Liu Mulan, Yu Hejuan, Li Guoqing
Key Laboratory of Monitoring and Management of Plant Diseases and Pests, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, China.
J Insect Physiol. 2008 Apr;54(4):656-62. doi: 10.1016/j.jinsphys.2008.01.002. Epub 2008 Jan 24.
Our previous results showed that an extract of the abdomens of mated females of the cotton bollworm, Helicoverpa armigera, deterred oviposition of conspecifics. In this paper, we found that the extract, in addition to reducing conspecifics' oviposition, could elicit strong electroantennogram responses from mated females. The EAG elicitors mainly came from mature chorionated eggs in the ovarioles. Laid eggs or their surface extract evoked similar EAG responses. The main chemical components of the EAG elicitors from mature chorionated and laid eggs were myristic, palmitic, stearic, and oleic acids. A blend of authentic fatty acids at the ratio found in the laid eggs and in an amount equivalent to 100 laid eggs mimicked the EAG response and deterring effect. Moreover, these four oviposition-deterring fatty acids and their corresponding methyl esters evoked significantly higher EAG responses from both mated females and males than hexane blank and background. The EAG values differed among the test chemicals and between sexes. These results demonstrate that the four fatty acids from eggs are at least partially responsible for the oviposition-deterring effect of the extract from the abdomens of mated female H. armigera and that the moths may detect these chemicals olfactorily by antennae.
我们之前的研究结果表明，棉铃虫（Helicoverpa armigera）交配雌虫腹部提取物可抑制同种个体的产卵。在本文中，我们发现该提取物除了能减少同种个体的产卵外，还能引起交配雌虫强烈的触角电位反应。触角电位激发物主要来自卵巢小管中成熟的有卵壳的卵。产下的卵或其表面提取物能引发类似的触角电位反应。成熟有卵壳的卵和产下的卵的触角电位激发物的主要化学成分是肉豆蔻酸、棕榈酸、硬脂酸和油酸。以产下的卵中发现的比例混合的真实脂肪酸，且数量相当于100个产下的卵，模拟了触角电位反应和抑制作用。此外，这四种抑制产卵的脂肪酸及其相应的甲酯引发的交配雌虫和雄虫的触角电位反应明显高于正己烷空白对照和背景。不同测试化学物质以及不同性别之间的触角电位值存在差异。这些结果表明，来自卵的四种脂肪酸至少部分导致了交配棉铃虫雌虫腹部提取物的产卵抑制作用，并且蛾类可能通过触角嗅觉检测这些化学物质。
