Female bees are the primary cause of death for male bees, known as drones, though the methods and motivations vary significantly by species. This lethality is driven by the fundamental biological needs of the colony, ranging from resource conservation in social species to the immediate requirements of reproduction. The fate of the male bee is often sealed by the female bees, whether through passive neglect or direct, targeted action.
The Unique Purpose of Male Bees
The existence of a male bee, or drone, is genetically and functionally temporary, serving almost exclusively to reproduce. This distinct role is rooted in a unique genetic system called haplodiploidy. Females develop from fertilized eggs and are diploid, possessing two sets of chromosomes, while males develop from unfertilized eggs, making them haploid with only one set.
A drone’s sole biological function is to mate with a virgin queen, typically from a different colony, during her mating flight. Drones do not possess a stinger, nor do they contribute to the colony’s daily maintenance, such as foraging or caring for the young. Once the mating season ends, or if a drone successfully mates, they become disposable to the colony’s long-term survival.
Seasonal Expulsion in Social Colonies
The most widely known form of male bee death is the mass, seasonal expulsion of drones from social colonies, such as the European honeybee (Apis mellifera). This event, called “drone eviction,” occurs in late summer or early autumn as the weather cools and food sources diminish. The female worker bees instinctively initiate this process to conserve resources for the winter months.
Drones consume a disproportionate amount of the colony’s stored honey and pollen while contributing nothing to winter preparation. Female worker bees push the drones out of the hive entrance and actively prevent them from re-entering. They may also block the males’ access to food within the hive days before the eviction, weakening them.
The death of the expelled drones is typically not instantaneous, but results from starvation and exposure to the cold outside the hive. This passive action ensures the males’ demise by denying them shelter and sustenance. Worker bees sometimes bite off the drones’ wings to prevent them from flying back inside, ensuring they cannot survive.
Active Lethality in Other Species
Beyond the seasonal eviction of honeybee drones, female bees cause male deaths through more direct actions, particularly during mating. In honeybees, the act of copulation is fatal for the male. During the mid-air mating flight, the drone everts his endophallus into the queen with such force that his abdomen ruptures, leaving part of his genitalia inside.
This explosive detachment fatally injures the drone, who falls to the ground and dies shortly after. The queen can mate with numerous drones during a single flight, leaving a trail of dead males in her wake. This reproductive suicide is a form of female-induced lethality.
In some other bee species, female workers may actively kill males that pose a threat to the colony’s integrity. If a drone is injured, diseased, or attempts to enter a hive that is not his own during a non-mating period, workers may sting him. In cases of genetic defects, such as the production of sterile diploid males due to inbreeding, female worker bees will cannibalize the abnormal male larvae upon hatching.