Mitogenome, Nuclear rRNA Gene Sequences, and the Phylogeny of Haemoniini Aquatic Leaf Beetles (Coleoptera: Chrysomelidae: Donaciinae)

Leaf beetles of the tribe Haemoniini (Chrysomelidae: Donaciinae) comprise two genera, Macroplea in the Palearctic region and Neohaemonia in the Nearctic region. These beetles are exceptional among aquatic insects in that they complete their entire life cycle underwater, obtaining oxygen either directly from the water or from the tissues of aquatic plants. Because they depend on clear, unpolluted water, their populations are considered highly vulnerable to decline and local extinction in habitats affected by human disturbance. In this study, we generated short-read genomic sequencing data for 11 specimens representing seven haemoniine species (four Macroplea and three Neohaemonia) and assembled mitochondrial genome (mitogenome) sequences and nuclear 18S ribosomal RNA gene sequences. These data were used to investigate phylogenetic relationships within the tribe and to provide reference sequences for DNA barcoding. Phylogenetic analyses based on mitogenome, 18S rRNA, and previously published 28S rRNA gene sequences were performed using maximum-likelihood methods. The analyses supported the monophyly of Macroplea and Neohaemonia and resolved most interspecific relationships within each genus. In addition, our divergence-time estimates suggest that the Japanese and continental East Asian populations of M. japana and M. mutica diverged around the transition from the Last Glacial Period to the early Holocene.