Bidefin of Enfomofogical'Research (1996) 86, 667-674 Inbreeding in the coffee berry borer, Hypothenemus hampei (Coleoptera: Scolytidae) estimated from endosulfan resistance phenotype frequencies D. Pierre Gingerich Section of Ecology and Systematics, Cornell University, Ithaca, New York, USA Philippe Borsa* ORSTOM, Institut Français de Recherche Scientifique pour le Développement en Coopération, Nouméa, New Caledonia D. Maxwell Suckling Horticulture and Food Research Institute of New Zealand Ltd., Lincoln, Christchurch, New Zealand Luc-Olivier Brun Développement en Coopération, Nouméa, New Caledonia ORSTOM, Institut Français de Recherche Scientifique pour le L~, Abstract An estimate of the inbreeding coefficient, FIS, of the coffee berry borer, Hypotkerzemus kainpei Ferrari, 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 Gf sampling date: Fls=0.491 & 0.059 (s.e.) for samples collected innSeptember, and F,s=0.215 10.108 for samples collected in April. These values of FIS are very high in comparison to those of most insects, but surprisingly low given current understandings of H. kanzpei mating pattems. The difference between April and September FIS estimates is discussed in terms of insecticide regimes and seasonal __- - -va;iability 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 _ I i] , I i _-- !.) l I -* exceeds that of heterozygotes, and will undermine any high-dose strategy l resistance evolution. 010010071 667 Correspondence: D.P. Gingerich, Section of Ecology and Systematics, Corson Hall, Come11 University, Ithaca, New York 14853, USA. "Present address: ORSTOM UR 33-Zoologie. B.P. 5045,34032 Montpellier cedex 1, France. I Documentaire ORSTOM