Selective breeding of honey bees (Apis sp.). Honey bee semen about to be injected into the oviducts of a queen bee. The sperm cells migrate to a storage pouch inside the queen, who will gradually release sperm from it to fertilize the eggs she lays during her lifetime. This is being done as part of a breeding program to strengthen a genetic trait that offers defence against Varroa mites, which can devastate bee colonies. Photographed at an Agricultural Research Service (ARS) facility in the USA.