Immature Stages of Genus Hexatoma (Diptera, Limoniidae) in the Korean Peninsula

The genus Hexatoma Latreille, 1809 is a large group of aquatic crane flies, with almost 600 species worldwide. The largest subgenus is Eriocera Macquart, 1838, which includes all nine species known from the Korean Peninsula. Molecular methods were used to associate Hexatoma larvae with their putative adult species from South Korea. Mitochondrial Cytochrome c Oxidase Subunit I (COI) gene fragment sequences (DNA barcodes) of recently collected adults of H. (E.) gifuensis, H. (E.) ilwola, H. (E.) pernigrina, and H. (E.) pianigra were compared with twelve sequences of Hexatoma larvae. The larvae of H. (E.) pernigrina, H. (E.) pianigra, and H. (E.) gifuensis were associated with their putative adults. The larvae of H. (E.) gifuensis and H. (E.) pianigra and the larvae and pupae of H. (E.) pernigrina are described and illustrated. The larvae of two species not associated with any adult are described, and their COI gene fragment sequences (DNA barcodes) are presented. This paper presents the morphological characteristics suitable for distinguishing larval species. A key for the identification of larvae of the genus Hexatoma on the Korean Peninsula has been compiled. H (E.) sachalinensis is recorded from the Korean Peninsula for the first time. Our study is the first contribution to the Hexatoma larvae taxonomy using phylogenetic analysis based on mitochondrial COI fragment (DNA barcode) and one of the first attempts to reveal phylogenetic relationships between Hexatoma species using molecular markers.

Automated summary

This study used molecular methods to associate Hexatoma larvae with their putative adult species and confirmed the relationships using DNA barcoding. The morphological characteristics and identification keys for Hexatoma larvae on the Korean Peninsula were also presented. In addition, the presence of H (E.) sachalinensis in the Korean Peninsula was recorded for the first time.