Queen and male ants have wings, while female worker ants do not. Queen and male ants need wings because they mate through a process called a nuptial flight.
During the breeding process, female queen ants and males leave the colony to mate. Normally, the male ants take flight first and are followed by the females. The males secrete a pheromone for the females to follow. Some species of female ants mate with one male, while others mate with 10 or more male ants. After mating, the females find a place to begin a colony and break off their wings, leaving visible stubs.