Jack jumper, Jumping jack, Hopper ant, Jumper ant
The jack jumper ant (Myrmecia pilosula), also known as the jack jumper, jumping jack, hopper ant, or jumper ant, is a species of venomous ant native to Australia. Most frequently found in Tasmania and southeast mainland Australia, it is a member of the genus Myrmecia, subfamily Myrmeciinae, and was formally described and named by British entomologist Frederick Smith in 1858. This species is known for its ability to jump long distances. These ants are large; workers and males are about the same size: 12 to 14 mm (0.47 to 0.55 in) for workers, and 11 to 12 mm (0.43 to 0.47 in) for males. The queen measures roughly 14 to 16 mm (0.55 to 0.63 in) long and is similar in appearance to workers, whereas males are identifiable by their perceptibly smaller mandibles.
Jack jumper ants are primarily active during the day and live in open habitats, nesting in bushland, woodlands, and dry open forests, surrounded by gravel and sandy soil, which can be found in rural areas and are less common in urban areas. They prey on small insects and use their barbless stingers to kill other insects by injecting venom. Other ants and predatory invertebrates prey on the jack jumper ant. The average worker has a life expectancy of over one year. Workers are gamergates, allowing them to reproduce with drones, whether or not a queen is present in the colony. The ant is a part of the Myrmecia pilosula species complex; this ant and other members of the complex are known to have a single pair of chromosomes.
Their sting generally only causes a mild local reaction in humans; however, it is one of the few ant species that can be dangerous to humans, along with other ants in the genus Myrmecia. The ant venom is particularly immunogenic for an insect venom; the venom causes about 90% of Australian ant allergies. In endemic areas, up to 3% of the human population has developed an allergy to the venom and about half of these allergic people can suffer from anaphylactic reactions (increased heart rate, falling blood pressure, and other symptoms), which can lead to death on rare occasions. Between 1980 and 2000, four deaths were due to anaphylaxis from jack jumper stings, all of them in Tasmania. Individuals prone to severe allergic reactions caused by the ant's sting can be treated with allergen immunotherapy (desensitisation).
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DiurnalDiurnal animals are active during the daytime, with a period of sleeping or other inactivity at night. The timing of activity by an animal depends ...
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TerrestrialTerrestrial animals are animals that live predominantly or entirely on land (e.g., cats, ants, snails), as compared with aquatic animals, which liv...
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OviparousOviparous animals are female animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive...
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starts withLike its relatives, the ant possesses a powerful sting and large mandibles. These ants can be black or blackish-red in colour, and may have yellow or orange legs. The ant is medium-sized in comparison to other Myrmecia species, where workers are typically 12 to 14 mm (0.47 to 0.55 in) long. Excluding mandibles, jack jumpers measure 10 millimetres (0.39 in) in length. The ant's antennae, tibiae, tarsi, and mandibles are also yellow or orange. Pubescence (hair) on the ant is greyish, short and erect, and is longer and more abundant on their gaster, absent on their antennae, and short and suberect on their legs. The pubescence on the male is grey and long, and abundant throughout the ant's body, but it shortens on the legs. The mandibles are long and slender (measuring 4.2 mm (0.17 in)), and concave around the outer border.
The queen has a similar appearance to the workers, but her middle body is more irregular and coarser. The queen is also the largest, measuring 14 to 16 mm (0.55 to 0.63 in) in length. Males are either smaller or around the same size as workers, measuring 11 to 12 mm (0.43 to 0.47 in). Males also have much smaller, triangular mandibles than workers and queens. The mandibles on the male contain a large tooth at the centre, among the apex and the base of the inner border. Punctures (tiny dots) are noticeable on the head, which are large and shallow, and the thorax and node are also irregularly punctuated. The pubescence on the male's gaster is white and yellowish.
Jack jumper ants are abundant in most of Australia, being among the most common bull ant to be encountered. The ants can be found in the south-western tip of Western Australia, where it has been seen in the sand hills around Albany, Mundaring, Denmark and Esperance. The ant is rarely sighted in the northern regions of Western Australia. In South Australia, it is commonly found in the south-east regions of the state, frequently encountered in Mount Lofty (particularly the Adelaide Hills), Normanville, Hallett Cove and Aldgate, but it is not found in north-western regions. There are dense populations on the western seaboard of Kangaroo Island. Jack jumpers are widespread throughout the whole of Victoria, but the species is uncommon in Melbourne. However, populations have been collected from the suburb of Elsternwick, and they are commonly found in the Great Otway Ranges, with many nests observed around Gellibrand. In New South Wales, nests are found throughout the entire state (with the exception of north-western New South Wales), but dense populations are mostly found in the Snowy Mountains, Blue Mountains and coastal regions. The ants are widespread in the Australian Capital Territory. In Queensland, the ants are only found along the south-eastern coastlines of the state, where populations are frequently encountered in the Bunya Mountains, Fletcher, Stanthorpe, Sunshine Coast, Tamborine Mountain and Millmerran, and have been found as far north as Atherton Tablelands. The ant also resides in all of Tasmania, and their presence in the Northern Territory has not been verified.
Jack jumper ants live in open habitats, such as damp areas, forests, pastures, gardens, and lawns, preferring fine gravel and sandy soil. Colonies can also be spotted around light bushland. Their preferred natural habitats include woodlands, dry open forests, grasslands, and rural areas, and less common in urban areas. Their nests are mounds built from finely granular gravel, soil, and pebbles, measuring 20 to 60 cm (8 to 24 in) in diameter and can be as tall as 0.5 m (20 in) in height. Two types of nests for this species have been described, one being a simple nest with a noticeable shaft inside, the other being a complex structure surrounded by a mound. These ants use the sun's warmth by decorating their nests with dry materials that heat in a quick duration, providing the nest with solar energy traps. They decorate their nests with seeds, soil, charcoal, stones, sticks, and even small invertebrate corpses. They also camouflage their nests by covering them with leaf litter, debris, and long grass. Nests can be found hidden under rocks, where queens most likely form their colonies, or around small piles of gravel, instead. Their range in southern Australia, like other regional ant species, appears like that of a relict ant. Jack jumpers have been found in dry sclerophyll forests, at elevations ranging from 121 to 1,432 m (397 to 4,698 ft), averaging 1,001 m (3,284 ft). Rove beetles in the genus Heterothops generally thrive in jack jumper nests and raise their brood within their chambers, and skinks have been found in some nests.
Populations are dense in the higher mountain regions of Tasmania. Widespread throughout the state, their presence is known on King Island, located north-west from Tasmania. The ant prefers rural areas, found in warm, dry, open eucalypt woodlands; the climate provides the ant with isolation and warmth. This environment also produces the ant's food, which includes nectar and invertebrate prey. In suburban areas, this ant is found in native vegetation, and uses rockeries, cracks in concrete walls, dry soil, and grass to build nests. One study found suburbs with voluminous vegetation cover such as Mount Nelson, Fern Tree and West Hobart host jack jumper populations, while the heavily urbanised suburbs of North Hobart and Battery Point, do not.
Pest control of the jack jumper ant is successful in maintaining their populations around suburban habitats. Chemicals such as bendiocarb, chlorpyrifos, diazinon, and permethrin are effective against them. Spraying of Solfac into nests is an effective way of controlling nests if they are in a close range of areas with considerable amounts of congestion and human activity. Pouring carbon disulfide into nest holes and covering entrances up with soil is another method of removing colonies. The Australian National Botanic Gardens have an effective strategy of marking and maintaining jack jumper nests.
Primarily diurnal, workers search for food during the day until dusk. They are active during warmer months, but are dormant during winter. Fights between these ants within the same colony is not uncommon. They are known for their aggression towards humans, attraction to movement, and well developed vision, being able to observe and follow intruders from 1 m (1.1 yd) away. This species is an accomplished jumper, with leaps ranging from 2 to 3 in (51 to 76 mm). William Morton Wheeler compared jack jumper ants to "Lilliputian cavalry galloping to battle" when disturbed, due to their jumping behaviour. He further wrote that they also made a ludicrous appearance as they emerge from their nests, in a series of short hops.
While no studies have established whether or not these ants contain alarm pheromones, their relative Myrmecia gulosa is capable of inducing territorial alarm using pheromones. If proven, this would explain their ability to attack en masse. Foraging workers are regularly observed on the inflorescences of Prasophyllum alpinum (mostly pollinated by wasps of the subfamily Ichneumonidae). Although pollinia are often seen in the ants' jaws, they have a habit of cleaning their mandibles on the leaves and stems of nectar-rich plants before moving on, preventing pollen exchange. Whether jack jumper ants contribute to pollination is unknown.
Like every ant, the life of a jack jumper ant starts from an egg. If the egg is fertilised, the ant will be a female (diploid); if not, it will become a male (haploid). They develop through complete metamorphosis, meaning that they pass through larval and pupal stages before emerging as an adult. Cocoons that are isolated from the colony are able to shed their pupal skin before hatching, allowing themselves to advance to full pigmentation. Pupae can also eclose (emerge from their pupal stage) without assistance from other ants. Once born, jack jumper ants can identify distinct tasks, an obvious primitive trait Myrmecia ants are known for.
Based on observations of six worker ants, the average life expectancy of the jack jumper is around 1.3 years, but workers were shown to live as little as 1.12 years or as long as 1.6, with the queen living much longer than the workers at 10 years or more. These data give a life expectancy of 401–584 days, with an average of 474 days. Egg clumping is common, as observed in laboratory colonies. These clumps are often carried by worker ants, and these clumps would contain two to 30 eggs, without any larvae to hold them together. This confirms that eggs from jack jumper colonies do not always lie singly apart. George C. Wheeler and Jeanette Wheeler (1971) studied and described larvae collected from New South Wales and South Australia. They noted that very young larvae of the jack jumper were 2.4 mm (0.094 in) in length, with two types of body hair. They also described young larvae (matured from very young larvae) at 2.7 mm (0.11 in), but with similar body characteristics to mature larvae, at 12.5 mm (0.49 in).
The jack jumper ant and its relatives in the genus Myrmecia are among the most dangerous ant genera and have fearsome reputations for their extreme aggression; Guinness World Records certifies the ant Myrmecia pyriformis as the world's most dangerous ant. The jack jumper have been compared to other highly aggressive ant species, such as Brachyponera chinensis, Brachyponera sennaarensis, and the red imported fire ant (Solenopsis invicta). 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 are known in jack jumpers, which produce the venom compounds later used to inject into their victims. Their venom contains haemolytic and eicosanoid elements and histamines. It contains a range of active ingredients and enzymatic activity, which includes phospholipase A2 and B, hyaluronidase, acid and alkaline phosphatase. The venom of the ant also contains several peptides; one being pilosulin 1, which causes cytotoxic effects, pilosulin 2, which has antihypertensive properties and pilosulin 3, which is known to be a major allergen. Other pilosulins include pilosulin 4 and pilosulin 5. The peptides have known molecular weights. The LD50 (lethal dose) occurs at a lower concentration than for melittin, a peptide found in bee venom. Its LD50 value is 3.6 mg/kg (injected intravenously in mice).
Loss of cell viability in the jack jumper's venom was researched through cytometry, which measures the proportions of cells that glow in the presence of fluorescent dye and 7-Aminoactinomycin D. Examinations of the rapidly reproducing Epstein–Barr B-cells showed that the cells lost viability within minutes when exposed to pilosulin 1. Normal white blood cells were also found to alter easily when exposed to pilosulin 1. However, partial peptides of pilosulin 1 were less efficient at lowering cell viability; the residue 22 N-terminal plays a critical role in the cytotoxic activity of pilosulin 1.
20 percent of jack jumper ants have an empty venom sac, so failure to display a sting reaction should not be interpreted as a loss of sensitivity. Substantial amounts of ant venom have been analysed to characterise venom components, and the jack jumper has been a main subject in these studies. An East Carolina University study which summarised the knowledge about ant stings and their venom showed that only the fire ant and jack jumper had the allergenic components of their venom extensively investigated. These allergenic components include peptides found as heterodimers, homodimers and pilosulin 3. Only six Myrmecia ants, including the jack jumper, are capable of inducing IgE antibodies. Due to the vast differentiation of venom produced in each Myrmecia species, and other species sharing similar characteristics to the jack jumper ant, diagnosing which ant is responsible for an anaphylactic reaction is difficult. A review of a patient's history with allergies while identifying a positive result of venom specific IgE levels helps to identify the species of ant that caused a reaction.
Queens are polyandrous, meaning that queens can mate more than once; queens mate with one to nine males during a nuptial flight, and the effective number of mates per queen ranges from 1.0 to 11.4. Most queen ants only mate with one or two males. If the number of available male mates increases, the number of effective matings per queen decreases. Colonies are polygynous, meaning that a colony may house multiple queens; one to four queens typically inhabit a colony, and in multiple-queen colonies, the egg-laying queens are unrelated to one another. Based on a study, 11 of the 14 colonies tested were polygynous (78.57%), showing that this is common in jack jumper colonies. When the queen establishes a nest after mating, she will hunt for food to feed her young, making her semiclaustral. Nests can hold as few as 500 ants or as many as 800 to 1,000. Excavated nests typically have populations ranging from 34 to 344 individuals. Jack jumper ant workers are gamergates, having the ability to reproduce in colonies with or without queens.
Colonies are mainly polygynous with polyandrous queens, but polyandry in jack jumper colonies is low in comparison to other Myrmecia ants, but it is comparable to M. pyriformis ants. In 1979, Craig and Crozier investigated the genetic structure of jack jumper ant colonies, and although queens are unrelated to each other, the occurrence of related queens in a single colony was possible. During colony foundation, suggestions exist of dependent colony foundation in jack jumper queens, although independent colony foundations can occur, as the queens do have fully developed wings and can fly. Isolation by distance patterns have been recorded, specifically where nests that tend to be closer to each other were more genetically similar in comparison to other nests farther away.
As colonies closer to each other are more genetically similar, independent colony foundation is most likely associated with nuptial flight if they disperse far from genetically similar colonies they originate from. Inseminated queens could even seek adoption into alien colonies if a suitable nest site area for independent colony foundation is restricted or cannot be carried out, known as the nest-site limitation hypothesis. Some queens could even try to return to their nests that they came from after nuptial flight, but end in another nest, in association that nests nearby will be similar to the queen's birth nest.
