Meat ant

Appearance

In general, meat ants are medium to large in size, measuring 6–12 mm , and can be easily recognised by their dark-bluish body and red head. Most of the time their heads and pronotums share similar colours and are lighter than the mesothorax and the propodeum, which are reddish brown. However, the head may sometimes be lighter, and the pronotum and mesothorax may share similar colours. The mesosomal setae are dark and sometimes translucent. The iridescence between the compound eyes and the lateral portion of the head ranges from slightly purple to strong and dark purple. The colour of the legs and coxae are darker than the mesothorax, and the petiole is reddish brown and also darker than the mesothorax. The lateral portion of the second gastral tergite is shiny, and the iridescence varies among workers, from green/blue to plain green and purple. The pilosity on the head is frequent around the occipital margin, and around the mandibular insertion, three to eight pale setae are usually seen. Examined specimens show no known ocelli. Erect setae on the pronotum are abundant, and the pilosity is common around the first gastral tergite. The anterodorsal portion of the propodeum is arched and flat.

There are no allometric differences among workers. On average, workers measure around 6–7 mm . The head and pronotum range from orange to brick-red, and the mesonotum and propodeum are either light, concolorous with, or darker than the head. The gaster can be brown or black with blue or purple iridescence and the legs are either orange or brown. The iridescence around the foreparts is blue, pink, pale greenish yellow and purple. The erect setae are brown. The head has a concave posterior margin with erect setae abundant in front of the face. The sides of the head are convex. Fully erect genal setae are either seen on the sides or the head or absent, although a small number of setae may be seen around the mandibular insertion. The eyes are semicircular and positioned around the midpoint of the ants' head capsule. The frontal carinae are convex and the antennal scapes extend beyond the head's posterior margin by two or three times the diameter. Erect setae are found all over the antennal scape and noticeably prominent on the clypeal margin. The mandibles are elongated and triangular, with long curved setae around the head capsule. The pronotum is evenly curved with at least 12 or more pronotal setae present. These setae are mostly short and bristly. The mesonotum is sinuous , and like the pronotum, has 12 or more mesonotal setae. The mesothoracic spiracles are very small and the propodeal dorsum is smooth or convex. There are also a number of propodeal setae. The dorsum of the node is thin, scale-like and sometimes vertical. There are both non-marginal and marginal setae present on the first gastral tergite around the gaster.c


Queens are easily distinguishable from workers, measuring 12.7 mm . Queens are black and fuscous, being mostly dark and sombre. The antennae and legs are ferruginous, the head is fusco-ferruginous, and the sides beneath the face and mandibles are ferruginous. The head is wider than the thorax and emarginate. There is an impressed line that runs from the anterior stemma to the base of the clypeus. The thorax is ovate-shaped and thinly covered with short reddish brown pubescence . The wings are subhyaline, exhibiting a glassy appearance. The wings are yellowish along the anterior margin of the superior pair and also around the base; the nervures are rufo-fuscous. Like the thorax, the abdomen is ovate and several abdominal segments appear rufo-piceous. Males are smaller than the queens, measuring 8 mm . Males are bright violet, and the antennae and tarsi are ferruginous. The first pair of the legs almost look ferruginous, and the head, legs and thorax are covered in black pubescence. Like the queen, the wings are subhyaline and the nervuvres are rufo-fuscous. The abdomen shows a bright green tinge when seen under certain light.


Larva measure 2.7–2.9 mm . The body is stout-shaped and the dorsal side is longer whereas the ventral side is shorter and more straight. The head and anus are ventral. The integument is covered in spinules that are either isolated from each other or in short rows on the posterior somite and on the ventral surface. The body hairs are very short, measuring 0.008–0.016 mm . The cranium on its dorsal side outlines a curve which is smooth, and the spinules are moderately large. These spinules are either isolated or seen in sub-parallel rows. Several head hairs are present but they are small at 0.013–0.025 mm in length. The labrum is narrow and bilobed, consisting of two lobes. Each lobe has spinules and three sensilla around the anterior surface. The ventral border only has two sensilla and a number of spinules, and on the posterior surface, there are several rows of spinules and three sensilla. The mandibles have a central apical tooth which is clearly noticeable and sharp. The maxillae are lobose, and the labial palps are knob-shaped.

Workers of the meat ant may be confused with those of ''I. lividus'', as the two appear similar, and are grouped in the same species complex. ''I. lividus'' and the much more localised ''I. spadius'' can be distinguished from other members of the ''I. purpureus'' group by the shape of the pronotum when specimens are being examined. Aside from colour differentiation that was a key morphological character to distinguish ''I. purpureus'' and the synonym ''I. greensladei'' from each other, some meat ant populations exhibit polymorphism despite being monomorphic. Examined workers once referred to as ''I. greensladei'' from the south-west of Western Australia have erect setae on the genae, whereas those studied elsewhere have glabrous genae. Such patterns are most likely clinal, where several characteristics may gradually differentiate over a geographical area. The colour of the setae found throughout the ants body may vary, and the iridescence also varies to some extent. For example, populations restricted to the southern coasts of Western Australia usually have pale setae, compared to most colonies throughout the country, which have the common blackish setae. However, Shattuck could not separate populations with pale setae when other and more important key characteristics were used to separate species. Meat ants from the Western Australian wheatbelt and goldfields show different iridescence; the iridescence in some collected specimens ranged from pale greenish-blue to yellowish-green, especially around the humeri and frons. The variation of the iridescence is, however, a consistent pattern found in other ''Iridomyrmex'' species with little distinction, making it a subtle character. The colour variation is less marked in all collected specimens of ''I. purpureus'', as well as its close relative ''I. viridiaeneus'', which is found in dry regions around the south-western regions. Shattuck further notes that populations found throughout the Northern Territory and South Australia have reduced pubescence on the first gastral tergite, but this is different elsewhere.

Naming

The specific epithet of the meat ant, ''purpureus'', derives from Latin, in which it means "purple", "purple-coloured" or "dark-red", referencing the coloured appearance of the ant. In classical Latin, ''purpureus'' primarily translated to "dyed purple", while the word ''purpura'', originally used as the specific name for the meat ant , translates to "purpled-dyed cloth". The name of the genus of the meat ant, ''Iridomyrmex'', translates to "rainbow ants", another reference which points to its appearance; this, in particular, is due to its blue-green iridescence colour. The word ''Irido'', meaning "rainbow", derives from Ancient Greek, and ''myrmex'', another Greek word, means "ant". The ant is commonly known as the meat ant because of its habit of stripping the meat off dead vertebrates, but it is also known as the gravel ant, Greenslade's meat ant, meat-eater ant, mound ant, or southern meat ant. The name "southern meat ant" is due to its extreme abundance in the southern regions of Australia.

Distribution

The meat ant is one of the best-known species of ant endemic to Australia with an enormous geographical range, covering at least one-third of the continent. Its range spans 4,000 kilometres from east to west, and 3,000 kilometres from north to south. This large range has allowed the meat ant to form large nesting grounds in areas where no development has occurred, and large amounts of gravel and open space have led to an abundant supply of materials used to construct nests. Its isolation has also allowed meat ants to form associations with neighbouring nests of the same species. The ant is particularly dominant and frequently seen across the coastal and inland regions of southeastern Australia. Based on examined material, the meat ant is common in the southwestern regions of Western Australia but in the north, it is less common. However, The CSIRO's Division of Entomology states that the ant's presence in the state has not been verified. In the Northern Territory, specimens have been collected in the north and south regions but compared to other jurisdictions the ant is uncommon. Most specimens collected in South Australia are from the south-east, but some populations are known in the north-west and northeast regions of the state. In Queensland, they are frequently encountered in the eastern areas of the state, whereas their abundance is limited around the north and central parts. They are widespread throughout New South Wales, the Australian Capital Territory and Victoria. No specimens have been collected from Tasmania or any outlying islands surrounding Australia.

Meat ants thrive in varied habitats, especially where it is open and warm. The ants are adapted to warm climates because of their large distribution and the fact that temperatures are always warm. The meat ant shares its distribution with many other animals and insects, some of which may cause harm to the ants or form rivalries with other ant species, such as the banded sugar ant . Body size among meat ants may vary depending on their location; particularly, those that are found in very hot regions tend to be larger, whereas those found in regions of high humidity tend to be smaller than average. Nests are seen in Box-pine scrubs, ''Callitris'' forests, dry sclerophyll woodland, ''Eucalyptus'' woodland and eucalypt open woodland, in farm pastures, flat savannah woodland, mallee woodland, heath, mulga, riparian woodland, around roads and cracks in sidewalks, urban areas such as urban gardens and parkland, and wet sclerophyll woodland. Nests are also common in lateritic ridges, granite outcrops and clay formations. Meat ants are able to survive in dry areas if there is a rich supply of water and food resources, especially along river banks, station properties and irrigated areas. Meat ants are mostly found at altitudes of between 5 and 1,170 m above sea level, but most of the time they are not found above 915 m . Those that are found at such altitudes are always associated with ''Eucalyptus rubida'', and colonies situated in eastern New South Wales tend to nest near ''Eucalyptus melliodora'' and ''Eucalyptus blakelyi''. In the south coast of New South Wales, meat ants are mainly found in heath shrubland, but they are absent from heavily timbered slopes and cannot build nests in quartz. They also do not occur in dense pastures, dense bushes, tropical rainforests and open treeless areas. For example, the Canberra suburb of Turner was constructed on subterranean clover pasture, which meat ants do not nest around. Their populations would later flourish and nests were numerous around houses after shrubs and trees were planted.

Behavior

Nuptial flight usually occurs during spring, in October. Reproductive females only mate with a single male and begin establishing their own colonies afterwards. Nuptial flight occurs after rain, where the males emerge from their nest first, followed by the virgin queens; groups of 20 to 40 females emerge after the males have flown away. The alates position themselves on top of the nest in order to heat themselves, and all fly at the same time once they are warm. This process may happen multiple times unless the weather had changed, otherwise, the queens would return to their nest. Nuptial flight may continue for days until all virgin queens have withdrawn from the nest. Most of the time, a single queen will start her own colony and lay eggs that will take around 44 to 61 days to fully develop and emerge as adults, but colonies can also be founded through multiple queens cooperating with each other, adoption into an existing colony, or "budding" , where a subset of the colony including queens, workers and brood leave the main colony for an alternative nest site. Around 10% of queens will have at least another queen with them during colony foundation. Many queens are killed during colony founding; major aspects include predation by birds and other ants, even those of the same species, due to the fact they attempt to establish their nests near large colonies. However, some queens are successful, sometimes with the assistance of neighbouring workers, who help the queen dig some chambers. Other causes of queen deaths include disease and starvation. A queen's ovaries may take four weeks to mature, and she lays around 20 eggs that may develop into larvae in less than a month. Workers have been observed laying eggs, presumably trophic eggs.

The number of individuals in a colony varies. A mature nest of several years old can hold between 11,000 to 64,000 ants, while other colonies can house around 300,000. In some cases, enormous colonies can have as many as a million ants. Observed colonies are known to contain nearly 70,000 larvae and 64,000 workers; some can have 20,000 males and over 1,000 virgin queens, but others may have more virgin queens than males. The ratio of worker ants to the number of the larvae in colonies ranges from one worker for every two larvae or two larvae for every worker. The population of a nest can be affected or altered by several factors: human interference can severely damage or completely destroy nests which potentially devastates the nest population, and overshadowing is the main cause of a nests' demise. As well as that, neighbouring nests may increase in population if damaged or abandoned sites are taken over. Meat ants also rely on their nests to withstand climatic stress in summer and winter, as foraging activity and food sources are sometimes limited in summer, and in winter plant growth is almost impossible and workers are unable to survive cold temperatures. As a result, meat ants overwinter and the population may be affected greatly.



Most colonies are monogyne, meaning that a colony only has a single queen, but based on observations, some nests contain more than a single queen. Some nests are known to contain two queens, with some even having as many as four in a single colony, making them polygynous; a high proportion of queens living in polygynous nests are unrelated to one another. Some colonies are oligogynous, which means that multiple queens are present in a colony, but they are tolerated by all workers birthed from different queens and treated equally. Tolerance still occurred even when new reproductive females and males are born, but recognition based on kin from queens and workers is known, hinting brood discrimination when the larvae are fed or groomed; queens will only take care of their own brood and neglect to look after broods laid by other queens. The queens, on the other hand, will only cooperate with each other during nest founding, but will be antagonistic once there are workers present in the colony. Queens become more intolerant of each other as the colony grows, and eventually separate within the nest, resulting in the queen laying more eggs. Such cases usually happen when pleometrotic founding occurs, or if a queen ant is adopted by a colony, setting up aggressive relationships. Physical fights between queens in the same colony are rare.

As most meat ant colonies rarely have a second queen, polydomy is not always associated with polygyny, although the two are frequently associated with each other because polygynous colonies reproduce by budding. This means that the ecological factors that promote polydomy and polygny both differ. Studies show that most meat ants are produced by a single, inseminated queen due to the high level of relatedness in all but one tested colonies. Colonies that are not closely related are the result of colony fusion . Meat ants also show nest fidelity: in polydomous colonies, workers from different nests will always mingle with others from different nests but never return to a nest they do not originate from. Instead, they return to the nest they enclosed in. This means that colonies may only homogenise through brood transfer. As discussed before, nestmates from different nests will always be aggressive towards each other, but this is due to a number of factors: genetic and spatial distance in nests can correlates with the level of aggression exhibited by the ants. However, they exhibit more aggression to ants of different species from adjoining territories. They are also aggressive to conspecific ants from distant colonies, suggesting that environmental cues play a vital role in nestmate recognition. One example includes that background odours in a particular environment may impair ants from identifying their own nestmates, and may need to make more attempts to determine an ants identity.

Habitat

The meat ant is one of the best-known species of ant endemic to Australia with an enormous geographical range, covering at least one-third of the continent. Its range spans 4,000 kilometres from east to west, and 3,000 kilometres from north to south. This large range has allowed the meat ant to form large nesting grounds in areas where no development has occurred, and large amounts of gravel and open space have led to an abundant supply of materials used to construct nests. Its isolation has also allowed meat ants to form associations with neighbouring nests of the same species. The ant is particularly dominant and frequently seen across the coastal and inland regions of southeastern Australia. Based on examined material, the meat ant is common in the southwestern regions of Western Australia but in the north, it is less common. However, The CSIRO's Division of Entomology states that the ant's presence in the state has not been verified. In the Northern Territory, specimens have been collected in the north and south regions but compared to other jurisdictions the ant is uncommon. Most specimens collected in South Australia are from the south-east, but some populations are known in the north-west and northeast regions of the state. In Queensland, they are frequently encountered in the eastern areas of the state, whereas their abundance is limited around the north and central parts. They are widespread throughout New South Wales, the Australian Capital Territory and Victoria. No specimens have been collected from Tasmania or any outlying islands surrounding Australia.

Meat ants thrive in varied habitats, especially where it is open and warm. The ants are adapted to warm climates because of their large distribution and the fact that temperatures are always warm. The meat ant shares its distribution with many other animals and insects, some of which may cause harm to the ants or form rivalries with other ant species, such as the banded sugar ant . Body size among meat ants may vary depending on their location; particularly, those that are found in very hot regions tend to be larger, whereas those found in regions of high humidity tend to be smaller than average. Nests are seen in Box-pine scrubs, ''Callitris'' forests, dry sclerophyll woodland, ''Eucalyptus'' woodland and eucalypt open woodland, in farm pastures, flat savannah woodland, mallee woodland, heath, mulga, riparian woodland, around roads and cracks in sidewalks, urban areas such as urban gardens and parkland, and wet sclerophyll woodland. Nests are also common in lateritic ridges, granite outcrops and clay formations. Meat ants are able to survive in dry areas if there is a rich supply of water and food resources, especially along river banks, station properties and irrigated areas. Meat ants are mostly found at altitudes of between 5 and 1,170 m above sea level, but most of the time they are not found above 915 m . Those that are found at such altitudes are always associated with ''Eucalyptus rubida'', and colonies situated in eastern New South Wales tend to nest near ''Eucalyptus melliodora'' and ''Eucalyptus blakelyi''. In the south coast of New South Wales, meat ants are mainly found in heath shrubland, but they are absent from heavily timbered slopes and cannot build nests in quartz. They also do not occur in dense pastures, dense bushes, tropical rainforests and open treeless areas. For example, the Canberra suburb of Turner was constructed on subterranean clover pasture, which meat ants do not nest around. Their populations would later flourish and nests were numerous around houses after shrubs and trees were planted.

Reproduction

Meat ants are well known for their large, oval-shaped nest-mounds that are frequently encountered, and obvious to identify. These nests are often accompanied with many entrance holes; most nests have 20 to 35 holes. On the surface on the nest, workers clear the area of vegetation and cover the mound with gravel, but may use other materials that are available, including sand, pebbles dead vegetation, eucalyptus fruits and twig fragments. Nests are often found in the sun and never in shaded areas, which allow the nests to warm up. The ant is a polydomous species, meaning that they live in more than one nest. Some colonies are known to create "super-nests": workers construct many nests connected through established paths, extending up to 650 metres in length. In one extreme case, a single colony was found to occupy over 10 hectares of land with 85 individual nests and 1,500 entrance holes. While meat ants are never aggressive to their nest mates, they are aggressive to those who live in different nests within the same colony. Foraging efficiency is an important factor favouring polydomy within a colony, as workers deliver most of their food to a nest that is closest to any site they forage in.

At any size, a meat ant nest always has a possibility of dying out in any year, but the site may be reoccupied by another colony. Such scenario leads to the extreme ageing of nests as suggested in one study. Some nests may never be reoccupied, although it is unknown why they are not. The regrowth of vegetation which shades the nest, soil damage or even a disease may wipe out a colony and leave the nest site completely abandoned. The death of a colony may be obvious when competing colonies increase in population and size by expanding their territories with well-established satellite nests in order exploit the food sources once used by a former colony. Satellite nests may diverge from their parent nests to become independent, as suggested by the antagonism of worker ants from different nests or when others are uninhabitable by insecticide treatment. After the eradication of a nest, satellite nests emerge nearby, and may sever their connections with the parent nest. The separation of a satellite nest is an effective way for a nest to exploit food sources, and a colony with less than 11 entrance holes are recognised as non-mature . As most satellite nests have 11 holes and accepted a queen of their own, a satellite nest may easily develop maturity in one year.


All entrance holes of a given nest lead into a separate set of galleries. Entrance holes tend to be very small with only enough space for a single worker to fit through, but others may be 1 centimetre wide. Beneath the surface, there are widened circular vertical shafts which are 1.5 centimetres wide. Below these shafts, the tunnels turn into irregular gallery systems with paths going outward and downward which form more galleries. Almost all of these galleries are clustered together 15 to 20 centimetres beneath the soil, which is extensively reworked by worker ants in the area above the nest. These sets of galleries are isolated from others connecting to neighbouring holes, although some may come close. However, there is no known physical connection. Each gallery has a flat floor, a domed roof and irregularly oval-shaped. A gallery is typically 1.5 centimetres high and 5 to 7 centimetres wide. Below the galleries are a small number of shafts in undisturbed soil with large, yet scattered chambers where the population remains during the winter. In the upper areas of the colony, the galleries and shafts only account for 7-10% of nest space. For example, the galleries of excavated colonies occupy 420 cubic centimetres whereas the total volume is around 5,000 cubic centimetres . Overall, a nest may dwell extremely deep beneath the soil as excavated nests are as deep as {{convert|3|m|ft}}.Nuptial flight usually occurs during spring, in October. Reproductive females only mate with a single male and begin establishing their own colonies afterwards. Nuptial flight occurs after rain, where the males emerge from their nest first, followed by the virgin queens; groups of 20 to 40 females emerge after the males have flown away. The alates position themselves on top of the nest in order to heat themselves, and all fly at the same time once they are warm. This process may happen multiple times unless the weather had changed, otherwise, the queens would return to their nest. Nuptial flight may continue for days until all virgin queens have withdrawn from the nest. Most of the time, a single queen will start her own colony and lay eggs that will take around 44 to 61 days to fully develop and emerge as adults, but colonies can also be founded through multiple queens cooperating with each other, adoption into an existing colony, or "budding" , where a subset of the colony including queens, workers and brood leave the main colony for an alternative nest site. Around 10% of queens will have at least another queen with them during colony foundation. Many queens are killed during colony founding; major aspects include predation by birds and other ants, even those of the same species, due to the fact they attempt to establish their nests near large colonies. However, some queens are successful, sometimes with the assistance of neighbouring workers, who help the queen dig some chambers. Other causes of queen deaths include disease and starvation. A queen's ovaries may take four weeks to mature, and she lays around 20 eggs that may develop into larvae in less than a month. Workers have been observed laying eggs, presumably trophic eggs.

The number of individuals in a colony varies. A mature nest of several years old can hold between 11,000 to 64,000 ants, while other colonies can house around 300,000. In some cases, enormous colonies can have as many as a million ants. Observed colonies are known to contain nearly 70,000 larvae and 64,000 workers; some can have 20,000 males and over 1,000 virgin queens, but others may have more virgin queens than males. The ratio of worker ants to the number of the larvae in colonies ranges from one worker for every two larvae or two larvae for every worker. The population of a nest can be affected or altered by several factors: human interference can severely damage or completely destroy nests which potentially devastates the nest population, and overshadowing is the main cause of a nests' demise. As well as that, neighbouring nests may increase in population if damaged or abandoned sites are taken over. Meat ants also rely on their nests to withstand climatic stress in summer and winter, as foraging activity and food sources are sometimes limited in summer, and in winter plant growth is almost impossible and workers are unable to survive cold temperatures. As a result, meat ants overwinter and the population may be affected greatly.



Most colonies are monogyne, meaning that a colony only has a single queen, but based on observations, some nests contain more than a single queen. Some nests are known to contain two queens, with some even having as many as four in a single colony, making them polygynous; a high proportion of queens living in polygynous nests are unrelated to one another. Some colonies are oligogynous, which means that multiple queens are present in a colony, but they are tolerated by all workers birthed from different queens and treated equally. Tolerance still occurred even when new reproductive females and males are born, but recognition based on kin from queens and workers is known, hinting brood discrimination when the larvae are fed or groomed; queens will only take care of their own brood and neglect to look after broods laid by other queens. The queens, on the other hand, will only cooperate with each other during nest founding, but will be antagonistic once there are workers present in the colony. Queens become more intolerant of each other as the colony grows, and eventually separate within the nest, resulting in the queen laying more eggs. Such cases usually happen when pleometrotic founding occurs, or if a queen ant is adopted by a colony, setting up aggressive relationships. Physical fights between queens in the same colony are rare.

As most meat ant colonies rarely have a second queen, polydomy is not always associated with polygyny, although the two are frequently associated with each other because polygynous colonies reproduce by budding. This means that the ecological factors that promote polydomy and polygny both differ. Studies show that most meat ants are produced by a single, inseminated queen due to the high level of relatedness in all but one tested colonies. Colonies that are not closely related are the result of colony fusion . Meat ants also show nest fidelity: in polydomous colonies, workers from different nests will always mingle with others from different nests but never return to a nest they do not originate from. Instead, they return to the nest they enclosed in. This means that colonies may only homogenise through brood transfer. As discussed before, nestmates from different nests will always be aggressive towards each other, but this is due to a number of factors: genetic and spatial distance in nests can correlates with the level of aggression exhibited by the ants. However, they exhibit more aggression to ants of different species from adjoining territories. They are also aggressive to conspecific ants from distant colonies, suggesting that environmental cues play a vital role in nestmate recognition. One example includes that background odours in a particular environment may impair ants from identifying their own nestmates, and may need to make more attempts to determine an ants identity.

Food

Like other ''Iridomyrmex'' species, the meat ant is an omnivore, retrieving food sources from various insects it tends, including caterpillars and various sorts of butterflies, particularly the larvae of the Waterhouse's hairstreak . Meat ants usually feed on honeydew from sap-sucking insects, flower nectar, sugar and other sweet substances. In captive colonies, workers prefer to consume small pieces of grapes rather than honey solutions and other sweet foods. These ants prey on various insects and animals, collecting both live and dead invertebrates and acquire meat from dead vertebrates. Insects the meat ants prey on includes giant lacewings, which they swarm up trees to kill, ''Ogyris genoveva'' butterflies, Indian mealmoths, almond moths, the Western Australian jarrah leafminer and ''Trichogramma'' wasp larvae. Large and developed larvae of the cabbage butterfly are often attacked by workers in an effective manner, whereas the larvae are usually left alone by smaller ''Iridomyrmex'' species. On sandy beaches, this species is observed preying on the polychaete annelid worm, ''Armandia intermedia'', causing high mortality rates on them . These ants will feed on a number of dead or alive animals, including metamorphic crucifix toads, snakes, lizards, and birds. On some occasions, swarms of workers have been found on dead foxes. The meat ant is the only known ant in Australia that feeds on fresh guano. The collection of guano by a nearby meat ant colony shows the opportunistic nature of the species. Observations show that trails of workers in groups of two to four were found collecting the guano under an active bat roost within an abandoned mine and proceeded to return it to the nest. The collection of guano by any Australian ant was never recorded prior to these observations, but it is unknown why meat ants collect fresh guano.


Meat ants are among the very few native species of Australia that are not harmed by the toxins of the cane toad, an invasive species. Most of the time, foraging workers target metamorph toads. Observations show that workers would forage around ponds and seize any toadlet. This normally starts with a single worker making contact with an individual and tracing its movements, followed by three or four workers capturing it. All the participating ants would grab a limb and sever the legs, returning the prey item back to their nest. Most of the time these tactics do not work. For example, most toadlets are able to escape the ants by displaying aversion-like behaviour; an individual may escape by struggling erratically or forcing the ants to release their grip by returning to the water. This aversion behaviour leads to most toadlets remaining in the water or staying on objects such as water lilies, pieces of bark that the ants cannot access, or moving around on moist substrates. It is unknown if meat ant predation on the toadlets affected the population, but based on the population density of the toadlets within the studied site and the foraging time and efficiency, approximately 2,700 toadlets could be removed per day. As the toadlet population density is extremely high, the impact of meat ant predation is minor. However, the survivability of the toadlets may be affected if the ants prevent the toadlets from foraging into many areas of moist substrate.

Water is an important resource for colonies living in dry and arid environments, but sometimes it may not be available. To counter this, workers are able to extract a significant amount of water from the sand with 2% to 4% water content and 4% from the soil. Meat ants are unable to retrieve as much water from the soil, whereas with sand they are able to attain a greater amount of water; however, the soil contains a wide variety of particles, including clay and coarse sand, which causes water to be bound firmly. Ants may retrieve it by digging or directly suck on the soil itself at a low metabolic cost. This may be an evolved response based on tested ants, but no observations show meat ants doing this. Meat ants are known to dig into moist soil to gain access to water or where water has been spilt, either if the site is nearby their nest or far away.

Predators

Despite its dominance among ants, a number of animals are known to prey on meat ants. The short-beaked echidna is a prominent predator of the meat ant, mostly due to the virgin queens containing high levels of fat. These queens can almost contain 47% fat, and when no queens are available after an attack, an echidna may stop attacking the nest. However, these ants are normally consumed either in low numbers or avoided entirely. Attacking echidnas burrow down into the hole they have made and consume them while handling the bites from the ants, as they frequently scratch themselves on the head and chest. The echidna does not consume meat ants throughout the whole year; instead, echidnas only attack meat ant nests from August to October, which is when nuptial flight occurs. This time period makes it much easier for echidnas to prey on the winged females since they are directly above on the nest.


Several birds prey on meat ants. The masked woodswallow and the white-browed woodswallow will gather around meat ant nests and swoop at them, catching several ants before eating them. Pieces of meat ants have been found in the feces of the red-capped robin , rufous whistler , hooded robin and the red-browed treecreeper . Meat ants that forage on ''Ventilago viminalis'' trees are often eaten by the apostlebird. Some large ground-feeding birds, such as currawongs, magpies and ravens dig out newly established colonies after a queen has found a suitable spot to nest. Small domes of excavated soil are present at such spots, revealing the queens' presence to these birds. As a result, many queens are consumed by birds, leaving many abandoned nest chambers.

The blind snake ''Ramphotyphlops nigrescens'' follow trails laid by meat ants to locate them, and the snakes are also known to feed on the brood. Various species of spiders prefer to prey on meat ants, mainly attracted by the alarm pheromone the ants release. One spider, in particular, the cursorial spider ''Habronestes bradleyi'', is a specialist predator against these ants and uses their alarm pheromones that are released during territorial disputes to locate them. These alarm signals are created by oscillating the body along the longitudinal axis, which are mostly released when an ant encounters a nest mate.

''Cyclotorna monocentra'' moths feed on meat ant broods. The larvae of these moths are parasites to leafhoppers and will move to meat ant colonies to complete their development, where they will proceed to consume the brood; the females lay many eggs near ant trails which are close to the leafhoppers tended by ants. Other observations show that the ''Iphierga macarista'' larvae are scavengers in meat ant nests, while ''Sphallomorpha'' beetles live in burrows near nests of meat ants, where the larvae capture and prey on workers passing by. The larvae of the spitfire sawfly and ''Pseudoperga guerini'' are able to regurgitate a fluid against the meat ant if they are getting attacked by them; depending on how much is regurgitated, an ant will either walk away and clean itself or become fatally affected by it. Lizards such as the thorny dragon, which is a sit and wait predator, consume meat ants, but other lizards which eat ''Iridomyrmex'' ants usually reject this species.