基于柞蚕卵为中间寄主的赤眼蜂种间竞争机制研究

The oak-silkworm, Antheraea pernyi Guerin-Meneville, is one of the best factitious hosts for Trichogramma mass production in China due to the advantages of low cost and simple production craft with it, and enduring long-term storage with good quality. However, presently only T. dendrolimi is massively produced with the large host eggs of oak-silkworm so that mass productions of most Trichogramma species and their implications for pest biological control have been limited. Previous results indicated that some Trichogramma species, such as T. ostriniae and T. leucaniae, had the capacity of parasitizing eggs of A. Pernyi and developing to adults, but the parasitoids could not break and craw out the host-egg shell. In this study, the interspecific competition will be investigated between T. dendrolimi and T. ostriniae (or T. leucaniae) under various conditions with different temperature, humidity, light, parasitoid source, host-egg age, ratio of parasitoid to host egg, and ways of introducing parasitoid. Through estimating and observing the host selection and developmental adaption between two Trichogramma species under different conditions, we will determine the mechanisms of competitive interactions of Trichogramma species on eggs of A. pernyi. The present study will improve the development of Trichogramma mass production technology with large host eggs, provide theoretical bases for developing products of several Trichogramma species concurrently reared with one host egg, and create a new pattern of Trichogramma production and implication with eggs of A. pernyi.

柞蚕是我国的特色优势资源，因用其卵繁育赤眼蜂具有成本低、生产工艺简单、成品蜂耐储藏等优点，目前已成为人工大量繁育赤眼蜂的优良替代繁殖寄主。但因柞蚕卵可繁育优势赤眼蜂种类过少（目前主要用于松毛虫赤眼蜂繁育），而极大限制了多数优势赤眼蜂种类的生产和推广应用。已有研究结果表明，一些赤眼蜂种类（如玉米螟赤眼蜂和黏虫赤眼蜂）可以寄生柞蚕卵并完成发育，但很难穿破柞蚕卵壳正常出蜂。本项目重点研究松毛虫赤眼蜂和玉米螟赤眼蜂及黏虫赤眼蜂在不同条件下柞蚕卵上的竞争作用，涉及影响因素包括温度、湿度、光照、蜂种来源、寄主卵龄、蜂卵比、接蜂方式等，通过测定并观察不同条件下各蜂种组合对柞蚕卵的寄生选择和发育适合度，明确松毛虫赤眼蜂和其它赤眼蜂种类在柞蚕卵上的竞争互作机制。本研究可为尝试开发基于柞蚕卵的“一卵多蜂”技术提供理论基础，有利于开创基于柞蚕卵为中间繁育寄主的赤眼蜂繁育与利用新模式。

柞蚕是我国的特色优势资源，因用其卵繁育赤眼蜂具有成本低、生产工艺简单、成品蜂耐储藏等优点，目前已成为人工大量繁育赤眼蜂的优良替代繁殖寄主。但因柞蚕卵可繁育优势赤眼蜂种类过少（目前主要用于松毛虫赤眼蜂和螟黄赤眼蜂繁育），而极大限制了多数优势赤眼蜂种类的生产和推广应用。本项目通过研究松毛虫赤眼蜂（螟黄赤眼蜂）和玉米螟赤眼蜂（黏虫赤眼蜂）在不同条件下对柞蚕卵共寄生作用，测定并观察不同条件下各蜂种组合对柞蚕卵的寄生选择和发育适合度，明确了不同赤眼蜂种类在柞蚕卵上的共寄生竞争互作机制。主要研究发现：（1）温度、湿度和光照条件明显影响两种赤眼蜂对柞蚕卵的共寄生效果，综合来看，在26℃、80%RH和L24：D0 h条件下，两种赤眼蜂对柞蚕卵的寄生率和羽化率最高，单卵羽化玉米螟赤眼蜂或黏虫赤眼蜂数量最多；（2）接蜂方式明显影响两种赤眼蜂对柞蚕卵的共寄生作用，黏虫赤眼蜂和松毛虫赤眼蜂同期接蜂比错期接蜂具有更高的寄生率和单卵羽化黏虫赤眼蜂数；（3）繁育寄主种类明显影响两种赤眼蜂对柞蚕卵的共寄生作用，综合来看，共寄生组合中只要有柞蚕卵繁育的赤眼蜂，对柞蚕卵均表现出较高的寄生率，而以柞蚕卵繁育的螟黄赤眼蜂和黏虫赤眼蜂共寄生柞蚕卵后的羽化率最高，单卵可羽化黏虫赤眼蜂31.7头；（4）赤眼蜂羽化后的蜂龄明显影响两种赤眼蜂对柞蚕卵的共寄生作用，同羽化当天的玉米螟赤眼蜂相比，羽化3d的玉米螟赤眼蜂与螟黄赤眼蜂共寄生柞蚕卵，表现出更强的竞争作用和适应性，寄生率由20%增加到76%。本研究为尝试开发基于柞蚕卵的“一卵多蜂”技术提供理论基础，有利于开创基于柞蚕卵为中间繁育寄主的赤眼蜂繁育与利用新模式。