米蛾对三种赤眼蜂的适合性及被寄生后卵内游离氨基酸含量的变化

寄生发生前寄生蜂的寄生行为及寄生发生后寄生蜂的生长发育情况能够反映出寄主对寄生蜂的适合性，而寄生蜂对寄主营养物质的吸收和利用是寄生蜂完成发育的生理基础。为了从寄生蜂利用寄主营养能力的角度探讨寄主对不同种赤眼蜂适合性变化的原因，本文观察了以米蛾Corcyra cephalonica Stainton卵为寄主时拟澳洲赤眼蜂Trichogramma confusumViggiani、松毛虫赤眼蜂T. dendrolimi Matsumura和玉米螟赤眼蜂T. ostriniae Pang et Chen的寄生行为及发育和存活情况，测定了被寄生米蛾卵内游离氨基酸的含量 。结果发现，玉米螟赤眼蜂的产卵时间为84.9 s，显著长于拟澳洲赤眼蜂和松毛虫赤眼蜂的产卵时间。拟澳洲赤眼蜂检测寄主所需时间为30.8 s，显著长于玉米螟赤眼蜂和松毛虫赤眼蜂所需时间，但从每寄主卵中羽化出的拟澳洲赤眼蜂数量显著高于松毛虫赤眼蜂及玉米螟赤眼蜂寄生的结果。3种赤眼蜂卵+幼虫的发育历期间不存在显著差异，但卵成虫的发育历期间存在显著差异。玉米螟赤眼蜂幼虫期和预蛹期的死亡率均显著高于拟澳洲赤眼蜂和松毛虫赤眼蜂相应虫期的死亡率。这些结果表明：米蛾卵对松毛虫赤眼蜂及拟澳洲赤眼蜂的适合性高于对玉米螟赤眼蜂的适合性。未被寄生的米蛾卵内游离氨基酸的总量在24～96 h时间段内从开始的2.194 mg/mL逐渐下降到1.565 mg/mL，而被寄生的米蛾卵内游离氨基酸总量均出现先升高后下降的现象。被松毛虫赤眼蜂和拟澳洲赤眼蜂寄生的米蛾卵内游离氨基酸总量在48 h达到最高值，分别为4.239 mg/mL和3.222 mg/mL，被玉米螟赤眼蜂寄生的米蛾在72 h达到最高值，为4 .323 mg/mL，显示同玉米螟赤眼蜂相比，松毛虫赤眼蜂和拟澳洲赤眼蜂能够更快地分解利用寄主营养。这些结果提示，3种赤眼蜂利用米蛾卵内营养物质能力的不同导致了米蛾卵对3种蜂适合性的不同。

Suitability of Corcyra cephalonica to three trichogramma species and change of the content of free amino acids in its eggs parasitized

The suitability of host to parasitoid could be investigated by observing the parasitizing behavior and the development of parasitoid, and the development of parasitoid was based on the ability of parasitoid in using host nutrients. In order to find the relationship between the suitability of host to trichogramma wasps and the ability of trichogramma wasps in using host nutrient, we investigated the parasitizing behavior, development and survival of Trichogramma confusum, T. dendrolimi, and T. ostriniae on Corcyra cephalonica, and measured the content of free amino acids in parasitized and unparasitized host eggs in the laboratory. The results indicated that the oviposization time of T. ostriniae was 84.9 s, which was significantly longer than that of T. dendrolimi and T. confusum. The host-checking time of T. confusum was 30.8 s, which was significantly longer than that of T. dendrolimi and T. ostriniae, but the number of T. confusum emerged from per host was significantly more than that of T. dendrolimi and T. ostriniae. There were no significant differences in developmental duration of egg larvae, but significant differences were found in developmental duration from egg to adult among three trichogramma species. Both the larva and prepupa mortality rates of T. ostriniae were significantly higher than those of the correspondent developmental stage of T. confusum and T. dendrolimi. These results indicated that the suitability of C. cephalonica to T. confusum and T. dendrolimi were higher than that to T. ostriniae. The content of total free amino acids in unparasitized C. cephalonica eggs decreased from 2.194 mg/mL at 24 h to 1.565 mg/mL at 96 h, whereas it increased at first and then decreased in eggs parasitized. The content of total free amino acids in eggs parasitized by T. confusum and T. dendrolimi reached the highest values, which were 3.222 mg/mL and 4.239 mg/mL, respectively, at 48 h, and the content of total free amino acids in eggs parasitized by T. ostriniae reached the highest value, which was 4.323 mg/mL at 72 h after parasitization, indicating that T. confusum and T. dendrolimi could degrade and use host nutrients more quickly than T. ostriniae. These results suggested that the differences in ability of trichogramma in using the host nutrients caused the differences in suitability of C. cephalonica to three trichogramma species.