Intraspecific and interspecific competition among three grasshopper adults in the middle of Qilian Mountain

The intraspecific and interspecific competition among the adults of three grasshoppers,Angaracris rhodopa,Oedaleus decorus asiaticus and Chorthippus fallax were studied by field cage method.The results showed that A.rhodopapreferred to feverfew while O.decorus asiaticus and C.fallaxto gramineous plants.A.rhodopahad stronger intraspecific competition than O.decorus asiaticus and C.fallax.The interspecific competition between A.rhodopaand O.decorus asiaticus or C.fallax was weak while competition between O.decorus asiaticus and C.fallax was strong.Intraspecific competition among three species was strong at high densities and decreased along with the densities down.In mixed feeding of two or three grasshopper populations,the mortality of A.rhodopawas higher than that of O.decorus asiaticus or C.fallax,which showed that interspecific competition was asymmetric.