South American Fire Ant

• comportamientoIt can form living rafts that behave like a non-Newtonian fluid, changing shape under pressure, to survive floods.
• It is on the IUCN list of the 100 most damaging invasive alien species in the world.
• In the areas it has invaded it damages crops, livestock, native wildlife and even electrical installations, where it builds up inside cabinets and causes short circuits.
• Its scientific name, invicta, means unconquered.
• When the nest floods, the workers link together to form floating rafts up to 45 cm across that keep the queen and the brood out of the water, and that can stay adrift for weeks.
• A mature colony has between 200,000 and 400,000 workers, and the queens live up to seven years.
• In its native range there are about 30 mounds per hectare; in invaded areas the figure reaches 5,000.
• It gets into electrical equipment — traffic lights, air conditioners, well pumps — and gnaws the insulation; in the United States the total cost attributed to it exceeds 6 billion dollars a year.

Skeleton type

Invertebrate - chitin exoskeleton (insect)

Habitat and environment

Open, sunny ground — grassland, abandoned fields, verges, gardens — where it raises earth mounds up to a metre across and a metre high

Sexual maturity

The reproductives are produced in spring and wait inside the nest for the nuptial flight, which happens at midday or in late afternoon, at 21-32 °C and within the 24 hours following rain. The male dies after copulating; the mated female tears off her wings, digs a chamber and starts to lay within 24 hours

Gestation / incubation

The eggs hatch in 8-10 days; the larva goes through four instars and full development from egg to adult takes 22 to 38 days depending on the temperature

Litter / clutch size

The queen lays up to 800 eggs a day on a sustained basis, with reported peaks of 1,500 to 2,000; a founding queen's first clutch is only a dozen. A mature colony holds 80,000 to 500,000 workers

Sources consulted: https://es.wikipedia.org/wiki/Solenopsis_invicta; LSU AgCenter, ficha Red imported fire ant; The Nature Conservancy (Morisawa); Texas A&M, guia de insectos; Bugwoodwiki, Solenopsis invicta; IUCN GISD; University of Florida, ficha Red imported fire ant; IUCN GISD, ficha Solenopsis invicta; University of Florida; LSU AgCenter; Bugwoodwiki (Vinson & Sorenson 1986, Hedges 1997)

Best time: Nuptial flights in spring and autumn after rain; the dome-shaped mounds stand 20 to 30 cm high in open ground