Another revision post for my BBKA Module 6 Honeybee Behaviour exam on Saturday.

Section 6.5: the methods of communication used by the honeybee including food sharing (trophallaxis), dancing, scenting and vibration;

Of all the ways human beings communicate, probably the only one we have in common with honeybees is dancing. We don’t generally regurgitate food into each other’s mouths or waggle our bum in the air to release pheromone messages, for which we can all be grateful.

In bee world, the main communication methods between one bee and another are:

• Trophallaxis (fancy word for food sharing)
• Pheromones
• Dancing
• Vibrations

Many of these can occur simultaneously, for example during the waggle dance foragers will offer other bees a taste of the nectar source.

The world of bees: the colony is in constant communication

Trophallaxis

A Greek commenter below has kindly explained that ‘trophallaxis’ is an ancient Greek word over 5,000 years old, from the words trophi (food) and allaxis (exchange). Thanks Alex!

One of the ways a guard bee patrolling the hive entrance recognises fellow colony members is the colony’s common smell. Experiments using coloured nectar have found that within 24 hours of nectar being brought back by just ten foragers 50% of the colony had the nectar within their honey stomach. If several colonies are close by and sharing large areas of a single crop such as rape, they will often become irritable because lots of drifting occurs and they cannot tell each other apart.

Trophallaxis more often takes place by an older worker giving to a younger worker rather than vice versa. One bee will beg from another by pushing its tongue towards their mouth parts. The giver bee will respond by opening her mandibles, regurgitating a drop of nectar and pushing it forward on her tongue.

During trophallaxis the antennae of the two bees will touch, allowing them to pass on scent messages such as queen substance.

Pheromones

Smell is as useful to bees as sight is to humans. They live in a world of scent which we unfortunately have reduced and polluted by introducing cars and concrete where flowers once wafted their heavy perfume into the breeze.

Pheromones were only discovered in the 1950s and are substances which are secreted to the outside by an individual and received by a second individual of the same species, in which they release a specific reaction which may be behavioural, developmental or physiological. Some important honeybee pheromones:

Pheromones which are attractive to bees…

• Queen substance, mainly made up of the queen’s mandibular 9-oxodec-2-enoic acid (9-ODA) secretion, which attracts drones on mating flights, keeps the colony calm and inhibits workers laying.
• Open-brood pheromone – really two pheromones, brood ester pheromone (BEP) and E-β-Ocimene – is a pheromone given off by uncapped brood. It is attractive to workers and they are loath to leave uncapped brood, so can be used as a way to encourage a newly captured swarm to stay. It also has the effect of suppressing workers’ ovaries, preventing laying workers. Read more about this on Rusty at Honey Bee Suite’s blog post ‘What is open-brood pheromone?‘
• Nasonov pheromone, a lemony aroma which is released by workers raising their abdomens in the air to reveal their Nasonov glands and fanning their wings to disperse the scent. It is used to mark scentless locations such as water or a new colony location. I have seen my bees do it when their hive was moved a couple of feet, presumably to help returning foragers find their way home. Similarly, when a virgin queen leaves the hive to mate, workers will mark the entrance with Nasonov pheromone to guide her back.A chemical called Geraniol is part of the scent produced by the Nasonov gland. It is so alluring to bees that they can be side-tracked while flying even by something as visually unappealing as a fishing line which has had its end dipped in geraniol (BBKA News, April 2018, p.117). Its seductive smell is also used by waggle-dancers to mark their flight trails and the flowers they lead recruits to.

The Nasonov gland being revealed at the tip of this bee’s abdomen

Pheromones which are unattractive warning signals…

• Isopentyl acetate, the primary alarm pheromone from the honeybee’s sting gland, a strong banana like aroma which attracts all the other bees to come and sting you. Queens and young worker bees up to three days old do not produce it.

Pheromones which are defence mechanisms…

• 2-heptanone is a pheromone produced from the worker mandibular glands. Until as recently as 2011, it was thought to be an alarm pheromone used by guard bees to ward off robbers or used by foragers to scent-mark recently visited and depleted flowers.

However, 2012 research by a team of researchers from Greek and French organisations in collaboration with Vita (Europe) Ltd, the UK-based honey bee health specialist, has contradicted these theories. Their work uncovered for the first time that the compound has local anaesthetic properties. Independent tests have verified these findings.

Astoundingly, honey bees can use their mandibles to bite smaller parasites like varroa mites and wax moth larvae, in the process secreting 2-heptanone into the bite wound. The compound’s paralysing effect works for up to nine minutes, giving the time bee to eject the enemy from the hive – a particularly effective defence against pests which are too small to sting.

The ‘grooming’ behaviour which some beekeepers believe helps ‘hygienic’ honey bees to control varroa populations may reveal itself to be biting behaviour.

For more on this fascinating discovery:

• • BBKA News, No:210 – February 2013, ‘In the News: Secrets of the Honey Bee Bite Revealed’, p17.
  • HoneyBeeSuite, ‘Watch out! They bite!‘, Rusty, 17 Oct 2012
  • PLOS ONE journal, ‘The Bite of the Honeybee: 2-Heptanone Secreted from Honeybee Mandibles during a Bite Acts as a Local Anaesthetic in Insects and Mammals’, 16 Oct 2012
  • The Telegraph,  ‘Bees can bite as well as sting‘ , Louise Gray, 17 Oct 2012

Dancing/vibrations

The waggle dance is the famous one, but there are many different types of bee dances: round, transition, buzzing runs and the DVAV (dorsoventral abdominal vibrating dance).

The most amazing thing is that these dances are done in the dark of the hive. The bees rely not on watching the waggle dance but on feeling its vibrations to understand the complex information contained. Their Johnston’s organs at the base of their antennae pick up movement and vibrations and are most sensitive in the range of 200-350Hz. There are other similar vibration sensors in many of their joints, particularly in their legs. Whilst walking around on comb, bees are constantly experiencing the vibrations produced by the colony.

One of the simplest dances is the round dance, used to tell other foragers that there is high sugar content food somewhere within 15m of the hive, and to go out and find it. No indication of direction is given. It’s the dance that encourages robbing if a silly beekeeper leaves some honey out in the apiary.

The transition dance is usually given if food is between 15 and 100m away. It’s half way between a round dance and a waggle dance. Some species have a slower transition dance, others more direct.

The well-known waggle dance tells bees where food sources over 100m are located. It’s a figure of eight shape with the waggle in the middle. The dancer will stop to exchange the nectar she’s collected with watching workers so they know what they’re looking for.

The direction of the dance relative to the vertical face of the comb indicates the direction of the nectar or pollen in relation to the sun. As honeybees can perceive polarized light, the sun does not have to be shining for the dance to be successful. The nearer and more high quality the forage, the faster the dance and the more waggles in the middle.

Waggle dance diagram:

The DVAV (dorsoventral abdominal vibrating dance) is believed to be ‘get a move on’ message. A worker will mount or grab another bee and vibrate their abdomen on top of her. It’s used to recruit more foragers during a nectar flow and also on queens just before a swarm exits the nest.

The buzzing run seems to be an excited dance. The worker runs through the colony buzzing her wings. Other workers she runs into will pick up her movement and start running around buzzing too. It’s used as a signal for a swarm to exit the hive or take off once a new home has been found.

The shaking dance is thought to be a grooming request. A worker will stand on the spot shaking her body from side to side until another worker runs over and nibbles the difficult-to-reach spot between the thorax and abdomen.

References:

• ‘Fragrant clues: Geraniol points the way’, Jurgen Tautz, BBKA News April 2018, p.117
• ‘Honey factory‘ – this post on ‘The Prospects of Bees’ blog has some interesting notes on honey bee dances, taken from a 2013 lecture by Dr. Thomas Seeley, a Professor in the Department of Neurobiology and Behavior at Cornell University and renowned bee genius.
• ‘Honey bee pheromones: common scents’ by Rusty Burlew, Honeybeesuite.com, February 2016 – explanations of honey bee pheromones, in alphabetical order by common name.
• Why do bees buzz’, Dan Basterfield, BBKA News October 2013, p.13

More revision/Module 6 themed posts:

• 1st Honey bee behaviour revision post: bee jobs
• 2nd Honey bee behaviour revision post: honey bee mating
• 3rd Honey bee behaviour revision post: the queen’s egg laying behaviour and seasonal variations in the size of a colony
• 4th Honey bee behaviour revision post: social organisation of the colony
• 6th Honey bee behaviour revision post: bee foraging
• Passed 🙂
• BBKA exam feedback