Abstract: This study aims to analyze the relationship between population density of the long-horn beetle, Monochamus alternatus Hope and environmental factors. In ten standard monitoring sites in pine forest of Wuyishan Scenic Spot, six density indices and seven environmental factors were sampled and the survey results were analysed corresponding to the coordinate transformation. The results showed that altitude (Y1) had a positive effect on the six density indices, while canopy size (Y6) and ground cover area (Y7) had negative effects on them. Tree age (Y2) and height (Y3) and slope position (Y4) also had positive but not significant effects. Slope position (Y5) mostly was not closed with the index. The population densities of larvae (X1), female adults (X2) and adults at the lower layer (X5) were most susceptive to the environmental factors, followed by the population densities of male adults (X3), and adults at the canopy (X4). The adult catches in trap were the most insensitive to the environmental factors. It is so concluded that the effect of environmental factors on population densities of M. alternatus is significant but different.

Key words: Monochamus alternatus, Pinus massoniana, population density, environmental factor, correspondence analysis by coordinate transformation