Dinoponera gigantea
Encyclopedia
Dinoponera gigantea is one of the world's largest species of ant
Ant
Ants are social insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from wasp-like ancestors in the mid-Cretaceous period between 110 and 130 million years ago and diversified after the rise of flowering plants. More than...

. It is found only in South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

. The females of the species are larger than males, with lengths ranging from 3 to 4 cm (1.2 to 1.6 in). The females are coal-black in color, while the much smaller males are dark red.

Nesting

D. gigantea colonies have as many as eight entrances to their underground chambers, each being 3 to 8 cm (1.2 to 3.1 in) in diameter. The entrances are, as is typical for ants, surrounded by the soil removed to make the nest, but, in contrast with other species, no mound is formed. Nests have been found to be about 40 centimetres (15.7 in) deep, with chambers approximately 3 centimetres (1.2 in) in height and 20 centimetres (7.9 in) in width.

At least in some instances, the species is polydomous, with a single colony occupying and maintaining more than one nest at a time. Some instances of this were recorded in Fourcassie and Oliveira's 2002 study, which found colonies using multiple nests, the entrances of which were 40 to 250 cm (1.3 to 8.2 ft) apart.

Foraging

Activity outside the nest is highest at sunrise and sunset, though there some activity likely occurs at night. Individuals search for food alone, generally within about 10 metres (32.8 ft) of the nest. Items brought back range from 10 to 400 milligrams, and are of wide variety, including both plant and animal matter. Food items include fruits of vismia
Vismia
Vismia is a genus of flowering plants in the family Hypericaceae. Like many members of the Hypericaceae, these plants contain xanthonoids.Species include:*Vismia baccifera*Vismia guianensis*Vismia jefensis*Vismia micrantha...

 plants, inga
Inga
Inga is a genus of small tropical, tough-leaved, nitrogen-fixing trees and shrubs, subfamily Mimosoideae. Ingas leaves are pinnate, and flowers are generally white...

 seeds, and various small animals such as spiders, crickets, and snails. A relatively small number, around 10%, of foraging trips turn out to be successful. Successful foraging trips are typically thirty to sixty minutes in duration, though they may take as long as three hours.

Territorialism

Neighboring colonies of D. gigantea have distinct foraging areas. On the occasion that ants from different colonies meet on the border of these areas, the individuals face each other, locking their mandibles. The two then repeatedly poke each others' head with their antennae
Antenna (biology)
Antennae in biology have historically been paired appendages used for sensing in arthropods. More recently, the term has also been applied to cilium structures present in most cell types of eukaryotes....

 while kicking with the forelegs. At some point, one of the ants gains a dominant position, eventually biting the other on the top of the head and pressing the gaster
Gaster
The gaster is the bulbous posterior portion of the metasoma found in Apocrita Hymenoptera . This begins with abdominal segment III on most ants, but some make a postpetiole out of segment III, in which case the gaster begins with abdominal segment IV....

against the loser's body. The entire encounter can last up to half an hour. In Fourcassie and Oliveira's study, both ants were invariably found to be uninjured.
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