Circadian rhythmicity of feeding and reproductive behaviors in the western flower thrips

The western flower thrips (WFT), Frankliniella occidentalis, is spread to most cultivating areas and gives serious economic damages to various crops. The economic damage is devastating by transmitting plant disease by vectoring tospovirus such as TSWV. The viral transmission is based on its feeding behavior. Larvae usually uptake TSWV by feeding the infected hosts and multiply the virus in their body. Then the viral particles migrate to salivary gland during adult stage. The adults transmit the viral particles to uninfected hosts during feeding. In this study, feeding behavior was monitored based on circadian rhythm at bot larval and adult stages. Interestingly, both larvae and adults exhibited a diurnal rhythmicity. To further analyze their circadian rhythm, clock genes related with circadian rhythm were predicted from F. occidentalis genome.Per/Tim and Clk/Dbt genes are clustered in a chromosome. Their expression levels oscillate during photo- and scoto-phase. These results suggest that the feeding behavior of WFT is regulated by circadian machinery.