Endosymbiotic Bacteria Spiroplasma and Wolbachia in a Laboratory-Reared Insect Collection

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.