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Dorylus
Dorylus
Dorylus
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Dorylus
Dorylus gribodoi
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Leach, 1815
Subfamily: Dorylinae
Leach, 1815
Genus: Dorylus
Fabricius, 1793
Type species
Vespa helvola
Diversity[1]
61 species
Synonyms

Cosmaecetes Spinola, 1851
Shuckardia Emery, 1895
Sphecomyrmex Schulz, 1906
Sphegomyrmex Imhoff, 1852

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. Their colonies are enormous compared to other ant species, and can contain over 20 million individuals.[3] 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. A large part of their diet consists of earthworms. [4] 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.[5]

Life cycle

[edit]
Some soldier safari ants make tunnels to provide a safe route for the workers.

Seasonally, when food supplies become short, they leave the hill and form marching columns of up to 20,000,000 ants, which constitute a considerable threat to humans, though they can be easily avoided as 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.[6] The presence of a mobile column of safari ants is, conversely, beneficial to certain human communities, such as the Maasai. They perform a pest prevention service in farming communities, consuming the majority of other crop-pests, from insects to large rats.[7] 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.[4] 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. 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. the Maasai moran), when suffering from a laceration in the wilds, 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 for natural healing.[8] All Dorylus species are blind, and, like most varieties of ants, communicate primarily through pheromones.[4]

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.[4]

A male driver ant

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 recently hatched queen. As in the majority of ant species, males die shortly afterward.[4] Driver ant queens exhibit polyandry; young queens from some species with large colony sizes must mate with 10–20 males before they have gathered enough sperm for their reproductive lives.[9] Once the queen is ready, roughly half of the workers in the colony will leave with her to found a new colony.[10] Driver ant queens are the largest ants on Earth and have the greatest egg-laying capacity among insects, laying several million eggs each month.[11]

Several species in this genus carry out raids on termitaria, paralyzing or killing termites and carting them back to the nest.[12]

Colonies of driver-ant species have only one queen.[13] 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.[citation needed]

Species

[edit]
Dorylus sp. in Cameroon, consuming a grasshopper
Dorylus sp. in Zambia, consuming mayonnaise
A column of safari ants in Kakamega Forest, Kenya, guarded by soldiers

See also

[edit]

References

[edit]
[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Dorylus

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from Grokipedia
Dorylus is a of army in the Dorylinae, comprising highly specialized, nomadic predators characterized by enormous sizes, extreme worker polymorphism, and collective strategies that position them as dominant predators in tropical ecosystems. Primarily distributed across with extensions into southern and southeastern , the includes over 60 described divided into subgenera such as Anomma and Dorylus stricto, though phylogenetic analyses indicate these groupings are not monophyletic. These exhibit a derived involving periodic colony migrations and obligate group hunting, with foraging niches ranging from subterranean predation—often targeting nests—to spectacular surface swarm raids that can span up to 1,000 m² and attract opportunistic birds. Epigaeic species, particularly in the subgenus Anomma, form temporary above-ground bivouacs or subterranean nests, while raids are typically unlinked to emigration trails and occur unpredictably. Colonies are monogynous, featuring dichthadiiform queens that produce vast numbers of eggs, and workers vary dramatically in size, from minute minors weighing as little as 0.12 mg to large soldiers with specialized, ice-tong-like mandibles for defense and prey capture. Ecologically, Dorylus species play a pivotal role in regulating populations, particularly in forests where their raids influence community dynamics and serve as a resource for ant-following birds; some subterranean forms, like D. juvenculus, are obligate specialists. Molecular phylogenies trace the genus's origins to approximately 100 million years ago in , with evolutionary shifts from basal subterranean habits to surface foraging driving their diversification. Notable species include the widespread D. nigricans and D. wilverthi, feared locally as "driver ants" or "siafu" for their aggressive swarms that can overwhelm large prey, including small vertebrates.

Taxonomy and Classification

Etymology and Naming

The genus name Dorylus derives from the Greek word dory (δόρυ), meaning "spear" or "wooden shaft," alluding to the prominent, spear-like mandibles of the soldier caste used in aggressive foraging raids. This nomenclature reflects the ants' formidable predatory apparatus, which enables them to overpower and dismember prey efficiently. The full etymological breakdown ties into the subfamily Dorylinae, where the root emphasizes the weaponized morphology central to their ecology. Common names for Dorylus species vary regionally and highlight their behavioral traits. In English-speaking contexts, they are widely called "driver ants" due to their swarming raids that drive other animals and ahead of the column, a term popularized in 19th-century accounts describing their relentless pursuit of prey. They are also known as "safari ants" or "army ants," evoking images of organized military expeditions across African landscapes. In , the term "siafu" is commonly used, originating from to denote these invasive, nomadic predators that disrupt local communities during migrations. The genus was formally established by Danish entomologist Johan Christian Fabricius in 1793, based on the type species Vespa helvola Linnaeus, 1764, originally described from a male specimen collected in South Africa. Early taxonomy was complicated by the dimorphism between castes and sexes, leading to fragmented descriptions; for instance, workers and queens were often classified separately from males until connections were clarified. Subsequent revisions, including subgeneric divisions into six groups (e.g., Anomma for epigaeic raiders), have refined the classification, though molecular phylogenetic analyses indicate these subgenera are not monophyletic; comprehensive overviews provided in monographic works addressing morphological and phylogenetic ambiguities.

Phylogenetic Position

Dorylus belongs to the Dorylinae within the Formicidae, where it is the sole classified in the tribe Dorylini. This placement reflects the of Dorylinae, a group of predatory characterized by specialized lifestyles, as supported by molecular phylogenetic analyses that resolve Dorylus as sister to the Aenictogiton within the doryline . Dorylus shares a close evolutionary relationship with the army ants of the subfamily Ecitoninae, both exhibiting the army ant syndrome, including nomadic colony behavior and collective raiding. Fossil-calibrated phylogenies estimate the divergence between dorylines (including Dorylus) and New World ecitonines at approximately 80–100 million years ago, aligning with the radiation of ants during the angiosperm diversification. Key synapomorphies uniting Dorylinae, including Dorylus, encompass the permanent winglessness of (ergatoid morphology) and extreme worker polymorphism, which facilitate the division of labor in large, nomadic colonies. These traits, conserved across lineages, underscore the evolutionary stasis of the legionary syndrome, as detailed in comprehensive phylogenetic reviews.

Physical Description

Morphology of Workers and Soldiers

Dorylus workers exhibit pronounced polymorphism, divided into distinct subcastes such as minors, medias, majors, and soldiers, which vary significantly in size and form to fulfill specialized roles within the . Minor and media workers typically measure 2–5 mm in length, featuring compact bodies with mandibles that are triangular in shape and equipped with multiple denticles for efficient cutting of prey tissues and transportation of small food particles. In contrast, major workers and soldiers can reach lengths of 10–15 mm or more in certain , such as Dorylus nigricans and Dorylus arcens, with disproportionately enlarged heads that accommodate powerful musculature. The s of soldiers are a hallmark , being oversized, sickle-shaped (falcate), and often featuring smooth inner margins with minimal or no , optimized for seizing and slashing larger prey during raids or repelling threats. These structures provide a in predation and defense, reflecting evolutionary shifts correlated with strategies across Dorylus subgenera. Worker polymorphism in mandible and —ranging from the finely toothed versions in minors for versatile manipulation to the robust, curved blades in soldiers—enhances colony efficiency in resource acquisition and protection. Like other army ants, Dorylus workers and soldiers are blind, possessing no compound eyes and only rudimentary or absent ocelli in some individuals, an adaptation suited to their predominantly subterranean or low-light environments. Compensation for visual limitations occurs through enhanced antennal chemoreception, where elongated antennae in epigaeic detect volatile pheromones over distances, guiding swarm raids and maintaining integrity. This sensory reliance underscores the caste-specific morphological specializations that enable coordinated, mass- behaviors without visual input.

Queen and Male Characteristics

The queens of Dorylus species, also known as driver ants, are among the largest insects in the world, measuring 40–63 mm in total body length, with their size varying by species and physiological state. These queens are wingless after mating, a condition typical of the dichthadiiform morphology in the genus, where they develop a massively enlarged gaster adapted for egg production. The head is bulbous, featuring poorly developed, falcate mandibles that are short and lack serrations or distinct teeth, reflecting their specialized reproductive role rather than foraging. They are blind, lacking compound eyes and possessing only rudimentary or absent ocelli, which aligns with their subterranean or protected lifestyle within the colony. Reproductively, Dorylus queens exhibit extreme , capable of laying 3–4 million eggs per month during peak periods, contributing to sizes exceeding 20 million individuals over their lifespan. This high output is facilitated by the enlarged gaster, which stores vast quantities of sperm from multiple matings, as queens practice , inseminating with 10–20 males or more to ensure and colony robustness. Unlike some genera, Dorylus lacks gamergates—reproductive workers—relying solely on the true queen for egg production, which underscores the genus's dependence on a single, highly specialized reproductive individual. Males, referred to as alates or "sausageflies" due to their distinctive elongated abdomens, measure 25–35 mm in length and are winged for nuptial flights. Their morphology includes a transverse head with large compound eyes containing thousands of ommatidia and prominent ocelli, enabling navigation during mating swarms, while their mandibles are exceptionally large and falcate, far exceeding those of queens in size and adapted for brief adult functions. The abdomen is sausage-like and cylindrical, housing genitalia specialized for multiple inseminations, but males have a short lifespan, typically dying within days after mating once their reproductive role is fulfilled.

Distribution and Habitat

Geographic Range

The genus Dorylus, known for its species, ranges from through to Asia Minor and , with the majority of species occurring in central, eastern, and southern African regions. This distribution includes countries such as , , the , , , and , reflecting the genus's adaptation to diverse African tropical and subtropical environments. The highest species diversity within Dorylus is concentrated in , particularly in forested and habitats of the and surrounding areas, where over 50 have been recorded. In contrast, the genus is entirely absent from the , where analogous roles are filled by New World taxa like Eciton, and from , limiting its global presence to the Old World tropics. Extensions of the Dorylus range occur in , with several distributed from through to , including notable occurrences in , , , and . These Asian populations, comprising fewer than ten , represent peripheral extensions of the primarily African-centered genus. The broad historical spread of Dorylus is hypothesized to trace back to Gondwanan origins, with phylogenetic evidence indicating between African and Asian lineages following ancient continental fragmentation around 100-160 million years ago. As of assessments through 2024, no significant range expansions or invasions by Dorylus have been documented post-2020, maintaining the established distribution patterns.

Environmental Preferences

Dorylus species, commonly known as driver ants or army ants, exhibit a strong preference for tropical environments in and parts of , thriving in rainforests, savannas, and woodlands where vegetation provides ample cover and prey resources. These habitats offer the humid, resource-rich conditions essential for their subterranean foraging and raiding activities, with colonies often establishing in areas of dense undergrowth or secondary forests disturbed by human activity. They actively avoid extreme regions, which lack the moisture and abundance required for sustained colony survival, as well as high-altitude zones above approximately 3,000 meters where temperatures drop below optimal levels. Colonies construct temporary bivouacs that are predominantly subterranean, excavating chambers in soil, leaf litter, or pre-existing cavities such as mounds, which provide protection from predators and environmental fluctuations. While some species may occasionally utilize arboreal sites like hollows in forested areas, the majority favor underground structures to maintain and stability. This nomadic lifestyle is closely linked to resource availability, with colonies frequently emigrating—sometimes daily—to follow prey concentrations, ensuring access to food in dynamic tropical ecosystems. Dorylus ants are adapted to a temperature range of 20–30°C, characteristic of their tropical niches, where ambient warmth supports metabolic rates and brood development without exceeding thermal tolerances. They demonstrate sensitivity to conditions, responding by burrowing deeper into the to access moister layers and conserve , a behavioral adjustment that helps mitigate the impacts of seasonal dry periods in savannas and woodlands.

Life Cycle

Reproduction and Colony Founding

The queens of Dorylus species exhibit extreme , mating with an exceptionally high number of males—up to 17 or more—during brief swarming events that facilitate dispersal and . These alate males, often called "sausage flies" due to their distended, sperm-filled abdomens, emerge in large swarms primarily at night to locate and inseminate virgin near colony sites. Following mating, the queens store the collected sperm in their for lifelong use, enabling continuous egg production without remating throughout their extended lifespan. This stored sperm supports the queen's prodigious reproductive output, with Dorylus wilverthi queens capable of laying up to 3–4 million eggs per month, primarily workers, in massive synchronized batches that sustain the colony's nomadic lifestyle. The highly physogastric queens, which can weigh around 2 grams and measure up to 5 cm in length, achieve this rate through their enlarged ovaries adapted for bulk egg production. Sexual brood, consisting of new queens and males, is produced less frequently, approximately every 2–3 years depending on species and environmental conditions, marking a shift in the colony's reproductive cycle. Unlike many species with independent colony founding by single mated , Dorylus colonies reproduce exclusively through fission, where a mature colony divides into multiple independent units during the sexual brood emergence. In this process, the old queen ceases laying eggs as the colony produces thousands of males and a small number of new virgin ; after , one or more new lead daughter colonies, each inheriting a portion of the workforce—often hundreds of thousands of workers—bypassing a vulnerable single-foundress stage. This fission strategy ensures rapid establishment of robust , with excess new typically cannibalized by workers to maintain monogyny in each unit.

Developmental Stages

The developmental stages of Dorylus ants encompass the standard holometabolous progression observed in Formicidae: , , , and . Eggs, laid by the colony queen, undergo incubation for approximately 2-3 weeks under the regulated conditions of the bivouac, where workers maintain optimal and through clustering and ventilation behaviors. Upon , the resulting larvae are legless, eruciform grubs that depend entirely on worker care for survival. Larval development spans 3-4 weeks and involves multiple instars (typically four), during which workers feed via trophallaxis—regurgitating predigested liquids and solids derived from raided prey. This nutritional provisioning is critical, as differential feeding determines fate: well-nourished larvae develop into soldiers or reproductives, while underfed ones become smaller workers, a polyphenic response driven by larval size at the onset of pupation. Larvae grow rapidly, molting several times as they consume vast quantities of protein-rich food transported back to the . Pupation follows larval maturity, occurring without cocoons—a trait unique to Dorylus and certain other dorylines—directly within the protective bivouac structure formed by interlocked workers. The pupal stage lasts about 2-3 weeks, during which the immobile, exarate pupae undergo , with eclosion yielding callow adults that harden over several days before integrating into activities. This naked pupation exposes to greater risk but aligns with the colony's mobile lifestyle. Throughout these stages, Dorylus colonies exhibit asynchronous brood development, lacking the strict synchrony seen in some army ants, which allows continuous growth rather than phased bursts. New colonies formed via fission, each with a new queen and portion of the , expand rapidly through successive brood cycles, potentially reaching up to 20 million individuals within months as worker production accelerates capacity and resource intake.

Behavior and Social Structure

Foraging and Raiding Patterns

Dorylus colonies exhibit highly organized foraging strategies characterized by mass raids that enable efficient resource acquisition across diverse habitats. These raids typically form as dense columns of workers extending from the colony's temporary nest, allowing the ants to exploit prey in a coordinated manner. In epigaeic species, such as those in the subgenus Anomma, raids can manifest as expansive swarms that overrun surface areas, while hypogaeic species like Dorylus laevigatus rely on subterranean columnar trails for more targeted incursions. Columnar raids in Dorylus can reach lengths of up to 100 meters, advancing at speeds of approximately 20 meters per hour, facilitating the coverage of large grounds. These formations consist of thousands of workers, with minor workers scouting ahead and major workers recruited to subdue larger prey upon discovery. Swarm foraging complements this by deploying broader fronts, up to several meters wide and 3 to 8 meters long, lasting 2 to 3 hours and targeting clustered arthropods in leaf litter or . Such patterns allow colonies to harvest resources opportunistically without fixed nest-bound trails. The diet of Dorylus primarily consists of , including earthworms, , beetles, and caterpillars, particularly targeting social insects such as and . Dietary preferences vary; hypogaeic species often specialize on social insects like and , while epigaeic species exhibit more generalist predation. Raids occasionally extend to vertebrate carrion, such as small mammals or experimental baits like , providing supplemental protein when available. This broad opportunistic predation underscores the ants' role as generalist apex , preying on live arthropods encountered during advances rather than pursuing specific taxa. During extended raids, Dorylus workers establish temporary bivouacs—living nests formed by interlocking bodies—to house the queen, brood, and resting foragers, often in cavities or elevated structures. These bivouacs, measuring up to 11 cm wide, serve as mobile hubs that shift with the raid's progression, ensuring colony cohesion. trails laid by workers' gaster tips guide subsequent recruits along exploratory and trunk paths, with stable hypogaeic systems enabling persistent efficiency over distances up to 4 meters deep.

Communication and Defense

Dorylus ants, like other army ants, rely heavily on chemical signaling through pheromones for internal coordination. Trail pheromones are deposited by scout workers to guide foraging columns to prey sources, enabling efficient mass recruitment during raids; this mechanism is particularly prominent in large-colony species such as Dorylus, where pheromones reinforce paths and facilitate collective . pheromones, released from mandibular or Dufour's glands, alert nestmates to threats by triggering rapid mobilization and aggressive responses, ensuring quick defensive postures across the colony. In addition to pheromones, soldiers employ —rubbing a file-like structure on their against a scraper to produce vibrational signals—as a supplementary alert mechanism, which propagates through the colony substrate to summon reinforcements without visual cues. Defensive strategies in Dorylus emphasize the role of specialized castes, which form compact formations to protect the colony core during raids or emigrations. These s, equipped with oversized heads and powerful, serrated mandibles capable of locking onto intruders, create interlocking barriers that deter predators by inflicting severe bites; such mandibular snaps provide both offensive and defensive capabilities, often resulting in the predator's withdrawal due to pain and injury. Colony-level defense is further enhanced by nestmate recognition pheromones embedded in cuticular hydrocarbons, which allow workers to distinguish familiar colony members from outsiders, thereby avoiding costly inter-colony conflicts through evasion or selective . This chemical discrimination promotes spatial separation between colonies, minimizing direct confrontations in shared habitats. Given their blindness, Dorylus workers navigate raids and migrations using a combination of tactile and chemical cues, with maintaining contact via antennae and body linkages to follow trails in dense columns. Tactile feedback from neighboring ensures column cohesion, while chemical gradients provide directional guidance, allowing the swarm to advance blindly yet purposefully over . In response to predators such as birds that opportunistically feed on flushed prey during raids or mammals like aardvarks that excavate bivouacs, the colony mounts a coordinated ; soldiers rush to the site, locking mandibles onto the intruder to immobilize it, often forcing retreat through sheer numbers and persistence. These defenses highlight the superorganism-like integration of Dorylus colonies, where individual sacrifices bolster collective survival.

Ecological Interactions

Role in Ecosystems

Dorylus ants serve as top predators in African ecosystems, exerting significant control over pest populations through their aggressive raids. For instance, such as Dorylus helvolus prey on larvae of the sugarcane borer Eldana saccharina, a major agricultural pest in , with serological tests confirming predation rates contributing to 33% of ant-mediated attacks on this pest in South African sugarcane fields. This predatory role helps regulate herbivorous densities, preventing outbreaks that could otherwise devastate crops and native vegetation. Their subterranean nesting and foraging behaviors also contribute to soil aeration and structure modification. Colonies actively excavate extensive underground tunnels and nests, displacing soil and enhancing soil porosity, water infiltration, and oxygen availability in floors. Related hypogaeic Dorylus , such as D. laevigatus, further support this by constructing stable trail systems at depths of 8-20 cm, promoting nutrient cycling through the of consumed prey and waste deposition. Dorylus form a critical link in food webs as prey for larger vertebrates. Chimpanzees (Pan troglodytes) across Central and East African forests actively hunt these using tools like sticks to extract them from nests and raids, with rare observations in Ugandan sites like Budongo Forest documenting this behavior, though ant-feeding remains uncommon in their diet. Similarly, various bird species, including ant-following specialists in Afrotropical rainforests, consume Dorylus individuals disturbed during swarm raids, integrating them into avian diets while also exploiting the raids to capture fleeing arthropods. By curbing populations, Dorylus indirectly supports plant health and reproductive processes, including , as reduced pest pressure allows for better flower development and access in disturbed habitats. Their raids can temporarily disrupt local by decimating prey in raided areas, yet this predation promotes overall nutrient cycling by redistributing through colony waste and prey remains, fostering in tropical ecosystems. Primarily native to and parts of southern and southeastern , Dorylus exhibit no invasive tendencies, maintaining balanced ecological dynamics without expanding beyond their natural range.

Relationships with Humans and Other Species

Dorylus provide several benefits to human communities in their native range, particularly through their role in natural . Among the of and , these are valued for preying on crop-damaging , helping to protect agricultural fields without the need for chemical interventions. In broader contexts across tropical , driver ants like those in the genus Dorylus consume vast numbers of pest species during their foraging raids, contributing to biological control efforts in ecosystems where they occur. Additionally, indigenous groups have long utilized the powerful mandibles of Dorylus soldier as natural sutures in ; the ant is positioned to bite the edges of a , and its body is then removed, leaving the head clamped in place to close the injury until healing occurs. Despite these advantages, interactions between Dorylus and humans often involve significant conflicts due to the ' aggressive raiding behavior. During swarm raids, which can move at speeds of 6–14 meters per hour, columns of may invade homes or camps, leading to painful encounters where soldiers bite exposed skin, leaving that cause intense pain from the ' alkaloid venom. Such invasions have resulted in severe medical cases, including , , and ulcerated lesions, as documented in a Ugandan incident where a man sleeping outdoors suffered multiple bites leading to systemic shock. Encounters with red Dorylus ants, such as D. helvolus, are particularly noted during hiking and trekking activities in Uganda, where they can be aggressive if disturbed, such as when stepped on, leading to painful bites and occasional stings, as mentioned in travel guides for gorilla trekking in areas like Bwindi Impenetrable Forest. Cultural perceptions exacerbate these tensions, with Dorylus often mythologized as "killer " capable of overwhelming and consuming large animals or even humans, though such accounts are greatly exaggerated—healthy individuals can easily evade swarms, and fatalities are extremely rare, typically limited to immobilized victims like infants. Interspecific relationships of Dorylus extend beyond predation to include avoidance strategies and opportunistic with non-prey . Colonies of different Dorylus or even conspecifics typically avoid direct encounters during raids to minimize costly intercolony battles. A notable occurs with various African , which follow Dorylus raids—particularly those of D. wilverthi and D. molestus—as indicator events, on flushed by the ants; up to 56 , including specialized ant-followers like the fire-crested alethe (Alethe castanea), attend these swarms, relying on them for a significant portion of their diet in habitats. However, no mutualistic relationships between Dorylus and other ant or have been documented, with interactions largely limited to predation or evasion.

Species Diversity

Overview of Species

The genus Dorylus comprises over 60 recognized . These are traditionally divided into subgenera such as Anomma and Dorylus stricto, though a 2016 taxonomic revision synonymized several subgenera under the main due to non-monophyly in some cases. Over 50 are distributed across , with notable in the , while fewer than 10 occur in , mainly in the Indomalayan region of . remains challenging, as many are known only from males or workers, complicating worker-male associations.

Notable Species and Variations

Dorylus nigricans, commonly known as the siafu or driver ant, is renowned for hosting some of the largest colonies among army ants, with estimates reaching up to 20 million workers per colony. These massive societies are primarily distributed across West and Central Africa, where the species exhibits highly aggressive raiding behavior, forming extensive swarms that overwhelm prey through sheer numbers. The dry biomass of such colonies can range from 9 to 15 kg, underscoring their ecological dominance in tropical forest understories. In contrast, Dorylus helvolus is a primarily African species distributed across sub-Saharan Africa, including Uganda, with additional occurrences in Southeast Asia, and notably smaller colony sizes compared to many African counterparts. This species features workers with a distinctive yellowish to reddish coloration and a broad size polymorphism, ranging from small majors to larger soldiers equipped for subterranean . D. helvolus exhibits aggressive behavior, with workers capable of biting or stinging if disturbed, such as when stepped on during hikes in Ugandan forests. While less prone to surface raids, D. helvolus maintains the nomadic lifestyle typical of Dorylus, adapting to diverse habitats from forests to agricultural edges. Intraspecific variations within the include notable color morphs, spanning black to reddish hues depending on geographic populations, which may reflect adaptations to local environmental conditions. Size differences also occur across populations, with some exhibiting larger workers in resource-rich areas, influencing foraging efficiency. Additionally, Dorylus gribodoi is prevalent in West African regions like .

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  50. https://www.jstor.org/stable/3068104
  51. https://www.antwiki.org/wiki/Dorylus_nigricans
  52. https://antwiki.org/wiki/Dorylus_helvolus
  53. https://www.wildwonderfulworld.com/post/gorilla-trekking-faq-tips-tricks
  54. https://www.alexanderwild.com/Ants/Taxonomic-List-of-Ant-Genera/Dorylus/i-7KzD3S2
  55. http://antsofafrica.org/ant_species_2012/colours.htm
  56. https://www.antwiki.org/wiki/Dorylus_gribodoi
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