森林生态系统中植食性昆虫与寄主的互作机制、假说与证据

Abstract

This paper analyzed the concepts,different mechanisms of herbivorous insect-host interactions and hypotheses based on their academic origins and recent experimental evidence.The theories we analyzed include diversity-stability mechanism,associational resistance hypothesis,associational susceptibility hypothesis,plant vigor hypothesis,plant stress hypothesis,bottom-up forces,top-down forces,and push-pull mechanism,etc.Diversity-stability mechanism focuses on functioning of forest ecosystem that is developed using evidence collected at community and landscape scale.Associational resistance and associational susceptibility is a resistance type of diversity-stability.The foundation for associational resistance hypothesis was built based on resource concentration hypothesis and natural enemy hypothesis.The resource concentration hypothesis predicted that herbivores were more likely to be found in patches where their host plants were abundant.The enemy hypothesis can explain why herbivores are fewer in forest ecosystems with a more abundant and diverse community of natural enemies.This was consistent with the diversity-stability hypothesis,which predicts that a community becomes more stable with higher diversity.These theories were easily understandable at population scale.Bottom-up forces and Top-down forces discuss the interaction between herbivorous insects and host plants along the food chains,in which bottom-up refers to restriction mechanism caused by resources on the bottom of food web while Top-down refers to natural enemies on the top of food chain.Therefore,there was a corresponding relationship between resources concentration hypothesis and bottom-up forces,and enemy hypothesis corresponds to top-down forces.Plant vigor hypothesis and plant stress hypothesis predict that herbivores tend to select host plants based on their growth conditions population size.The above herbivore-host interaction theories are proposed based on different levels in a forest ecosystem,which might result in different conclusion due to the differences in ecosystem levels.This paper then elaborated the guiding roles of these theories on forest pest control based on recent progresses.Among these theories,Associational resistance and associational susceptibility may be applicable to guide forest management,specifically forest pest control.The evidence suggested that associational resistance and associational susceptibility interactions may be mediated by biotic and abiotic mechanisms.However,there were few studies on how habitats,the spatial and temporal availability of resources determine landscape-level impacts of associational resistance and associational susceptibility,and how the strength,consistency,and relative impact of associational resistance and associational susceptibility on plant fitness vary temporally and spatially as environmental conditions,herbivore and plant abundance change.These are the questions urgently needed to be answered in this field.