The effect of larval age, and wet and dry grafting, on the rearing of queen bees using the Doolittle grafting method

Honey, which is medicinally very important, is the major product of honeybees. The role of the honeybee queen is crucial in maintaining the health and stability of the colony as it is responsible for reproducing and maintaining the population of the hive. Productive and healthy honeybee queens ensure the success of the colony. Various factors, such as parasites, diseases, lack of food and habitat, climate change, genetic defects, and exposure to pesticides, can lead to the failure of the queen bee. Therefore, applications of artificial queen-rearing techniques in beekeeping positively affect the growth of honeybee queens with desirable characteristics. This current research was conducted at the KUST Model Bee Form of Kohat University of Science and Technology, on Apis mellifera honeybee colonies during spring 2021. In this study, the Doolittle grafting method was used for the rearing of the A. mellifera queen bee. A total of 230 larvae of different ages (12–24, 24–48, and 48–72 h old larvae were used for grafting. Of these 230 grafted larvae, the number of queen cup cells accepted was 139 and the number of emerged queen cup cells was 82. The queen cell acceptance rate was significant (P = 0.000; P < 0.05). The effect of larval age, and the addition of royal jelly in queen cup cells prior to grafting, on the acceptance rate of queen cup cells was also studied. Young larvae, that is, from 12–24 up to 48 h of age, showed high acceptance rates. The acceptance rates of 12–24, 24–48 and 48–72 h old larvae were 76.7%, 55.7% and 20.0%, respectively. This shows that a queen produced from a 1 day old larva has the highest acceptance rate. The addition of royal jelly into queen cup cells before grafting showed the highest larval acceptance rate in March and April. In this study the acceptance rate for queen cup cells with wet and dry grafting were 89.5% and 46.1%, respectively. However further studies are recommended to determine the effect of all factors on the morphology of the queen.