Why do bees feed each other mouth to mouth?
Short answerTrueEstablished evidence
It is called trophallaxis, and it does two jobs at once. It distributes food through the colony, and it distributes information: pheromones, including queen substance, and the odours of whatever is currently being collected, circulate through the same exchanges. It is how a colony behaves as a connected system.
What is being passed
- Nectar, from returning foragers to receiver bees, which is also the first stage of turning it into honey.
- Processed food between in-hive bees, including to the queen and to drones, neither of which feeds itself as an adult.
- Pheromones, including the queen mandibular blend picked up by her retinue and passed onwards.
- Floral odours, which spread information about what is currently worth collecting.
The network
Automated tracking of individually marked bees has mapped the exchanges, and the network is dense: a substance introduced to one individual reaches a large share of the colony within hours. There is no broadcast channel in a beehive. There is a very large number of brief pairwise contacts, and the colony-level effects fall out of the network structure.
Sources
- The Biology of the Honey Bee — Harvard University Press (1987) · Textbook
- The Lives of Bees: The Untold Story of the Honey Bee in the Wild — Princeton University Press (2019) · Monograph
- Pheromone communication in the honeybee (Apis mellifera L.) — Journal of Chemical Ecology (2005) · Peer-reviewed article
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