When a bee appears to be “drunk,” it is a real biological event caused by the accidental consumption of naturally occurring ethanol. Worker bees, driven by the need to forage, occasionally encounter fermented sugars in the environment, leading to impaired function. The subsequent behavioral changes and the colony’s defensive reaction to an intoxicated member highlight a fascinating aspect of honey bee social organization and survival.
How Bees Encounter Ethanol in Nature
Bees are primarily drawn to sugary liquids, which are the precursors to ethanol through a natural process called fermentation. This process begins when wild yeast consumes the sugars in nectar, tree sap, or fruit juice, converting them into alcohol and carbon dioxide. Fermented nectar is a common source, particularly in tropical regions where high humidity and temperature accelerate yeast activity.
Another frequent source of accidental intoxication is the sap from trees, such as the lime tree, which can ferment under high heat after being exposed. Fallen, overripe fruit is also a significant attractant for bees seeking sugar. When the outer skin of a fruit breaks, the sugars inside are quickly colonized by yeast, creating a small, temporary source of ethanol.
Honey bees do not intentionally seek out these fermented sources, but their drive to collect carbohydrates means they occasionally ingest the ethanol-laced material. The concentration of alcohol in these natural sources is typically low, though some tropical flower nectars have been observed to contain ethanol levels up to 6.9%. Even small amounts of this substance can noticeably affect the bee’s behavior and motor control.
Behavioral and Neurological Effects of Alcohol
Once consumed, the ethanol is rapidly absorbed and begins to affect the bee’s central nervous system. This neurological impact causes a dose-dependent disruption of motor function and coordination. A mildly intoxicated bee may exhibit erratic flight patterns, frequently wobbling or crashing into objects on its return flight to the hive.
As the amount of ingested ethanol increases, the bee’s ability to walk and maintain balance severely diminishes. Researchers have observed highly intoxicated bees losing their postural control entirely, spending a majority of their time lying on their backs and unable to right themselves. This loss of physical control is compounded by impairments to cognitive function, including a disruption of memory and learning processes.
Ethanol also affects the bee’s complex social behaviors, such as the waggle dance used for communication, making it sloppy and inaccurate. The effects can be long-lasting, with behavioral recovery from a high dose sometimes taking up to 48 hours.
The Colony’s Response to Intoxicated Bees
The presence of an intoxicated forager returning to the hive triggers a swift and organized defensive reaction from the colony. Guard bees stationed at the entrance are responsible for identifying and managing any bee that poses a risk to the hive’s internal environment. They detect the intoxicated members primarily through their altered movements, such as a lack of coordination or a failure to perform the appropriate landing sequence.
An additional detection method involves the chemical signature of the ethanol itself, which the guard bees can sense on the returning forager. The primary concern is that the intoxicated bee carries fermented nectar, which could contaminate the entire honey supply. Introducing fermented material would spoil the colony’s food source.
The consequence for the “drunk bee” is immediate expulsion and temporary exile from the hive. In less severe cases, the guard bees may physically push the bee away from the entrance and prevent reentry until the alcohol has been metabolized and the bee’s behavior returns to normal. However, if the intoxicated bee becomes aggressive or repeatedly attempts to enter, the guards may resort to more severe measures, sometimes physically harming the disruptive individual to protect the integrity of the colony.