Why Do Bees Buzz?

The gentle sound of bees buzzing among the flowers in the garden has to be one of my favourite sounds of summer.  But why do bees buzz, and how do they make that buzzing sound?

Of course, we can't get into the minds of bees! But by observing their behaviours, we can make a few guesses.

I looked into this subject using some of my favourite books about bees, as it's a question I have been asked whilst giving my talks.

I found that theories and ideas had changed over time - no surprise there: history shows we form ideas about a thing, only to learn more and change our minds later!

So let's look at this question:

Why Do Bees Buzz And How Do Bees Make The Buzzing Sound?

The sound of bees buzzing is caused by the rapid movement of their wings.  The rapid contraction of their wing flight muscles is what causes the high pitched whining (buzzing) sound.

However, explanations have varied through time and with research.  Back in 1912, a researcher called Sladen thought that the noise was caused by air passing over the edge of a membrane in tiny holes in the segments of the abdomen (body).  These holes are called 'spiracles'

Considering the same question, author of 'Bumblebees', and 'Solitary Bees', Ted Benton notes:

    "Whatever the truth of this, it seems that the buzzing sound made by bumblebees is at least greatly amplified by the vibration of the wing membranes".

As we observe bees, this seems obvious to us now - and certainly the buzzing sound varies with the activities and movement of the wings.  However, I recall as a child that I assumed bees made the buzzing sound via the mouth as that is where most noise created by humans comes from!  

Bumble bee in flight toward purple loosestrife.Bumble bee in flight toward purple loosestrife.

When Do Bees Buzz?

Firstly, buzzing is of course, commonly heard when bees are simply flying, during which time, the wings are vibrating very fast.

In the same way that bees have different flight movements (for example, the hairy footed flower bee has a darting flight and a high pitched buzz.

Comparing Different Bee Buzzing Sounds

The next time you are in your garden watching bees, take time to observe how different species engaged in various activities, emit a unique buzzing sound.

Here are a few to look out for:

Bees buzzing as they fly about defending and patrolling a flower patch

Wool carder bees buzz from flower to flower, and the males buzz as they dart around patrolling patches of flowers - typically Lamb's ear, which is a favourite for foraging and gathering nesting materials.  As they buzz about patrolling the flower patch, they are waiting for the opportunity to pounce on and mate with females.

wool carder bee approaching lamb's earWool carder bee in flight. They not only buzz from flower to flower, males buzz as they patrol patches of flowers.

Buzzing: self defence and threat, being trapped

Most people are aware that bees seem to buzz more aggressively if their nests are disturbed, or if they are disrupted during foraging.

A classic example is if you happen to see a bee trapped in a spider web, buzzing as it frees itself to get out.

Similarly, I have noted that bumble bees trapped in a bottle were buzzing - seemingly very angrily trying to get out a buzz quite different from the relaxed buzzing from flower to flower that I often witness in my garden.

They will also buzz  if under attack or whilst defending themselves from threat or predators, or during conflict with other members of the colony, such as the queen.

Buzzing whilst foraging and pollinating

Bumble bees buzz pollinate by placing the upper part of their body (thorax), close to the anthers, then vibrating their flight muscles very fast.Bumble bees buzz pollinate by placing the upper part of their body (thorax), close to the anthers, then vibrating their flight muscles very fast.

If you have seen my page about bumble bee pollination you will have read that bumble bees engage in buzz pollination.

The anthers of some flowers (i.e. the parts carrying the pollen) only release their pollen if they are shaken. Bumble bees achieve this by placing the upper part of their body (thorax), close to the anthers, then vibrating their flight muscles very fast. 

At the same time, they make a lovely buzzing sound. Buzz pollination is especially beneficial for tomatoes and other fruits, resulting in a more abundant crop, but it can be witnessed when bumble bees forage on a variety of flowers such as oriental poppies and roses.

Buzzing and communication in honey bee colonies 

One particular type of high-pitched buzzing sound made by
honey bees is called 'piping'.  Piping occurs directly prior to swarming, but can also occur during the disturbance of a hive.

There are differing views about which bees in the honey bee colony initiate the piping prior to swarming.

Some sources state that the queen starts first (Werner, 1964). Others state that the piping begins with a small group of experienced forager bees called 'nest-site scouts', who produce a "piping-signal" that primes the workers for swarming (Rangel, 2008).

It is also now believed that when honey bees 'waggle dance' to communicate the locations of food (flowers upon which to forage) to other members of the colony, it is not only the movements of the honey bee, but also the buzzing sounds made, that help to convey the whereabouts of the forage sources (Goodman 2003).

Do bees sleep?
Apparently they do, but how do we know?

Sleeping honey bees, links to the page 'Do bees sleep?'