Phylogeny and species delimitation of the genus Longgenacris and Fruhstorferiola viridifemorata species group (Orthoptera: Acrididae: Melanoplinae) based on molecular evidence

The Complete Mitogenomes of Three Grasshopper Species with Special Notes on the Phylogenetic Positions of Some Related Genera

Clarifying phylogenetic position and reconstructing robust phylogeny of groups using various evidences are an eternal theme for taxonomy and systematics. In this study, the complete mitogenomes of Longzhouacris mirabilis, Ranacris albicornis, and Conophyma zhaosuensis were sequenced using next-generation sequencing (NGS), and the characteristics of the mitogenomes are presented briefly. The mitogenomes of the three species are all circular molecules with total lengths of 16,164 bp, 15,720 bp, and 16,190 bp, respectively. The gene structures and orders, as well as the characteristics of the mitogenomes, are similar to those of other published mitogenomes in Caelifera. The phylogeny of the main subfamilies of Acrididae with prosternal process was reconstructed using a selected dataset of mitogenome sequences under maximum likelihood (ML) and Bayesian inference (BI) frameworks. The results showed that the genus Emeiacris consistently fell into the subfamily Melanoplinae rather than Oxyinae, and the genus Choroedocus had the closest relationship with Shirackiacris of the subfamily Eyprepocnemidinae in both phylogenetic trees deduced from mitogenome protein coding genes (PCGs). This finding is entirely consistent with the morphological characters, which indicate that Emeiacris belongs to Melanoplinae and Choroedocus belongs to Eyprepocnemidinae. In addition, the genera Conophymacris and Xiangelilacris, as well as Ranacris and Menglacris, are two pairs of the closest relatives, but their phylogenetic positions need further study to clarify.

The efficiency of the COI gene as a DNA barcode and an overview of Orthoptera (Caelifera and Ensifera) sequences in the BOLD System

Orthoptera, among the oldest and most numerous insect lineages, is an excellent model for evolutionary studies but has numerous taxonomic problems. To mitigate these issues, the cytochrome c oxidase subunit I (COI), standardized with the DNA barcode for Metazoa, is increasingly used for specimen identification and species delimitation. We tested the performance of COI as a DNA barcode in Orthoptera, using two analyses based on intra- and interspecific distances, barcode gap and Probability of Correct Identification (PCI); and estimated species richness through Automatic Barcode Gap Discovery (ABGD) and Assemble Species by Automatic Partitioning (ASAP). We filtered all sequences of Orthoptera available in Barcode of Life Data System (BOLD) and used 11,605 COI sequences, covering 1,132 species, 226 genera, and 18 families. The overall average PCI was 73.86%. For 82.2% of genera the barcode gap boxplots were classified as good or intermediate, indicating that COI can be effective as a DNA barcode in Orthoptera, although with varying efficiency depending on the need for more information. ABGD and ASAP inferred species richness similar to labels informed by BOLD for the suborders Caelifera and Ensifera. The representation of Orthoptera in the BOLD database and the results of these analyses are discussed.

Molecular phylogeny and species delimitation of the genus Tonkinacris (Orthoptera, Acrididae, Melanoplinae) from China

Tonkinacris is a small group in Acrididae. While a few species were occasionally sampled in some previous molecular studies, there is no revisionary research devoted to the genus. In this study, we explored the phylogeny of and the relationships among Chinese species of the genus Tonkinacris using the mitochondrial COI barcode and the complete sequences of ITS1 and ITS2 of the nuclear ribosomal DNA. The phylogeny was reconstructed in maximum likelihood and Bayesian inference frameworks, respectively. The overlap range between intraspecific variation and interspecific divergence was assessed via K2P distances. Species boundaries were delimitated using phylogenetic species concept, NJ tree, K2P distance, the statistical parsimony network as well as the GMYC model. The results demonstrate that the Chinese Tonkinacris species is a monophyletic group and the phylogenetic relationship among them is (T. sinensis, (T. meridionalis, (T. decoratus, T. damingshanus))). While T. sinensis, T. meridionalis and T. decoratus were confirmed being good independent species strongly supported by both morphological and molecular evidences, the validity of T. damingshanus was not perfectly supported by molecular evidence in this study.