Many insects buzz but I imagine for most of us the first insect that comes to mind when we mention buzzing is bees. Have you ever wondered though why they do it … why do bees buzz?
Bees in flight
There are more than 20, 000 different species of bees and they all buzz but some do so in very unique ways and for very specific purposes. Starting with the basics… all bees buzz when they fly. The buzzing sound we hear is because bees can flap their wings at a pretty impressive 230 beats per second. This rapid wing beat causes the air around the bee to vibrate and that vibration travels to our ear and we interpret that vibration as a buzzing sound.
Don’t ruin my buzz
Bees don’t just buzz as a consequence of flight however, they buzz for other reasons too. If you have ever disturbed a nest of bees you may have noticed how their buzz gets a lot louder; bees buzz as a defence mechanism. They also communicate with each other through buzzing, but some use buzzing for another very important task.
We all know that bees are good pollinators and they are very important in transferring pollen from one plant to another. At specific times of the year, many plants will have parts of their flower, called the anther, coated in pollen. Some plants however have their pollen locked away inside special anthers (called poricidal anthers) that only release the pollen through small pores or slits.
It is much more tricky to get at pollen in these plants, but some bees have developed a neat little trick to do just that; they wrap their legs around the anther and then vibrate their bodies, using sound to shake the pollen out. It’s called buzz pollination, or flower buzzing, and it is very important in the pollination process of more than 20,000 different plants, including potatoes, tomatoes and blueberries.
Scientists have studied the mechanisms that bees use for each type of buzzing to see if there are any differences. These studies have shown that bees do indeed use different types of buzzing for different tasks. Flower buzzing is a much more powerful and high pitched buzz than flight buzzing or the buzzing used for communication or defence. In fact, flower buzzing can produce forces of 50 G, that’s five times more than the forces experienced by fighter jet pilots. It’s no wonder the pollen gets shaken from the anther.
Each of the different types of buzzing the bee produces is created by contracting and relaxing the same set of powerful muscles, the flight muscles; the mechanics can vary though. For non-flight buzzing the bees lay their wings flat against their backs and effectively uncouple them from the flight muscles, vibrating their bodies instead.
Do all bees do it?
Not all bees can do this flower buzzing, it is more common among bumble bees and some other solitary bees. It is estimated that about 58 percent of bee species can harvest pollen in this way. Although we associate honey bees with the pollination of plants, it seems they are not able to buzz pollinate at all.
Hitting the right note
The beautiful orchestral piece called The flight of the Bumblebee may be in the key of A minor but when bumble bees are flower buzzing they do so in the tone of middle C. Apparently a (C) tuning fork can produce the same effect.