Colonies of dorylus driver ant's can grow to 6,000,000 strong. This type of ant splits their trails up to resemble a tree. They are varacious predators, their main tactic is to overwhelm their prey with numbers, i would guess maybe 100 ants on any prey exseading 1 inch in length. Now what's very interesting is that they build the tunnels and chambers of their nests out of their own bodies, and that they don't have eyes instead they use chemical trails secreated from the dufour's gland located near the anus by other nestmates. I leave the rest of the article for people to write about this amazing ant.
Workers small or of medium size, without eyes or ocelli, highly polymorphic, constituting a series of forms which may be grouped as maximae, or soldiers, mediae and minimae. In the maxima the head is very large and usually broader in front than behind, the mandibles are long and narrow, with a small number of teeth on the inner border, the clypeus is very short and not marked off from the remainder of the head by sutures. Frontal carinae very short, erect, close together, not concealing the insertions of the antennae. Antennae short, inserted very near the mouth, 9- to 12- jointed, according to the species. Mediae smaller, with much smaller and shorter head, but the latter not narrowed in front; anterior border of clypeus more or less projecting in the middle over the mouth. Antennae as in the maxima. Minima very small, with the head narrowed anteriorly and the anterior border of the clypeus strongly projecting in the middle. Number of antennal joints reduced, seven being the minimum. Promesonotal suture distinct in all three forms of worker; mesoepinotal suture obsolete. Epinotum always unarmed. Petiole nodiform; postpetiole narrowed anteriorly, not or only indistinctly separated from the first gastric segment. Pygidium with a dorsal impression and terminating in three points. Posterior tibiae each with a pectinated spur.
Female very much larger than the worker, dichthadiiform, i. e. wingless, with long and voluminous abdomen. The head has the occipital lobes swollen and rounded, separated by a median longitudinal furrow. Eyes and ocelli absent, as in the workers. Clypeus as in the worker maxima, or soldier. Mandibles narrow, edentate. Antennae 11-jointed (12-jointed in the subgenus Dichthadia ). Thorax segmented, but the mesonotum without differentiated scutum and scutellum; alar insertions vestigial. Petiole large, its posterior corners prolonged as blunt points. Postpetiole shorter than the first gastric segment, but not followed by a constriction. Pygidium and hypopygium gaping or separated so as to expose to view the eighth pair of abdominal spiracles, the anal segment and sting; the pygidium not impressed; the hypopygium surpassing the pygidium considerably and terminating in two lobes or appendages.
Male very large, with very large eyes and ocelli. Clypeus short, prolonged backward between the short, diverging frontal carinae. Mandibles edentate. Antennae 13-jointed; scape one-third or one-fourth as long as the funiculus which is filiform. Legs short; femora flattened, tibiae narrow. Wings with narrow, poorly defined pterostigma, placed near the apical third; radial cell elongate and open; one closed cubital cell, usually one recurrent nervure (two in the subgenus Rhogmus and in some anomalies). Petiole nodiform or saucer-shaped, its concavity turned toward the postpetiole, the latter not separated from the gaster by a constriction. Gaster long, cylindrical or club-shaped. Pygidium rounded or split at the posterior border ( Rhogmus fimbriatus ). Genital armature voluminous, completely retractile; annular lamina narrow; stipes and volsella simple; lacinia absent; subgenital plate deeply furcate.
Emery, who has devoted much careful study to the Dorylinae, divides Dorylus into six subgenera ( Dorylus , sensu stricto; Dichthadia , Gerstaecker; Anomma , Shuckard; Typhlopone Westwood ; Rhogmus Shuckard; Alaopone Emery) mainly on the number of antennal joints and structure of the pygidium in the worker, the number of antennal joints and shape of the hypopygium in the female, and the shape of the; mandibles and petiole in the male. The genus (Map 4) occurs throughout Africa, India, Indochina, the Malayan Region, and Indonesia (Borneo, Java, Sumatra, and Celebes). All but one of the subgenera and most of the species are found in Africa; in Asia there are less than half a dozen species belonging to the subgenera Dichthadia , Typhlopone , and Alaopone .
In the 'Genera Insectorum' (Dorylinae, 1910, p. 7) Emery makes the following statement on the ethology of the genus Dorylus:Apart from the subgenus Anomma all the species of Dorylus lead a subterranean life and come to the surface of the soil only on exceptional occasions, as, e. g., during inundations or in order to accompany the males when they take flight. Their societies are very populous. The soldiers and workers make subterranean expeditions for the. purpose of capturing insects and other small animals, and exploit manure piles, cadavers and probably also the nests of termites. The males come to lights at night. Search for the heavy and voluminous apterous females is beset with difficulties so that they are rare in collections. It may be noted that in all the specimens hitherto described, with the exception of the female of D. fimbriatus described by Brauns, the terminal tarsal joints are lacking. I infer that the workers tear them off durin g the underground forays, while they are dragging the colossal queen by all her legs through the narrow galleries.
Map
Dorylus, also known as driver ants, safari ants, or siafu, is a large genus of army ants found primarily in central and east Africa, although the range also extends to southern Africa and tropical Asia. The term siafu is a loanword from Swahili,[2] and is one of numerous similar words from regional Bantu languages used by indigenous peoples to describe various species of these ants. Unlike the New World members of the former subfamily Ecitoninae (now Dorylinae), members of this genus form temporary subterranean bivouacs in underground cavities which they excavate and inhabit - either for a few days or up to three months. Also unlike some New World army ants, driver ants are not specialized predators of other species of ant, instead being more generalistic with a diet consisting of a diversity of arthropods. Colonies are enormous compared to other army ants and can contain over 20 million individuals. As with their American counterparts, workers exhibit caste polymorphism with the soldiers having particularly large heads that power their scissor-like mandibles. They are capable of stinging, but very rarely do so, relying instead on their powerful shearing jaws.[3] Driver ant queens are the largest living ants known, with the largest measuring between 40 - 63 millimeters (1.5 - 2.4 inches) in total body length depending on their physiological condition.[4]
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 metres in an hour. It is for those unable to move, or when the columns pass through homes, that there is the greatest risk.[5] 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.[6] For example, driver ants prey on larvae of the African sugarcane borer, a pest moth in sub-Saharan Africa.
The characteristic long columns of ants will fiercely defend themselves against anything that attacks them.[3] Columns are arranged with the smaller ants being flanked by the larger soldier ants. These instinctively take up positions as sentries, and set a perimeter corridor through 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 it releasing its hold. Large numbers of ants can kill small or immobilized animals and strip them to husks. A large part of their diet is earthworms. All Dorylus species are blind, and, like most varieties of ants, communicate primarily through pheromones.[3]
In the mating season, alates (winged drones, queens of driver-ant species do not grow wings) are formed. The drones are larger than the soldiers and the queens are even larger. Driver ants do not perform a nuptial flight, but mate on the ground and the queens go off to establish new colonies. As with most ants, workers and soldiers are sterile females, and so do not reproduce.[3]
Male driver ants, sometimes known as "sausage flies" (a term also applied to males of New World dorylines) due to their bloated, sausage-like abdomens, are among the largest ant morphs 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 they reach sexual maturity. When a colony of driver ants encounters a male, they tear his wings off and carry him back to the nest to be mated with a virgin queen. As in the majority of ant species, males die shortly afterward.[3] After mating, the queen will lay up to 1,000,000 eggs per month.
Such is the strength of the ant's jaws that, in East Africa, they are used as natural emergency sutures. Various East African indigenous tribal peoples (e.g. Maasai moran), when suffering from 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 use of ants as makeshift surgical staples creates a seal that can hold for days at a time, and the procedure can be repeated, if necessary, allowing natural healing to commence.[7]
Several species in this genus carry out raids on termitaria, paralyzing or killing termites and carting them back to the nest.[8]
Colonies of driver-ant species have only one queen. When she dies, the surviving workers may try to join another colony, but in other cases, when two colonies of the same driver-ant species meet, they usually change the marching directions to avoid conflicts.
Dorylus, also known as driver ants, safari ants, or siafu, is a large genus of army ants found primarily in central and east Africa, although the range also extends to southern Africa and tropical Asia. The term siafu is a loanword from Swahili, and is one of numerous similar words from regional Bantu languages used by indigenous peoples to describe various species of these ants. Unlike the New World members of the former subfamily Ecitoninae (now Dorylinae), members of this genus form temporary subterranean bivouacs in underground cavities which they excavate and inhabit - either for a few days or up to three months. Also unlike some New World army ants, driver ants are not specialized predators of other species of ant, instead being more generalistic with a diet consisting of a diversity of arthropods. Colonies are enormous compared to other army ants and can contain over 20 million individuals. As with their American counterparts, workers exhibit caste polymorphism with the soldiers having particularly large heads that power their scissor-like mandibles. They are capable of stinging, but very rarely do so, relying instead on their powerful shearing jaws. Driver ant queens are the largest living ants known, with the largest measuring between 40 - 63 millimeters (1.5 - 2.4 inches) in total body length depending on their physiological condition.
