RELATIONSHIP BETWEEN CHROMOSOMAL TRANSLOCATION AND ESTERASE ACTIVITY ASSOCIATED WITH INSECTICIDE RESISTANCE IN THE GREEN PEACH APHID, MYZUS PERSICAE

摘要

Karyotype of ten aphid clones, eight malathion-resistant and two -susceptible, was examined in relation to esterase activity toward α-naphthyl acetate. The two susceptible clones showed normal karyotype and had low esterase activity, while six resistant clones showed chromosomal translocation between A1 and A3 and exhibited high esterase activity at varying degrees. There was one resistant clone, however, which showed normal karyotype despite having high esterase activity. Another resistant clone consisted of a mixture of individuals showing normal and translocated chromosomes. A 229 fold difference was observed in esterase activity between the lowest (0.83 nmol/min/ aphid) and the highest (190 nmol/min/aphid) individuals.