Relationship between dead pupa removal and season and productivity of honey bee (Apis mellifera, Hymenoptera: Apidae) colonies

This study was conducted to evaluate the dead pupae removal behaviour of 90 honey bee (Apis mellifera L.) colonies during the beekeeping season and the relationships between removal and colony productivity. The liquid nitrogen technique was used in May, June, July, August, and September. The number of removed pupae was significantly (P < 0.01) correlated with the month and changed throughout the season. The highest cleaning efficiency of the colonies were recorded in July and September, and the lowest were in May and August. While the average dead pupae removal was 83.75% in the 90 colonies, the percentage of removed pupae varied between 56.4% and 99.3% during the 5 months. There were significant positive correlations between dead pupae removal and honey yield (P < 0.01; r = 0.295), bee wax production (P < 0.01; r = 0.334), and adult worker bee population (P < 0.05; r = 0.233). No correlation was found between dead pupae removal and brood production and average temperature. Although hygienic behaviour has positive effects on many characters relating to productivity in untreated breeding populations, it is affected by many biotic and abiotic factors. This behaviour decreases with many stressful conditions (wasps, Merops sp., predators, honey harvesting) and increases with colony strength during the season.