A novel negative thermotaxis behavior in rice planthoppers is regulated by TRPA1 channel

In the field, we observed that many white-backed planthoppers (Sogatella furcifera, WBPHs) stayed in the top region of rice plants exposed to direct sunshine. It was known that WBPHs frequently took flight when the ground temperature was about 25 °C, then climbed to and flew in a dense layer corresponding to an air temperature of about 16 °C in the sky. Its migration height was higher than the top of the surface temperature inversion. It is still unclear whether WBPHs prefer warm or cold regions, and therefore we studied the thermal responses of WBPHs and other insects using a simulated system.

We found that WBPHs preferred a cold region to a warm one, unexpectedly below their comfort temperature zone. After comparative analysis with other insect species, such as small brown planthoppers, brown planthoppers, Trialeurodes vaporariorum (stinkbugs, a predator of planthoppers) and Bemisia tabaci (whitefly), only three planthoppers showed cold preference behavior. RNA interference experiments revealed that this behavior of WBPHs can be regulated by the transient receptor potential (TRP) channels TRPA1 channel. Furthermore, podocarpic acid, an agonist of TRPA1, weakened the cold preference, whereas A-967079, an antagonist of TRPA1, had the opposite effect.

We reported a novel cold preference (negative thermotaxis) in rice planthoppers that was regulated in WBPHs by the TRPA1 channel. Cold preference of rice planthoppers is probably related to its choice behavior of the special migratory temperature layer. Our results expanded a new perspective to develop novel strategies for behavioral manipulation and management of rice planthoppers. © 2020 Society of Chemical Industry.