Abstract: A huge variety of Phytophagous insects live on Castanopsis sclerophylla leaves.In order to study relationship between insects and plants in island habitats,a survey was carried out of intensity and patterns of Castanopsis sclerophylla leaf eating by insects on several isles in the Qiandao Lake,Zhejiang Province.A total of 16 leaf-eating patterns were identified,varying in frequency.In terms of frequency and damage of leaves,edge defoliation,excavating defoliation,top defoliation,lower epidermis defoliation and middle vein defoliation were the most important types damaging leaves of Castanopsis sclerophylla.Results of correlation analysis show that among the 16 patterns significant positive correlations were found between six pairs.About 84% of the Castanopsis sclerophylla leaves were damaged as a result of leaf-eating by insects,but the damage mostly was not serious.