KnowHOW team explains: Bees’ buzz is caused by a rapid beating of their wings. This leads to vibrations that give off the sound.

When someone approaches a hive, the bees detect the intruder by sensing the chemical scents. They consider anyone standing in their flight-path as a potential intruder who might disrupt their normal activities around the bee hive. They are also bothered by dark colours, perceived as a threat to the hive.

If you look at a hive carefully, you’ll notice a line of sentry bees patrolling the entrance, allowing only the members of the hive to enter it. Whenever the guards perceive a danger, they point their stings at the stranger and beat their wings frantically.

They also release a chemical scent, or pheromone, and their fanning wings spread the alarm around the hive. Other members catch up with the guards and set about beating their wings to help the chemical spread across. The buzzing sound makes the alarm signal audible, provoking the rest of the members to launch an attack on the intruder.

In addition, some bees, such as bumblebees, shake their wings furiously to get the sticky pollen grains off the flowers’ anthers. Such frantic wingbeats not only help them collect the pollen, but also aid pollination of flowers. This is known as buzz pollination.

The question was sent by P.S. Sinha Ray from Bokaro Steel City