Abstract: The interaction between the changes of some chemicals (amino acids andsecondary metabolites) in damaged pine needles and the population parameters of pine caterpillars, Dendrolimus punctatus Walker, was explored in this paper. The results showed that: (1) less amino acids and more tannins and phenolics were detected to change in pine needles after fed by pine caterpillar; (2) slower development, lighter weight, less fecundity, high mortality and higher activity of detoxification enzymes (peroxidase and carboxylesterase activity) were found in pine caterpillar population as fed ondamaged pine needles.

Key words: damaged pine needles, Dendrolimus punctatus, interaction