INDIVIDUAL VARIATION IN 2 HOST PLANTS OF THE LADYBIRD BEETLE, EPILACHNA-PUSTULOSA (COLEOPTERA, COCCINELLIDAE)

Individual variation in two species of host plants (thistle, Cirsium k amtschaticum, and blue cohosh, Caulophyllum robustum) of the herbivoro us ladybird beetle Epilachna pustulosa was examined under laboratory c onditions for their acceptability to adult beetles as a food resource, for adult preference and for larval performance. When clones of these plants were subjected to non-choice tests using posthibernating femal e beetles, there was found to be significant intraspecific variation a mong clones in terms of their acceptability, but interspecific variati on was not detected. Significant intraspecific as well as interspecifi c variation were frequently detected in the two host plants when clone s of these plants were subjected to choice tests using posthibernating female beetles, the magnitude of interspecific plant variation for be etle preference is not necessarily larger than that of intraspecific p lant: variation. Individual variation across plant species with respec t: to beetle larval performance was also significant. A positive corre lation between adult preference and larval performance is suggested ac ross the two taxonomically remote host plant species, thistle and blue cohosh, although this needs further investigation.