Plant-derived volatiles play a significant role in host selection of phytophagous insects, but their role in seasonal host shifts remain unclear. The polyphagous mirid bug Apolygus lucorum displays marked seasonal host alternation. During summer, volatiles from flowering plants play a key role in A. lucorum foraging. Though A. lucorum adults deposit overwintering eggs on jujube (Ziziphus jujuba) and grape (Vitis vinifera) during autumn, it is unclear whether plant volatiles equally mediate this host selection behavior. During 2015 and 2016, we found that population densities of A. lucorum adults on cotton (Gossypium hirsutum) during August were higher than those in September, whereas the opposite pattern was observed on fruit trees (i.e., jujube and grape). The dispersal factor of the adult population that dispersed from cotton fields during September was higher than in August, whereas opposite patterns were observed in the neighboring jujube/grape orchard. In Y-tube olfactometer trials, A. lucorum adults preferred cotton plant volatiles over fruit tree odors in August, whereas the opposite patterns were found in September. Three electro-physiologically active volatiles (butyl acrylate, butyl propionate and butyl butyrate) were identified from jujube and grape plants. During September, active volatiles are emitted in considerably greater amounts by jujube and grape than in August, while the amount of volatile emissions in cotton decreases in September. Temporal shifts in plant volatile emission thus may modulate host plant foraging of A. lucorum, and appear to guide its colonization of different host plants. Our findings help understand the role of plant volatiles in the host plant selection and seasonal dynamics of polyphagous herbivores.

植物来源的挥发物在植物吞噬性昆虫寄主选择中起着重要作用，但它们在季节性寄主转变中的作用仍不清楚。多食性mi虫Apolygus lucorum显示出明显的季节性寄主交替。在夏季，开花植物中的挥发物在A. lucorum觅食中起关键作用。尽管秋季时A. lucorum成年人在枣（Zipziphus jujuba）和葡萄（Vitis vinifera）上存入越冬卵，但尚不清楚植物挥发物是否同样介导了这种寄主选择行为。在2015年和2016年期间，我们发现棉上的A. lucorum成年人的种群密度（陆地棉）在8月高于9月，而在果树（枣和葡萄）上观察到相反的模式。9月从棉田中散布的成年人口的扩散因子高于8月，而在邻近的枣/葡萄果园中观察到相反的模式。在Y型管嗅觉仪试验中，A。lucorum在八月份，成年人比棉花树上的气味更喜欢棉花植物的挥发物，而在九月份则发现了相反的模式。从枣和葡萄植物中鉴定出三种电生理活性挥发物（丙烯酸丁酯，丙酸丁酯和丁酸丁酯）。9月期间，枣和葡萄中的活性挥发物排放量比8月高得多，而9月棉花中的挥发性挥发物排放量减少。因此，植物挥发物释放的时间变化可能会调节寄主土壤杆菌的觅食，并似乎指导其在不同寄主植物中的定殖。我们的发现有助于理解植物挥发物在寄主植物选择中的作用以及多食性草食动物的季节性动态。