A colony consists of over 10,000 individuals. If these individuals did not communicate, the bees would likely perform random tasks, have too many foragers or nurses, the colony could not defend itself because only a few members would know of the danger, worker would defy queens and lay their own eggs, and foragers may have trouble finding their way home from a flight. These are many examples of why honey bees communicate, and why the colony would most likely fail without some semblance of communication.
While honey bees can communicate through other avenues, honey bees primarily communicate through pheromones. Pheromones are effective for a few reasons:
1. Pheromones can be release by one individual, and spread to every member of the colony in a fast and consistent manner.
2. Pheromones are chemicals, so they can change the behavior and/or physical characteristics of other bees. I go into more detail below.
3. Pheromones can come in different types, properties, and characteristics, so bees can easily distinguish the differences.
4. Pheromones seem to be the easiest form of communication for bees because they live in a small, high dense area. Thus, audible or other forms of communication may be less effective.
Honey bees primarily use pheromones as their method of communication. Pheromones are chemical signals released into the environment the can change the behavior and physiology of other colony members. I have included a list below:
Queen Mandibular
Queens release a pheromone called the Queen Mandibular Pheromone (QMP). This pheromone physically suppresses worker ovary development and attracts drones to mating sites. QMP is a great example of how a pheromone can both alter the physical and behavior characteristics of other colony members.
Honey bee queen. The queen releases a pheromone called the Queen Mandibular Pheromone, which suppresses egg laying behavior. Photo courtesy of Garett Slater
Alarm
Honey bees have two major alarm pheromones. Alarm pheromones often causes significant behavioral changes to exposed honey bees. For examples, alarm pheromones often make bees defensive and begin running to the colony entrance.
Brood Recognition
Larvae and pupae emit pheromones that actually cause physiological changes in worker bees! If worker bees are exposed to the brood pheromones, then their reproductive ovary development is inhibited and they cannot reproduce. This is why broodless and queenless colonies produce laying workers, because workers can now develop ovaries and begin laying unfertilized eggs.
Capped and uncapped brood can release physiological and behavioral altering pheromones. Photo Courtesy of Garett Slater
Drone
Drone, male honey bees, can also produce pheromones that impact the behavior of other males. Drones produce a pheromone called the Drone pheromone, a very original name! Ha Drones release this pheromone during mating flights, and it attracts other drones to the area. Effectively, the pheromone changes the behavior of other drones, and attracts them to the mating congregation area.
Drone, male honey bees, can also release pheromones. Their pheromones typically attract other drones to mating congregation areas. Photo Courtesy of Garett Slater
Dufours Gland
The dufours gland releases pheromones within the vaginal cavity of queen honey bees. When queens oviposit eggs, the dufour gland covers the egg with a pheromone, which make these eggs more attractive to nursing bees. Thus, these nurse bees are more likely to care for these pheromone laden eggs. If these eggs do not contain the dufour’s gland pheromone, such as when laying workers produce eggs, than the nurse bees effectively take less care of these bees.
Egg Marking
The egg marking pheromone is very similar to the pheromone described in the dufours gland section. The egg marking pheromone distinguishes eggs laid by the queens and worker, and effectively make queen laid eggs more attractive than worker laid eggs.
This picture shows a queen laying an egg. When the queen lays an egg, she covers the egg with a pheromone to make it more attractive. Photo Courtesy of Garett Slater
Foraging
The foraging pheromone is one of the most important pheromones in the colony because this pheromone controls the number of nurses and foragers in the colony. The colony needs to have a certain number of nurse bees to care for brood and convert nectar to honey, but also a certain number of foragers to collect pollen, nectar, resin, and water. If the colony has too many nurses or foragers, the colony may effectively fail. Because of this, the foraging pheromone is very important. The foraging pheromone is released by older foragers, and inhibits “maturation” of nurse bees. As nurse bees get older, the characteristics and traits they have for brood care regresses. A great example of this is the nurse bees glands. Their glands for brood food shrivels and deteriorates as they mature. Without highly functioning glands, nurse bees cannot properly care for brood, and thus, they mature to become foragers. The foraging pheromone is a fountain of youth for the nurse bees because it physically alters and slows down this maturation process. Because of this, nurse bees can continue tending brood for a longer period of time.
Nasonov
The Nasonov pheromone may be the most commonly known pheromone because it is the most visible. Beekeepers often notice bees release this pheromone at the hive entrance, as the bees stick their abdomen in the air to release the chemical. This chemical helps recruit and orient bees to the colony. Without the pheromone, foragers are shown to have a difficult time finding their colony when returning from foraging flights. The nasonov pheromone also orients swarming to their future home. When scout bees find a new home, they will release the nasonov pheromone around the area. When the colony swarms, they are immediately attracted to the new home, and can then easily orient to the new area.
Honey bees release pheromones through the nasonov gland, which help foragers orient and find their way home! Photo Courtesy of Rob Snyder and the Bee Informed Partnership.
Not all pheromones are alike, however. Honey bees use small and low volatile pheromonal signals. In short, these pheromones are not strong and only effect individuals in a small area. If the pheromonal odor was strong, then the pheromones may effect unintended individuals. Because honey bees live in a small and dense area, low volatile pheromones are a necessity. Thus, the goal of honey bee pheromones is to communicate between colony members, not necessarily with ALL colony members in a hive. Other organisms use pheromones with the goal of effecting and communicating all members of a group. These pheromones have a strong odor and are highly volatile.
Some pheromones are non-volatile, which means they do not become vapor and spread throughout the group. Honey bees use a non-volatile pheromone to distinguish nest members with non-nest members. Each colony has a specific mixture of oils called hydrocarbons and these hydrocarbons are similar to DNA because each colony has a specific mixture. When colony members interact, they spread these hydrocarbons to other members of the colony, so each member has the same mixture. But, the bees can use these hydrocarbons to determine whether or not the individual is a nest mate or not. For example, robbing bees have different mixture of hydrocarbons, so they are not easily accepted. For bees to become accepted to a foreign colony, other colony members must spread the right mixture of hydrocarbons to them.
