麦蛾茧蜂雌蜂对寄主印度谷螟挥发物的选择行为研究

    Study on the selective behavior of female Habrobracon hebetor toward volatile compounds of its Host Plodia interpunctella

    • 摘要: 在粮食–寄主–寄生蜂三级营养系统中,寄主挥发物是寄生蜂定位寄主的关键化学信号。麦蛾茧蜂对印度谷螟的搜寻与定位主要受其挥发物调控。为探究不同日龄印度谷螟幼虫及其生境相关挥发物对麦蛾茧蜂雌蜂选择行为的影响,采用“Y”型嗅觉仪测试未交配、已交配且无寄生经验以及已交配且有寄生经验的麦蛾茧蜂雌蜂对不同日龄印度谷螟幼虫及其生境相关物质的选择行为,并利用GC-MS鉴定其挥发物成分,再结合触角电位与行为测定筛选对麦蛾茧蜂雌蜂具有显著吸引作用的化合物。结果表明:在对不同日龄印度谷螟幼虫及其生境相关物质的行为选择中,未交配、已交配且无寄生经验以及已交配且有寄生经验的麦蛾茧蜂雌蜂均对老熟幼虫表现出显著偏好,选择率分别为57.78%、81.11%和85.56%;已交配且有寄生经验的麦蛾茧蜂雌蜂对被印度谷螟为害的饲料亦表现出显著偏好,选择率为72.22%;进一步通过GC-MS、触角电位及行为学测定发现,3类麦蛾茧蜂雌蜂对D-柠檬烯的触角电位反应最为强烈,分别为0.95、1.00和1.33 mV;在D-柠檬烯浓度为1 μg/μL时,其选择率最高,分别为56.67%、60.00%和87.78%。本研究结果可为今后利用麦蛾茧蜂对印度谷螟开展高效生物防治提供理论依据。

       

      Abstract: In tritrophic systems involving stored grains, hosts, and parasitoids, host-derived volatile compounds play a key role in host location by parasitoid wasps. The host-searching and orientation behavior of Habrobracon hebetor (Say) toward the Indian meal moth Plodia interpunctella is largely regulated by these volatile cues. To investigate the effects of volatiles emitted by larvae of different developmental stages of P. interpunctella and their habitat-related substrates on the host-selection behavior of female H. hebetor, behavioral assays were conducted using a Y-tube olfactometer. Three physiological states of female parasitoids were tested, including unmated females, mated females without oviposition experience, and mated females with oviposition experience. In addition, volatile compounds from the host larvae and their habitat were identified using gas chromatography-mass spectrometry (GC-MS). Electroantennogram recordings and behavioral bioassays were further performed to screen and verify compounds that showed significant attractiveness to female parasitoids.The results showed that female H. hebetor of different mating and parasitic states exhibited significant preferences for mature larvae of P. interpunctella. The selection rates for mature larvae were 57.78%, 81.11%, and 85.56% for unmated females, mated females without oviposition experience, and mated females with oviposition experience, respectively. In addition, mated females with oviposition experience showed a significant attraction to diets damaged by P. interpunctella, with a selection rate of 72.22%, suggesting that host habitat cues also play an important role in host localization.Further analyses combining GC-MS identification, electroantennogram recordings, and behavioral assays revealed that female H. hebetor showed the strongest electrophysiological responses to D-limonene among the tested compounds. The electroantennogram amplitudes of unmated females, mated females without oviposition experience, and mated females with oviposition experience reached 0.95, 1.00, and 1.33 mV, respectively. Behavioral experiments further demonstrated that D-limonene significantly attracted female parasitoids, with the highest selection rates observed at a concentration of 1 μg/μL. At this concentration, the selection rates were 56.67%, 60.00%, and 87.78% for unmated females, mated females without oviposition experience, and mated females with oviposition experience, respectively. The results provide a theoretical basis for improving the efficiency of biological control of P. interpunctella using H. hebetor in stored-grain ecosystems.

       

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