蝗虫种群密度对牧草生长与损失量的影响

在贺兰山东麓天然草地，以黄胚小车ｅｄａｌｅｕｓ ｉｎｆｅｒｎａｌｉｓ Ｓａｕｓｓ为对象，进行了不同植物群落组成下不同蝗虫密度对牧草生长和损失影响的测定。田间笼养供试成虫，以实际取食日计取食时间，用目测法和收获法进行牧草生长量测定，用相关方差分析进行数据处理。结果表明；蝗虫取食对牧草生长的影响具有双重作用，在低密度时，有利于禾本科牧草的生长，随着种群密度的增多，对禾本科牧草的过量取食，会导致杂草增长

THE EFFECTS OF GRASSHOPPER POPULATION DENSITY ON THE GROWTH OF GRASS AND FORAGE LOSS IN NATURAL GRAZING GROUND

The effects of population density of Oedaleus infernalis Sauss. ,the designated target insect, on the growth of grass complex and forage loss under different plant community compositions were studied in a natural grazing ground at the eastern foot of Alashan Mountain. The test adults of O. infernalis were reared in field cages, to use the number of feeding days as feeding time and apply ocular estimation and actual mowing for determining the increment of grass. The results of correlation variance analysis showed that there were double roles of the feeding of grasshopper on the growth of grass. Under low density of grasshopper,its feeding was beneficial to the growth of forage grass, while under excessive damage of its high density population, the rank grass became more and more overgrown, and the quality of pasture ground decreased with the increace of grasshopper density. The community structures of plants. The timely precipitation in growing season has promoted the growth of various plants and reduced the damage of gress hopper.