Performance of honey bee (Apis mellifera) queens reared in beeswax cells impregnated with coumaphos

The sublethal effects of coumaphos on developing queens were investigated. Young honey bee larvae were transferred into beeswax cups containing known concentrations (0 to 1000 mg/kg) of coumaphos. The cups with larvae were placed in queenless colonies for rearing and 10 days later acceptance was determined by recording mature queen cells. The queen cells were placed in small mating colonies for 21 days, when the queens were collected after being rated for commercial acceptability. The queens were then either introduced to production colonies and monitored for six months or dissected to determine mating success. All but one queen failed to develop at 1000 mg/kg of coumaphos, and greater than 50% of cells were rejected at 100 mg/kg coumaphos. The queens that were reared were lighter in weight as pre-emergence pupae. The effects on other characters related to queen performance are discussed. The presence of coumaphos in queen rearing cells can reduce the number of queens still functioning in colonies at six months by as much as 75%.