多寄主型寄生性天敌昆虫的寄主适应性及其影响因素

Host adaptations of the generalist parasitoids and some factors influencing the choice of hosts

寄生性天敌昆虫对不同寄主资源的适应能力是其存活和繁殖的必要条件,它们的寄主选择行为则是其重要的适应结果。多寄主型寄生性天敌昆虫虽然对某种特定寄主资源的利用效率可能不如单寄主型寄生蜂,但却有利于拓展更宽的寄主范围,因此对环境的适应能力更强,更容易在自然界维持其种群的生存。统计结果也表明多寄主型天敌的生物防治效果往往比专食性天敌更高。有时生物防治成功的关键可能并不在于所利用的天敌种类的不同,而在于天敌的不同生物型或地理宗。总结了多寄主型寄生性天敌昆虫的寄主适应能力及其影响因素。寄生性天敌昆虫不仅因地理隔离产生种群分化,也可能因寄生不同的寄主产生种群内的分化,从而更加适应寄主的生活特性和栖境条件。寄主种类、寄主发育阶段、寄主大小、寄主营养、寄主免疫反应、寄主逃避反应、其它天敌的竞争、寄主共生或共栖生物的存在、寄主植物、天敌自身的学习能力及其共生微生物等多种因素对寄生性天敌昆虫的寄主适应性可产生影响。展望了多寄主型寄生性天敌昆虫对新寄主资源的拓展利用能力和适应性在生产上的可能应用前景和途径,以期为明确天敌与寄主间的互作关系,人工驯化寄生性天敌昆虫增强对靶标害虫的控制作用,合理利用天敌提高生物防治效率提供新的思路和理论支持。

Adaptations of parasitoids to fluctuating host resources are essential for their survival and reproduction. Among these adaptations,host selection behaviors have important consequences for adapting to an ever changing environment. Generalists parasitoids are perhaps less efficient at discovering and using one particular host resource compared to specialists,but they have the advantage of exploiting a wider range of host resources. When one host population is at low density,generalist parasitoids have ability to maintain a relative high population density on other hosts. The effectiveness of biological control statistically tends to be higher when the agents used are generalists than when they are specialists. Sometimes the key to successful biological control may not lie in discovering another species,but instead may rely on the use of different biotypes or geographic races of biocontrol agent. The present paper summarizes the host adaptations of generalist parasitoids and some factors influencing the choice of hosts. Parasitoids will differentiate among populations of themselves not only due to geographic isolates,but also duo to different hosts they parasitized for better adaptations to some particular attributes of hosts＇ life and the microhabitats therein. The selection by parasitoids of which species to use as hosts is influenced by multiple factors such as host species,host developmental stages,host sizes,host nutrition,host immunoreactions,host escape responses,competition from other natural enemies,presences of host associated symbionts or mutualists,host plants,learning behaviors of parasitoids,and symbiotic microorganisms of parasitoids,etc. In addition,the potential utilization of novel host resources,the mechanisms of exploitation,and host adaptations of generalist parasitoids are discussed. This discussion may provide new ideas and theoretical support for improving biological control efficiency by enhancing our understanding on host-parasitoid interactions and artificially selecting for novel parasitoid/host relationships for augmenting the management of target insect pests.