Bacterial Endosymbionts and Sex-Ratio Deviation in Predatory Mite Ambelyseius Swirski (Acari: Phytoseiidae)

Background and aim: the symbiotic relationship between microorganisms and arthropods is very common in nature. some cytoplasmic symbiotic microorganisms alter the normal sex-determining mechanisms in arthropods, causing sex-ratio deviation, killing males and eventually leading to asexual reproduction and the possibility of species extinction. in the biocontrol of agricultural pests, predatory mites of the phytoseiidae family are of great importance. in this study, regarding to the observance of sex-ratio deviation in ambelyseius swirskii (acari: phytoseiidae), the presence of three endosymbiotic bacterial genera, i.e. cardinium, rickettsia and wolbachia was investigated in adult mitesmethods: firstly, investigation of the female:male ratio in commercial mites showed that the ratio was about 42:58. thus, there was a significant deviation from normal sex ratio (50:50). therefore, to determine the presence of sex-determinig bacteria, the whole dna was isolated from a. swirski mites. using specific primers of the above mentioned bacteria for 16s rdna, gtla and wsp gene sequences, multiplex pcr was applied. the pcr products were sequenced, and the sequences were processed using mega-x software and blasted and identified in ncbi gene bankresults: the results indicated the presence of wolbachia and rickettsia as sexual endosymbiontic bacteria in a. swirski.conclusion: therefore, the sex-ratio deviation in this organism could be due to the presence of sexual bacterial endosymbionts. this needs to be further investigated.