To avoid excessive use of pesticides in controlling varroa mites (Varroa jacobsoni) in honey bee (Apis mellifera) colonies, a method for monitoring the population size of the mites was developed. The relationship between the size of mite populations (y) in full-size honey bee colonies and natural mite mortality, measured as the number of mites falling on plastic inserts (drop-down), was investigated in Danish apiaries. The results suggest that a straight linear model (y = + x) describes the relationship between the mite population present in a colony and the calculated daily number of naturally dead mites collected on inserts during either 1-week or 3-week periods before sampling. The parameters of the straight line relationship between the population size and the daily mite drop-down during a 1-week period are: β = 0.0069 and α = -1.858 ( r2 = 0.77, p < 0.0001). For a 3-week period, the parameters are: β = 0.0063 and α = -0.403 ( r 2 = 0.83, p < 0.0001). If the model input is adjusted for the brood-rearing pattern of the sampled colonies, i.e. colonies with capped brood cells covering less than one side of a comb in total (2800–3200 cells) are excluded from the input, the fit of the model is improved. In this case, the parameters for the 1-week sampling period are: β = 0.0075 and α = -1.184 ( r2 = 0.88, p < 0.0001), and the parameters for the 3-week sampling period are: β = 0.0071 and α = -0.864 ( r2 = 0.91, p < 0.0001).
Expression of acetylcholinesterase 1 is associated with brood rearing status in the honey bee, Apis mellifera