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为研究甜菜夜蛾Spodoptera exigua幼虫被斑痣悬茧蜂Meteorus pulchricornis寄生后的取食以及食物利用情况,在室内采用重量法测定了甜菜夜蛾4龄幼虫被寄生后取食量、体重增加量、营养指标的变化。结果表明:被寄生甜菜夜蛾幼虫的取食量、生长率和食物利用效率等明显受到抑制,幼虫被寄生后第3-6d取食量显著小于未被寄生幼虫,寄生后第4d的幼虫取食量只有正常幼虫的29.89%,第5d只有48.69%。幼虫在寄生后的第3-5d体重增加量显著小于未被寄生幼虫,分别为正常幼虫的21.51%,38.87%和14.42%,相对生长率则也显著低于后者。被寄生甜菜夜蛾幼虫的营养利用表现也明显不同于未被寄生幼虫,反映生长和代谢效率的食物利用率(ECI)和食物转化率(ECD)均显著降低,而反映吸收效率的近似消化率(AD)则提高。虽然在寄生后第4d出现了相反的现象,其原因可能在于第4d取食量明显减少,而体重仍在增加。本研究表明,斑痣悬茧蜂寄生明显抑制寄主甜菜夜蛾幼虫的取食、食物利用效率和生长。
In order to study the feeding and food utilization of Spodoptera exigua larvae after parasitization by Meteorus pulchricornis, the fourth instar larvae of beet armyworm parasitized were measured their food intake, body weight gain, Changes in nutritional indicators. The results showed that the food intake, growth rate and food use efficiency of the parasitized beetle larvae were significantly inhibited. The larvae parasitized 3-6 days after the larvae were significantly less than the unparasitic larvae and parasitic larvae on the 4th day after parasitization Food intake is only 29.89% of normal larvae, only 48.69% on the 5th. After 3-5 days of parasitism, the weight gain of larvae was significantly less than that of unparasitic larvae, which was 21.51%, 38.87% and 14.42% of that of normal larvae respectively, while the relative growth rate was also significantly lower than the latter. The nutritive utilization of parasitized beet armyworm larvae was also significantly different from that of unparasitic larvae, the ECI and ECD decreased significantly, and the approximate digestibility of absorption efficiency (AD) is increased. Although the opposite phenomenon occurs on the 4th day after the parasitism, the reason may be that the amount of food intake decreased obviously on the 4th day and the weight is still increasing. The present study shows that parasitism of M. albacares significantly inhibits the feeding, food use efficiency and growth of host beet armyworm larvae.