Selective predation of Sphedanolestes impressicollis on preys
环斑猛猎蝽对猎物的选择捕食作用

A laboratory study was made on the selective predation of female Sphedanolestes impressicollis adults on Ostrinia furnacalis and Chaitophorus populialbae. The results showed that when the second and third instar larvae of O. furnacalis coexisted, the female S. impressicollis adults had positive preference to O. furnacalis but no preference to C. populialbae in all degrees of total prey densities. The female S. impressicollis adults also showed different switching to O. furnacalis in different degrees of total prey densities, i.e., no switching in the density of 60 and 90 individuals per canned food bottle, and negative switching in the density of 120. However, the female adults had negative switching to C. populialbae in the density of 60 and 90, and no switching to C. populialbae in the density of 120. When the second and third instar larvae of O. furnacalis and C. populialbae coexisted, the female S. impressicollis adults had positive preference and positive switching to the third instar of O. furnacalis, but negative preference and negative switching to C. populialbae in the total density of 90.