# Characterization of the Mitogenome of the Genus Dendrocerus Ratzeburg (Hymenoptera: Megaspilidae) with the Specific Designed Primers

## TL;DR

This study sequenced two mitochondrial genomes of Dendrocerus wasps, analyzed their features, and designed new primers to improve COX1 gene amplification in Megaspilidae.

## Contribution

Designed specific primers for COX1 gene amplification in Megaspilidae and provided new insights into the phylogeny of Evaniomorpha.

## Key findings

- Evaniomorpha is not a monophyletic group, supported by PBD values.
- Ceraphronoidea is monophyletic and sister to Aulacidae + Gasteruptiidae.
- MegaF/MegaR primers achieved 60% amplification success for Dendrocerus COX1 genes.

## Abstract

In this study, we sequenced two mitochondrial genomes of Dendrocerus (Hymenoptera: Megaspilidae) to analyze the mitochondrial genomic features of Dendrocerus and provide new molecular data for phylogenetic studies of Evaniomorpha. The phylogenetic results revealed that Evaniomorpha is not a monophyletic group, which is also supported by the PBD (Pairwise breakpoint distances) values. Additionally, Ceraphronoidea is a monophyletic group and is a sister to Aulacidae + Gasteruptiidae. Furthermore, specific primers MegaF/MegaR were designed for Megaspilidae based on the “conserved regions” of COX1 sequences. They exhibited a good amplification efficiency of 60% for the genus Dendrocerus. This study provides new molecular data for phylogenetic studies of Evaniomorpha, further offering the possibility of solving a controversial problem in the phylogeny of Evaniomorpha and providing a solution to the problem of difficult amplification of the COX1 gene in Ceraphronoidea.

In Hymenoptera, the monophyly of Evaniomorpha has been the focus of debate among different scholars. In this study, we sequenced two mitochondrial genomes of Dendrocerus (Hymenoptera: Megaspilidae) to analyze the mitochondrial genomic features of Dendrocerus and provide new molecular data for phylogenetic studies of Evaniomorpha. The mitogenome sizes of D. bellus and D. anisodontus were 15,445 bp and 15,373 bp, respectively, with the trnG of D. bellus missing. The nucleotide composition was significantly biased toward adenine and thymine, with A + T contents of 81.2% (D. bellus) and 82.4% (D. anisodontus). Using Ceraphron sp. (Ceraphronidae) as reference, the Ka/Ks values of NAD4L and NAD6 in D. anisodontus were both greater than one, indicating that non-synonymous mutations are favored by Darwinian selection, which is rare in other hymenopteran species. Compared with Ceraphon sp. gene order, nine operations were identified in D. anisodontus, including four reversals, four TDRLs (tandem duplication random losses) and one transposition, or four reversals and five TDRLs. Phylogenetic analysis of 40 mitochondrial genomes showed that Evaniomorpha was not a monophyletic group, which was also supported by the PBD values. Ceraphronoidea is a monophyletic group and is a sister to Aulacidae + Gasteruptiidae. Based on the conserved region of the newly sequenced mitochondrial genomes, a pair of specific primers MegaF/MegaR was designed for sequencing the COX1 genes in Megaspilidae and a 60% rate of success was achieved in the genus Dendrocerus.