【作者】 吴琦；

【导师】 徐建祥；

【作者基本信息】 扬州大学 ， 农业昆虫与害虫防治， 2018， 硕士

【摘要】 斜纹夜蛾(Spodoptera litura Fabricius)是一种鳞翅目多食性害虫,广泛分布于世界各地,对农业生产造成极大危害。斜纹夜蛾的寄主选择特性对其发生格局、区域种群动态及为害具有重要影响。大量的研究表明,植食性鳞翅目昆虫的寄主喜好性在遗传决定的基础上也受其取食植物、经历等多种因素的影响。但目前多数研究同代或亲代对子代寄主选择的影响,缺乏对多代取食影响的评价,且植物生育期对斜纹夜蛾寄主选择影响的研究较少。现已有部分研究表明植物挥发物成分可以影响斜纹夜蛾的寄主选择,但大多只研究单一成分的作用,对植物挥发物的共同作用研究较少。本论文研究了斜纹夜蛾连续4代取食同种寄主植物,其幼虫及成虫的寄主选择的变化,评估了斜纹夜蛾多代取食寄主经历对寄主选择的影响;使用不同生育期的甘蓝和大豆,探究斜纹夜蛾对同种植物不同生育期的寄主选择及多种寄主植物存在的环境下,植物生育期对斜纹夜蛾寄主选择的影响;采用四臂嗅觉仪和触角电位技术,以甘蓝源挥发物为例,探究植物挥发物在斜纹夜蛾寄主选择中的共同作用,主要结果如下:1.多代寄主植物的取食经历可以改变斜纹夜蛾幼虫的取食偏好,但对斜纹夜蛾成虫的产卵偏好的影响并不显著。使用不同寄主植物饲喂斜纹夜蛾4代,斜纹夜蛾幼虫对四种供试寄主的取食偏好顺序产生了变化,其中3龄幼虫的变化较大,但变化规律并不一致。使用作物寄主甘蓝或大豆进行多代饲喂后,后代幼虫对该寄主的偏好有一定提高,而非作物寄主空心莲子草或三叶草饲喂,斜纹夜蛾并没有表现出对该寄主偏好的变化。多代饲喂同种植物的斜纹夜蛾成虫对4种植物的产卵偏好顺序没有发生显著的改变。2.斜纹夜蛾对同种植物不同生育期的偏好不同。斜纹夜蛾3龄幼虫更偏好取食苗期甘蓝和花芽分化期大豆的叶片,5龄幼虫偏好取食莲座期甘蓝和花芽分化期大豆的叶片,成虫偏好在进入生殖生长的结球始期甘蓝和结荚初期大豆上进行产卵。在多种寄主存在的环境中,植物生育期会影响斜纹夜蛾幼虫对不同寄主植物的偏好顺序,如斜纹夜蛾3龄幼虫对结球始期甘蓝、花芽分化期大豆、成株期三叶草和空心莲子草4种寄主植物的取食偏好差异不显著。斜纹夜蛾成虫对不同寄主植物的偏好顺序并没有因为植物生育期的不同而发生改变。3.斜纹夜蛾对植物挥发物的触角电位值随浓度的升高而升高,对甘蓝中的反-2己烯醛、壬醛、苯甲醛、芳樟醇有较强的电生理反应,而葵醇、法呢烯、月桂烯、香芹酮、石竹烯、苯甲醇只有在较大的浓度下才会使斜纹夜蛾产生显著的电生理反应。挥发性物质的共同作用并不只是单纯的叠加,100mg/ml浓度下,对斜纹夜蛾有忌避作用的芳樟醇和对斜纹夜蛾有吸引作用的苯甲醛复合后,反而显著提高了斜纹夜蛾雄虫的电生理反应。对斜纹夜蛾有相同行为反应的植物挥发物同浓度复合后,并不一定会使斜纹夜蛾产生更强烈的电生理反应。100 mg/ml浓度下均对斜纹夜蛾有忌避作用的反-2己烯醛和芳樟醇复合后,显著提高了斜纹夜蛾的电生理反应,而100mg/ml浓度下均对斜纹夜蛾有吸引作用的壬醛和苯甲醛复合后,斜纹夜蛾的电生理反应却并没有显著升高。复合挥发物中不同组分的浓度也会影响对斜纹夜蛾的共同作用,100 mg/ml的苯甲醛和10 mg/ml的芳樟醇复合后,斜纹夜蛾的电生理反应强度不如100 mg/mml的同浓度复合物。此外,雌雄虫对于复合挥发物的电生理反应有较大的差别。更多还原

【Abstract】 Spodoptera litura Fabricius is a Lepidoptera polyphagous pest that widely distributed around the world and causes great harm to agricultural production.The host selection characteristics of S.litura have important effects on its occurrence pattern,regional population dynamics and damage.A large number of studies had shown that the host preference of herbivorous Lepidoptera insects was also influenced by many factors such as the feeding plants and their experiences on the basis of genetic determination.However,most of the existing studies only carried out a short-term trial(the same generation or their offspring),did not evaluate the impact of multi-generation feeding,and there were few studies on the influence of different plant growth periods on host selection of S.litura.Existing studies had shown that some plant volatiles could affect the host selection of S.litura,but most of them only studied the effects of a single component,and few studies focused on the compound effect of plant volatiles.In this paper,we studied the host selection changes of larvae and adults of S.litura after feeding for four generations of same host plants,and evaluated the impact of multi-generation S.litura feeding host experiences on host selection.Using different growth stages of cabbage and soybeans to explore the host selection of S.litura to different plant growth stages and effects of plant growth stages on host selection of S.litura in the presence of various host plants.Using the four-arm olfactometer and electroantennogram technology to explore the effect of the cabbage volatiles on the host selection of S.litura.The main results are as follows:1.Multigenerational feeding experience of host plants could change the feeding preference of S.litura larvae,but there was no significant effect on the oviposition preference of adults of S.litura.Feeding four generations with different host plants,S.litura larvae produced a greater change in the order of feeding preference for the four host plants,but the changes were not consistent.After feeding multiple generations with cabbages or soybeans,the offspring larvae had an increased preference for the host,while feeding on non-crop plants Alternanthera philoxeroides or Trifolium repens Linn,S.litura did not show changes in preference for the host.Adult S.litura that fed the same plant for several generations showed no significant changes in the order of oviposition preference of four species.2.S.litura had different preferences for different growth periods of plants.The 3rd instar larvae of S.litura prefered to eat seedling cabbage while 5th instar larvae prefered the rosette Cabbage,both prefered the soybeans during flower bud differentiation,adults prefered to oviposit on the knot cabbage and pod bearing soybean.In the presence of multiple host environments,plant growth period affected the host selection of S.litura larvae,The 3rd insatar larvae of S.litura had no significant feeding preferences for the four host plants:seedling cabbage,flower bud differentiation period soybean,adult-plant stage T.repens and A.philoxeroides.The preference of S.litura adults for different host plants did not be changed by the different growth periods of plants.3.The electroantennogram of S.litura increased with the concentration of plant volatiles,and had strong electrophysiological responses to trans-2-hexenal,nonanal,benzaldehyde and linalool in cabbage,while decanol,farnesene,myrcene,carvone,caryophyllene,benzyl alcohol could only produce significant electrophysiological responses to S.litura at higher concentrations.The compound effects of volatile substances were not a simple superposition.100 mg/ml of linalool with repellent effect against S.litura mixed with benzaldehyde which had attractive effect,the electrophysiological response of male adult S.litura was significantly improved.The combination of plant volatiles with the same behavioral responses to S.litura did not necessarily result in a stronger electrophysiological response to S.litura.The combination of trans-2-hexenal and linalool with repellent effects against S.litura at 100 mg/ml significantly improved the electrophysiological response of S.litura.However,the electrophysiological response of S.litura did not increase significantly after the combination of nonanal and benzaldehyde which had an attraction effect on S.litura at concentrations of 100 mg/ml.The physiological response did not increase significantly.The concentration of components in the complex volatiles also affects the electrophysiological response to S.litura.The combination of 100 mg/ml benzaldehyde and 10 mg/ml linalool had weaker electrophysiological responses to S.litura than compounds of the same concentration at 100 mg/ml.In addition,the electrophysiological responses of male and female insects to compound volatiles were quite different.更多还原