Abstract: 【Aim】 Wolbachia is a bacterial endosymbiont that is found in a wide variety of arthropods, and affects the biological characteristics of host. The flower thrips, Frankliniella intonsa (Trybom), is an important pest, and can cause damages to crops and garden plants. This study aims to examine the infection status of Wolbachia and its relationship with the mtDNA diversity of the host flower thrips.【Methods】 The Wolbachia infection in 26 natural populations of F. intonsa was analyzed by using multilocus sequence typing (MLST) in China. The genetic diversity and genetic differentiation of F. intonsa were investigated by using COI genetic markers. The COI data between the Wolbachiainfected and uninfected individuals were compared to explore the relationship between Wolbachia diversity and host mtDNA diversity. 【Results】 The prevalence of Wolbachia in theF. intonsa populations ranged from 0% to 60%. Five Wolbachiastrains (wFint1, wFint2, wFint3, wFint4 and wFint5) were detected. All the detected strains were assigned to supergroup B and formed a monophyletic group.The mitochondrial diversity of these populations (except CC, GZ, TA and TY, N<5) was associated with Wolbachia infection. The mtDNA haplotype diversity (Hd) and nucleotide diversity (Pi) of the uninfected group were higher than those in the infected group. Wolbachia infection was significantly negatively correlated with Hd (P<0.05). Furthermore, the analysis of molecular variance (AMOVA) revealed that the geneticdifferentiation of F. intonsa mtDNA is related to the presence of Wolbachia infection. 【Conclusion】 Genetic differentiation of Wolbachia occurred after infecting host F. intonsa populations. Wolbachia infection is associated with host mtDNA haplotype diversity.

Key words: Frankliniella intonsa, Wolbachia, multilocus sequence typing (MLST), mtDNA, genetic differentiation, genetic diversity