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Drone surrounded by worker bees. © INRA, MORISON Nicolas

Scientists flying to the rescue of bees

Communicating through all the senses

Sounds, odours, dances, contacts or pheromones; bees have numerous ways in which they communicate with each other. This is not surprising for such a complex society that must consider both its immediate and future needs. Each message causes a change in behaviour, or even a physiological adaptation that may be extremely profound. Bee communication is a fascinating subject for the researchers who try to penetrate its secrets, including the genes involved and their regulatory mechanisms.

Updated on 03/23/2017
Published on 05/01/2014

Pheromones: chemical instructions

Much of the order that reigns in a colony can be attributed to pheromones. All bees emit these substances from a very young age. Alarm pheromones cause the bees to defend their colony, even at the price of their lives; cohesion pheromones, serve to attract bees to the hive or to a source of water or food; brood recognition pheromones tell the nurse bees how to care for the larvae... there are no activities in which a pheromone is not involved. Two types of pheromone can be distinguished: incentive pheromones that induce behaviours in the bees that perceive them, and modifying pheromones, which act profoundly on their physiology. The chemical arsenal of the queen is the richest, because it is she who directs the efforts of worker bees. Mention should also be made of the QMP (queen mandibular pheromone), which drives young workers to look after their queen, staying close by to feed her and clean her body and antennae.

Messages from larvae to nurse bees

"Do not leave me", is the principal message sent by larvae via their pheromones to the bees responsible for feeding them and keeping them warm. INRA researchers in Avignon have identified around ten brood-related pheromones by which larvae communicate with their nurse bees regarding their age and needs. These chemical messages can also profoundly modify the physiology of worker bees; for example, by stimulating the glands that prepare food for the larvae and inhibiting the development of their ovaries. Brood-related pheromones are also highly manipulative in that they can delay the moment at which the bees become foragers, so that they can spend longer looking after the larvae!

Recognising each other

It is important for bees to be able to distinguish between other members of their hive and those who are foreign. To achieve this, a bee must learn from birth to recognise the characteristic odour of its colony. This faculty is vital, notably in the autumn when pillaging can occur between hives. Colonies that perform poorly regarding this self-recognition are at risk of seeing neighbouring bees using their reserves.  Scientists discovered that this ability is linked to octopamine, a hormone and neurotransmitter that exerts a stimulating effect on the brains of bees and allows them to boost their memory capacities.

Swarmonitor: listening to bees

It would be very useful if beekeepers could know whether a swarm might be in preparation in a hive, so that they could implement measures to prevent it, for example by dividing the colony in two. So what if this could be achieved just by listening to the bees? That is the idea behind Swarmonitor, a research programme in which INRA is participating. On the surface, a hive is a jumble of buzzing and scraping noises.  But in fact there are patterns in this confusion that scientists are now learning to read using a vibration sensor and appropriate software program. Thus around ten days before swarming, the vibration pattern of the hive changes. But that is not all: the scientists think that the vibration of a hive may also indicate its state of health.