Wednesday word file: footprint pheromone
Footprint pheromones, also known as trail pheromones, are common in social insects. Researchers found that surfaces where honey bees have walked become attractive to other honey bees. This observation led to the discovery that honey bees secrete a chemical signal (pheromone) from their feet as they go about their daily business.
At present not much is known about the chemistry of these pheromones. But if worker bees are forced to walk over a surface, especially of glass or plaster of Paris, these surfaces can be moved and used to attract worker bees to a different location.
In theory, footprint pheromone is used for orientation and may aid the workers in finding the hive entrance or in locating a good food source, but the specifics are not known.
Some research on bumble bees has shown that footprint pheromone left on flowers is at first repellent to other bumble bees (perhaps indicating the nectar has already been taken) and later turns attractive (perhaps signaling that the flower has had time to replenish the nectar supply.) But again, the research is preliminary and much remains to be discovered.