Everything you need to know about Argentine Ants

Description:

The worker ants are about 3 millimetres (0.12 in) long and can easily squeeze through cracks and holes no more than 1 millimetre (0.039 in) in size. Queens are two to four times the length of workers. These ants will set up quarters in the ground, in cracks in concrete walls, in spaces between boards and timbers, even among belongings in human dwellings.

Distribution:

The native range of Argentine ants is limited to around major waterways in the lowland areas of the Paraná River drainage; They have recently spread into parts of Argentina, Brazil, Chile, Colombia, Ecuador, and Peru. The species has become established in at least 15 countries throughout the world, on six continents as well as many oceanic islands.

Behavior:

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 not only a key attribute responsible for the ecological domination of these ants, but also an evolutionary paradox and a potential problem for kin selection theory because relatedness between nest mates is effectively zero.

Reproduction:

Argentine ant workers are unable to lay reproductive eggs, but can direct the development of eggs into reproductive females; the production of males appears to be controlled by the amount of food available to the larvae.The queens seldom or never disperse in winged form. Instead, colonies spread by budding off into new units, with Argentine ants routinely moving their nests. As few as ten workers and a single queen can establish a new colony.

Impact:

The ants are ranked among the world's 100 worst animal invaders.In its introduced range, the Argentine ant often displaces most or all native ants. This can, in turn, imperil other species in the ecosystem, such as native plants that depend on native ants for seed dispersal, or lizards that depend on native ants for food. For example, the recent severe decline in coastal horned lizards in southern California is closely tied to Argentine ants displacing native ant species on which the lizards feed.

Argentine ants also cause problems in agricultural areas by protecting plant pests, such as aphids and scale insects, from predators and parasitoids. In return for this protection, the ants receive a sweet excretion, known as "honeydew". Thus, when Argentine ants invade an agricultural area, the population densities of these plant parasites increase, and so too does the damage they cause to crops.