大气CO2浓度升高对森林食叶昆虫的潜在影响

评述了大气CO₂浓度升高对森林食叶昆虫的影响，昆虫对森林取食为害水平的潜在变化，以及研究中的主要实验方法.大气CO₂浓度升高通过引起叶片化学变化进而影响食叶昆虫个体的取食和生长；但物种对环境变化反应的特异性、植物化学对高浓度CO₂的反应强度、昆虫对植物生理变化的敏感性和适应性、研究周期的长短、其它环境因子的协同效应以及不同实验中植物生长条件和研究方法的差异均将影响昆虫反应的方向和强度；CO₂气体浓度增高本身可能不足以对食叶昆虫个体的新陈代谢构成影响；大气CO₂浓度升高也可能影响森林食叶昆虫种群的大小.

Potential effects of elevated carbon dioxide on forest leaf-feeding insects

Elevated atmospheric CO_2 concentration may result in a decline of leaf nutritional quality(especially N) and an increase in some kinds of defensive secondary components such as phenolic compounds.The changes in tree phytochemistry,combined with the effects of elevated CO_2 per se,have a potential impact on leaf-feeding insects.This paper reviewed the effects of elevated CO_2 on the performance of leaf-feeding forest insects at individual level and community level.The elevated CO_2 per se had very little influence on the metabolism of insect.Over half of the tree-insect experimental system showed that under high CO_2,the performance of individual insect became poorer,while the others showed that insect had little or no response to the treatments.The direction and magnitude of the changes in insect performance could be affected by various factors,and the effects of treatments were strongly species-dependant.The magnitude of the changes in phytochemistry,the sensitivity and adaptive capacity of insect to poorer leaf quality,the differences in plant growth conditions and experimental methods,and the mediated effects of other environment factors,e.g.,soil NO_3~-,light,temperature,and O_3,were all closely related to the final performance of insect.But,the larvae's consumption usually increased under enriched CO_2 treatment,which was widely thought to be a compensatory response for poorer plant quality.The experiments on forest community level found identically a reduction in herbivory,which was contrary to the results from small-scale experiments.The change of insect population and the true response of consumption by leaf-feeding forest insects under CO_2 enrichment environment remain unclear,and more field-based experiments need to be conducted.