Population Dynamics of Wolbachia in the Leafhopper Vector Yamatotettix flavovittatus (Hemiptera: Cicadellidae)

Wolbachia (Rickettsiales: Alphaproteobacteria) infections induce abnormalities in the reproductive system and affect various biological traits of the host insects. The density of Wolbachia is one of the major parameters that influence induced phenotypes and interactions with the hosts. Wolbachia occurs naturally in populations of the leafhopper Yamatotettix flavovittatus Matsumura (Hemiptera: Cicadellidae), which transmits phytoplasma that cause white leaf disease in sugarcane. However, the quantity and dynamics of Wolbachia in this leafhopper are not well understood. In the current study, we estimated the number of Wolbachia by absolute quantification of the copy number of wsp, which encodes the outer surface protein, using real-time quantitative polymerase chain reaction (PCR). This investigation was performed using natural populations and laboratory colonies from three lineages of leafhoppers (designated as UD, KK, and SK). There was no significant difference in the number of wsp copies in most of field-collected adults. During the immature developmental stages, there were differences in the dynamics of Wolbachia infection between the UD lineage and the other two lineages. However, the number of wsp copies increased in the early instar and plateaued in the later nymphal instars. Sex had no influence on the number of Wolbachia within the same lineages. The number of Wolbachia was relatively constant during the adult stage in the UD lineage but fluctuated in the other two lineages. In conclusion, the present data provide a framework for exploring the relationship between Wolbachia and the leafhopper and could facilitate future research into management strategies using Wolbachia.