Codon usage bias analysis in the mitochondrial genomes of five Rhingia Scopoli (Diptera, Syrphidae, Eristalinae) species.

• Reconstructed the phylogenetic relationship of the Syrphidae based on the different datasets of mitogenomes, and analysed and discussed the topological structures among different tribes. • Hoverfly genus Rhingia is resulted in a monophyletic group. • Natural selection, rather than mutation pressure, is exposed the main impact factor for codon usage bias in Rhingia. • It has strong AT bias in the nucleotide composition and optimal codons within Rhingia. • There are three optimal codons, GUU, ACU, and GGA, which are common to all five species of Rhingia. This study presents the sequencing and annotation of mitochondrial genomes from five Rhingia species of the family Syrphidae, focusing on codon bias. Each species possessed 22 tRNAs genes, 13 protein-coding genes, 2 rRNAs genes, and a control region, without any observed gene rearrangements. Nucleotide composition analysis revealed a higher AT content compared with GC content, indicating AT enrichment. Neutrality plot, Parity rule 2 bias, and effective number of codons plot analyses collectively indicated that natural selection primarily influences the codon usage bias in the five Rhingia species. Relative synonymous codon usage analysis identified the optimal codons for Rhingia binotata , R. fromosana , R. campestris , R. louguanensis , and R. xanthopoda as 10, 14, 10, 11, and 12, respectively, all ending with A/U and exhibiting AT preference. Phylogenetic analysis, based on maximum likelihood and Bayesian inference methods applied to three datasets, confirmed the monophyly of Rhingia. In conclusion, this research establishes a foundation for understanding the phylogenetic evolution and codon usage patterns in Rhingia , offering valuable for future studies. [ABSTRACT FROM AUTHOR]