Argentine ant paralleled only by human society", and had probably been spread and maintained by human travel. They have been extraordinarily successful, in part, because different nests of the introduced Argentine ants seldom attack or compete with each other, unlike most other species of ant. In their introduced range, their genetic makeup is so uniform that individuals from one nest can mingle in a neighboring nest without being attacked. Thus, in most of their introduced range, they form supercolonies. "Some ants have an extraordinary social organization, called unicoloniality, whereby individuals mix freely among physically separated nests. This type of social organization is
Slave-making ant slave-maker ant offspring. This is because "slaves can gain indirect fitness benefits by reducing parasite pressure on nearby host colonies, because these are often closely related to the slaves". Thus, the slave ants protect their native colonies from further raids by slave-maker ants. The reproductive behavior of slave-making ants usually consists in synchronous emergence of sexuals followed by a nuptial flight and the invasion of a host nest, but also in some cases females display a mating call around the natal nest to attract males and immediately after mating search for a host nest to usurp. Only one slave species