Until 1989 it was considered that bees are not capable of hearing, and they are deaf. But this was proven wrong by Towne and Kirchner in 1989 through a series of experiments.
Honey bees don’t have ears, however they can detect sound and music up to 500Hz with their entire body. Especially efficient for the detection of sound are their antennas and sensitive body hair. Those can sense the vibrations of the air particles.
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How are honeybees capable to detect sound?
There are two major organs responsible for the bee to be able to pick up sound waves and vibrations:
- The Johnston’s organ is present in the 2nd segment of each of the two antennae. This organ consists of many sensory cells that are sensitive to vibrations. Almost 300 nerve cells present in a bowl shape in the antenna (scolopidia).
Each of these cells detects minute vibration of the antennal flagella (end segment of the antenna). And this antennal flagellum detects the movement of air particles in a range up to 20nm and is more sensitive to a low frequency like 250Hz.
- The Subgenual organ is an organ that insects have and it is involved in the perception of sound. It is located beneath the knee of the bee.
However no one has really proven that this is the way bees can detect sound or movement of particles. This is just the nearest and most logical explanation scientists and experts have come to.
Can honeybees detect a wide frequency range of human voice?
When a sound wave travels it has both the pressure and the air particle movement. And these sound waves are measured in Hz or cycle in one second (frequency). This frequency is heard as pitch.
A higher sound wave frequency has a higher pitch and the lower sound wave frequency has a lower pitch. Bees produce from less than 10 HZ to 1000Hz wave frequency.
- Human voice( speaking) frequency ranges from 120 Hz to 8000 Hz (minimum and maximum ).
- But when two normal persons are talking to each other or a complex speech has a range from 125 Hz to 500 Hz.
- And bees can detect up to 500 Hz (10 to 500 Hz).
Can they understand human language?
No, bees are not able to understand and translate the human language or of any other animal. However in the case of humans, bees can detect the sound signal.
Can honeybees produce sound?
With Vibrations and tremulation, those are the two basic ways that honeybees can produce sound signals. The vibration comes through their continuous motion of the wings in the air.
Tremulation is used for acoustic signals but it has some other benefits, due to these vibrations pollens shake off from the flower and gets attached to the legs of the bees, and when the bee moves to other flowers the pollen deposits to that flower causing pollination.
Honey bees can also produce sound through the vibratory movement of the thoracic muscles and the wings. These thoracic muscles are also used to vibrate the wings and sometimes bees uncouple their wings for the sake of heat and to produce acoustic signals.
- When bees vibrate their wings rapidly it sounds as a little buzzing. Larger bee has slower wingbeats as a result the pitch of the buzzer is also lower.
- Bees also vibrate their abdomen to create lower frequency sounds for other bees to convey the message about the location of food.
Communication among the honeybees
Honeybees communicate in two ways:
- BY chemicals or pheromones
- BY waggle dance ( movement )
Young ones in the hive also interact through pipping voice.
Pheromones are used to signalize different situations. Usually, the queen bee signalizes through specific pheromones that she is ready to be fertilized and by those pheromones, male drones can find her. Her pheromones are actually the reason why bees can find their hive even if it is relocated. Through pheromones bees can also signalize that there is an attack on their hive and also very important, they can tell other bees where a food source is located.
Wobble / waggle dance (dance language)
This is a special 8 figure dance of honeybees which is used as a specific language to communicate and to know about the exact location and distance of flowers, water, or resins from the hive.
Whenever a honey bee finds a source of food that is more than 500 feet away from the honeycomb, then this bee tells the other ones through the waggle dance.
When a honey bee finds some food it comes back to the nest with some sample food, so that other bees taste the quality. Then this honey bee performs a waggle dance for the others to explain the precise location of the food source.
In this dance, the honey bee runs straight ahead for a small distance and returns to the beginning line, forming a semicircle. Then, she runs through the straight route again but by making a half-circle in the opposite way.
How does the honey bee tell the distance of the food from the honeycomb to other bees?
If the bee takes longer to end the waggle dance, this means the food source is further away. Every second the bee dances it represents 1km distance from food. For example, if a bee takes 10 seconds to complete the dance, it means the food source is 10km away.
How does the honey bee tell the direction of the food to the other bees?
To illustrate directions to the food, the followers must watch the direction of the dancing bee during the waggle move. If the dancing bee moves upward then it means the food is in the direction of the sun. If the food is in another direction, the bee runs at an angle that matches the direction of the food outside. Outside, follower bees observe the position of the sun and fly at the identical angle that the dancing bee showed them inside the nest.
Journey towards the food using vibrations
After this, the same honey bee starts to fly to the described source of food while others follow, using vibrations and sounds during flight.
During the waggle dance sound is produced by the forager bee. The forager bee vibrates her wings with the continuous movement of the thoracic muscles and the abdomen. These vibrations and movements simultaneously produce…
- Airborne sounds (near field sounds)
- Substrate vibrations
- And jets of air
These airborne sounds and air jets produced by the forager are detected by the follower bees through the antenna (Johnston’s organ).
In this way, the follower bees know the same location and distance of the food source. As the dancing bee beats its wings it promotes the thoracic movement and the honeybee start to vibrate her thoraces and abdomen vigorously which is then transmitted through legs to the flower and produce substrate vibrations.
How do we know that honey bees can pick up the sound?
- In 1989 two researchers named Towne and Kirchner did an experiment in which honeybees were trained to leave the feeder in response to the sound signals.
- During an experiment in 1991 by Kirchner, honeybees were trained to move right and left when entering the feeder according to special sound signals.
- In 1993 another experiment was performed by Dreller and Kirchner in which they confirmed that the sensitive structure to the sound is antenna or hair sensilla .
When bees become trained to the sound signals then their antenna or sensilla were removed. As a result, the bees showed no response to the sound signals. So it was confirmed that the sensitive structure is the antenna.
Recently, scientists are trying to do new and modern experiments to know exactly how bees detect sound waves.
Afterword
This article has explained how bees use different ways of hearing and communication. Despite having no ears, bees can hear and detect sounds in a range up to 500 Hz (from 10-500 Hz). Bees are also able to produce sounds like buzzers, tooting and quacking (pipping sound). Bees also do a waggle dance to explain to the other forager bees where a food source is located. All this information that we have now was concluded from different experiments done in the end of the 20th century. However scientists today, work on newer methods to explain, how exactly bees can hear without ears!