Abstract: There is a great spatiotemporal variability in the feeding level of folivorous insects in forest canopy. This paper discussed the significance of quantitatively determining the feeding level of folivorous insects in forest canopy, introduced the related approaches, including sampling design and leaf area analysis, and analyzed the advantages and disadvantages of each of the approaches. Comments were given to the related researches in China. The research approaches for quantitatively estimating this feeding level were categorized as the approaches based on green leaf samples and those based on fallen leaf samples, and the sampling techniques were classified as canopy-based and ground-based. The approaches based on green leaf samples included destructive leaf sampling and in situ continuous observation; while those based on fallen leaf samples were to collect the fallen leaves within forest stand, measure the percentage of leaf area lost, and then, estimate the feeding level at forest stand scale. Three key research areas related to the feeding level of folivorous insects in forest canopy were proposed.

Key words: Climbing plant, Morphological plasticity, Biomass allocation, Momordica charantia