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A drone is a male honey bee that is the product of an unfertilized egg. Unlike the female worker bee, drones do not have stingers and do not participate in nectar and pollen gathering. A drone's primary role is to mate with a fertile queen. ==Drone genetics== Drones carry only one type of allele at each chromosomal position, because they are haploid (containing only one set of chromosomes from the mother). During the development of eggs within a queen, a diploid cell with 32 chromosomes divides to generate haploid cells called gametes with 16 chromosomes. The result is a haploid egg, with chromosomes having a new combination of alleles at the various loci. This process is also called arrhenotokous parthenogenesis or simply arrhenotoky. Because the male bee technically has only a mother, and no father, its genealogical tree is rather interesting. In the first generation there is one member (the male). One generation back there is also one member (the mother). Two generations back there are two members (the mother and father of the mother). Three generations back there are three members. Four back there are five members. That is, the numbers in each generation going back are 1, 1, 2, 3, 5, 8, ... the Fibonacci Sequence. There is much debate and controversy in the scientific literature about the dynamics and apparent benefit of the combined forms of reproduction in honey bees and other social insects, known as the haplodiploid sex-determination system. The drones have two reproductive functions. They convert and extend the queen's single unfertilized egg into about 10 million genetically identical male sperm cells. Secondly, they serve as a vehicle to mate with a new queen to fertilize her eggs. Female worker bees develop from fertilized eggs and are diploid in origin, which means that the sperm from a father provides a second set of 16 chromosomes for a total of 32one set from each parent. Since all the sperm cells produced by a particular drone are genetically identical, full sisters are more closely related than full sisters of other animals where the sperm is not genetically identical. A laying worker bee will exclusively produce totally unfertilized eggs, which develop into drones. As an exception to this rule, laying worker bees in some sub-species of honey bees may also produce diploid (and therefore female) fertile offspring in a process called thelytoky. In thelytoky the second set of chromosomes comes not from sperm, but from one of the three polar bodies during anaphase II of meiosis. In honey bees, the genetics of offspring can best be controlled by artificially inseminating a queen with drones collected from a single hive, where the drones' mother is known. In the natural mating process, a queen mates with multiple drones, which may not come from the same hive. Therefore, in the natural mating process, batches of female offspring will have fathers of a completely different genetic origin. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Drone (bee)」の詳細全文を読む スポンサード リンク
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