Abstract: Samples of Echinocnernus squameus from 36 paddy fields are analyzed to determine its population spatial pattern in terms of pattern parameters I,C_A、I_δ、m^*/m, α and β. Anegative binomial distribution with common k values is shown for both larvae and adults when the average density of adults X ≥0.6 head per quadrat (1 quadrat=0.5m²) and a complete randomness is found for adults when X <0.6 head per quadrat. The dynamics of adult patchiness, such as patch size and occupied area, seems to be related with average density. The population aggregation is influenced by environmental heterogeneity when the average density is low, but mainly determined by its own behavioral custom when the density is relatively high. The aggregation intensity of larvae population and the overwintering mortality will increase with increasing intensity of tillage.

Key words: Echinocnemus squameus, Population spatial pattern, Minimum and no tillage, state-space method, optimum population, carrying capacity, Jilin Province.