山西省阳高县不同月份草地蝗虫的数量变化研究

Studyon population dynamics of grasshopper in different months in Yanggao County of Shanxi Province

研究了山西省阳高县4~9月草地蝗虫发生规律和数量。结果表明：4、5月蝗虫群落以各龄级的若虫为主,数量较多,且几乎只分布在茭蒿草原和狗牙根草甸中,说明这两类生境是上年蝗虫的主要产卵地和当年幼虫的主要栖息地；5月比4月数量略有下降,但5月以后数量呈逐渐增加趋势,7月底数量最多、密度最大,之后数量呈逐渐减少趋势,9月的数量最少、密度最小；逐月进行 F 测验,结果表明：4、5、6、7、8月各样本之间的虫口密度差异均达到极显著水平（P 〈0.01）,9月各样本之间的虫口密度差异为显著水平（P 〈0.05）；标准误差普遍较小,表明研究抽样误差较小,样本统计量与总体参数的值比较接近。

Based on the investigation of population density of grasshopper in Yanggao County of Shanxi Province during April to September,the population dynamics and its influencing factors were analyzed.The re-sults showed that the nymphs of each age class dominated in April and May,and only distributed in Artemisia giraldii grassland and Cynodon dactylon meadow,which suggested that the two types of habitat was the main spawning and the reproduction habitats;During the end of April to the end of May,the number decreased slight-ly,from the end of the May to the end of July the number increased gradually,which reached the peak at the end of July,then gradually reduced,and reached the lowest in September;F test showed that the population density difference among April,May,June,July,August and September was significant （P ＆lt;0.05）.