Nuptial flight
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Nuptial flight is an important phase in the reproduction of most ant species. During the flight virgin ant queens mate with males and then land to start a new colony.
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[edit] Before the flight
A mature ant colony seasonally produces winged virgin queens and males. Unfertilized eggs will develop into males. Fertilized eggs usually develop into wingless, sterile workers, but may develop into virgin queens if the larvae receive special attention.
Young queens and males stay in their parent colony until conditions are right for the nuptial flight. The flight requires clear weather since rain is disruptive for flying insects. Different colonies of the same species often use environmental cues to synchronize the release of males and queens so that they could mate with individuals from other nests, thus avoiding inbreeding. The actual "take off" from the parent colony is also often synchronized so that predators could not eat the ants one by one.
[edit] During the flight
Typically the virgin queens and males first scatter to ensure outbreeding. The queens then release pheromones to attract males. However, the queens often try to escape the males, allowing only the fastest and the fittest males to mate. This takes place in the air.
One queen will usually mate with several males. The sperm is stored in a special organ in the queen's abdomen and will last throughout its lifetime. This can be as long as 20 years, during which time the sperm can be used to fertilize tens of millions of eggs.
[edit] After the flight
The males usually die very rapidly after mating. The young mated queens land and remove their wings. They then attempt to found a new colony. The details of this vary from species to species, but typically involve the excavation of the colony's first chamber and the subsequent laying of eggs. The queen usually nurses the first brood alone. After the first workers appear, the queen becomes strictly an egg-laying machine. For an example of a colony founding process, see Atta sexdens.
The young queens have an extremely high failure rate. During its lifetime a very large ant colony can send out millions of virgin queens. Assuming that the total number of ant colonies in the area remains constant, on average only one of these queens will succeed. The rest are destroyed by predators (most notably other ants), environmental hazards or failures in raising the first brood at various stages of the process. This strict selection ensures that the queen has to be both extremely fit and extremely lucky to pass on its genes to the next generation.
[edit] Variations
Not all ants follow the basic pattern described earlier. In army ants only males have wings. They fly out from their parent colony in search of other colonies where virgin queens wait for them. A colony with an old queen and one or more mated young queens then divides, each successful queen taking a share of the workers. The reason for this behavior is the fact that army ants don't have a physical nest. The queens are thus absolutely dependent on workers to protect them.
Another variation is found in species with multi-queen colonies, such as Solenopsis invicta. The males and virgin queens mate and the queens then often return to the parent colony, where the they will then remain. This process greatly increases the success rate of virgin queens and allows the creation of extremely large colonies or networks of cooperating colonies. The colony also becomes essentially immortal as it is no longer dependent on the continued health of a single queen. This allows Solenopsis invicta colonies to become entrenched in their surroundings, achieving a dominant position in the ecosystem. However, the price for this is inbreeding and the resulting loss of adabtability. This may result in sudden collapses in population when the environment changes or a new predator or parasite is introduced.
