Temporal and Spatial Dynamics of Cicadulina bipunctella Natural Populations
二点叶蝉自然种群的时空动态

The K value of negative binomial distribution less affected by density was chosen to describe the spatial and temporal patterns of the natural population of Cicadulina bipunctella (Mats) at three elevations.Spatial distribution information of the population showed either clumped (aggregated) or uniform patterns during the period of maize growth.The population of C.bipunctella distributed uniformity (K<0) at the last twenty days in April,and spatial aggregation (K>0) in May,then dispersal (K<0) from the first ten-day period to the middle ten days of June and aggregation (K>0) again from the last ten-day period of June to the first ten-day period of July.The high elevation had the highest degree of aggregation in May,followed by the low elevation from the last ten-day of June to the first ten-day of July according to the K values.Based on the coefficients of Taylor's power law and Iwao's M *-X regression,the degree of aggregation of the high elevation and the middle elevation were higher than the low elevation during the whole period of maize growth.