HOME

TheInfoList



OR:

''Myrmecia'' is a
genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomencla ...
of
ants Ants are eusocial insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from vespoid wasp ancestors in the Cretaceous period. More than 13,800 of an estimated total of 22,0 ...
first established by Danish
zoologist Zoology ()The pronunciation of zoology as is usually regarded as nonstandard, though it is not uncommon. is the branch of biology that studies the animal kingdom, including the structure, embryology, evolution, classification, habits, and dis ...
Johan Christian Fabricius Johan Christian Fabricius (7 January 1745 – 3 March 1808) was a Danish zoologist, specialising in "Insecta", which at that time included all arthropods: insects, arachnids, crustaceans and others. He was a student of Carl Linnaeus, and is co ...
in 1804. The genus is a member of the subfamily
Myrmeciinae Myrmeciinae is a subfamily of the Formicidae, ants once found worldwide but now restricted to Australia and New Caledonia. This subfamily is one of several ant subfamilies which possess gamergates, female worker ants which are able to mate an ...
of the family Formicidae. ''Myrmecia'' is a large genus of ants, comprising at least 93 species that are found throughout Australia and its coastal islands, while a single species is only known from
New Caledonia ) , anthem = "" , image_map = New Caledonia on the globe (small islands magnified) (Polynesia centered).svg , map_alt = Location of New Caledonia , map_caption = Location of New Caledonia , mapsize = 290px , subdivision_type = Sovereign st ...
. One species has been introduced out of its natural distribution and was found in
New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island country ...
in 1940, but the ant was last seen in 1981. These ants are commonly known as bull ants, bulldog ants or jack jumper ants, and are also associated with many other
common names In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often contrast ...
. They are characterized by their extreme aggressiveness, ferocity, and painful stings. Some species are known for the jumping behavior they exhibit when agitated. Species of this genus are also characterized by their elongated
mandibles In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bone ...
and large
compound eyes A compound eye is a visual organ found in arthropods such as insects and crustaceans. It may consist of thousands of ommatidia, which are tiny independent photoreception units that consist of a cornea, lens, and photoreceptor cells which disti ...
that provide excellent vision. They vary in colour and size, ranging from . Although workers and queens are hard to distinguish from each other due to their similar appearance, males are identifiable by their perceptibly smaller mandibles. Almost all ''Myrmecia'' species are monomorphic, with little variation among workers of a given species. Some queens are
ergatoid An ergatoid (from Greek '' ergat-'', "worker" + '' -oid'', "like") is a permanently wingless reproductive adult ant or termite. The similar but somewhat ambiguous term ergatogyne refers to any intermediate form between workers and standard gynes. ...
and have no wings, while others have either stubby or completely developed wings. Nests are mostly found in soil, but they can be found in rotten wood and under rocks. One species does not nest in the ground at all; its colonies can only be found in trees. A queen will mate with one or more males, and during colony foundation she will hunt for food until the brood have fully developed. The life cycle of the ant from egg to adult takes several months. ''Myrmecia'' workers exhibit greater longevity in comparison to other ants, and workers are also able to reproduce with male ants. ''Myrmecia'' is one of the most primitive group of ants on earth, exhibiting differentiated behaviors from other ants. Workers are solitary hunters and do not lead other workers to food. Adults are
omnivores An omnivore () is an animal that has the ability to eat and survive on both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize the nut ...
that feed on sweet substances, but the larvae are carnivores that feed on captured prey. Very few predators eat these ants due to their sting, but their larvae are often consumed by
blindsnake The Scolecophidia, commonly known as blind snakes or thread snakes, are an infraorder of snakes. They range in length from . All are fossorial (adapted for burrowing). Five families and 39 genera are recognized. The Scolecophidia infraorder is mos ...
s and
echidna Echidnas (), sometimes known as spiny anteaters, are quill-covered monotremes (egg-laying mammals) belonging to the family Tachyglossidae . The four extant species of echidnas and the platypus are the only living mammals that lay eggs and the ...
s, and a number of parasites infect both adults and brood. Some species are also effective pollinators. ''Myrmecia'' stings are very potent, and the venom from these ants is among the most toxic in the insect world. In
Tasmania ) , nickname = , image_map = Tasmania in Australia.svg , map_caption = Location of Tasmania in AustraliaCoordinates: , subdivision_type = Country , subdi ...
, 3% of the human population are allergic to the venom of ''M. pilosula'' and can suffer life-threatening anaphylactic reactions if stung; at least three human deaths have been recorded since 1936. People prone to severe allergic reactions can be treated with
allergen immunotherapy Allergen immunotherapy, also known as desensitization or hypo-sensitization, is a medical treatment for environmental allergies, such as insect bites, and asthma. Immunotherapy involves exposing people to larger and larger amounts of allergen in ...
(desensitisation).


Etymology and common names

The
generic Generic or generics may refer to: In business * Generic term, a common name used for a range or class of similar things not protected by trademark * Generic brand, a brand for a product that does not have an associated brand or trademark, other ...
name ''Myrmecia'' derives from Greek word ''Myrmec-'' ( + -''ia''), meaning "ant". In
Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to t ...
, the
Indigenous Australians Indigenous Australians or Australian First Nations are people with familial heritage from, and membership in, the ethnic groups that lived in Australia before British colonisation. They consist of two distinct groups: the Aboriginal peoples ...
called these ants ''kallili'' or ''killal.'' Ants of this genus are popularly known as bulldog ants, bull ants, or
jack jumper ant Jack may refer to: Places * Jack, Alabama, US, an unincorporated community * Jack, Missouri, US, an unincorporated community * Jack County, Texas, a county in Texas, USA People and fictional characters * Jack (given name), a male given name, ...
s due to their ferocity and the way they hang off their victims using their mandibles, and also due to the jumping behaviour displayed by some species. Other common names include "inch ants", "sergeant ants", and "soldier ants". The jack jumper ant and other members of the ''Myrmecia pilosula'' species group are commonly known as "black jumpers", "hopper ants", "jumper ants", "jumping ants", "jumping jacks", and "skipper ants".


Taxonomy and evolution

Genetic evidence suggests that ''Myrmecia'' diverged from related groups about 100 million years ago (Mya). The subfamily Myrmeciinae, to which ''Myrmecia'' belongs, is believed to have been found in the
fossil record A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in ...
of 110 Mya ago. However, one study suggests that the age of the
most recent common ancestor In biology and genetic genealogy, the most recent common ancestor (MRCA), also known as the last common ancestor (LCA) or concestor, of a set of organisms is the most recent individual from which all the organisms of the set are descended. The ...
for ''Myrmecia'' and ''
Nothomyrmecia ''Nothomyrmecia'', also known as the dinosaur ant or dawn ant, is an extremely rare genus of ants consisting of a single species, ''Nothomyrmecia macrops''. These ants live in South Australia, nesting in old-growth mallee woodland and ''Eucalyp ...
'' is 74 Mya, and the subfamily is possibly younger than previously thought. Ants of the extinct genus '' Archimyrmex'' may possibly be the ancestor of ''Myrmecia''. In the Evans' vespoid scala, ''Myrmecia'' and other primitive ant genera such as ''
Amblyopone ''Amblyopone'' is a genus of 10 species of ants, found in Australia, New Caledonia, New Guinea and New Zealand.Yoshimura, M.; Fisher, B.L. 2012: A revision of male ants of the Malagasy Amblyoponinae (Hymenoptera: Formicidae) with resurrections of ...
'' and ''Nothomyrmecia'' exhibit behavior which is similar to a clade of soil-dwelling families of vespoid wasps. Four species groups form a
paraphyletic In taxonomy, a group is paraphyletic if it consists of the group's last common ancestor and most of its descendants, excluding a few monophyletic subgroups. The group is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...
assemblage while five species groups form a
monophyletic In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gro ...
assemblage. The following
cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to ...
shows the phylogenetic relationships within ''Myrmecia'':


Classification

''Myrmecia'' was first established by Danish
zoologist Zoology ()The pronunciation of zoology as is usually regarded as nonstandard, though it is not uncommon. is the branch of biology that studies the animal kingdom, including the structure, embryology, evolution, classification, habits, and dis ...
Johan Christian Fabricius Johan Christian Fabricius (7 January 1745 – 3 March 1808) was a Danish zoologist, specialising in "Insecta", which at that time included all arthropods: insects, arachnids, crustaceans and others. He was a student of Carl Linnaeus, and is co ...
in his 1804 publication ''Systema Piezatorum'', in which seven species from the genus ''
Formica ''Formica'' is a genus of ants of the family Formicidae, commonly known as wood ants, mound ants, thatching ants, and field ants. ''Formica'' is the type genus of the Formicidae, and of the subfamily Formicinae. The type species of genus ''For ...
'' were placed into the genus along with the description of four new species. ''Myrmecia'' has been classified into numerous families and subfamilies; in 1858, British entomologist Frederick Smith placed it in the family Poneridae, subfamily Myrmicidae. It was placed in the subfamily
Ponerinae Ponerinae is a subfamily of ants in the Poneromorph subfamilies group, with about 1,600 species in 47 extant genera, including ''Dinoponera gigantea'' - one of the world's largest species of ant. Mated workers have replaced the queen as the ...
by Austrian entomologist
Gustav Mayr Gustav L. Mayr (12 October 1830 – 14 July 1908) was an Austrian entomologist and professor in Budapest and Vienna. He specialised in Hymenoptera, being particularly known for his studies of ants.Myrmicinae Myrmicinae is a subfamily of ants, with about 140 extant genera; their distribution is cosmopolitan. The pupae lack cocoons. Some species retain a functional sting. The petioles of Myrmicinae consist of two nodes. The nests are permanent and ...
three years later. In 1877, Italian entomologist
Carlo Emery Carlo Emery (25 October 1848, Naples – 11 May 1925) was an Italian entomologist. He is remembered for Emery's rule, which states that insect social parasites are often closely related to their hosts. Early in his career Carlo Emery pursued ...
classified the genus into the newly established subfamily Myrmeciidae, family Myrmicidae. Smith, who had originally established the Myrmicidae as a family in 1851, reclassified them as a subfamily in 1858. He again treated them as a family in 1871. Swiss
myrmecologist Myrmecology (; from Greek: μύρμηξ, ''myrmex'', "ant" and λόγος, ''logos'', "study") is a branch of entomology focusing on the scientific study of ants. Some early myrmecologists considered ant society as the ideal form of society and ...
Auguste Forel Auguste-Henri Forel (1 September 1848 – 27 July 1931) was a Swiss myrmecologist, neuroanatomist, psychiatrist and eugenicist, notable for his investigations into the structure of the human brain and that of ants. For example, he is considered a ...
initially treated the Poneridae as a subfamily and classified ''Myrmecia'' as one of its constituent genera but later placed it in the Ponerinae. William H. Ashemad placed the genus in the subfamily Myrmeciinae in 1905, but it was later placed back in the Ponerinae in 1910 by American entomologist
William Morton Wheeler William Morton Wheeler (March 19, 1865 – April 19, 1937) was an American entomologist, myrmecologist and Harvard professor. Biography Early life and education William Morton Wheeler was born on March 19, 1865, to parents Julius Morton Wheeler ...
. In 1954, ''Myrmecia'' was placed into the Myrmeciinae; this was the last time the genus was placed into a different ant subfamily. In 1911, Emery classified the
subgenera In biology, a subgenus (plural: subgenera) is a taxonomic rank directly below genus. In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed between t ...
''Myrmecia'', ''Pristomyrmecia'', and ''Promyrmecia'', based on the shape of their mandibles. Wheeler established the subgenus ''Halmamyrmecia'', and the ants placed in it were characterized by their jumping behavior. The taxon Wheeler described was not referred to in his later publications, and the genera ''Halmamyrmecia'' and ''Pristomyrmecia'' were synonymised by John Clark. At the same time, Clark reclassified the subgenus ''Promyrmecia'' as a full genus. He revised the whole subfamily Myrmeciinae in 1951, recognizing 118 species and subspecies in ''Myrmecia'' and ''Promyrmecia''; five species groups were assigned to ''Myrmecia'' and eight species groups to ''Promyrmecia''. This revision was rejected by entomologist William Brown due to the lack of morphological evidence that would make the two genera distinct from each other. Due to this, Brown classified ''Promyrmecia'' as a synonym of ''Myrmecia'' in 1953. Clark's revision was the last major taxonomic study on the genus before 1991, and only a single species was described in the intervening years. In 2015, four new ''Myrmecia'' ants were described by Robert Taylor, all exclusive to Australia. Currently, 94 species are described in the genus, but as many as 130 species may exist. Under the present classification, ''Myrmecia'' is the only extant genus in the tribe Myrmeciini, subfamily
Myrmeciinae Myrmeciinae is a subfamily of the Formicidae, ants once found worldwide but now restricted to Australia and New Caledonia. This subfamily is one of several ant subfamilies which possess gamergates, female worker ants which are able to mate an ...
. It is a member of the family Formicidae in the order
Hymenoptera Hymenoptera is a large order of insects, comprising the sawflies, wasps, bees, and ants. Over 150,000 living species of Hymenoptera have been described, in addition to over 2,000 extinct ones. Many of the species are parasitic. Females typic ...
. The
type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen( ...
for the genus is '' M. gulosa'', discovered by
Joseph Banks Sir Joseph Banks, 1st Baronet, (19 June 1820) was an English naturalist, botanist, and patron of the natural sciences. Banks made his name on the 1766 natural-history expedition to Newfoundland and Labrador. He took part in Captain James C ...
in 1770 during his expedition with
James Cook James Cook (7 November 1728 Old Style date: 27 October – 14 February 1779) was a British explorer, navigator, cartographer, and captain in the British Royal Navy, famous for his three voyages between 1768 and 1779 in the Pacific Ocean and ...
on HMS ''Endeavour''. ''M. gulosa'' is among the earliest Australian insects to be described, and the specimen Banks collected is housed in the Joseph Banks Collection in the
Natural History Museum, London The Natural History Museum in London is a museum that exhibits a vast range of specimens from various segments of natural history. It is one of three major museums on Exhibition Road in South Kensington, the others being the Science Museum an ...
. ''M. gulosa'' was described by Fabricius in 1775 under the name ''Formica gulosa'' and later designated as the type species of ''Myrmecia'' in 1840.


Genetics

The number of
chromosomes A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins are ...
per individual varies from one to over 70 among the species in the genus. The
genome In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding gen ...
of ''M. pilosula'' is contained on a single pair of chromosomes (males have just one chromosome, as they are
haploid Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Sets of chromosomes refer to the number of maternal and paternal chromosome copies, respecti ...
). This is the lowest number possible for any animal, and workers of this species are homologous. Like ''M. pilosula'', ''M. croslandi'' also contains a single chromosome. While these ants only have a single chromosome, ''M. pyriformis'' contains 41 chromosomes, while ''M. brevinoda'' contains 42. The chromosome count for ''M. piliventris'' and ''M. fulvipes'' is two and 12, respectively. The genus ''Myrmecia'' retains many traits that are considered basal for all ants (i.e. workers foraging alone and relying on visual cues).


Species groups

''Myrmecia'' contains a total of nine species groups. Originally, seven species groups were established in 1911, but this was raised to 13 in 1951; ''Promyrmecia'' had a total of eight, while ''Myrmecia'' only had five. '' M. maxima'' does not appear to be in a species group, as no
type specimen In biology, a type is a particular specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to anchor or centralizes th ...
is available.


Description

''Myrmecia'' ants are easily noticeable due to their large mandibles, large compound eyes that provide excellent vision and a powerful sting that they use to kill prey. Each of their eyes contains 3,000 facets, making them the second largest in the ant world. Size varies widely, ranging from in length. The largest ''Myrmecia'' species is ''M. brevinoda'', with workers measuring ; ''M. brevinoda'' workers are also the largest in the world. Almost all species are monomorphic, but ''M. brevinoda'' is the only known species where polymorphism exists. It is well known that two worker subcastes exist, but this does not distinguish them as two different polymorphic forms. This may be due to the lack of food during winter and they could be incipient colonies. The
division of labour The division of labour is the separation of the tasks in any economic system or organisation so that participants may specialise (specialisation). Individuals, organizations, and nations are endowed with, or acquire specialised capabilities, and ...
is based on the size of ant, rather than its age, with the larger workers foraging for food or keeping guard outside the nest, while the smaller workers tend to the brood. Their coloration is variable; black combined with red and yellow is a common pattern, and many species have golden-colored pubescence (hair). Many other species are brightly colored which warns predators to avoid them. The formicine ant '' Camponotus bendigensis'' is similar in appearance to ''M. fulvipes'', and data suggest ''C. bengdigensis'' is a
batesian mimic Batesian mimicry is a form of mimicry where a harmless species has evolved to imitate the warning signals of a harmful species directed at a predator of them both. It is named after the English naturalist Henry Walter Bates, after his work on bu ...
of ''M. fulvipes''. The number of
malpighian tubules The Malpighian tubule system is a type of excretory and osmoregulatory system found in some insects, myriapods, arachnids and tardigrades. The system consists of branching tubules extending from the alimentary canal that absorbs solutes, wat ...
differs between castes; in ''M. dispar'', males have 16 tubules, queens range from 23 to 26, and workers have 21 to 29. Worker ants are usually the same size as each other, although this is not true for some species; worker ants of ''M. brevinoda'', for example, vary in length from . The mandibles of the workers are long with a number of teeth, and the clypeus is short. The antennae consist of 12 segments and the eyes are large and convex. Based on a study on the antennal sensory of ''M. pyriformis'', the antennal
sensilla A sensillum (plural ''sensilla'') is an arthropod sensory organ protruding from the cuticle of exoskeleton, or sometimes lying within or beneath it. Sensilla appear as small hairs or pegs over an individual's body. Inside each sensillum there are ...
are known to have eight types. Large
ocelli A simple eye (sometimes called a pigment pit) refers to a form of eye or an optical arrangement composed of a single lens and without an elaborate retina such as occurs in most vertebrates. In this sense "simple eye" is distinct from a multi-le ...
are always present. Queens are usually larger than the workers, but are similar in colour and body shape. The head, node, and postpetiole are broader in the queen, and the mandibles are shorter and also broad. ''Myrmecia'' queens are unique in that particular species either have fully winged queens, queens with poorly developed wings, or queens without any wings. For example, ''M. aberrans'' and ''M. esuriens'' queens are
ergatoid An ergatoid (from Greek '' ergat-'', "worker" + '' -oid'', "like") is a permanently wingless reproductive adult ant or termite. The similar but somewhat ambiguous term ergatogyne refers to any intermediate form between workers and standard gynes. ...
, meaning that they are wingless. Completely excavated nests showed no evidence of any winged queen residing within them. Some species have queens which are subapterous, meaning they are either wingless or only have rudiments of wings; the queens can be well developed with or without these wing buds. ''M. nigrocincta'' and ''M. tarsata'' are " brachypterous", where queens have small and rudimentary wings which render the queen flightless. Dealated queens with developed wings and thoraces are considered rare. In some species, such as ''M. brevinoda'' and ''M. pilosula'', three forms of queens exist, with the dealated queens being the most recognisable. Males are easy to identify due to their perceptibly broad and smaller mandibles. Their antennae consist of 13 segments, and are almost the same length as the ants' bodies. Ergatandromorph (an ant that exhibits both male and worker characteristics) males are known; in 1985, a male ''M. gulosa'' was collected before it hatched from its cocoon, and it had a long but excessively curved left mandible while the other mandible was small. On the right side of its body, it was structurally male, but the left side appeared female. The head was also longer on the female side, its colour was darker, and the legs and
prothorax The prothorax is the foremost of the three segments in the thorax of an insect, and bears the first pair of legs. Its principal sclerites (exoskeletal plates) are the pronotum ( dorsal), the prosternum (ventral), and the propleuron (lateral) on e ...
were smaller on the male side. Male genitalia are retracted into a genital cavity that is located in the posterior end of the gaster. The sperm is structurally the same to other animal sperm, forming an oval head with a long tail. Among the largest
larvae A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. Th ...
examined were those of ''M. simillima'', reaching lengths of . The
pupae A pupa ( la, pupa, "doll"; plural: ''pupae'') is the life stage of some insects undergoing transformation between immature and mature stages. Insects that go through a pupal stage are holometabolous: they go through four distinct stages in their ...
are enclosed in dark cocoons.


Distribution and habitat

Almost all species in the genus ''Myrmecia'' are found in Australia and its coastal islands. ''M. apicalis'' is the only species not native to Australia and is only found in the Isle of Pines,
New Caledonia ) , anthem = "" , image_map = New Caledonia on the globe (small islands magnified) (Polynesia centered).svg , map_alt = Location of New Caledonia , map_caption = Location of New Caledonia , mapsize = 290px , subdivision_type = Sovereign st ...
. Only one ant has ever established nests outside its native range; ''M. brevinoda'' was first discovered in New Zealand in 1940 and the ant was recorded in Devonport in 1948, 1965 and 1981 where a single nest was destroyed. Sources suggest the ant was introduced to New Zealand through human activity; they were found inside a wooden crate brought from Australia. While no eradication attempt was made by the New Zealand government, the ant has not been found in the country since 1981 and is presumed to have been eradicated. Ants of this genus prefer to inhabit grasslands, forests,
heath A heath () is a shrubland habitat found mainly on free-draining infertile, acidic soils and characterised by open, low-growing woody vegetation. Moorland is generally related to high-ground heaths with—especially in Great Britain—a cooler a ...
, urban areas and woodland. Nests are found in ''
Callitris ''Callitris'' is a genus of coniferous trees in the Cupressaceae (cypress family). There are 16 recognized species in the genus, of which 13 are native to Australia and the other three (''C. neocaledonica, C. sulcata'' and ''C.  ...
'' forest, dry marri forest, ''
Eucalyptus ''Eucalyptus'' () is a genus of over seven hundred species of flowering trees, shrubs or mallees in the myrtle family, Myrtaceae. Along with several other genera in the tribe Eucalypteae, including ''Corymbia'', they are commonly known as eucal ...
'' woodland and forests, mallee scrub, in paddocks,
riparian A riparian zone or riparian area is the interface between land and a river or stream. Riparian is also the proper nomenclature for one of the terrestrial biomes of the Earth. Plant habitats and communities along the river margins and banks a ...
woodland, and wet and dry sclerophyll forests. They also live in dry sandplains, and coastal plain. When a queen establishes a new colony, the nest is at first quite simple structurally. The nest gradually expands as the colony grows larger. Nests can be found in debris, decaying tree stumps, rotten logs, rocks, sand, and soil, and under stones. While most species nest underground, ''M. mjobergi'' is an
arboreal Arboreal locomotion is the locomotion of animals in trees. In habitats in which trees are present, animals have evolved to move in them. Some animals may scale trees only occasionally, but others are exclusively arboreal. The habitats pose nu ...
nesting species found on
epiphytic An epiphyte is an organism that grows on the surface of a plant and derives its moisture and nutrients from the air, rain, water (in marine environments) or from debris accumulating around it. The plants on which epiphytes grow are called phoroph ...
ferns of the genus ''
Platycerium ''Platycerium'' is a genus of about 18 fern species in the polypod family, Polypodiaceae. Ferns in this genus are widely known as staghorn or elkhorn ferns due to their uniquely shaped fronds. This genus is epiphytic and is native to tropical and ...
''. Two types of nests have been described for this genus: a simple nest with a noticeable shaft inside, and a complex structure surrounded by a mound. Some species construct dome-shaped mounds containing a single entrance, but some nests have numerous holes that are constantly used and can extend several metres underground. Sometimes, these mounds can be 0.5 m (20 in) high. Workers decorate these nests with a variety of items, including charcoal, leaves, plant fragments, pebbles, and twigs. Some ants use the warmth by decorating their nests with dry materials that heat quickly, providing the nest with
solar energy Solar energy is radiant light and heat from the Sun that is harnessed using a range of technologies such as solar power to generate electricity, solar thermal energy (including solar water heating), and solar architecture. It is an essenti ...
traps.


Behaviour and ecology


Foraging

The genus ''Myrmecia'' is among the most primitive of all known living ants, and ants of the genus are considered specialist predators. Unlike most ants, workers are solitary hunters, and do not lay
pheromone trail Trail pheromones are semiochemicals secreted from the body of an individual to affect the behavior of another individual receiving it. Trail pheromones often serve as a multi purpose chemical secretion that leads members of its own species towards a ...
s; nor do they recruit others to food.
Tandem running Tandem running is a pair movement coordination observed in ants and termites. In ants, tandem running is used for social learning, by which one ant leads another native ant from the nest to the food source it has found. Tandem running is also u ...
does not occur, and workers carrying other workers as a method of transportation is rare or awkwardly executed. Although ''Myrmecia'' is not known to lay pheromone trails to food, ''M. gulosa'' is capable of inducing territorial alarm using pheromones while ''M. pilosula'' can attack ''en masse'', suggesting these ants can also induce alarm pheromones. ''M. gulosa'' induces territorial alarm behaviour using pheromones from three sources; an alerting substance from the rectal sac, a pheromone found in the
Dufour's gland Dufour's gland is an abdominal gland of certain insects, part of the anatomy of the ovipositor or sting apparatus in female members of Apocrita. The diversification of Hymenoptera took place in the Cretaceous and the gland may have developed at a ...
, and an attack pheromone from the mandibular gland. Despite ''Myrmecia'' ants being among the most primitive ants, they exhibit some behaviours considered "advanced"; adults will sometimes groom each other and the brood, and distinct nest odors exist for each colony. Most species are diurnal, and forage on the ground or onto low vegetation in search of food, but a few are
nocturnal Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnal meaning the opposite. Nocturnal creatures generally have highly developed sens ...
and only forage at night. Most ''Myrmecia'' ants are active during the warmer months, and are dormant during winter. However, ''M. pyriformis'' is a nocturnal species that is active throughout the whole year. ''M. pyriformis'' also has a unique foraging schedule; 65% of individuals who went out to forage left the nest in 40–60 minutes, while 60% of workers would return to the nest in the same duration of time at dusk. Foraging workers rely on landmarks for navigation back home. If displaced a short distance, they will scan their surroundings, and then rapidly move in the direction of the nest. ''M. vindex'' ants carry dead nest-mates out of their nests and place them on refuse piles, a behaviour known as necrophoresis.


Pollination

While pollination by ants is somewhat rare, several ''Myrmecia'' species have been observed pollinating flowers. For example, the orchid '' Leporella fimbriata'' is a
myrmecophyte Myrmecophytes (; literally "ant-plant") are plants that live in a mutualistic association with a colony of ants. There are over 100 different genera of myrmecophytes. These plants possess structural adaptations that provide ants with food and/o ...
which can only be pollinated by the winged male ant ''M. urens''. Pollination of this orchid usually occurs between April and June during warm afternoons, and may take several days until the short-lived males all die. The flower mimics ''M. urens'' queens, so the males move from flower to flower in an attempt to copulate with it. ''M. nigrocincta'' workers have been recorded visiting flowers of ''
Eucalyptus regnans ''Eucalyptus'' () is a genus of over seven hundred species of flowering trees, shrubs or mallees in the myrtle family, Myrtaceae. Along with several other genera in the tribe Eucalypteae, including ''Corymbia'', they are commonly known as euca ...
'' and '' Senna acclinis'', and are considered a potential pollination vector for ''E. regnans'' trees. Although ''Senna acclinis'' is self-compatible, the inability of ''M. nigrocincta'' to appropriately release
pollen Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametophy ...
would restrict its capacity to effect
pollination Pollination is the transfer of pollen from an anther of a plant to the stigma of a plant, later enabling fertilisation and the production of seeds, most often by an animal or by wind. Pollinating agents can be animals such as insects, birds, a ...
. Foraging ''M. pilosula'' workers are regularly observed on the
inflorescences An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed on ...
of '' Prasophyllum alpinum'' (mostly pollinated by
wasps A wasp is any insect of the narrow-waisted suborder Apocrita of the order Hymenoptera which is neither a bee nor an ant; this excludes the broad-waisted sawflies (Symphyta), which look somewhat like wasps, but are in a separate suborder. T ...
of the family
Ichneumonidae The Ichneumonidae, also known as the ichneumon wasps, Darwin wasps, or ichneumonids, are a family of parasitoid wasps of the insect order Hymenoptera. They are one of the most diverse groups within the Hymenoptera with roughly 25,000 species curr ...
). Although
pollinia A pollinium (plural pollinia) is a coherent mass of pollen grains in a plant that are the product of only one anther, but are transferred, during pollination, as a single unit. This is regularly seen in plants such as orchids and many species of mil ...
are often seen in the ants' jaw, they have a habit of cleaning their mandibles on the leaves and stems of nectar-rich plants before moving on, preventing pollen exchange. Whether ''M. pilosula'' contributes to pollination is unknown.


Diet

Despite their ferocity, adults are nectarivores, consuming honeydew (a sweet, sticky liquid found on leaves, deposited from various insects), nectar, and other sweet substances. The larvae, however, are
carnivorous A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other so ...
. After they reach a certain size, they are fed insects that foragers capture and kill. The workers also regurgitate food for other ants to consume. Young ants are rarely fed food regurgitated by adults. Adult workers prey on a variety of insects and arthropods, such as beetles, caterpillars, earwigs, '' Ithone fusca'' moths, ''
Perga Perga or Perge ( Hittite: ''Parha'', el, Πέργη ''Perge'', tr, Perge) was originally an ancient Lycian settlement that later became a Greek city in Pamphylia. It was the capital of the Roman province of Pamphylia Secunda, now located in ...
'' saw flies, and spiders. Other prey include invertebrates such as bees, cockroaches, crickets, wasps and other ants; in particular, workers prey on ''Orthocrema'' ants (a subgenus of ''
Crematogaster ''Crematogaster'' is an ecologically diverse genus of ants found worldwide, which are characterised by a distinctive heart-shaped gaster (abdomen), which gives them one of their common names, the Saint Valentine ant. Members of this genus are a ...
'') and '' Camponotus'', although this is risky since these ants are able to call for help through chemical signals. Slaters, earthworms, scale insects, frogs, lizards, grass seeds, possum feces and kangaroo feces are also collected as food. Flies such as the
housefly The housefly (''Musca domestica'') is a fly of the suborder Cyclorrhapha. It is believed to have evolved in the Cenozoic Era, possibly in the Middle East, and has spread all over the world as a commensal of humans. It is the most common fly ...
and blowfly are consumed. Some species, such as ''M. pilosula'', will only attack small fly species and ignore larger ones. Nests of the
social spider A social spider is a spider species whose individuals form relatively long-lasting aggregations. Whereas most spiders are solitary and even aggressive toward other members of their own species, some hundreds of species in several families show a ...
''
Delena cancerides ''Delena cancerides'', the communal huntsman, flat huntsman or social huntsman, is a large, brown huntsman spider native to Australia. It has been introduced to New Zealand, where it is sometimes known as the Avondale spider. This was the specie ...
'' are often invaded by ''M. pyriformis'' ants, and nests once housing these spiders are filled with debris such as twigs and leaves by the workers, rendering them useless. These "
scorched earth A scorched-earth policy is a military strategy that aims to destroy anything that might be useful to the enemy. Any assets that could be used by the enemy may be targeted, which usually includes obvious weapons, transport vehicles, communi ...
" tactics prevent the spiders competing with the ants. ''M. gulosa'' attacks Christmas beetles, but workers later bury them. ''Myrmecia'' is one of the very few genera where the workers lay
trophic egg A trophic egg, in most species that produce them, usually is an unfertilised egg because its function is not reproduction but nutrition; in essence it serves as food for offspring hatched from viable eggs. The production of trophic eggs has been ...
s, or infertile eggs laid as food for viable offspring. Workers laying trophic eggs have only been reported in two species; these species are ''M. forceps'' and ''M. gulosa''. Depending on the species, colonies specialise in
trophallaxis Trophallaxis () is the transfer of food or other fluids among members of a community through mouth-to-mouth ( stomodeal) or anus-to-mouth ( proctodeal) feeding. Along with nutrients, trophallaxis can involve the transfer of molecules such as pher ...
; queens and larvae eat eggs that are laid by worker individuals, but the workers do not feed on eggs. Neither adults nor larvae consume food during winter, but cannibalism among larvae is known to occur throughout the year. The larvae only cannibalise each other; this is most likely to happen when no dead insects are available.


Predators, parasites and associations

''Myrmecia'' ants deter many potential predators due to their sting. The
blindsnake The Scolecophidia, commonly known as blind snakes or thread snakes, are an infraorder of snakes. They range in length from . All are fossorial (adapted for burrowing). Five families and 39 genera are recognized. The Scolecophidia infraorder is mos ...
'' Ramphotyphlops nigrescens'' consumes the larvae and pupae of ''Myrmecia'', while avoiding the potent sting of the adults, which it is vulnerable to. The
short-beaked echidna The short-beaked echidna (''Tachyglossus aculeatus''), also called the short-nosed echidna, is one of four living species of echidna and the only member of the genus ''Tachyglossus''. It is covered in fur and spines and has a distinctive snout ...
(''Tachyglossus aculeatus'') also eats the eggs and larvae.
Nymphs A nymph ( grc, νύμφη, nýmphē, el, script=Latn, nímfi, label=Modern Greek; , ) in ancient Greek folklore is a minor female nature deity. Different from Greek goddesses, nymphs are generally regarded as personifications of nature, are typ ...
of the assassin bug species ''
Ptilocnemus lemur ''Ptilocnemus lemur'' is a species of feather-legged bug in the family Reduviidae native to Australia. Commonly known as the feather-legged assassin bug, it is a predator with a specialized gland called a trichome that it uses to attract and para ...
'' lure these ants to themselves by trying to make the ant sting them, by waving its hind legs around to attract a potential prey item. Body remains of ''Myrmecia'' have been found in the stomach contents of the
eastern yellow robin The eastern yellow robin (''Eopsaltria australis'') is an Australasian robin of coastal and sub-coastal eastern Australia. The extent of the eastern yellow robin's residence is from the extreme southeast corner of South Australia through most ...
''(Eopsaltria australis)''. The
Australian magpie The Australian magpie (''Gymnorhina tibicen'') is a black and white passerine bird native to Australia and southern New Guinea. Although once considered to be three separate species, it is now considered to be one, with nine recognised subspe ...
(''Gymnorhina tibicen''), the
black currawong The black currawong (''Strepera fuliginosa''), also known locally as the black jay, is a large passerine bird endemic to Tasmania and the nearby islands within the Bass Strait. One of three currawong species in the genus ''Strepera'', it is clo ...
(''Strepera versicolor''), and the
white-winged chough The white-winged chough (''Corcorax melanorhamphos'') is one of only two surviving members of the Australian mud-nest builders family, Corcoracidae, and is the only member of the genus ''Corcorax''. It is native to southern and eastern Australi ...
(''Corcorax melanorhamphos'') prey on these ants, but few are successfully taken. The host association between ''Myrmecia'' and eucharitid wasps began several million years ago; ''M. forficata'' larvae are the
host A host is a person responsible for guests at an event or for providing hospitality during it. Host may also refer to: Places * Host, Pennsylvania, a village in Berks County People *Jim Host (born 1937), American businessman *Michel Host ...
to '' Austeucharis myrmeciae'', being the first recorded eucharitid
parasitoid In evolutionary ecology, a parasitoid is an organism that lives in close association with its host at the host's expense, eventually resulting in the death of the host. Parasitoidism is one of six major evolutionary strategies within parasitis ...
of an ant, and '' Austeucharis fasciiventris'' is a parasitoid to ''M. gulosa'' pupae. ''M. pilosula'' is affected by a gregarines parasite that changes an ant's colour from their typical black appearance to brown. This was discovered when brown workers were dissected and found to have ''gregarinasina'' spores, while black workers showed no spores. Another unidentified gregarine parasite is known to infect the larvae of ''M. pilosula'' and other ''Myrmecia'' species. This gregarine parasite also softens the ant's
cuticle A cuticle (), or cuticula, is any of a variety of tough but flexible, non-mineral outer coverings of an organism, or parts of an organism, that provide protection. Various types of "cuticle" are non- homologous, differing in their origin, structu ...
. Other parasites include ''
Beauveria bassiana ''Beauveria bassiana'' is a fungus that grows naturally in soils throughout the world and acts as a parasite on various arthropod species, causing white muscardine disease; it thus belongs to the entomopathogenic fungi. It is used as a biologica ...
'', ''
Paecilomyces lilacinus ''Purpureocillium lilacinum'' is a species of filamentous fungus in the family Ophiocordycipitaceae. It has been isolated from a wide range of habitats, including cultivated and uncultivated soils, forests, grassland, deserts, estuarine sediment ...
'', '' Chalcura affinis'', '' Tricoryna'' wasps, and various mermithid
nematodes The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant- parasitic nematodes also known as eelworms. They are a diverse animal phylum inhabiting a bro ...
. ''M. hirsuta'' and '' M. inquilina'' are the only known species in this genus that are
inquilines In zoology, an inquiline (from Latin ''inquilinus'', "lodger" or "tenant") is an animal that lives commensally in the nest, burrow, or dwelling place of an animal of another species. For example, some organisms such as insects may live in the h ...
and live in other ''Myrmecia'' colonies. An ''M. inquilina'' queen has been found in an '' M. vindex'' colony. ''Myrmecia'' is a larval attendant to the butterfly '' Theclinesthes serpentata'' (saltbush blue), while some species, particularly ''M. nigrocincta'',
enslave Slavery and enslavement are both the state and the condition of being a slave—someone forbidden to quit one's service for an enslaver, and who is treated by the enslaver as property. Slavery typically involves slaves being made to perf ...
other ant species, notably those in the genus ''
Leptomyrmex A video on how Spider Ant colonies function) ''Leptomyrmex'', or spider ants, is a genus of ants and a distinctive member of the ant subfamily Dolichoderinae. Commonly known as "spider ants" for their long legs and spider-like movements, these oran ...
''. ''M. nigriceps'' ants are able to enter another colony of the same species without being attacked, as they may be unable to recognize alien conspecifics, nor do they try to distinguish nestmates from ants of another colony. '' Formicoxenus provancheri'' and ''M. brevinoda'' share a form of
symbiotic relationship Symbiosis (from Greek , , "living together", from , , "together", and , bíōsis, "living") is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or parasi ...
known as xenobiosis, where one species of ant will live with another and raise their young separately, with ''M. brevinoda'' being the host. '' Solenopsis'' may sometimes nest in ''Myrmecia'' colonies, as a single colony was found to have three or four ''Solenopsis'' nests inside. '' Lagria'' beetles and
rove beetle The rove beetles are a family (Staphylinidae) of beetles, primarily distinguished by their short elytra (wing covers) that typically leave more than half of their abdominal segments exposed. With roughly 63,000 species in thousands of genera, the ...
s in the genus '' Heterothops'' dwell inside colonies and
skinks Skinks are lizards belonging to the family Scincidae, a family in the infraorder Scincomorpha. With more than 1,500 described species across 100 different taxonomic genera, the family Scincidae is one of the most diverse families of lizards. Ski ...
and frogs have also been found living unmolested within ''Myrmecia'' nests. '' Metacrinia nichollsi'', for example, has been reported living inside ''M. regularis'' colonies.


Life cycle

Like other ants, ''Myrmecia'' ants begin as an
egg An egg is an organic vessel grown by an animal to carry a possibly fertilized egg cell (a zygote) and to incubate from it an embryo within the egg until the embryo has become an animal fetus that can survive on its own, at which point the a ...
. If the egg is fertilised, the ant becomes a
diploid Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Sets of chromosomes refer to the number of maternal and paternal chromosome copies, respectiv ...
female; if not, it becomes a
haploid Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Sets of chromosomes refer to the number of maternal and paternal chromosome copies, respecti ...
male. They develop through
complete metamorphosis Holometabolism, also called complete metamorphosis, is a form of insect development which includes four life stages: egg, larva, pupa, and imago (or adult). Holometabolism is a synapomorphic trait of all insects in the superorder Endopterygota. ...
, meaning that they pass through larval and pupal stages before emerging as adults. During the process of founding a colony, as many as four queens cooperate with each other to find a suitable nesting ground, but after the first generation of workers is born, they fight each other until one queen is left alive. However, occasional colonies are known to have as many as six queens coexisting peacefully in the presence of workers. A queen searches for a suitable nest site to establish her colony, and excavates a small chamber in the soil or under logs and rocks, where she takes care of her young. A queen also hunts for prey instead of staying in her nest, a behaviour known as claustral colony founding. Although queens do provide sufficient amounts of food to feed their larvae, the first workers are "nanitics" (or minims), smaller than the smallest workers encountered in older developed colonies. Several species do not have any worker caste, and solitary queens will raid a colony, kill the residing queen, and take over the colony. The first generation of workers may take a while to fully develop into adults; for example, ''M. forficata'' eggs take around 100 days to fully develop, while other species may take up to eight months. Queens lay around eight eggs, but less than half of these eggs develop. Some species, such as ''M. simillima'' and ''M. gulosa'', lay their eggs singly on the colony floor, while ''M. pilosula'' ants may lay eggs in a clump. These clumps have two to 30 eggs each with no larvae present. Certain ''Myrmecia'' species do not lay their eggs singly and form clumps of eggs, instead. The larvae are capable of crawling short distances without the assistance of adult workers, and workers will cover the larvae in dirt to help them spin into a cocoon. If cocoons are isolated from a colony, they are capable of shedding their skins before hatching, allowing themselves to advance to full
pigment A pigment is a colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic compou ...
ation. Sometimes, a newborn can emerge from its pupa without the assistance of other ants. Once these ants are born, they are able to identify distinct tasks, a well known primitive trait. ''Myrmecia'' lifespans vary in each species, but their longevity is greater than many ant genera: ''M. nigrocincta'' and ''M. pilosula'' have a lifespan of one year, while ''M. nigriceps'' workers can live up to 2.2 years. The oldest recorded worker was a ''M. vindex'', living up to 2.6 years. If a colony is deprived of workers, queens are able to revert to colony-founding behaviours until a sustainable workforce emerges. A colony may also emigrate to a new nesting spot altogether.


Reproduction

Winged, virgin queens and males, known as
alate Alate (Latin ''ālātus'', from ''āla'' (“wing”)) is an adjective and noun used in entomology and botany to refer to something that has wings or winglike structures. In entomology In entomology, "alate" usually refers to the winged form o ...
s, appear in colonies during January, before their
nuptial flight Nuptial flight is an important phase in the reproduction of most ant, termite, and some bee species. It is also observed in some fly species, such as ''Rhamphomyia longicauda''. During the flight, virgin queens mate with males and then land to ...
. Twenty females or fewer are found in a single colony, while males are much more common. The nuptial flight begins at different times for each species; they have been recorded in mid-summer to autumn (January to early April), but there is one case of a nuptial flight occurring from May to July. Ideal conditions for nuptial flight are hot stormy days with windspeeds of 30 km/h (18 mi/h) and temperatures reaching 30 °C (86 °F), and elevations of 91 metres (300 ft). Nuptial flights are rarely recorded due to queens leaving their nest singly, although as many as four queens may leave the nest at the same time. Species are both
polygynous Polygyny (; from Neoclassical Greek πολυγυνία (); ) is the most common and accepted form of polygamy around the world, entailing the marriage of a man with several women. Incidence Polygyny is more widespread in Africa than in any ...
and
polyandrous Polyandry (; ) is a form of polygamy in which a woman takes two or more husbands at the same time. Polyandry is contrasted with polygyny, involving one male and two or more females. If a marriage involves a plural number of "husbands and wives" ...
, with queens mating with one to ten males. Polygynous and polyandrous societies can occur in a single nest, but particular species are either primarily polygynous or primarily polyandrous. For example, nearly 80% of tested ''M. pilosula'' colonies are polygynous while ''M. pyriformis'' colonies are mostly polyandrous. Nuptial flight takes place during the morning and can last until late afternoon. When the alates leave the nest, most species launch themselves into the air from trees and shrubs, although others launch themselves off the ground. Queens discharge a glandular secretion from the tergal gland, which males are strongly attracted to. As many as 1,000 alates will gather to mate. A queen was once found to have five or six males attempting to copulate with her. The queen is unable to bear the weight of the large number of males trying to mate with her, and will drop to the ground, with the ants dispersing later on. ''M. pulchra'' queens are ergatoid and cannot fly; the males meet the queen out in an open area away from the nest and mate, and these queens do not return to their nest after mating. Both independent and dependent colony foundation can occur after mating. Isolation by distance (IBD) patterns have been recorded with ''M. pilosula'' queens, where nests that tend to be closer together were more genetically related to each other in comparison to other nests further away. Independent colony foundation is closely associated with queens which engage in nuptial flight in areas far from their home colony, showing that dependent colony foundation mostly occurs if they mate near their nest. In some cases, queens could seek adoption into alien colonies if there are no suitable areas to find a nest or independent colony foundation cannot be carried out. Other queens could try to return to their home nest after nuptial flight, but they may end up in another nest near the nest they originally came from. In multiple-queen societies, the egg-laying queens are generally unrelated to one another, but one study showed that it is possible for multiple queens in the same colony to be genetically related to each other. Depending on the species, the number of individuals present in a colony can range from 50 to over 2,200 individuals. A colony with less than 100 workers is not considered a mature colony. ''M. dispar'' colonies have around 15 to 329 ants, ''M. nigrocincta'' have over 1,000, ''M. pyriformis'' have from 200 to over 1,400 and ''M. gulosa'' have nearly 1,600. A colony can last for a number of years. Foraging behaviour among smaller workers which never usually leave the nest can be a sign of a colony's impending demise. Workers are known to produce their own eggs, but these eggs are unfertilised and hatch into male ants. There is a chance of workers attacking a particular individual who has successfully produced male offspring due to a change in a workers cuticular hydrocarbon; cuticular hydrocarbons are believed to play a vital role in the regulation of reproduction. However, this is not always the case. ''Myrmecia'' is one of several ant genera which possess
gamergate Gamergate may refer to: * Gamergate (ant), a worker ant that can store sperm and reproduce sexually * Gamergate (harassment campaign), targeting women in the video game industry * Lt. Gamergate, a character in the ''Adventure Time'' episode "Dent ...
workers, where a female worker is able to reproduce with mature males when the colony is lacking a queen. ''Myrmecia'' workers are highly fertile and can successfully mate with males. A colony of ''M. pyriformis'' without a queen was collected in 1998 and kept in captivity, during which time the gamergates produced viable workers for three years. Ovarian dissections showed that three workers of this colony mated with males and produced female workers. Queens have bigger ovaries than the workers, with 44
ovarioles An ovariole is a tubular component of the insect ovary, and the basic unit of egg production. Each ovariole is composed of a germarium (the germline stem cell niche) at the anterior tip, a set of developing oocytes contained within follicles, and ...
while workers have 8 to 14.
Spermatheca The spermatheca (pronounced plural: spermathecae ), also called receptaculum seminis (plural: receptacula seminis), is an organ of the female reproductive tract in insects, e.g. ants, bees, some molluscs, oligochaeta worms and certain other ...
is present in ''M. gulosa'' workers, based on eight dissected individuals showing a spermatheca structurally similar to those found in queens. These spermathecas did not have any sperm. Why the queen was not replaced is still unknown.


Vision

While most ants have poor eyesight, ''Myrmecia'' ants have excellent vision. This trait is important to them, since ''Myrmecia'' primarily relies on
visual cues The visual system comprises the sensory organ (the eye) and parts of the central nervous system (the retina containing photoreceptor cells, the optic nerve, the optic tract and the visual cortex) which gives organisms the sense of sight (the a ...
for navigation. These ants are capable of discriminating the distance and size of objects moving nearly a metre away. Winged alates are only active during the day, as they can see better. Members of a colony have different eye structures due to each individual fulfilling different tasks, and nocturnal species have larger
ommatidia The compound eyes of arthropods like insects, crustaceans and millipedes are composed of units called ommatidia (singular: ommatidium). An ommatidium contains a cluster of photoreceptor cells surrounded by support cells and pigment cells. The ou ...
in comparison to those that are active during the day. Facet lenses also vary in size; for example, the diurnal species ''M. croslandi'' has a smaller lens in comparison to ''M. nigriceps'' and ''M. pyriformis'' which have larger lenses. ''Myrmecia'' ants have three photoreceptors that can see
UV light Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30  PHz) to 400 nm (750  THz), shorter than that of visible light, but longer than X-rays. UV radiation i ...
, meaning they are capable of seeing colours that humans cannot. Their vision is said to be better than some mammals, such as cats, dogs or wallabies. Despite their excellent vision, worker ants of this genus find it difficult to find their nests at night, due to the difficulty of finding the landmarks they use to navigate. They are thus more likely to return to their nests the following morning, walking slowly with long pauses.


Sting

''Myrmecia'' workers and queens possess a sting described as "sharp in pain with no burning." The pain may last for several minutes. In the Starr sting pain scale, a scale which compares the overall pain of hymenopteran stings on a four-point scale, ''Myrmecia'' stings were ranked from 2–3 in pain, described as "painful" or "sharply and seriously painful". Unlike in
honeybees A honey bee (also spelled honeybee) is a eusocial flying insect within the genus ''Apis'' of the bee clade, all native to Afro-Eurasia. After bees spread naturally throughout Africa and Eurasia, humans became responsible for the current cosm ...
, the sting lacks barbs, and so the stinger is not left in the area the ant has stung, allowing the ants to sting repeatedly without any harm to themselves. The retractable sting is located in their abdomen, attached to a single venom gland connected by the venom sac, which is where the venom is accumulated.
Exocrine glands Exocrine glands are glands that secrete substances on to an epithelial surface by way of a duct. Examples of exocrine glands include sweat, salivary, mammary, ceruminous, lacrimal, sebaceous, prostate and mucous. Exocrine glands are one of tw ...
are known in some species, which produce the venom compounds later used to inject into their victims. Examined workers of larger species have long and very potent stingers, with some stings measuring .


Interaction with humans

''Myrmecia'' is one of the best-known genera of ants. ''Myrmecia'' ants usually display defensive behaviour only around their nests, and are more timid while foraging. However, most species are extremely aggressive towards intruders; a few, such as ''M. tarsata'', are timid, and the workers retreat into their nest instead of pursuing the intruder. If a nest is disturbed, a large force of workers rapidly swarms out of their nest to attack and kill the intruder. Some species, particularly those of the ''M. nigrocincta'' and ''M. pilosula'' species groups, are capable of jumping several inches when they are agitated after their nest has been disturbed; jumper ants propel their jumps by a sudden extension of their middle and hind legs. ''M. pyriformis'' is considered the most dangerous ant in the world by the ''
Guinness World Records ''Guinness World Records'', known from its inception in 1955 until 1999 as ''The Guinness Book of Records'' and in previous United States editions as ''The Guinness Book of World Records'', is a reference book published annually, listing world ...
''. ''M. inquilina'' is the only species of this genus that is considered vulnerable by the
IUCN The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...
, although the conservation status needs updating. Fatalities associated with ''Myrmecia'' stings are well known, and have been attested to by multiple sources. In 1931 two adults and an infant girl from New South Wales died from ant stings, possibly from ''M. pilosula'' or ''M. pyriformis''. Another fatality was reported in 1963 in Tasmania. Between 1980 and 2000, there were six recorded deaths, five in Tasmania and one in New South Wales. Four of these deaths were due to ''M. pilosula'', while the remaining two died from a ''M. pyriformis'' sting. Half of the victims had known ant-sting allergies, but only one of the victims was carrying adrenaline before being stung. Most victims died within 20 minutes of being stung, but one of the victims died in just five minutes from a ''M. pyriformis'' sting. No death has been officially recorded since 2003, but ''M. pilosula'' may have been responsible for the death of a man from Bunbury in 2011. Prior to the establishment of a desensitisation program, ''Myrmecia'' stings caused one fatality every four years.


Venom

Each ''Myrmecia'' species has different venom components, so people who are allergic to ants are advised to stay away from ''Myrmecia'', especially from species they have never encountered before. Based on five species, the
median lethal dose In toxicology, the median lethal dose, LD50 (abbreviation for "lethal dose, 50%"), LC50 (lethal concentration, 50%) or LCt50 is a toxic unit that measures the lethal dose of a toxin, radiation, or pathogen. The value of LD50 for a substance is t ...
(LD50) is 0.18–0.35 mg/kg, making it among the most toxic venoms in the insect world. The toxicity of the venom may have evolved due to the intense predation by animals and birds during the day, since ''Myrmecia'' is primarily diurnal. In Tasmania, 2–3% of the human population is allergic to ''M. pilosula'' venom. In comparison, only 1.6% people are allergic to the venom of the
western honeybee The western honey bee or European honey bee (''Apis mellifera'') is the most common of the 7–12 species of honey bees worldwide. The genus name ''Apis'' is Latin for "bee", and ''mellifera'' is the Latin for "honey-bearing" or "honey carrying", ...
(''Apis mellifera''), and 0.6% to the venom of the European wasp (''Vespula germanica''). In a 2011 Australian ant-venom allergy study, the objective of which was to determine what native Australian ants were associated with ant sting
anaphylaxis Anaphylaxis is a serious, potentially fatal allergic reaction and medical emergency that is rapid in onset and requires immediate medical attention regardless of use of emergency medication on site. It typically causes more than one of the follow ...
, 265 of the 376 participants in the study reacted to the sting of several ''Myrmecia'' species. Of these, the majority of patients (176) reacted to ''M. pilosula'' venom and to those of several other species. In Perth, ''M. gratiosa'' was responsible for most cases of anaphylaxis due to ant stings, while ''M nigriscapa'' and ''M. ludlowi'' were responsible for two cases. The green-head ant (''Rhytidoponera metallica'') was the only ant other than ''Myrmecia'' species to cause anaphylaxis in patients. Dogs are also at risk of death from ''Myrmecia'' ants;
renal failure Kidney failure, also known as end-stage kidney disease, is a medical condition in which the kidneys can no longer adequately filter waste products from the blood, functioning at less than 15% of normal levels. Kidney failure is classified as eit ...
has been recorded in dogs experiencing mass
envenomation Envenomation is the process by which venom is injected by the bite or sting of a venomous animal. Many kinds of animals, including mammals (e.g., the northern short-tailed shrew, ''Blarina brevicauda''), reptiles (e.g., the king cobra), spiders ...
, and one dog was euthanised due to its deteriorating health despite treatment. Sensitivity is persistent for many years. Pilosulin 3 has been identified as a major allergen in ''M. pilosula'' venom, while pilosulin 1 and pilosulin 4 are minor allergens.


Sting treatment

The nature of treatment for a ''Myrmecia'' sting depends on the severity of stingose, and the use of
antihistamine Antihistamines are drugs which treat allergic rhinitis, common cold, influenza, and other allergies. Typically, people take antihistamines as an inexpensive, generic (not patented) drug that can be bought without a prescription and provides r ...
tablets are other methods to reduce the pain. Indigenous Australians use bush remedies to treat ''Myrmecia'' stings, such as rubbing the tips of bracken ferns onto the stung area. ''
Carpobrotus glaucescens ''Carpobrotus glaucescens'', commonly known as pigface or iceplant, is a species of flowering plant in the family Aizoaceae and is endemic to eastern Australia. It is a succulent, prostrate plant with stems up to long, glaucous leaves, daisy-li ...
'' is also used to treat stung areas, using juices that are squeezed and rubbed onto the area, which quickly relieves the pain from the sting. Emergency treatment is only needed if a person is showing signs of a severe allergic reaction. Prior to calling for help, stung persons should be laid down, and their legs elevated. An
EpiPen An epinephrine autoinjector (or adrenaline autoinjector, also known by the trademark EpiPen) is a medical device for injecting a measured dose or doses of epinephrine (adrenaline) by means of autoinjector technology. It is most often used for the ...
or an Anapen is given to people at risk of anaphylaxis, to use in case they are stung. If someone experiences anaphylactic shock,
adrenaline Adrenaline, also known as epinephrine, is a hormone and medication which is involved in regulating visceral functions (e.g., respiration). It appears as a white microcrystalline granule. Adrenaline is normally produced by the adrenal glands an ...
and intravenous infusions are required, and those who suffer
cardiac arrest Cardiac arrest is when the heart suddenly and unexpectedly stops beating. It is a medical emergency that, without immediate medical intervention, will result in sudden cardiac death within minutes. Cardiopulmonary resuscitation (CPR) and possi ...
require
resuscitation Resuscitation is the process of correcting physiological disorders (such as lack of breathing or heartbeat) in an acutely ill patient. It is an important part of intensive care medicine, anesthesiology, trauma surgery and emergency medicine. We ...
. Desensitisation (also called allergy immunotherapy) is offered to those who are susceptible to ''M. pilosula'' stings, and the program has shown effectiveness in preventing anaphylaxis. However, the standardisation of ''M. pilosula'' venom is not validated, and the program is poorly funded. The
Royal Hobart Hospital The Royal Hobart Hospital is a public hospital in the Hobart CBD, Tasmania, Australia. The hospital also functions as a teaching hospital in co-operation with the University of Tasmania. The hospital's research facilities are known as the Roya ...
and the
Royal Adelaide Hospital The Royal Adelaide Hospital (RAH), colloquially known by its initials or pronounced as "the Rah", is South Australia's largest hospital, owned by the state government as part of Australia's public health care system. The RAH provides tertiary hea ...
are the only known hospitals to run desensitisation programs. During immunotherapy, patients are given an injection of venom under the skin. The first dose is small, but dosage gradually increases. This sort of immunotherapy is designed to change how the immune system reacts to increased doses of venom entering the body. Before venom immunotherapy, whole-body extract immunotherapy was widely used due to its apparent effectiveness, and it was the only immunotherapy used for ant stings. However, fatal failures were reported, and this led to scientists to research for alternative methods of desensitisation. Before 1986 allergic reactions were not recorded and there was no study on ''Myrmecia'' sting venom; whole body extracts were later used on patients during the 1990s, but this was found to be ineffective and was subsequently withdrawn. In 2003, ant venom immunotherapy was shown to be safe and effective against ''Myrmecia'' venom.


Prevention

''Myrmecia'' ants are frequently encountered by humans, and avoiding them is difficult. Wearing closed footwear such as boots and shoes can reduce the risk of getting stung; these ants are capable of stinging through fabric, however. A risk of being stung while gardening also exists; most stings occur when someone is gardening and is unaware of the ants' presence. Eliminating nearby nests or moving to areas with low ''Myrmecia'' populations significantly decreases the chances of getting stung. Due to their large mandibles, ''Myrmecia'' ants have been used as
surgical suture A surgical suture, also known as a stitch or stitches, is a medical device used to hold body tissues together and approximate wound edges after an injury or surgery. Application generally involves using a needle with an attached length of threa ...
s to close wounds. The ant is featured on a
postage stamp A postage stamp is a small piece of paper issued by a post office, postal administration, or other authorized vendors to customers who pay postage (the cost involved in moving, insuring, or registering mail), who then affix the stamp to the fa ...
and on an
uncirculated coin The term uncirculated coin can refer to three things: * A coin that is released to the public but not intended for general circulation (i.e. not used as money although it is still legal tender) but is available through a mint or through a local ...
which are part of the ''Things That Sting'' issue by
Australia Post Australia Post, formally the Australian Postal Corporation, is the government business enterprise that provides postal services in Australia. The head office of Australia Post is located in Bourke Street, Melbourne, which also serves as a post ...
, and ''M. gulosa'' is the emblem for the Australian Entomological Society. ''Myrmecia'' famously appears in the philosopher
Arthur Schopenhauer Arthur Schopenhauer ( , ; 22 February 1788 – 21 September 1860) was a German philosopher. He is best known for his 1818 work ''The World as Will and Representation'' (expanded in 1844), which characterizes the phenomenal world as the prod ...
's major work, ''
The World as Will and Representation ''The World as Will and Representation'' (''WWR''; german: Die Welt als Wille und Vorstellung, ''WWV''), sometimes translated as ''The World as Will and Idea'', is the central work of the German philosopher Arthur Schopenhauer. The first edition ...
'', as a paradigmatic example of strife and constant destruction endemic to the "will to live". Notable Australian poet Diane Fahey wrote a poem about ''Myrmecia'', which is based on Schopenhauer's description, and a music piece written by German composer Karola Obermüller was named after the ant.


See also

*
Ant Ants are eusocial insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from vespoid wasp ancestors in the Cretaceous period. More than 13,800 of an estimated total of 22,0 ...
*
Bullet ant A bullet is a kinetic projectile, a component of firearm ammunition that is shot from a gun barrel. Bullets are made of a variety of materials, such as copper, lead, steel, polymer, rubber and even wax. Bullets are made in various shapes and con ...
*
Fire ant Fire ants are several species of ants in the genus ''Solenopsis'', which includes over 200 species. ''Solenopsis'' are stinging ants, and most of their common names reflect this, for example, ginger ants and tropical fire ants. Many of the nam ...
*
List of ants of Australia The ant fauna of Australia is large and diverse. As of 1999, Australia and its external territories represent 1,275 described taxa (subspecies included) divided into 103 genera and 10 subfamilies. No publication since 1999 has estimated the c ...


Notes


References


Cited texts

* * * * * * * * *


External links


''Myrmecia'' at the AntWiki – Bringing Ants to the World

''Myrmecia''
in the
Catalogue of Life The Catalogue of Life is an online database that provides an index of known species of animals, plants, fungi, and microorganisms. It was created in 2001 as a partnership between the global Species 2000 and the American Integrated Taxonomic Info ...

Video about Bull ants
YouTube YouTube is a global online video sharing and social media platform headquartered in San Bruno, California. It was launched on February 14, 2005, by Steve Chen, Chad Hurley, and Jawed Karim. It is owned by Google, and is the second most vis ...

JJA Desensitisation Program website
{{Good article Myrmeciinae Ant genera Hymenoptera of Australia Hymenoptera of Oceania Insects of New Caledonia Slave-making ants Parasitic Hymenoptera Extant Early Cretaceous first appearances Taxa named by Johan Christian Fabricius