The horse chestnut communicates with bees.
The majestic horse chestnut, whose flowering is more pollen-rich than nectar-rich and begins in April–May, provides bees with a valuable cue that attracts them to flowers that have not yet been pollinated.
What is it ?
- Once pollinated, its flowers change colour.
- The flower emits an attractive pheromone.
- The pollen contains an addictive molecule that encourages pollinators to return to the same place.
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Correct answer: 1 (Once pollinated, its flowers change colour)
A helping hand between the plant and animal kingdoms. During foraging, the bee marks the flowers it has just visited with a “repellent” pheromone. This pheromone, produced by the Dufour abdominal gland, has a short-lived effect and improves the forager’s efficiency by preventing it from returning to flowers from which it has already collected nectar or pollen. The majestic horse chestnut, whose flowering is more pollen-rich than nectar-rich and begins in April–May, provides bees with a valuable cue to direct them to flowers that have not yet been pollinated.
Its inflorescence (thyrse) is pyramidal in shape and pink or white in colour. If a flower has not yet been pollinated, its centre is marked with yellow; once pollinated, it turns red. As bees perceive red less well, they are more strongly attracted to unpollinated flowers whose yellow centre is more easily perceived. A win–win situation thanks to complex organic chemistry!