Nakamatsu Y, Gyotoku Y, Tanaka T
Yatsushiro Dai-ichi Highschool, Yatsushiro, Kumamoto Prefecture, Japan
J Insect Physiol. 2001 Jun;47(6):573-584. doi: 10.1016/s0022-1910(00)00147-5.
It was previously demonstrated that parasitization by Cotesia kariyai caused a decrease in weight gain and food consumption in host larvae, resulting in a lower final weight for parasitized hosts. It is predicted that C. kariyai regulates the physiological condition of the host to obtain maximum food under restricted nutritional conditions. Approximate digestibility (AD) was higher following parasitization but the efficiency of conversion of digested food (ECD) of the parasitized hosts was lower. This suggests that resources available to the parasitoid larvae are enhanced in the parasitized hosts. We evaluated the physiological changes caused by injection of calyx fluid (polydnavirus) plus venom (C+V) in nonparasitized hosts. Injection of C+V into the nonparasitized hosts duplicated the effects of parasitism, namely it increased the AD and decreased the ECD. Furthermore, C+V injections elevated trehalose concentrations in nonparasitized host 7 to 10 d after injection (2nd stadium of the parasitoid larva). Protein content also increased on days 9 and 10 after C+V injection. These results suggest that the nutrients that parasitoid larvae require for their growth increase in the hemolymph of the host during the 2nd stadium of the parasitoid larva.
先前的研究表明，被狩野氏茧蜂寄生会导致寄主幼虫的体重增加和食物消耗量减少，从而使被寄生寄主的最终体重降低。据推测，狩野氏茧蜂会调节寄主的生理状态，以便在营养条件受限的情况下获取最多的食物。被寄生后，近似消化率（AD）较高，但被寄生寄主的消化食物转化率（ECD）较低。这表明在被寄生的寄主体内，可供寄生蜂幼虫利用的资源有所增加。我们评估了在未被寄生的寄主中注射萼液（多角体病毒）加毒液（C+V）所引起的生理变化。向未被寄生的寄主注射C+V会产生与寄生相同的效果，即增加AD并降低ECD。此外，注射C+V后7至10天（寄生蜂幼虫的第二龄期），未被寄生寄主中的海藻糖浓度升高。注射C+V后第9天和第10天，蛋白质含量也有所增加。这些结果表明，在寄生蜂幼虫的第二龄期，寄主血淋巴中寄生蜂幼虫生长所需的营养物质有所增加。
