Dorylus
| Driver ants | |
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| Safari ants in Kenya | |
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| Genus: | Dorylus
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| Diversity | |
| > 60 species | |
The army ant genus Dorylus, also known as driver ants, safari ants, or siafu, is found primarily in central and east Africa, although the range also extends to tropical Asia. Unlike the New World members of the subfamily Ecitoninae, members of this genus do form temporary anthills lasting from a few days up to three months. Each colony can contain over 20 million individuals. As with their New World counterparts, there is a soldier class among the workers, which is larger, with a very large head and pincer-like mandibles. They are capable of stinging, but very rarely do so, relying instead on their powerful shearing jaws.[1]
Life cycle
Seasonally, when food supplies become short, they leave the hill and form marching columns of up to 50,000,000 ants which are considered a menace to people, though they can be easily avoided; a column can only travel about 20 meters in an hour. It is for those unable to move, or when the columns pass through homes, that there is the greatest risk. There have been reported cases of people—usually the young, infirm, or otherwise debilitated who could not escape—being killed and eventually consumed by them, often dying of asphyxiation.[2] Their presence is, conversely, beneficial to certain human communities, such as the Maasai, as they perform a pest prevention service in farming communities, consuming the majority of other crop-pests, from insects to large rats.[1]
The characteristic long columns of ants will fiercely defend against anything that encounters them.[1] Columns are arranged with the smaller ants being flanked by the larger soldier ants. These automatically take up positions as sentries, and set a perimeter corridor in which the smaller ants can run safely. Their bite is severely painful, each soldier leaving two puncture wounds when removed. Removal is difficult, however, as their jaws are extremely strong, and one can pull a soldier ant in two without its releasing its hold. Large numbers of ants can kill small or immobilized animals and eat the flesh. A large part of their diet is earthworms. All Dorylus species are blind, though they, like most varieties of ants, communicate primarily through pheromones.[1]
In mating season alates (winged queens and drones) are formed. The drones are larger than the soldiers and the queens are much larger. They mate on the wing, and the queens go off to establish new colonies. As with most ants, workers and soldiers are sterile (or non-reproducing) females.[1]
Male driver ants, sometimes known as "sausage flies" (a term also applied to males of New World ecitonines) due to their bloated, sausage-like abdomens, are the largest known ants, and were originally believed to be members of a different species. Males leave the colony soon after hatching, but are drawn to the scent trail left by a column of siafu once it reaches sexual maturity. When a colony of driver ants encounters a male, they tear its wings off and carry it back to the nest to be mated with a virgin queen. As with all ants, the males die shortly afterward.[1]
Such is the strength of the ant's jaws, in East Africa they are used as natural, emergency sutures. Maasai moran, when they suffer a gash in the bush, will use the soldiers to stitch the wound, by getting the ants to bite on both sides of the gash, then breaking off the body. This seal can hold for days at a time.[3][4]
Several species in this genus carry out raids on termitaria, paralysing or killing some of the termites and carting them back to the nest. [5]
Species
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Cultural references
Film
Dorylus ants (called jaglavak by the Mofu people of northern Cameroon) were featured in the documentary Master of the Killer Ants, which aired on PBS in November 2007.[6]
Dorylus ants were featured in Indiana Jones and the Kingdom of the Crystal Skull, in which Indiana Jones calls them siafu ants, when he says, "Siafu. Big Damn Ants. Run!" They are portrayed as very violent ants, killing two Russian soldiers and carrying the bodies whole into their colonies. The ants are oversized in the film, and out of their natural habitat; siafu are not native to Peru or Brazil.
Dorylus ants were featured in Hellstrom Chronicle, a 1971 film in which a scientist explains the savagery and efficiency of the insect world.
Literature
Driver ants in The Poisonwood Bible take over an entire village, forcing the residents to flee.[7]
In Max Brooks' novel World War Z: An Oral History of The Zombie War, "Siafu" is the Japanese nickname given to Zombies due to their swarming nature and their habit of consuming everything in their wake.
In the 1934 novel Fear Cay, Kenneth Robeson (Lester Dent) wrote of flesh-eating ants (Carnivorous jormicoidea, according to Johnny) which swarmed over a cay in the Pacific, eating humans and animals alike.
See also the classic short story by Carl Stephenson, "Leinigen versus the ants" in which a Brazilian man fights against a swarm of army ants. (http://www.classicshorts.com/stories/lvta.html)
More recently, they have been referred to in Vertigo's comic, "Unknown Soldier #9", by Joshua Dysart and Alberto Ponticelli. Referred to as "responsible for more deaths than lions," they are used as a metaphor for the way that minor items can change society more than major events.
References
- ^ a b c d e f Hölldobler, Bert; Wilson, Edward O. (1990). The Ants. Belknap Press of Harvard University Press. ISBN 0674040759.
- ^ Master of the Killer Ants
- ^ Gottrup, F. & David Leaper (2004). "Wound healing: historical aspects" (PDF). EWMA Journal. 4 (2): p. 22.
{{cite journal}}:|pages=has extra text (help) - ^ Gudger, E. W. (1925). "Stitching Wounds With the Mandibles of Ants and Beetles". Journal of the American Medical Association. 84: pp. 1861–64.
{{cite journal}}:|pages=has extra text (help) - ^ Biotropics
- ^ Master of the Killer Ants
- ^ SparkNotes - The Poisonwood Bible
External links
