椰心叶甲啮小蜂对椰叶及寄主挥发物的行为反应

为探讨椰心叶甲啮小蜂(Tetrastichus brontispae Ferriere)主动搜索和识别寄主的机理,采用Y型嗅觉仪测定椰心叶甲啮小蜂Brontispa longissima(Gestro)]对椰子健康心叶、健康老叶、虫害叶和机械损伤心叶、以及椰心叶甲幼虫、蛹、成虫和四龄幼虫虫粪的行为反应进行了研究.结果表明,椰心叶甲啮小蜂对椰子的健康心叶、老叶、机械损伤心叶、椰心叶甲各龄幼虫、蛹和成虫、1龄幼虫和成虫为害心叶的气味没有趋向反应,而对椰心叶甲4龄幼虫虫粪和2～5龄幼虫为害24 h后的心叶具有明显的趋向反应,选择气味源的虫数显著高于对照,而且对幼虫为害心叶的趋向反应随着为害叶的幼虫数的增多和为害时间的延长而增强.

Behavior Response of Tetrastichus brontispae Ferriere to Volatiles from Coconut Leaf and Brontispa longissima(Gestro)

The wasp Tetrastichus brontispae Ferrière is an important pupal parasitoid of coconut leaf beetle Brontispa longissima (Gestro), and plays an important role in controlling the population dynamics of B. longissima. In order to understand how the wasps find their victims, their responses to volatile compounds from host, host-plant, 4-larval frass and herbivores damaged coconut leaves were tested using Y- tube olfactometer. The results showed that female wasps had little response to volatiles from healthy fold leaves, healthy mature leaves, mechanically damaged fold leaves, all larva instars of coconut leaf beetle, pupal coconut leaf beetle, adult coconut leaf beetle, fold coconut leaves damaged by adult coconut leaf beetle and 1 instar larva coconut leaf beetle, but an obviously higher response to the volatiles from 4-larva frass and coconut fold leaves damaged after 24 h by 2~5 larva coconut leaf beetle. These results indicate that some different volatiles from healthy leaves can be released to attract T. brontispae after larva coconut leaf beetle of 2~5 instars damaged host plant leaves.