Dp. Gingerich et al., INBREEDING IN THE COFFEE BERRY BORER, HYPOTHENEMUS-HAMPEI (COLEOPTERA, SCOLYTIDAE) ESTIMATED FROM ENDOSULFAN RESISTANCE PHENOTYPE FREQUENCIES, Bulletin of entomological research, 86(6), 1996, pp. 667-674
An estimate of the inbreeding coefficient, F-IS of the coffee berry bo
rer, Hypothenemus hampei Ferrari, was calculated from genotype frequen
cies of endosulfan resistance in beetles collected from berries in 41
different fields on the East Coast of New Caledonia. Two different est
imates were obtained as a function of sampling date: (F) over cap(IS)=
0.491+/-0.059 (s.e.) for samples collected in September, and (F) over
cap(IS)=0.215 +/- 0.108 for samples collected in April. These values o
f (F) over cap(IS) are very high in comparison to those of most insect
s, but surprisingly low given current understandings of H. hampei mati
ng patterns. The difference between April and September F-IS estimates
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 heterozyg
otes. Inbreeding will accelerate resistance evolution whenever the fit
ness of homozygous resistant insects exceeds that of heterozygotes, an
d will undermine any high-dose strategy to control resistance evolutio
n.