Honey bees communicate in many different ways. Without good communication, how would a family with thousands of individual members get anything done? One amazing method of bee communication in the hive is the use of pheromones. Honey bee pheromones regulate many of the activities that happen in everyday colony life.
Bee Pheromones – Chemical Messengers
What is a pheromone? These are chemical substances that are secreted externally and cause certain behaviors or responses in members of the same species.
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Honey bees produce pheromones much like we humans produce sweat. But, instead of a liquid to cool the body, their pheromones serve other purposes. They tell members of the hive a lot of important information about colony status.
The bee colony still holds some mysteries that we don’t understand. But, some of these chemical messengers have been identified.
Because of her importance to the colony, much research has been done on the queen bee. She is the most studied colony member.
So, what do they do for her? Well, some of her pheromones help identify her as “the queen”. This is a signal to the colony that all is well. Daily life inside the hive continues. With a good laying queen on the job, they have no reason to build new queen cells.
The queen’s pheromones inhibit the development of worker ovaries. All the workers in the hive are female. They do not normally reproduce.
But, if a queen dies, is accidentally killed or just fails to produce pheromones due to sickness or age – the colony is a risk.
When the colony has been without a queen for a long time, laying workers may develop. The ovaries of these workers can develop enough to lay a few eggs but they are not able to mate. Therefore, they cannot lay fertilized eggs that will develop into new workers. They only produce drones.
Bees may kill a failing queen and attempt to replace her before the situation becomes dire for the hive. If their attempt fails, the colony is in true danger.
One of the most important pheromone components in the colony is spread by contact. It is called “queen substance”. A combination of at least 3 substances synthesized in the mandibular glands (located in mouth) of the queen make up this compound.
Queen Mandibular Pheromone
- 9-oxo-2-decenoci acid (9-ODA)
- 9-hydroxy-2-decenoic acid (9-HDA)
- 10-hydroxy-2-decenoic acid (10-HDA)
So, what do all these big words mean to the average backyard beekeeper? It is not so important that you remember their names or how to spell them. But, you do need to know what they do and their importance.
HDA & ODA stimulate brood rearing. Their presence tells the workers that they should prepare for raising more young.
The queen will only lay eggs in cells that have been cleaned and polished by workers. The presence of good queen substance pheromones tells the workers it is time to get to work preparing cells.
They also help maintain the “queen retinue”. This refers to the small group of workers that you often see surround the queen. They follow her around the comb to feed and groom her.
The queen is not the only member of the colony to produce important pheromones. Worker bees produce them as well. One pheromone response that any beekeeper can observe takes place at the nasonov gland.
This is the scenting gland located near the tip of the workers abdomen. These gland secretions produce geraniol and citral – this is a “calling substance”.
Bees can be seen doing this at the entrance of the nest, on the surface of a swarm or any time you capture bees and move them to a new spot.
Another worker pheromone is “isopentyl acetate” that is produced near the stinger. An alarm-danger signal, it calls other members of the colony to come and help defend the hive.
Honey bees are not the only insects with alarm pheromones. Yellow Jackets do the same thing when stinging. This is why is it so important to move away before their sisters arrive to sting you too.
How Brood Pheromones Control Workers
Adults are not the only members of the colony that produce chemicals to control behavior. The youngest members of the colony produce pheromones too.
Developing from the tiny bee egg, larvae are eating machines. Their only occupation is to eat and grow. Young adult workers have the task of being nurses and feeding the young. They do this constantly 24/7 until the cell is capped.
Brood pheromones are produced on the surface of the larval skin (cuticle). In addition to possibly inhibiting ovary development in workers – like queen substance – they cause other actions.
Lots of brood pheromones in the hive encourages foragers to collect more pollen. It will be needed to feed these developing bees. It also encourages the development of the hypopharyngeal glands in the nurse bees to produce more brood food.
A colony with little to no developing brood does not need to focus on collecting pollen to rear young. But, then we know it likely has other problems – as brood rearing is a constant task during the warm season.
Enemies of the colony also make use of brood pheromones. The Varroa mite pests are able to locate brood – especially drone brood that they prefer by these chemicals.
Colony Communication Through Pheromonal Signals
We have looked at only a few of many honey bee pheromones, yet it is easy to understand why they are so important.
Their presence or absence allows workers to understand much about the condition of the colony. This is done quickly without having to tell each one of your 20,000 – 60,000 sisters.
Due to her primary role, a queen bee with failing pheromones levels is a danger to the colony. The workers will likely replace her in due time.
The presence of pheromones are also the reason a beekeeper can not usually requeen a hive without an introduction period. The new queen doesn’t “smell” right.
Same situation for foragers returning to the hive. Any worker that approaches the entrance is inspected to insure she is not a robber. Bee behavior is a curious thing and we don’t understand everything they do.
Some activities such as washboarding are a mystery but we continue to learn more and more. Aren’t bees wonderful!