Atta sexdens
FAMILY
Formicidae
TAXONOMY
Formica sexdens Linnaeus, 1758, Paramaribo, Surinam.
OTHER COMMON NAMES
Spanish: Hormigas cortadoras, sepes.
PHYSICAL CHARACTERISTICS
The dorsum of the thorax bears three pairs of teeth or spines. The body surface is partly tuberculate and reddish. Major workers or soldiers are 0.43–0.47 in (11–12 mm) in length.
DISTRIBUTION
Costa Rica, Panama, Colombia, Venezuela, Guiana, Ecuador, Peru, Bolivia, Brazil (Rondônia, Acre, Amazonas, Pará, Amapá, Maranhao, Piaui, Ceará, Rio Grande do Norte, Paraiba, Pernambuco, Sergipe, Alagoas, Bahia, Minas Gerais, Goias, and Mato Grosso), Paraguay, and Argentina.
HABITAT
Colonies are found throughout the rainforest floor, tropical deciduous forest, and tropical scrub forest.
BEHAVIOR
Eusocial insects, living in large colonies. Their nests are in the ground, and they bring cut-up leaves from several kinds of plants into them. These materials are chewed and processed to make a nutrient medium on which a certain species of fungus grows. The colony is formed when a queen has been fertilized. There are two major female castes, the reproductive queen (winged) and the workers (wingless). Males are winged. Distinct subcastes are called, according to their size, minor, media, or major workers or soldiers. They exhibit an elaborate range of behaviors, including foraging, cutting living plant tissues, defense of the nest, and care of broods. The nest of leaf cutters expands into labyrinths of chambers located near the surface, which contains the fungus gardens. Large dipper pits hold detritus and waste. A few of these pits contain more soil than organic matter, which is needed as a cover, especially for pathogenic waste. There are ventilation channels in which hot air rises from the refuse chambers and cools, and oxygen-rich air is drawn into the nest.
FEEDING ECOLOGY AND DIET
Feeds on fungus.
REPRODUCTIVE BIOLOGY
The female mates with three to eight males. She stores 206–320 million sperm for ten or more years. A queen can produce up to 150 million daughters, the majority of them workers. The queen establishes the nest and continues to produce eggs for the duration of the nest's existence. At the appropriate time, reproductive males and females make their nuptial flight, mate, and the females attempt to found a new colony.
CONSERVATION STATUS
Not threatened.
SIGNIFICANCE TO HUMANS
Because they attack most kinds of vegetation, including crop plants, they are serious economic pests. Leaf cutter ants dominate the ecosystems in which they occur. These ants are a good source of protein for humans, and they are eaten in parts of Mexico. Indians used the jaws of the soldier ant as sutures to hold together the edges of wounds.
