How Honey Bees Hear, Taste, Smell and Feel!
By: Ed Erwin - Master Beekeeper
Mentor Director Montgomery County Beekeepers Association Founder: BeeHarmony.org
Inside of a bee hive, honey bees live in virtual darkness, making smell and touch critical to the communication with other honey bees within the colony. To achieve this communication in both light and dark environments, the honey bee has evolved with two long, graceful, and mobile segmented antenna attached on the sides of its forehead. Each antenna contains thousands of different sensory organs it uses for smell, touch, taste, and hearing. Essentially, the antennae are a bee’s major data collection tool.
The bee’s antennae is a wonder of dexterity, since it has the ability to move in any direction. In order to understand the uniqueness of the antenna, let’s start at the brain and work our way out to the tip of the antenna. Each of the antennae are connected to the brain by a large double nerve to accommodate all of the crucial sensory input. Inside the antenna the nerves lead from the receptors within the antenna to the antennal lobe of the brain. Because the antenna has so many functions, the base of each antennae contains an auxiliary hemolymph pump to help pump blood through the antenna providing the nerves and muscles with extra oxygen.
Next is the scape, which is the segment attached to the honey bee's head and sits in a bowl-like depression in the bee’s head, sometimes called the antennal socket. The scape has four muscle attachments that allow each antenna to rotate 360 degrees.
Next comes the pedicel, which is a modified flagellum, which has a rounded appearance and sits on top of the scape. It has two muscle attachments allowing it to move up and down, independent of the motion of the scape.
Located, inside the pedicel, is the Johnston’s organ, sometimes called the “bee’s ear.” Although the honey bee cannot actually hear, it uses the Johnston’s organ to detect vibrations and slight changes in antennal position. The Johnston’s organ can detect extremely slight deflections, even those caused by electric and magnetic fields. It’s this detection that allow the bees to detect the waggle dance inside the hive. So, the scape and pedical work together and are responsible for the way the antenna moves.
The last section of the antenna is called the flagellum. Both antennae, regardless of gender, possess a Flagellum, Pedicel, and a Scape. There are 11 separate flagellum segments in the female antennae and 12 in the male. The male’s segments are much longer than the female’s, giving him a noticeably longer antenna. They are not true segments as they have no independent musculature, but each of the flagellum contain thousands of sensory organs of 3 different types.
The most important sensory organ is the peg organs. Each antenna has thousands of the tiny chemoreceptors and are used for smelling (like a nose). It is estimated that worker bee antenna have approximately 3,000 chemoreceptors,while queens only about 1,600. Drones have approximately 300,000 in order to find virgin queens during flight at a Drone Congregation Area.
Another major olfactory sensor is known as pore plats. They are located on the last eight segments of the flagellum. The honey bee’s sense of smell is so sensitive that it can detect a trace of a scent and sometimes even the direction of the scent - even in flight. This ability equips the bee to effectively and efficiently locate nectar and pollen-rich flowers.
Plate organs are another type of organ on the flagellum. Some evidence suggests they are used as chemoreceptors and photoreceptors, but the experts are not even sure what they do, so they may be used for smell or sensing light.
Once the scent is detected on the flagellum, the bee’s hyper-sensitive olfactory path processes the information, enabling the bee to determine the relevance of the scent to her search for
resources. In addition to finding food, honey bees use their sense of smell to locate other worker bees, drones, queen cells, eggs, younger and older larvae, over-ripe larvae, pollen, unrefined and mature honey, wax and propolis. Other duties of the honey bee require their sense of smell in order to collect information needed for the social structure of the entire colony and the bee’s survival. Thread-like gustatory sensors chemoreceptors can detect sucrose concentrations as low as two percent.
The honey bee flagellum is a sensitive movement detector. Additionally, the neurons have the ability to preserve both frequency and temporal information of acoustic stimuli including the “waggle dance” movement. The response of neurons has been found to be age-dependent, thus, the dance communication is only possible between mature foragers. Also, the last six segments of the flagellum can detect temperature, humidity, carbon dioxide, gravity, shape, wind speed and their flight speed.
The worker honey bee has a tuft of sensory hairs on the tip of the flagellum which is used to determine the texture of a surface. Their hairs are highly useful for making sense of the world around them. These sensory hairs serve as mechanoreceptors used for tactical functions and possibly respond to sound waves.
Understanding the function and purposes of the honey bee antenna will help the beekeeper better understand bee behavior.