典型草原三种蝗虫种群死亡率和竞争的研究

Study on the Mortality and Competition of Three Dominant Grasshoppers (Orthoptera:Acrididae) in the Steppe

通过田间罩笼试验研究内蒙古典型草原3种蝗虫成虫种群死亡率和竞争。供试蝗虫分别为:亚洲小车蝗(Oedaleus asiaticus B.Bienko),宽须蚁蝗(Myrmeleotettix palpapis(Zub.))和短星翅蝗(Calliptamus abbreviatusIkonn.)。结果表明:亚洲小车蝗和宽须蚁蝗食性相似,喜食禾本科牧草,而短星翅蝗则喜食菊科牧草,为了获取更多食物,短星翅蝗种内竞争强于亚洲小车蝗和宽须蚁蝗;30 d后在3种密度(24、16、8头/m2)下,亚洲小车蝗存活数均高于另两种,其竞争也强于另两种;3种蝗虫24头/m2死亡率均高于80%,其中短星翅蝗达86%,说明在高密度下有很强的种内竞争,随着密度的减少死亡率降低,种内竞争也随之减少;3种蝗虫混养时,亚洲小车蝗和宽须蚁蝗的死亡率比在单种时有所降低,而短星翅蝗死亡率比单种时则有所增加,表明亚洲小车蝗和宽须蚁蝗有较强的种间竞争,短星翅蝗的竞争较弱。

The three dominant species of adult grasshoppers, Oedaleus asiaticus B. Bienko, Myrmeleotettix palpapis （Zub.）, and Calliptamus abbreviatus Ikonn, were studied for their mortality and competition by field cage method in Inner Mongolian Steppe. The results showed that O. asiaticus and M. palpapis had similar food preference of gramineous forages while C. abbreviatus prefered composite forage. In order to obtain more food, C. abbreviatus had stronger intraspecific competition than O. asiaticus and M. Dalpapis. O. asiaticus showed stronger competition ability and its survival numbers were more than that of other two species under the different feeding densities （24, 16, and 8 grasshoppers per m^2） in cages after 30 days. Meanwhile, the mortality of the three species were higher than 80% at the feeding density of 24 grasshoppers per m^2 , up to 86% for C. abbreviatus, which proved that there had been a strong intraspecifie competition at high densities and the mortality decreased along with the densities falling off. In mixed feeding of 3 grasshopper populations, the mortality of O. asiaticus or M. palpapis was lower than that of single species feeding, but C. abbreviatus was higher, which showed that O. asiaticus and M. palpapis had stronger interspecific competition ability than C. abbreviatus.