Bian Lei, Cai Xiao Ming, Luo Zong Xiu, Li Zhao Qun, Chen Zong Mao
Tea Research Institute, Chinese Academy of Agricultural Science, 9 Meiling South Road, Xihu District, Hangzhou 310008, China.
Key Laboratory of Tea Biology and Resource Utilization, Ministry of Agriculture, 9 Meiling South Road, Xihu District, Hangzhou 310008, China.
Insects. 2020 Jul 9;11(7):426. doi: 10.3390/insects11070426.
For many herbivorous insects, vision is more important than olfaction in the prealighting stage of host habitat location. Tea leafhoppers, (Hemiptera, Cicadellidae), are serious pests that preferentially inhabit the tender leaves of tea plants across China. Here, we investigated whether tea leafhoppers could distinguish foliage colors associated with different leaf ages and use this visual cue to guide suitable habitat location from short distances. Similar to honeybees, the adult has an apposition type of compound eye, and each ommatidium has eight retinular cells, in which three spectral types of photoreceptors are distributed, with peak sensitivities at 356 nm (ultraviolet), 435 nm (blue), and 542 nm (green). Both changes in spectral intensity and hue of reflectance light of the host foliage were correlated with varying leaf age, and the intensity linearly decreased with increasing leaf age. Behavioral responses also showed that adult could discriminate between the simulated colors of host foliage at different leaf ages without olfactory stimuli and selected the bright colors that strongly corresponded to those of tender leaves. The results suggest that, compared with the spectral composition (hue), the intensity of light reflectance from leaves at different ages is more important for adult leafhoppers when discriminating host foliage and could guide them to tender leaves at the top of tea shoots.
对于许多植食性昆虫而言，在寄主栖息地定位的降落前阶段，视觉比嗅觉更为重要。假眼小绿叶蝉（半翅目，叶蝉科）是严重害虫，在中国各地优先栖息于茶树的嫩叶上。在此，我们研究了假眼小绿叶蝉是否能够区分与不同叶龄相关的叶片颜色，并利用这种视觉线索从近距离引导其找到适宜的栖息地。与蜜蜂类似，成年假眼小绿叶蝉具有并列型复眼，每个小眼有八个视杆细胞，其中分布着三种光谱类型的光感受器，峰值敏感度分别在356纳米（紫外线）、435纳米（蓝光）和542纳米（绿光）处。寄主叶片反射光的光谱强度和色调变化均与叶龄变化相关，且强度随叶龄增加呈线性下降。行为反应还表明，成年假眼小绿叶蝉在无嗅觉刺激的情况下能够区分不同叶龄寄主叶片的模拟颜色，并选择与嫩叶颜色强烈对应的明亮颜色。结果表明，与光谱组成（色调）相比，不同叶龄叶片的光反射强度对成年叶蝉区分寄主叶片更为重要，并且能够引导它们找到茶梢顶部的嫩叶。
