低温贮藏对丽蚜小蜂生长发育和扩散的影响

丽蚜小蜂Encarsia formosa作为烟粉虱Bemisia tabaci和温室白粉虱Trialeurodes vaporariorum的重要寄生性天敌，目前已实现了规模化繁育，广泛应用于设施蔬菜粉虱类害虫的防控。该寄生蜂在大面积释放前往往要进行数量储备，因此低温贮藏是实现其规模化生产和应用的重要环节。本文在明确丽蚜小蜂蛹期最适贮藏发育阶段的基础上，研究了不同低温贮藏方式对丽蚜小蜂生长发育和适合度的影响，并在温室条件下明确了低温贮藏对其扩散和寄生的影响。结果表明，丽蚜小蜂的蛹在4℃和8℃下低温贮藏仍可继续发育，解剖低温贮藏后未羽化的丽蚜小蜂发现其死亡主要发生在蛹的发育初期和后期，蛹的发育中期死亡比例最低；贮藏前经历适度的低温诱导（12℃/7 d）可以显著提高丽蚜小蜂的羽化率、寄生量和成虫寿命（P<0.05）；温室条件下未经低温贮藏的丽蚜小蜂主要在1～4 m范围内扩散，而低温贮藏后羽化的丽蚜小蜂主要在1～2 m范围内扩散；适度的低温诱导（12℃/7 d）同样可以明显提高丽蚜小蜂在温室条件下的寄生率（P<0.05）。研究结果对于更好地发挥丽蚜小蜂在生物防治中的控害作用具有重要的应用意义。

Effect of Cold Storage on Development and Dispersal of Encarsia formosa (Hymenoptera: Aphelinidae)

Encarsia Formosa, which has been identified as an effective parasitic wasp of both Bemisia tabaci and Trialeurodes vaporariorum, has currently been mass produced for control of whiteflies on a wide range of greenhouse vegetable crops. The parasitic wasp usually needs to be stored before augmentative releases, and thus cold storage has been proved to be an important process for mass production and release of parasitoids. In the present study, we exposed pupae of E. formosa to different cold storage regimes, and determined the influence of cold storage on pupal development and several fitness-related traits. We also examined the dispersal ability and parasitic rates on post-storage in the greenhouse. The results showed that E. formosa pupae developed during cold storage at both 8℃ and 4℃. The middle stage pupae appeared to suffer lower mortality compared to the early or late stage pupae. The three fitness parameters (eclosion, parasitism and adult longevity) of E. formosa was obviously improved (P<0.05) when the pupae were exposed to a cold acclimation (12℃ for 7 days). The parasitic wasps that experienced non-cold storage dispersed mainly within a distance of 1-4 m from the released point while those underwent cold storage dispersed mainly within a distance of 1-2 m. The parasitism rate in the greenhouse was also obviously improved (P<0.05) when the pupae were exposed to cold acclimation (12℃ for 7 days). These results are significant for the biological control using E. formosa.