摘要：Body size of animals is an important feature. It is not only correlated with many life history and ecological traits,but also may reflect the species’ richness. The authors conducted statistical analysis through body size data of Acridoidea,Catantoidae,Arcypteridae,and Acrididae. The results showed the species’ body size distributions,all of this four taxa significantly skewed to the right,there are many modal-size species,a sharp decline in the number of small species, and there are more large species with a long thin tail of a few larger species. The skewness was from 1. 060 8 to 1. 696 1 with Catantoidae,the biggest and Acrididae,the smallest. In china this vast territory, the species’ body size distribution of grasshopper in the family level highly skewed to the right,that was the mode near smaller species (less than mean and median),while the species cumlative frequency smaller than mode distributed less than mean. In other words,in the given taxon the smaller species number was less than the larger. This conclusion was quite reliable. The reasons may be related to speciation and evolution of the species. It is generally accepted that in the animal phylogeny speciation usually begins from small species and evolve from small to large.%物种的身体大小是动物的一个重要特征.身体大小的频数分布很少呈正态分布或偏左分布,往往为偏右分布,研究的类群主要是在陆生哺乳类和鸟类.选择中国蝗虫(蝗总科,斑腿蝗科,网翅蝗科和剑角蝗科),在科级水平上检验这些单元的物种身体大小频数分布的正态性.结果表明它们都呈现为高度的偏右分布,即中等大小的种类很多,小的种类的数量急剧减少,大的种类分布得多且具有矮的长尾.斑腿蝗科的偏斜度最大为1. 696 1,剑角蝗科最小为1. 060 8.中国的地理区域很大,蝗虫身体大小的分布呈现出偏右分布,众数靠近较小种类(小于平均值和中位数);物种小于众数的累积频数(面积)小于平均值或中位数的左边的累积频数(面积).也就是说,在一个给定的蝗虫科级单元,小的物种数比大的少,其原因可能与物种的形成和演化有关.在动物的系统发育谱系中,物种形成常常从小的开始,并且按从小到大的趋势演化.
