Inbreeding in the coffee berry borer,Hypothenemus hampei(Coleoptera: Scolytidae) estimated from endosulfan resistance phenotype frequencies

Abstract

An estimate of the inbreeding coefficient,F_IS, of the coffee berry borer,Hypothenemus hampeiFerrari, was calculated from genotype frequencies of endosulfan resistance in beetles collected from berries in 41 different fields on the East Coast of New Caledonia. Two different estimates were obtained as a function of sampling date:F_IS=0.491 ± 0.059 (s.e.) for samples collected in September, andF_IS=0.215 ± 0.108 for samples collected in April. These values ofF_ISare very high in comparison to those of most insects, but surprisingly low given current understandings ofH. hampeimating patterns. The difference between April and September F_ISestimates is discussed in terms of insecticide regimes and seasonal variability of sib inbreeding levels. The high level of inbreeding in the coffee berry borer increases frequencies of homozygotes relative to heterozygotes. Inbreeding will accelerate resistance evolution whenever the fitness of homozygous resistant insects exceeds that of heterozygotes, and will undermine any high-dose strategy to control resistance evolution.