Founding a new colony is not an easy task for an ant. In a lot of ant species, there is a mating flight, where males and virgin queens fly out of their colonies and mate with each other in the air. The male immediately dies after this, but the female has a pretty tough (and probably pretty boring) life in front of her.
After mating, the female lands on the ground and digs or finds a hole in order to start a new colony. It many species, the queen will lay eggs and take care of them, but never go out to find food anymore. She just lives off her fat reserves, feeding the larvae until the first workers are born and start bringing in food.
This means that if she does not have enough fat reserves, the first workers will never be born and the queen will die of starvation.
One way of ensuring no calorie will go to waste has been long known. After mating, the queen will land and shed her wings. She then ‘dissolves’ her wing muscles (as she won’t need those anymore) and reabsorb their energy. However, there are more things a queen doesn’t need anymore after mating.
During the mating flight, the soon-to-be-queen will need good eyesight, as flying blind might not be an entirely good idea. Afterwards however, she will be underground, laying eggs for up to thirty years. Needless to say, it’s pretty dark down there, so what use would there be for good eyesight?
Glennis Julian and Wulfila Gronenberg found something fascinating regarding this in 2002. Very soon after mating, the queen will actually start ‘dissolving’ parts of her brain, mainly those parts involved in vision. It costs a lot of energy to maintain a fully functional brain, so in this way, she can save valuable calories in order to raise her first batch of workers.
Conclusion: Ant queens ‘dissolve’ parts of their brain in order to save energy.
Julian, G.E. & Gronenberg, W. (2002). Reduction of brain volume correlates with behavioral changes in queen ants. Brain, Behavior and Evolution 60, 152-164