Bee bearding is a common, often misunderstood, phenomenon where a significant portion of a honeybee colony gathers outside the hive, appearing as a dense cluster. While it might initially seem concerning, bearding is typically a healthy and adaptive response by the colony to its environment.
Understanding Bee Bearding
Bee bearding describes honeybees clustering on the exterior of their hive, often around the entrance or on the landing board, forming a beard-like shape. A large number of bees appear inactive outside the hive, but they are performing an important function. This phenomenon commonly occurs during warm weather, particularly in the late afternoon or evening when all forager bees have returned.
The clustered bees often fan their wings to circulate air. Bearding bees are generally calm, remaining stationary rather than flying erratically. This behavior directly responds to internal hive conditions, helping maintain a stable environment.
Primary Reasons for Bearding
Bearding is primarily a thermoregulatory strategy, allowing bees to manage the hive’s internal temperature, especially during hot and humid conditions. Each bee generates heat, and a crowded hive can quickly overheat. By moving outside, a portion of the colony reduces heat-producing bodies inside, lowering the hive’s overall temperature. This also decreases congestion, allowing better air circulation.
Honeybee colonies must maintain a precise temperature, typically between 90-97°F (32-36°C), for healthy brood development and proper nectar evaporation into honey. When internal temperatures rise, bees work to cool the hive. Some bees inside fan their wings to push hot air out and draw cooler air in, while those bearding outside reduce the heat load and facilitate airflow.
Humidity control is another factor contributing to bearding. High humidity inside the hive can lead to mold growth and affect brood health. By clustering outside, bees encourage air movement, which helps to remove excess moisture and maintain optimal humidity. This ventilation system helps prevent heat stress.
Overcrowding can also prompt bearding, even without immediate swarming intent. A thriving colony may run out of space, causing some bees to spill out. This temporary measure provides relief from congestion, allowing more room inside for resource storage and brood rearing. Bearding can also occur during a “nectar dearth,” when little nectar is available, causing foraging bees to remain in or near the hive, increasing internal temperatures and congestion.
When Bearding is a Concern
While bearding is usually a normal sign of a strong colony, it can sometimes indicate an underlying issue or impending event. Normal bearding involves calm bees clustered quietly, often in the evening or during hot weather, and they usually return inside as temperatures drop.
However, bearding can sometimes be a precursor to swarming, the natural process where a portion of the colony, along with the queen, leaves to establish a new home. Signs of swarming-related bearding include increased aerial activity, a loud buzzing sound, and queen cells inside the hive. Swarming usually occurs earlier in the day, from mid-morning to mid-afternoon, and involves more active, agitated bees compared to docile bearding.
Other stressors can also lead to bearding. Poor ventilation within the hive, caused by blocked entrances or inadequate hive design, can force bees outside in an attempt to improve airflow. Internal issues such as disease or pest infestations can also make the hive uncomfortable for bees, prompting them to beard. For instance, severe infestations of Varroa mites, which weaken bees and spread viruses, or diseases like American foulbrood, could stress a colony to exhibit unusual behaviors, including prolonged or unusual bearding.
If bearding is prolonged, occurring for days regardless of temperature, or is accompanied by signs of distress like dead bees outside the hive or unusual odors, a closer inspection may be warranted. In such cases, beekeepers might consider interventions such as providing additional ventilation, ensuring adequate space by adding more hive boxes, or inspecting for signs of disease or pests. In most situations, however, bearding is a testament to the bees’ ability to adapt and regulate their environment, requiring no human intervention beyond observation.