The defining feature of social insects is that societies contain:
– queens, which specialise in laying eggs;
– and workers, which are mostly infertile but take care of the offspring and the nest.
Only when the queen dies or is removed, workers begin laying eggs of their own.
Observations have suggested that queens possess a specific pheromone which keeps the workers infertile.
If the pheromone was found to be brain-washing the workers into doing something that was bad for them, this would suggest that sociality is rife with hidden conflicts. Alternatively, the pheromone might be more like an advertisement that demonstrates to the workers that the queen is doing a good job. Workers that can smell that their queen is laying lots of eggs are expected to remain infertile and let the queen do what she does best.
Researchers found that worker ants separated from their queen developed large ovaries in preparation for laying eggs.
However, if the orphaned ants were given a glass model queen coated in synthetic queen pheromone, they remained infertile.
It was also found that the queen’s eggs are covered in pheromone, and that sick queens produced less pheromone.
So, the queen pheromone lets the workers know that the queen is in good health and is laying many eggs.
Adapted from various sources