Abstract: 稻纵卷叶螟绒茧蜂是稻纵卷叶螟幼虫的重要天敌。以Y形嗅觉仪测定了稻纵卷叶螟2-3龄幼虫虫粪、4-5龄幼虫虫粪、健康水稻、稻纵卷叶螟幼虫为害后水稻在纵卷叶螟绒茧蜂对寄主的搜索过程中的作用。结果表明已交配的雌蜂显著趋向稻纵卷叶螟2-3龄幼虫虫粪和4-5龄幼虫虫粪,不趋向健康水稻、稻纵卷叶螟幼虫为害后的水稻。雄蜂、处女雌蜂不显著趋向健康水稻、稻纵卷叶螟幼虫为害后水稻、稻纵卷叶螟2-3龄幼虫虫粪、稻纵卷叶螟4-5龄幼虫虫粪。利用固相微萃取(SPME)及气相色谱/质谱(GC/MS)联用分析稻纵卷叶螟2-3龄幼虫虫粪的化学成分,并通过Y-形嗅觉仪测试已交配雌蜂对稻纵卷叶螟2-3龄幼虫虫粪化学成分标准品的嗅觉反应,结果表明已交配的雌蜂显著趋向1-十一烯和异缬草醛,稻纵卷叶螟幼虫虫粪中的1-十一烯和异缬草醛可能是稻纵卷叶螟绒茧蜂搜索寄主的利他素。;<em>Apanteles cypris</em> Nixon is one of the most important natural enemies of the larvae of rice leaf folder, <em>Cnaphalocrocis medinalis</em> Guenée. Through parasitizing their larvae, <em>A. cypris</em> wasps play a major role in biological control of <em>C</em>.<em> medinalis</em>; parasitized host larvae consume less rice leaf than non-parasitized counterparts, thus causing less damage. Previous studies suggest that some parasitoids using chemical cues to locate their hosts. In a tritrophic interaction system consisting of plants, herbivores, and their parasitoids, chemicals released from plants after herbivory are known to help many female parasitoids find their hosts efficiently. Chemical information associated with herbivory can act as an indirect defense for the plant by attracting natural enemies of the host herbivores. There are several potential sources of infochemicals used by parasitoids: the host plant, direct or indirect cues from the host. This study aims to determine if the host searching behavior of <em>A</em>. <em>cypris</em> is affected by volatiles from <em>C</em>.<em> medinalis</em>-infested and uninfested rice plants and frass produced by larvae of <em>C</em>. <em>medinalis</em>. We found that mated female <em>A</em>. <em>cypris</em> were attracted by the frass of 2nd/3rd or 4th/5th instar <em>C</em>. <em>medinalis</em> larvae but not by <em>C</em>. <em>medinalis-</em>infested and uninfested rice plants. In contrast, male and virgin female <em>A</em>. <em>cypris</em> did not respond significantly to any of the stimuli. These results indicate that the mating status of <em>A</em>. <em>cypris</em> females clearly influences their host-searching behavior in response to herbivory-associated chemical information, and we suggest that female parasitoids forage for hosts depending on their own physiological condition in a tritrophic system. To elucidate which chemicals are used by <em>A. cypris</em> to locate their hosts, we analyzed the chemical composition of frass produced by 2nd/3rd instar <em>C</em>.<em> medinalis</em> larvae using solid-phase micro-extraction (SPME) combined with gas chromatography/mass spectrometry (GC/MS). We collected 23 volatiles from the frass, including terpenoids, alcohols, ketones, amines, aldehyde. Chemical standards of the determined frass components are then tested for the chemotactic effect on mated female <em>A</em>. <em>cypris</em> using Y-tube olfactometer. We found that mated female <em>A</em>. <em>cypris</em> were significantly attracted by 1-undecene and 3-methylbutanal, and suggest that these compounds in the frass of <em>C</em>.<em> medinalis</em> larvae are the kairomones that attract endoparasitoid <em>A</em>. <em>cypris</em>. Our results may prove to be helpful for the agricultural industry through use of these kairomones as control agents for <em>C</em>. <em>medinalis</em>, and are the basis of further study into the tritrophic system of rice -<em>C</em>. <em>medinalis</em>-<em>A. cypris</em> and development of new control methods.