A STUDY ON THE SPATIAL DISTRIBUTION PATTERN OF LARVAE FRASS-DROP OF DENDROLIMUS PUNCTATUS AT LOW DENSITY POPULATION

Frass-drop and characteristics of spatial distribution patterns of the larvae of Dendrolimus punctatus in low population were studied by means of Frequency Distribution, Iwao's and Taylor's method, and some other aggregation indices. The result shows that:(1) The spatial distribution pattern of the overwintering larvae was aggregated, and the basic components of the distribution were single individuals which repel each other, and that of the frass-drop in the same generation tended to be uniform.(2) In the second generation, both larvae and the frass-drop were spatially aggregated, and the degrees of aggregation were higher than that of the overwintering generation. The experimental data were transformed seperately with three methods, among which the Iwao's method is the best for frass-drop data.