The inhabitants of a honey bee colony are divided into three specialised types of bee; one type of male and two types of females. The male bees are called drones. Their only significant function is the mating of the queen. Because drones are designed solely for this purpose, any physical structures related to other work are reduced while their mating related structures are enhanced. Drones are easily recognisable by their large size, big eyes and strong wings. They have highly developed olfactory organs. All these adaptations ensure strong mating flights and effective queen location.
Mating takes place in drone congregation areas which have probably developed to enhance the chances of drones and queens actually finding each other and maximise the chances of out crossing. Drones have no sting but an extraordinarily designed endophallus that breaks off from the drone during copulation ensuring that drones mate only once and then die.
Drones do no other work and have to be fed by the workers so they are a drain on the resources of the colony. This means their numbers are limited and they are not present at all points in the colonies development cycle. Drones are only produced and maintained when the colony can support them and when they are likely to be needed to mate with new queens. Drone rearing precedes queen rearing by 4 to 6 weeks because of the longer development times of the drone. Consequently, the appearance of drones is an indicator for the beekeeper that the time is close for both swarming and queen rearing. The number of drones reared is affected by the size of the colony and its stage of development. In practical terms the presence of drones is a measure of the strength and vigour of a colony. Several hundred drones will be present in a colony during the main colony development period, but they are expelled during the dearth periods when the colony reduces the number of occupants in order that it survives during the time of most limited resources.
Drones develop from unfertilised eggs by a process known as parthenogenesis. This means that the drones will be haploid and carry only half the number of chromosomes that the diploid females have. It also means that the entire genome of the queen will be carried in each drone - who in effect will be clones. This haplodiploid sex determination system means that the number of unproductive males is limited while allowing effective dispersal of the queen's genetic material.
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|Effect of population size on brood production, worker survival and honey gain in colonies of honeybees||Harbo, J.R.|
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