Comparative Mitogenomic Analysis of Two Cuckoo Bees (Apoidea: Anthophila: Megachilidae) with Phylogenetic Implications.

Bees (Hymenoptera, Apoidea and Anthophila) are distributed worldwide and considered the primary pollinators of angiosperm. Megachilidae is one of the largest families of Anthophila. In this study, two complete mitogenomes of cuckoo bees in Megachilidae, namely Coelioxys fenestrata and Euaspis polynesia, were amplified and sequenced, with a length of 17,004 bp (C. fenestrata) and 17,682 bp (E. polynesia). The obtained results show that 37 mitogenomic genes and one putative control region were conserved within Hymenoptera. Truncated stop codon T was found in the cox3 gene of E. polynesia. The secondary structure of small (rrnS) and large (rrnL) rRNA subunits contained three domains (28 helices) and five domains (44 helices) conserved within Hymenoptera, respectively. Compared with ancestral gene order, gene rearrangement events included local inversion and gene shuffling. In order to reveal the phylogenetic position of cuckoo bees, we performed phylogenetic analysis. The results supported that all families of Anthophila were monophyletic, the tribe-level relationship of Megachilidae was Osmiini + (Anthidiini + Megachilini) and Coelioxys fenestrata was clustered to the Megachile genus, which was more closely related to Megachile sculpturalis and Megachile strupigera than Euaspis polynesia.