College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China.
State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China.
BMC Biol. 2024 Aug 13;22(1):169. doi: 10.1186/s12915-024-01964-4.
Numerous insect species undertake long-distance migrations on an enormous scale, with great implications for ecosystems. Given that take-off is the point where it all starts, whether and how the external light and internal circadian rhythm are involved in regulating the take-off behaviour remains largely unknown. Herein, we explore this issue in a migratory pest, Cnaphalocrocis medinalis, via behavioural observations and RNAi experiments.
The results showed that C. medinalis moths took off under conditions where the light intensity gradually weakened to 0.1 lx during the afternoon or evening, and the take-off proportions under full spectrum or blue light were significantly higher than that under red and green light. The ultraviolet-A/blue light-sensitive type 1 cryptochrome gene (Cmedcry1) was significantly higher in take-off moths than that of non-take-off moths. In contrast, the expression of the light-insensitive CRY2 (Cmedcry2) and circadian genes (Cmedtim and Cmedper) showed no significant differences. After silencing Cmedcry1, the take-off proportion significantly decreased. Thus, Cmedcry1 is involved in the decrease in light intensity induced take-off behaviour in C. medinalis.
This study can help further explain the molecular mechanisms behind insect migration, especially light perception and signal transmission during take-off phases.
许多昆虫物种在巨大的规模上进行长距离迁徙，这对生态系统有重大影响。鉴于起飞是一切的起点，外部光线和内部生物钟节律是否以及如何参与调节起飞行为在很大程度上仍然未知。在此，我们通过行为观察和 RNAi 实验探索了这一问题在迁徙性害虫中，小菜蛾，通过行为观察和 RNAi 实验。
结果表明，小菜蛾在下午或傍晚光照强度逐渐减弱至 0.1 lx 的条件下起飞，全光谱或蓝光下的起飞比例明显高于红光和绿光。紫外线 A/蓝光敏感型 1 隐花色素基因（Cmedcry1）在起飞的飞蛾中显著高于非起飞的飞蛾。相比之下，不敏感的 CRY2（Cmedcry2）和生物钟基因（Cmedtim 和 Cmedper）的表达没有明显差异。沉默 Cmedcry1 后，起飞比例显著降低。因此，Cmedcry1 参与了小菜蛾在光强下降诱导的起飞行为。
本研究有助于进一步解释昆虫迁徙背后的分子机制，特别是起飞阶段的光感知和信号传递。
