Oligophagous Helicoverpa assulta (Guenée) and polyphagous H. armigera (Hübner) are two sibling species, with tobacco as the shared host-plant. The effects of plant volatiles from one variety of Nicotiana tabacum and four varieties of N. rustica on electrophysiological and behavioral responses of these two insect species were investigated in the laboratory. The results indicated that virgin and mated females of H. assulta elicited stronger EAG and behavioral responses to four tested N. rustica varieties than to N. tabacum, while H. armigera was reverse in responses. Females of the two Helicoverpa species responded more actively in EAG and behavioral experiments to the volatiles of tested tobacco varieties than males, so there were significant sexual differences of the two sibling species. The results of gas chromatography-mass spectrum (GC-MS) showed that, in comparison with K326, variety "makhorka" contained higher amount of nicotine, more sorts of green leaf volatiles and less amount of aromatic compounds, suggesting that the difference in sorts and relative concentrations of tobacco volatiles may lead to the different ovipositing preferences of two sibling Helicoverpa species to N. tabacum and N. rustica tobacco plants.%寡食性烟夜蛾Helicoverpa assulta (Guenée)和广食性棉铃虫H.armigera (Hübner)是铃夜蛾属2近缘种,烟草是其共同寄主.室内实验测定了1个普通烟草品种和4个黄花烟草品种叶片挥发物对二者电生理和行为反应的影响.结果表明,烟夜蛾处女雌蛾和交配雌蛾对4个黄花烟草品种叶片挥发物的EAG反应均显著高于普通烟草,而棉铃虫对普通烟草叶片挥发物的反应显著高于黄花烟草;二者的行为反应与EAG测试结果相似,黄花烟草叶片挥发物对烟夜蛾有较强的引诱作用,棉铃虫对普通烟草叶片挥发物有较强趋性;两种夜蛾雄蛾对这些挥发物的EAG和行为反应均没有雌蛾强烈,性别差异显著;GC-MS分析表明,与K326相比,马合烟叶片挥发物中尼古丁的相对含量高(76.91%),绿叶气味种类多但芳香族化合物种类少,挥发物种类和含量的不同是否与两种夜蛾产卵趋性差异相关,有待进一步研究.
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