When it’s time to find a queen, the hallways of Indian jumping ant nests are filled with the “princess pheromone”, like a Disney movie written by David Attenborough.
Colonies of Indian jumping ants (Harpegnathos saltator) start to raise their new generation of royalty around the first summer monsoon rains. These females go on to leave the colony after they mature, mate with winged males, and set up their own new dynasties. As with many areas of ant life, this is coordinated through pheromones.
In a study published in the journal Animal Behaviour, scientists have revealed that those ant larvae destined to be queens use a chemical signal, known as the “princess pheromone”, to communicate to worker ants that the time is right to prepare for a new crop of queens.
If the lava tries to develop into a queen at the wrong time then this pheromone also tells the worker ants to quell the uprising, which they do by chewing on the larva. This prompts them to stress out, understandably, causing them to suppress queen development and develop as a worker instead.
However, if the time is right, the pheromone cues the workers to provide the larvae with all the food and resources it needs to become a queen.
"People have been studying pheromones in ants for more than 50 years, and pretty much everything we've learned regards how adult ants use pheromones to communicate with each other," Clint Penick, a postdoctoral researcher at North Carolina State University and lead author of the study, said in a statement. "This is one of the only instances – maybe even the first time – that we've found ant larvae producing pheromones that influence colony behavior."
This discovery was made by taking samples of the wax layer found on the cuticle of larvae. They took samples from queen larvae and worker larvae and found their chemical composition was very different. When they switched around the cuticles between the two types of larvae, this prompted the workers to treat the larvae different. For a brief time, the mere worker larvae managed to trick themselves into a place of privilege.
“Signals like the princess pheromone are essential to social insects," added Penick. "Ants have to have a way to ensure that there are enough workers in the colony, otherwise all larvae could develop as queens and the insect 'society' would break down.”