Cascade effects of crop species richness on the diversity of pest insects and their natural enemies

• 作 者: SHI PeiJian HUI Cang MEN XingYuan ZHAO ZiHua OUYANG Fang GE Feng JIN XianShi CAO HaiFeng LI B.Larry
• 机 构: State Key Laboratory of Integrated Management of Pest Insects and Rodents in Agriculture,Institute o
• 出 处: Science China(Life Sciences)
• 发表日期: 2014年07期
• 关键词: richness highlight cascade trophic Species Sampling ecology parasitic crops conn

Understanding how plant species richness influences the diversity of herbivorous and predatory/parasitic arthropods is central to community ecology.We explore the effects of crop species richness on the diversity of pest insects and their natural enemies.Using data from a four-year experiment with five levels of crop species richness,we found that crop species richness significantly affected the pest species richness,but there were no significant effects on richness of the pests’natural enemies.In contrast,the species richness of pest insects significantly affected their natural enemies.These findings suggest a cascade effect where trophic interactions are strong between adjacent trophic levels,while the interactions between connected but nonadjacent trophic levels are weakened by the intermediate trophic level.High crop species richness resulted in a more stable arthropod community compared with communities in monoculture crops.Our results highlight the complicated cross-trophic interactions and the crucial role of crop diversity in the food webs of agro-ecosystems.

Understanding how plant species richness influences the diversity of herbivorous and predatory / parasitic arthropods is central to community ecology. We explore the effects of crop species richness on the diversity of pest insects and their natural enemies. Using data from a four-year experiment with five levels of crop species richness, we found that pest species richness, but there were no significant effects on richness of the pests’natural enemies.In contrast, the species richness of pest insects significantly affected their natural enemies.These findings suggest a cascade effect where trophic interactions are strong between adjacent trophic levels are connected but nonadjacent trophic levels are weakened by the intermediate trophic levels. High crop species richness resulted in a more stable arthropod community compared with communities in monoculture crops. Our results highlight the complicated cross-trophic int eractions and the crucial role of crop diversity in the food webs of agro-ecosystems.