SINGLE-STRANDED-DNA CONFORMATION POLYMORPHISM AT THE RDL LOCUS IN HYPOTHENEMUS-HAMPEI (COLEOPTERA, SCOLYTIDAE)

The homologue of the resistance to dieldrin gene (Rdl) in Drosophila m elanogaster was cloned and sequenced in the scolytid beetle Hypothenem us hampei, a coffee pest resistant to cyclodiene insecticides in New C aledonia. The amino acid sequence of the Rnl exon no. 7 protein produc t in H. hampei was identical to that in D. melanogaster and showed the same amino acid change as that characterizing susceptible vs. resista nt D. melanogaster. Samples from natural H. hampei populations (from A sia, the Pacific Islands, Africa and Central America), from reference susceptible (S) and resistant (R) laboratory strains, and from their h ybrid progenies, were analysed at the Rdl locus using single-stranded DNA conformation polymorphism on polymerase chain reaction products. T he susceptible allele was the only allele present in all samples from natural populations except in the only resistant population known to d ate (Ponerihouen, New Caledonia). Females and some males obtained as F -1 from RxS crosses were heterozygous at the Rnl locus, confirming tha t this local mate competing species is diplo-diploid.