Bacteria of the Wolbachia genus are maternally inherited symbionts of Nematoda and numerous Arthropoda hosts. There are approximately 20 lineages of Wolbachia, which are called supergroups, and they are designated alphabetically. Wolbachia strains of the supergroups A and B are predominant in arthropods, especially in insects, and supergroup F seems to rank third. Host taxa have been studied very unevenly for Wolbachia symbionts, and here, we turn to one of largely unexplored insect families: Acrididae. On the basis of five genes subject to multilocus sequence typing, we investigated the incidence and genetic diversity of Wolbachia in 41 species belonging three subfamilies (Gomphocerinae, Oedipodinae, and Podisminae) collected in Turkey, Kazakhstan, Tajikistan, Russia, and Japan, making 501 specimens in total. Our results revealed a high incidence and very narrow genetic diversity of Wolbachia. Although only the strains belonging to supergroups A and B are commonly present in present, the Acrididae hosts here proved to be infected with supergroups B and F without A-supergroup variants. The only trace of an A-supergroup lineage was noted in one case of an inter-supergroup recombinant haplotype, where the ftsZ gene came from supergroup A, and the others from supergroup B. Variation in the Wolbachia haplotypes in Acrididae hosts within supergroups B and F was extremely low. A comprehensive genetic analysis of Wolbachia diversity confirmed specific features of the Wolbachia allelic set in Acrididae hosts. This result can help to elucidate the crucial issue of Wolbachia biology: the route(s) and mechanism(s) of Wolbachia horizontal transmission.

Wolbachia symbionts are maternally inherited bacteria that are widely distributed among Arthropoda hosts. Wolbachia influence their host biology in diverse ways. They may induce reproductive abnormalities, protect hosts against pathogens and parasites, or benefit hosts through metabolic provisioning. The progeny of an infected female are ordinarily infected with Wolbachia; however, Wolbachia have no future in male host progeny because they cannot transmit the symbiont to the next generation. Here, we analyze native and invasive populations of the four-eyed fir bark beetle (Polygraphus proximus) for Wolbachia prevalence and symbiont genetic diversity. This species is a dangerous pest of Siberian fir (Abies sibirica) forests. The native range of P. proximus includes the territories of the Russian Far East, Japan, Korea, and Northeast China, whereas its invasive range includes West Siberia, with further expansion westward. Surprisingly, we revealed a difference in the patterns of Wolbachia prevalence for males and females. Infection rate and Wolbachia titers were higher in females than in males. ST-533, the only haplotype of Wolbachia supergroup B, was associated with a minimum of three out of the five described mitochondrial haplotypes.

Many insect and other arthropod species are maintained as non-model laboratory stocks and are used for fundamental and applied studies. Their biology may be affected by symbionts, such as Wolbachia and Spiroplasma. Thirty stocks of different insect species that are maintained at the Laboratory of biological control of phytophagous and phytopathogens in the Siberian Federal Scientific Centre of Agro-BioTechnologies were screened to find Spiroplasma/Wolbachia–host associations. We used 16S rDNA and fusA loci for Spiroplasma characterization and five MLST genes for Wolbachia. Seven out of thirty stocks harbored symbionts. Five stocks were infected with only Wolbachia, one with only Spiroplasma, and one with both symbionts. Two stocks were occasionally characterized by false-positive signals of Spiroplasma infection that were explained by contamination from food sources, viz. infected insects. Five Wolbachia isolates belonged to supergroup B and one to supergroup A. Only the MLST haplotype of Nabis ferus was previously known (ST-522), while the other haplotypes contained new alleles. One Spiroplasma isolate was clustered in the Ixodetis clade and another was basal to the Apis clade. We noted the importance of non-model insects for fundamental studies of host–symbiont interactions and their significance for applied research and practice.