烟青虫胚胎发育经历影响初孵幼虫的嗅觉偏好性

目的]探讨卵期发育经历对一种寡食性害虫烟青虫Helicoverpa assulta(Guenée)]初孵幼虫嗅觉偏好性的影响。方法]选择烟青虫的2种主要寄主烟草和辣椒作为测试植物,每种植物进一步分为繁殖器官和营养器官2类不同的组织,将这些组织的提取物分别涂布在棉纱布上作为雌蛾的产卵基质,分离出刚孵化的幼虫并测试其嗅觉偏好性。结果]和无经历的个体相比,只有来自烟草花器和辣椒叶片提取物环境的初孵幼虫嗅觉偏好性才会发生显著的改变。具有嗅觉调控能力的寄主组织与烟青虫成虫的自然产卵位置是一致的。然而,来自烟草花器和辣椒叶片的化学刺激物均能诱导出初孵幼虫对辣椒果实化学刺激的强烈嗅觉偏好性,与霍普金斯寄主选择原理是相反的。在植物种类的水平上(即将同种植物的不同器官合并分析),既不存在组内差异也不存在组间差异。在植物组织的水平上(即将不同植物的同类器官合并分析),胚胎发育期暴露于繁殖器官化学刺激的初孵幼虫对繁殖器官的嗅觉偏好性显著强于营养器官,这种趋势也和无经历组的行为有显著差异。繁殖器官诱导出嗅觉偏好性的机制可以用化学遗产假说(chemical legacy)来解释。结论]试验结果为经历在昆虫生活史中的功能研究提供了理论依据。

Experienced Host Chemical Stimuli during Embryonic Development Affects the Olfactory Preference of Subsequent Neonates of Helicoverpa assulta

Objective] The aim was to study the effect of egg experience on the olfactory preference of subsequently hatched larvae of a specialist herbivore,Helicoverpa assulta (Guenée).Method] Two main hosts,tobacco and hot pepper,were selected as the test plants;each host was further divided into reproductive parts and vegetative parts,whose extracts were applied on gauzes as an ovipositional substrates.Result] Only the chemical stimuli from tobacco flowers and hot pepper leaves significantly changed the olfactory preference of neonates,compared with naives.The host parts having the ability of olfactory modulation were in accordance with natural oviposition sites.However,these two stimuli could induce strong olfactory preference of subsequent hatched larvae to hot pepper fruit,contrary to the expectation being arisen by Hopkins' host selection principle.Neither the within-group difference nor between-group difference was significant in species effect.However,neonates exhibited significantly stronger olfactory preference to reproductive parts than vegetative parts after exposed to chemical stimuli from reproductive parts,differed significantly when compared with the na(i)ve group.The mechanism of induced olfactory preference by reproductive parts may be explained by chemical legacy.Conclusion] The result provides an insight into the role of experience in a whole life cycle.