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 melanogaster was cloned and sequenced in the scolytid beetle Hypothenemus hampei, a coffee pest resistant to cyclodiene insecticides in New Caledonia. The amino acid sequence of the Rnl exon no. 7 protein product in H. hampei was identical to that in D. melanogaster and showed the same amino acid change as that characterizing susceptible vs. resistant D. melanogaster. Samples from natural H. hampei populations (from Asia, the Pacific Islands, Africa and Central America), from reference susceptible (S) and resistant (R) laboratory strains, and from their hybrid progenies, were analysed at the Rdl locus using single-stranded DNA conformation polymorphism on polymerase chain reaction products. The susceptible allele was the only allele present in all samples from natural populations except in the only resistant population known to date (Ponerihouen, New Caledonia). Females and some males obtained as F-1 from RxS crosses were heterozygous at the Rnl locus, confirming that this local mate competing species is diplo-diploid.