中文摘要：

利用扩散系数（C）和离散分布的理论拟合，对越北腹露蝗Fruhstor feriola tonkinensis 1～5龄若虫的田间调查数据进行分析．结果表明，各龄蝗蝻均呈聚集分布，1～5龄蝗蝻的C分别为879．578、152．742、22．972、6．053和6．150，1龄蝗蝻聚集度最高，3龄后开始扩散．1～3龄蝗蝻的空间格局可用Neyman A型分布拟合，4～5龄可用负二项分布拟合，即1～3龄呈核心分布，4～5龄演变为嵌纹分布．1龄蝗蝻平均每个聚团的个体数（m2）为878头，2～3龄调查范围内的平均蝗团数（m1）增加，平均每蝗团的个体数（m2）减少．4～5龄聚团瓦解．

英文摘要：

The index of dispersion （C） and probability distributions fitting were applied to study the spatial pattern of nymphs of Fruhstorferiola tonkinensis in mulberry field. The results showed that the spatial distribution patterns were aggregated in all instars of the nymph. The dispersion indexes of the nymphs were 879.578, 152.742, 22. 972, 6.053 and 6.150 from the 1^st to 5^th instar, respectively. The spatial distribution pattern of the 1st to 3^rd instar nymphs were fitted to Neyman type A distribution, and the 4^th and 5^th instar nymphs turned into the negative binomial distribution. In the 1^st instar nymph, the number of individuals per cluster （ m2 ） was 878, and the number of clusters per unit （ m1 ） from the 2^nd to 3^rd instar was increased and m2 was decreased. The cluster was crashed in the stages from the 4^th to 5^th instar.