们对6个不同的膜翅目类群进行转录组组装，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、总长度超过10千碱基对（kb）的序列数据集。本研究的串联数据集得到了稳健且高支持度的系统发育拓扑结构，证实了全变态类（Holometabola）、膜翅目（Hymenoptera）、细腰亚目（Apocrita）、针尾类（Aculeata）、姬蜂总科（Ichneumonoidea）的单系性，同时明确了数据集内两个亲缘关系最近的广腹细蜂类群（Proctotrupomorpha）下的瘿蜂总科（Cynipoidea）与广腹细蜂总科（Proctotrupoidea）之间的姐妹群关系。该数据强烈支持针尾类（Aculeata）与广腹细蜂类群（Proctotrupomorpha）互为姐妹群，这一结果与此前提出的系统发育假说相悖。此外，研究获得强有力的证据支持姬蜂总科（Ichneumonoidea）为针尾类+广腹细蜂类群的姐妹群。这些系统发育关系不受缺失数据、核苷酸组成偏差、类群采样不足以及基因树间冲突信号的影响，展现出极高的稳健性。同时，研究还得到强有力的证据表明，小蜂总科（Chalcidoidea）并不隶属于广腹细蜂类群（Proctotrupomorpha）。