Abstract：
The Sitophilus zeamais (maize weevil) and Sitophilus oryzae (rice weevil) are two insect pests that have caused huge economic losses to stored grains worldwide. It is urgent to develop an environmentally friendly strategy for the control of these destructive pests. Here, the olfactory-mediated selection preference of the two weevil species to three stored grains was analyzed, which should help establish a pull-push system in managing them. Bioassays showed that maize weevil adults prefer to select maize, followed by paddy and wheat, while rice weevil adults mainly migrate towards wheat. Volatile analyses revealed that 2-ethylhexanol, piperitone, and (+)-Δ-cadiene are the major components in volatiles from both maize and wheat, but the abundance of these chemicals is much lower in maize than that in wheat. The volatile limonene was only detected in paddy. Y-tube bioassays suggest that 2-ethylhexanol, piperitone, and (+)-Δ-cadiene were all attractive to both weevils, whereas limonene was attractive only to rice weevils. Overall, maize weevil appeared more sensitive to the tested volatiles based on having much lower effective concentrations of these volatiles needed to attract them. The differences in volatile profiles among the grains and the sensitivity of the two species towards these volatiles may explain the behavioral differences between maize and rice weevils in selecting host grains. The differences in sensitivity of maize and rice weevils towards host volatile components with abundance differences are likely determinants driving the two insect species to migrate towards different host grains.
摘要：
Sitophiluszeamamais（玉米象鼻虫）和Sitophilusoryzae（水稻象鼻虫）是两种害虫，它们给全球储存的谷物造成了巨大的经济损失。迫切需要制定一种环境友好的策略来控制这些破坏性害虫。这里,分析了两种象鼻虫对三种储存谷物的嗅觉介导的选择偏好，这应该有助于建立一个推拉式系统来管理它们。生物测定表明，玉米象鼻虫成虫更喜欢选择玉米，其次是水稻和小麦，而水稻象鼻虫成虫主要向小麦迁移。挥发性分析表明，2-乙基己醇，胡椒酮,和（）-Δ-卡迪尼是玉米和小麦挥发物的主要成分，但是玉米中这些化学物质的丰度远低于小麦。仅在稻谷中检测到挥发性柠檬烯。Y管生物测定表明，2-乙基己醇，胡椒酮,和(+)-Δ-卡迪尼都对两种象鼻虫有吸引力，而柠檬烯只对水稻象鼻虫有吸引力。总的来说,玉米象鼻虫似乎对所测试的挥发物更敏感，因为吸引它们所需的这些挥发物的有效浓度要低得多。谷物之间挥发性成分的差异以及两个物种对这些挥发物的敏感性可能解释了玉米和水稻象鼻虫在选择宿主谷物时的行为差异。玉米和水稻象鼻虫对具有丰度差异的宿主挥发性成分的敏感性差异可能是驱动两种昆虫向不同宿主谷物迁移的决定因素。
