寄主植物-害虫-天敌三营养层系统相互作用的上行控制

寄主植物-害虫-天敌三营养层相互作用的重要性、害虫数量被其天敌所调节(下行控制)、寄主植物的物理和化学特性直接和间接影响害虫和其天敌的多度及分布(上行控制)已是生态学界活跃的研究主题。在不同的陆地生态系统中,作为害虫种群数量控制因子,寄主植物资源的上行控制可能比天敌的下行控制更普遍。寄主植物的基础营养物质、诱导产生的次生代谢物质和形态特征影响害虫的生理和行为,依次决定害虫的生殖、寿命和存活,直接控制害虫种群数量动态;影响天敌的行为和适合度,间接控制害虫种群数量动态。

Bottom-up Effect of the Tritrophic System Interactions Among Host Plants, Phytophagous Insects and Natural Enemies

The importance of the role of tritrophic interactions among host plants, phytophagous insects and natural enemies, herbivore numbers regulated by their natural enemies (top-down forces), and host plant physiological and chemical characteristics influencing directly or indirectly on population abundance and distribution of herbivores and their natural enemies (bottom-up forces) have been an active theme in ecology. Bottom-up control from host plant resources may be more common as a factor of regulating herbivore insects than top-down control from natural enemies in a variety of different terrestrial systems. Variation in host plant quality, such as basic nutrient substances, induced secondary metabolism substances and morphological characters, impacts on the physiology and behaviour of herbivore insects, which, in turn, determines their life-history parameters such as fecundity, longevity and survival, all directly relevant to their population dynamics; influences on the performance and fitness of their natural enemies in cascading up, resulting in indirectly suppressing the abundance of herbivore insects.