小菜蛾经历“保卫德”后产卵选择行为的变化

Changes of oviposition preference of diamondback moth after experiencing a neem-based repellent/deterrent BIOACT-T^(TM)

植食性昆虫成虫对非寄主植物源驱避素的经历,可导致其对这类化合物产生习惯性反应或诱导嗜好性.让小菜蛾雌蛾对源于印楝的驱避剂——“保卫德”(BIOACT-TTMEC508)经历2～6次或2～6日后,测定它们对经过保卫德处理的白菜植株的产卵选择行为.结果表明,保卫德对2日龄、4日龄、6日龄无经历雌蛾均有很强的驱避作用,它们在经过保卫德处理的白菜植株上的相对产卵率均只有10%左右;对保卫德有2次或2d经历的2日龄雌蛾,该产卵率平均上升到17%;对保卫德有4次或4d经历的4日龄雌蛾,该产卵率上升到21%～24%;对保卫德有6次或6d经历的6日龄雌蛾,该产卵率上升到29%.表明经历可导致雌蛾对保卫德产生习惯性反应或诱导嗜好性,使保卫德的驱避作用下降,但这种经历导致的产卵选择行为变化在个体之间存在较大差异.

For the adults of phytophagous insects, their experience of non-host plant-originated repellent/deterrent may produce habituation or induced preference to it. In this study, the experience-induced changes in oviposition responses of diamondback moth Plutelle xylostella L. to a neem-based repellent BIOACT-TTM EC508 were examined in laboratory. 2-6 days old female moths were offered with 2-6 times or 2-6 days experience of the repellent, and their ovipostion preference to untreated and BIOACT-treated Chinese cabbages were evaluated. The results showed that BIOACT had a strong repellent effect to all of the naive 2-6 days old females, that only laid approximately 10% of their eggs on BIOACT-treated plants. As for the 2, 4 and 6 days old females who experienced 2 times or 2 days, 4 times or 4 days, and 6 times or 6 days of BIOACT, their mean oviposition rate on BIOACT-treated plants increased to 17%, 21%-24%, and 29% , respectively, demonstrating that this experience of the females induced their habituation or preference to BIOACT, and consequently, the repellent effect of BIOACT decreased. However, there were substantial variations in the experience-induced changes of oviposition preference among the individuals of the moth.