针茅及羊草对亚洲小车蝗生活力影响的定量分析

Quantitative analysis of the effects of Stipa krylovii and Leymus chinensis on the factors of vitiality of Oedaleus decorus asiaticus

亚洲小车蝗是内蒙古草原主要优势种害虫,主要取食针茅、羊草等禾本科植物,植物种类对其生长发育影响可反映蝗虫群落与植物群落的关系。采用室内饲养与野外笼罩的方法,进行了不同生境亚洲小车蝗3个密度处理生活力指标定量分析,结果表明,针茅喂养的亚洲小车蝗雌虫相对生长率高于羊草。植物盖度和虫口密度是影响亚洲小车蝗生活力的主要因素。当针茅盖度<25%时,亚洲小车蝗生活力随盖度增加而缓慢增长,当针茅盖度>25%时,生活力增长较快。当羊草盖度<25%时,亚洲小车蝗生活力随盖度增加而逐渐减小,当羊草盖度>25%时,生活力随盖度增加而增长,且在针茅样地的生活力高于羊草样地。当亚洲小车蝗密度<18头/m2时,生活力随密度增大而增大。在牧草布局时应合理调整针茅、羊草盖度,监测蝗虫密度,预防蝗虫爆发。以上结果为草场植被的合理布局提供了参考,同时也为减少亚洲小车蝗危害提供了依据。

Oedaleus decorus asiaticus, mainly feeding on graminaceous, is one of most harmful grasshopper species in the Inner Mongolia. The effects of plant species on the growth and development of grasshopper reflect relationship between plant communities and grasshopper communities. In this study, by applying both the fields net and indoor independent feeding method, we compared the vitality index of three groups of O. asiatic- us with different population densities, and quantitatively analyzed the effect of Stipa krylovii and Leymus chinensis on the growth and development of O. asiaticus. The result indicated that the relative growth rate of female which feed on S. krylovii is higher than which feed on L. chinensis. The plant coverage and the popula- tion density are main factors to affect the vitality of O. asiaticus. When the coverage of S. krylovii less than 25%, the vitality value increased slowly with the increase of coverage, when the coverage more than 25%, the vitality value increased rapidly. When the coverage of L. chinensis less than 25%, the vitality value decreased with the increase of coverage,when the coverage more than 25%, the vitality value positively related with the coverage. The vitality of O. asiaticus in S. krylovii is better than in L. chinensis. We also found that when density of grasshopper is less than 18 heads/m2 , the vitality value increases with the density. When we plant grass should adjust coverage of S. krylovii and L. chinensis, monitor density of O. asiaticus. The results pro- vide an operational base for the rational distribution of grassland and harm reduction of grasshopper.