Characterization of light‐dependent rhythm of courtship vibrational signals in Nilaparvata lugens: essential involvement of cryptochrome genes

Abstract

BACKGROUNDVibrational signal plays a crucial role in courtship communication in many insects. However, it remains unclear whether insect vibrational signals exhibit daily rhythmicity in response to changes in environmental cues.RESULTSIn this study, we observed daily rhythms of both female vibrational signals (FVS) and male vibrational signals (MVS) in the brown planthopper (BPH), Nilaparvata lugens (Stål), one of the most notorious rice pests across Asia. Notably, oscillations of FVS and MVS in paired BPHs were synchronized as part of male‐female duetting interactions, displaying significant day‐night rhythmicity. Furthermore, we observed light dependency of FVS emissions under different photoperiodic regimes (18L:6D and 6L:18D) and illumination intensity levels (>300 lux, 50 lux, and 25 lux). Subsequently, the potential role of circadian clock genes cryptochromes (Nlcry1 and Nlcry2) in regulating FVS daily oscillations was examined using gene knockdown via RNA interference. We observed sharp declines and disrupted rhythms in FVS frequencies when either of the Nlcrys was downregulated, with Nlcry2 knockdown showing a more prominent effect. Moreover, we recorded a novel FVS variant (with a dominant frequency of 361.76±4.31 Hz) emitted by dsNlcry1‐treated BPH females, which significantly diminished the impact of courtship stimuli on receptive males.CONCLUSIONWe observed light‐dependent daily rhythms of substrate‐borne vibrational signals (SBVS) in BPH and demonstrated essential yet distinct roles of the two Nlcrys. These findings enhanced our understanding of insect SBVS and illustrated the potential of novel precision physical control strategies for disrupting mating behaviors in this rice pest.This article is protected by copyright. All rights reserved.