关键词: 茶小绿叶蝉； 草间小黑蛛； 网粒体； 蜘蛛网； 逃跑行为, 微观形态

Abstract: 【Aim】 The tea green leafhopper, Empoasca onukii, is a significant pest in tea plantations in China. Its body surface is covered with brochosomes. However, little is known about the defense function of brochosomes. This study aims to clarify the role of brochosome detachment in the escape of tea leafhoppers from spider webs. 【Methods】 E. onukii adults were thrown into lacy webs of Hylyphantes graminicola, and the behavior parameters and escape details of E. onukii adults in the presence and absence of spiders were analyzed by using high definition video camera and Vegas software. Touching of brochosomes on the wings of E. onukii adults with threads of spider webs was observed by the scanning electron microscope (SEM), and the distribution of brochosomes on body parts of escaping E. onukii adults contacting spider web was also analyzed. 【Results】 The escape rates of E. onukii adults from the webs within 60 min in the presence of spiders and in the absence of spiders were 45.0% and 76.7%, respectively. The escape time of adults from the webs in the presence of spiders was remarkably shorter than that in the absence of spiders. There were at least four different strategies for adults to escape from spider web. In both the groups with the presence and absence of spiders, the rolling rate was about 80% and the rolling time was approximately 0.5 s, suggesting that the adhesion force between the wing of E. onukii adults and spider web is small. The escape time of E. onukii adults was approximately 3 times as long as the rolling time. The body parts of E. onukii adults most uneasy to detach from spider web were forelegs and middle legs, which was inferred from the struggle behaviors and detaching parts of E. onukii adults from spider web. The SEM images showed that the wings of E. onukii adults were the parts most uniformly and densely distributed with brochosomes, with the covering density of 280±17 particles/25 μm². Brochosomes can be detached from wings and enfold a whole viscous capture thread. Brochosomes distributed on the femur and pretarsi of foreleg were non-uniform, with the covering density as low as 4±4 particles/25 μm² on the bare parts, which might be the reason that the foreleg of the insect is uneasy to detach from viscous capture threads. 【Conclusion】 The detachment of brochosomes covering the body surface of E. onukii adults can facilitate leafhopper adults escaping from spider web, and whether the leafhopper adults can escape quickly from spider web or not depends on the presence of brochosomes on the contacting parts.

Key words: Empoasca onukii; Hylyphantes graminicola, brochosome, spider web, escape behavior, micromorphology