MicroRNAs of the mesothorax in Qinlingacris elaeodes, an alpine grasshopper showing a wing polymorphism with unilateral wing form

MicroRNAs (miRNAs) are now recognized as key post-transcriptional regulators in regulation of phenotypic diversity. Qinlingacris elaeodes is a species of the alpine grasshopper, which is endemic to China. Adult individuals have three wing forms: wingless, unilateral-winged and short-winged. This is an ideal species to investigate the phenotypic plasticity, development and evolution of insect wings because of its case of unilateral wing form in both the sexes. We sequenced a small RNA library prepared from mesothoraxes of the adult grasshoppers using the Illumina deep sequencing technology. Approximately 12,792,458 raw reads were generated, of which the 854,580 high-quality reads were used only for miRNA identification. In this study, we identified 49 conserved miRNAs belonging to 41 families and 69 species-specific miRNAs. Moreover, seven miRNA*s were detected both for conserved miRNAs and species-specific miRNAs, which were supported by hairpin forming precursors based on polymerase chain reaction. This is the first description of miRNAs in alpine grasshoppers. The results provide a useful resource for further studies on molecular regulation and evolution of miRNAs in grasshoppers. These findings not only enrich the miRNAs for insects but also lay the groundwork for the study of post-transcriptional regulation of wing forms.

Characterization of the mitochondrial genome of the montane grasshopper, Qinlingacris elaeodes (Orthoptera: Catantopidae)

Qinlingacris elaeodes is the dominant grasshopper at an altitude of 3000 meters and above, and is a representative species of the genus Qinlingacris endemic to China. The sequenced mitochondrial genome of this grasshopper is 14,818 bp in length, including 13 protein-coding genes (ND1-6, COI-III, ATP6, ATP8, ND4L, CTYB), 21 transfer RNAs, and 2 ribosomal RNAs (12S and 16S). The orientation and gene order of these genes are identical to those found in the putative ancestral insect mitogenome. The 13 PCGs start with a typical ATN codon as their start codons. The usual TAA and TAG termination codons are found for 12 PCGs. However, the ND5 gene has an incomplete termination codon (T).