Toxicological and genetical studies of organophosphorus-resistance in Cimex lectularius L

Abstract

A range of insecticides were tested on a resistant strain of bed-bugs (Cimex lectularius L.) from Israel. Resistance was restricted to organophosphorus compounds. Only some of the phosphorothioate compounds were involved, but there was no simple indication of the resistance mechanism on basis of structure of the compounds.Nine malathion analogues were tested on the bed-bugs, and relative levels of resistance to them compared with insect strains specifically resistant to malathion. Distinct differences in the bed-bug spectrum suggested that a carboxyesterase was not solely responsible for resistance. This was further supported by the ineffectiveness of triphenylphosphate against malathion-resistance in the bugs.The F1 progeny from reciprocal mass crosses were tested with malathion. Their response, in both cases, resembled the susceptible type, indicating a recessive autosomal character, a result unique in organophosphorus-resistance. Tests on F2 and backcrosses indicated that a single gene was responsible. Results using fenchlorphos were quite similar and probably the same gene (and mechanism) is involved.