Odontomachus bauri
Encyclopedia
Odontomachus bauri is a species
of ponerinae
ant
known as trap jaw ants. The trap jaw consists of mandibles which contain a spring-loaded catch mechanism.
This mechanism permits the ants to accumulate energy before striking or releasing the mandibles rapidly. O. bauri is known for its powerful mandibles, which can open up to about 180° and within 10 ms of being stimulated and can close within 0.5 ms, which help with catching prey. The mandibles are able to sting and paralyze prey or crush prey to death. O. bauri also uses its mandibles to propel itself or prey off of the ground either vertically or horizontally. O. bauri can travel over 20 times their body length in a single jaw-propelled leap. To put this extraordinary ability in relative terms, a human would have to be able to throw one’s body 13 meters high or 40 meters long to match up to the O. bauri’s jumps. O. bauri is closely related to the genus Anochetus which is in the same family, Formicidae. It has been discovered from southern Costa Rica
throughout tropical South America
, the West Indies (excpet Cuba
and Bahamas), and on the Galapagos Islands
.
throughout tropical South America
, the West Indies (except Cuba
and the Bahamas), and on the Galapagos Islands
. O. bauri is most often discovered in lowlands usually residing in tropical rainforests, although the species appears more tolerant of dry conditions than many other Odontomachus species.
O. bauri typically forms nests in soft and humid grounds in areas protected from direct sunlight and areas where there is a low chance of disturbance by nature, i.e. wind, rain etc. One may be able to find nests under rocks, branches, and trunks of fallen trees. Additionally, if they are found in gardens, they are usually under rocks, plant containers, and vegetable residues.
Nests are usually small, roughly less than 200 ants. The foraging areas between each family of nests are strictly defined. O. bauri has been observed staying within the same area while foraging, because it would not dare step into its neighbor’s foraging area.
O. bauri usually spends its time below the leaf litter, classifying it as a leaf-litter ant. It is also widely known as a generalist predator. A few of O. bauri’s common prey include worms, spiders, termites, ants, butterflies, flies, and beetles. Usually prey would be around 3mm and 4mm in length. The most common prey O. bauri enjoys are soft bodied, for example, termites and wood lice. O. bauri is able to “exploit a food resource largely unavailable to other ants”. This was determined after a researcher found remnants of Nasuitermes a type of termite that as a defense will discharge material that irritates and can block the predator’s sensory organs. Finding parts of this type of termite prove that the mandibles of O. bauri are able to combat prey which is chemically protected.
Workers are observed returning to places where they had previously found food. The foraging success for an individual, which is measured by how many workers return with prey, would be 28%. About 41% of the workers who were returning from foraging were empty handed and the other 31% had no prey or the prey was too small to be distinguished.
The biology behind this amazing ability is that when one trigger hair is stimulated, it actually causes all four large motor neurons to become active. These large motor neurons are fully covered in a glial sheath which is a group of specialized cells that nourish and support neurons. A glial sheath is essential for sending signals at a fast rate, because it allows for a single smooth road rather than having the signal jump from neuron to neuron.
The mandibles are controlled by the stimulation of two large sensory neurons that project through the sensory mandibular nerve into the suboesophageal ganglion. To operate the mandible muscles, the ends of the sensory neurons lead to the thick dendritic trunks of the four motor neurons.
The mandibles of O. bauri are kept in place with a latch called the clypeus. Once the latch is released, all of the energy stored is quickly released and the mandibles close, very similar to a crossbow when fired.
The trigger muscles found in O. bauri are also found in the fastest synchronous muscles of cicadas. The muscles appear to have been sculpted for fast contraction. This is because the sarcomere length, which is the fundamental unit of muscle structure, is similar in length.
“Bouncer-defense jumps” are looked upon as mere accidents rather than purposeful acts performed by the trap-jaw ant. This is because they most frequently execute this jump when there are faced with a large harmless prey rather than with small prey. This evidence concludes that this type of jump is produced by a non-penetrating strike. “Bouncer-defense jumps” are usually horizontal jumps which can lead to the ant to land anywhere 40 centimeters away from its original position.
On the other hand, “escape jumps” propel the ant vertically and are proved to be intentional because of the behaviors that precede the jump. Patek et al. observed that before an “escape jump,” the ant will orient its antennae and head perpendicularly to the intruder. Additionally it will sway its entire body and then lift one leg vertically. This is quite an elaborate routine to prepare to propel itself 7 cm off of the ground. The reason behind this maneuver is to be able to grab onto vegetation usually located around their nests in order to provide a form of escape.
Trap-jaw ants do not have similar stingers as bees. Instead, their stings are retractable and not barbed in order to be used again. The sting is located at the end of the abdomen and is completely covered by a sheath, a protective covering. Besides the momentary sting from the bite, O. bauri contains a mixture of formic acid and protein, which may have a high toxic activity, and is discharged after the ant bite. Within humans, there have been records of immediate burning at the site of the sting but that usually dissipates after an hour. However, there was one case in which a young girl had an intense allergic reaction to the bite3. There were patches of red, itchy, swollen areas on her hands, arms, thorax and foot. Additionally, her eyelids were swollen. This lasted about a week and has been discovered in about 16% of ant bites.
Jaffe et al. were able to perform an experiment in which they discovered how O. bauri recognizes one another. The recognition signal does not pertain to environmental cues, since O. bauri attacked ants which were kept in the colony surrounded by a wire mesh capsule more than the controls, which were kept inside the colony. To further rule out environmental cues as an option, Jaffe et al. fed two different colonies the same diet and fed a single colony two different diets. When the trap jaw ants from the single colony but different diets met they did not attack each other. However, when the ants from two different colonies but same diets met they attacked each other roughly 75% of the time. Additionally, the recognition signal is not a sound or a particular behavior since O. bauri is able to recognize dead nestmates. Jaffe et al. was able to determine that the recognition signal must be a type of smell, since ants which were freeze dried or in a plastic wire mesh capsule were never attacked.
Jaffe et al. discovered that O. bauri uses a volatile substance, dichloromethane
(CH2Cl2), in order to recognize one another. The trick in knowing one’s relative is by the amount of substance produced upon antennation. Further analysis using gas chromatography was used to determine that each trap jaw ant from a different colony have different amounts of volatile chemicals within its system.
To use correct evolutionary terms, the mandibles and the muscles found in the mandibles are known as exaptation. Exaptations are useful traits that were not originally produced by natural selection for their current use. For example, the large mandibles were selected for in order to help the ants become better able to carry food, but then the ants were able to use these mandibles as a way of defense and for hunting.
There are other ants with killer jaws such as the Strumigenys
, Mystrium, Myrmoteras
and Anochetus
to name a few other ants within the same family with the same features. One commonly accepted theory suggests that the trap-jaw actually evolved independently at least four different times in ants’ history. This is because with the use of DNA sequencing
, the phylogenetic tree which found that those ants with trap-jaws were not nested neatly in one portion of the tree. Instead they were found scattered around the tree. Therefore, it did not evolve once leading to the hypothesis of a common ancestor. Instead it evolved multiple times and each time it evolved it used a different feature of the ant’s mouth to produce the trap jaw. For instance, O. bauri’s trap jaw is built from the mandible joint; however, Strumigenys
trigger is built from it upper lip. This type of evolution
would be deemed as convergent evolution
and the trap jaw would be considered an analogy. This is because they are all similar features but involved independently rather than a common ancestor.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of ponerinae
Ponerinae
Ponerinae is a subfamily of ants in the Poneromorph subfamilies group, with about 1,600 species in 28 extant genera, including Dinoponera gigantea - one of the world's largest species of ant....
ant
Ant
Ants are social insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from wasp-like ancestors in the mid-Cretaceous period between 110 and 130 million years ago and diversified after the rise of flowering plants. More than...
known as trap jaw ants. The trap jaw consists of mandibles which contain a spring-loaded catch mechanism.
This mechanism permits the ants to accumulate energy before striking or releasing the mandibles rapidly. O. bauri is known for its powerful mandibles, which can open up to about 180° and within 10 ms of being stimulated and can close within 0.5 ms, which help with catching prey. The mandibles are able to sting and paralyze prey or crush prey to death. O. bauri also uses its mandibles to propel itself or prey off of the ground either vertically or horizontally. O. bauri can travel over 20 times their body length in a single jaw-propelled leap. To put this extraordinary ability in relative terms, a human would have to be able to throw one’s body 13 meters high or 40 meters long to match up to the O. bauri’s jumps. O. bauri is closely related to the genus Anochetus which is in the same family, Formicidae. It has been discovered from southern Costa Rica
Costa Rica
Costa Rica , officially the Republic of Costa Rica is a multilingual, multiethnic and multicultural country in Central America, bordered by Nicaragua to the north, Panama to the southeast, the Pacific Ocean to the west and the Caribbean Sea to the east....
throughout tropical South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
, the West Indies (excpet Cuba
Cuba
The Republic of Cuba is an island nation in the Caribbean. The nation of Cuba consists of the main island of Cuba, the Isla de la Juventud, and several archipelagos. Havana is the largest city in Cuba and the country's capital. Santiago de Cuba is the second largest city...
and Bahamas), and on the Galapagos Islands
Galápagos Islands
The Galápagos Islands are an archipelago of volcanic islands distributed around the equator in the Pacific Ocean, west of continental Ecuador, of which they are a part.The Galápagos Islands and its surrounding waters form an Ecuadorian province, a national park, and a...
.
Identification
O. bauri‘s main feature is its dark brown color. Additionally, the face to the near margin of vertex is striated. The head is 2.09 millimetre long. There is pubescence or hair on the first gastral tergum and is partially found standing straight up and relatively uniform. The petiolar node (B on Figure 2) is dome-shaped when seen from the side.Habitat
O. bauri is found from southern Costa RicaCosta Rica
Costa Rica , officially the Republic of Costa Rica is a multilingual, multiethnic and multicultural country in Central America, bordered by Nicaragua to the north, Panama to the southeast, the Pacific Ocean to the west and the Caribbean Sea to the east....
throughout tropical South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
, the West Indies (except Cuba
Cuba
The Republic of Cuba is an island nation in the Caribbean. The nation of Cuba consists of the main island of Cuba, the Isla de la Juventud, and several archipelagos. Havana is the largest city in Cuba and the country's capital. Santiago de Cuba is the second largest city...
and the Bahamas), and on the Galapagos Islands
Galápagos Islands
The Galápagos Islands are an archipelago of volcanic islands distributed around the equator in the Pacific Ocean, west of continental Ecuador, of which they are a part.The Galápagos Islands and its surrounding waters form an Ecuadorian province, a national park, and a...
. O. bauri is most often discovered in lowlands usually residing in tropical rainforests, although the species appears more tolerant of dry conditions than many other Odontomachus species.
O. bauri typically forms nests in soft and humid grounds in areas protected from direct sunlight and areas where there is a low chance of disturbance by nature, i.e. wind, rain etc. One may be able to find nests under rocks, branches, and trunks of fallen trees. Additionally, if they are found in gardens, they are usually under rocks, plant containers, and vegetable residues.
Foraging behavior
O. bauri has a polydomous nest structure in which there are multiple nests for a single colony. This characteristic was confirmed when researchers observed that many neighboring nests do not fight with one another, but nests which are more than 10 m (32.8 ft) apart would be highly aggressive towards one another. Additionally, there were many times which observers saw trap jaw ants sharing food amongst their neighbors.Nests are usually small, roughly less than 200 ants. The foraging areas between each family of nests are strictly defined. O. bauri has been observed staying within the same area while foraging, because it would not dare step into its neighbor’s foraging area.
O. bauri usually spends its time below the leaf litter, classifying it as a leaf-litter ant. It is also widely known as a generalist predator. A few of O. bauri’s common prey include worms, spiders, termites, ants, butterflies, flies, and beetles. Usually prey would be around 3mm and 4mm in length. The most common prey O. bauri enjoys are soft bodied, for example, termites and wood lice. O. bauri is able to “exploit a food resource largely unavailable to other ants”. This was determined after a researcher found remnants of Nasuitermes a type of termite that as a defense will discharge material that irritates and can block the predator’s sensory organs. Finding parts of this type of termite prove that the mandibles of O. bauri are able to combat prey which is chemically protected.
Workers are observed returning to places where they had previously found food. The foraging success for an individual, which is measured by how many workers return with prey, would be 28%. About 41% of the workers who were returning from foraging were empty handed and the other 31% had no prey or the prey was too small to be distinguished.
Speed
O. bauri have the fastest moving predatory appendages within the animal kingdom. After stimulation of one of the four trigger hairs, the appendage will respond within 10ms. It has peak speeds of 126 kph, with the jaws closing within just 130 microseconds on average. This is about 2300 times faster than the blink of an eye. The peak force exerted was in the order of 300 times the body weight of the ant. The ants were also observed using their jaws as catapults to eject intruders or fling themselves backwards to escape a threat.The biology behind this amazing ability is that when one trigger hair is stimulated, it actually causes all four large motor neurons to become active. These large motor neurons are fully covered in a glial sheath which is a group of specialized cells that nourish and support neurons. A glial sheath is essential for sending signals at a fast rate, because it allows for a single smooth road rather than having the signal jump from neuron to neuron.
The mandibles are controlled by the stimulation of two large sensory neurons that project through the sensory mandibular nerve into the suboesophageal ganglion. To operate the mandible muscles, the ends of the sensory neurons lead to the thick dendritic trunks of the four motor neurons.
The mandibles of O. bauri are kept in place with a latch called the clypeus. Once the latch is released, all of the energy stored is quickly released and the mandibles close, very similar to a crossbow when fired.
The trigger muscles found in O. bauri are also found in the fastest synchronous muscles of cicadas. The muscles appear to have been sculpted for fast contraction. This is because the sarcomere length, which is the fundamental unit of muscle structure, is similar in length.
Jumping Records
O. bauri typically uses its appendages in capturing prey. However, it may also be used in propelling its body into the air and this may result in two different types of jumps. A “bouncer-defense jump” is when O. bauri throws itself backwards away from the potential prey due to the mandibles striking an upright object. An “escape jump” involves O. bauri positioning its jaws towards the ground before firing and is launched vertically into the air. Additionally, to distinguish an escape jump from a bouncer-defense jump, O. bauri will orient its head in a particular manner.“Bouncer-defense jumps” are looked upon as mere accidents rather than purposeful acts performed by the trap-jaw ant. This is because they most frequently execute this jump when there are faced with a large harmless prey rather than with small prey. This evidence concludes that this type of jump is produced by a non-penetrating strike. “Bouncer-defense jumps” are usually horizontal jumps which can lead to the ant to land anywhere 40 centimeters away from its original position.
On the other hand, “escape jumps” propel the ant vertically and are proved to be intentional because of the behaviors that precede the jump. Patek et al. observed that before an “escape jump,” the ant will orient its antennae and head perpendicularly to the intruder. Additionally it will sway its entire body and then lift one leg vertically. This is quite an elaborate routine to prepare to propel itself 7 cm off of the ground. The reason behind this maneuver is to be able to grab onto vegetation usually located around their nests in order to provide a form of escape.
Alarm and defense
O. bauri is a very aggressive species of ant. Once its nest is disturbed there are many worker ants performing the escape jump. If one lands on the intruder, then the workers immediately began stinging the prowler. Fortunately for the intruder, only a few of the workers in the nest will participate in stinging the intruder unlike ant species from the genus Solenopsis. The bites are not severe for humans, but they do produce an allergic reaction.Trap-jaw ants do not have similar stingers as bees. Instead, their stings are retractable and not barbed in order to be used again. The sting is located at the end of the abdomen and is completely covered by a sheath, a protective covering. Besides the momentary sting from the bite, O. bauri contains a mixture of formic acid and protein, which may have a high toxic activity, and is discharged after the ant bite. Within humans, there have been records of immediate burning at the site of the sting but that usually dissipates after an hour. However, there was one case in which a young girl had an intense allergic reaction to the bite3. There were patches of red, itchy, swollen areas on her hands, arms, thorax and foot. Additionally, her eyelids were swollen. This lasted about a week and has been discovered in about 16% of ant bites.
Recognition
O. bauri is able to recognize other workers from different nests by antennation. This process happens when two ants are front to front of one another, and either one is touching the other’s antennae with their antennae or head. There are four different behavioral patterns that may result after recognition of the other ant. These are basic alertness, alarm, attack with mandibles or attack with sting. Basic alertness occurs when both ants open their mandibles to about 180°. Alarm is composed of both basic alertness with fast random body movements and release of alarm pheromone. Attack with mandibles is a pattern in which the trap jaw ant will use its mandibles in order to strike a blow to the opponent10. Attack with sting is when the trap jaw ant will bend its abdomen forward and try to use its sting to hurt the opponent.Jaffe et al. were able to perform an experiment in which they discovered how O. bauri recognizes one another. The recognition signal does not pertain to environmental cues, since O. bauri attacked ants which were kept in the colony surrounded by a wire mesh capsule more than the controls, which were kept inside the colony. To further rule out environmental cues as an option, Jaffe et al. fed two different colonies the same diet and fed a single colony two different diets. When the trap jaw ants from the single colony but different diets met they did not attack each other. However, when the ants from two different colonies but same diets met they attacked each other roughly 75% of the time. Additionally, the recognition signal is not a sound or a particular behavior since O. bauri is able to recognize dead nestmates. Jaffe et al. was able to determine that the recognition signal must be a type of smell, since ants which were freeze dried or in a plastic wire mesh capsule were never attacked.
Jaffe et al. discovered that O. bauri uses a volatile substance, dichloromethane
Dichloromethane
Dichloromethane is an organic compound with the formula CH2Cl2. This colorless, volatile liquid with a moderately sweet aroma is widely used as a solvent. Although it is not miscible with water, it is miscible with many organic solvents...
(CH2Cl2), in order to recognize one another. The trick in knowing one’s relative is by the amount of substance produced upon antennation. Further analysis using gas chromatography was used to determine that each trap jaw ant from a different colony have different amounts of volatile chemicals within its system.
Evolution
The mandibles of O. bauri are an exaggerated form of the sturdy and long mandibles found in many ant species. Additionally, the muscles found in the mandibles of O. bauri are found in other ants, although those found in O. bauri are large and look very similar to those found in cicadas.To use correct evolutionary terms, the mandibles and the muscles found in the mandibles are known as exaptation. Exaptations are useful traits that were not originally produced by natural selection for their current use. For example, the large mandibles were selected for in order to help the ants become better able to carry food, but then the ants were able to use these mandibles as a way of defense and for hunting.
There are other ants with killer jaws such as the Strumigenys
Strumigenys
Strumigenys is a genus of myrmicine ants in the tribe Dacetini.-Biology:Strumigenys form small nests in soil, under or between rocks, or in and under logs or under cattle dung. Some species nest in association with other ants such as Bothriomyrmex mayri or Rhytidoponera metallica. Although they are...
, Mystrium, Myrmoteras
Myrmoteras
Myrmoteras is a genus of ants in the subfamily Formicinae. They have enormous eyes, a character found in other ancient genera, and extremely elongate mandibles with eight to sixteen teeth...
and Anochetus
Anochetus
Anochetus is a genus of carnivorous ants found in the tropics and subtropics throughout the world.- Species :This is an incomplete list of species in this genus....
to name a few other ants within the same family with the same features. One commonly accepted theory suggests that the trap-jaw actually evolved independently at least four different times in ants’ history. This is because with the use of DNA sequencing
DNA sequencing
DNA sequencing includes several methods and technologies that are used for determining the order of the nucleotide bases—adenine, guanine, cytosine, and thymine—in a molecule of DNA....
, the phylogenetic tree which found that those ants with trap-jaws were not nested neatly in one portion of the tree. Instead they were found scattered around the tree. Therefore, it did not evolve once leading to the hypothesis of a common ancestor. Instead it evolved multiple times and each time it evolved it used a different feature of the ant’s mouth to produce the trap jaw. For instance, O. bauri’s trap jaw is built from the mandible joint; however, Strumigenys
Strumigenys
Strumigenys is a genus of myrmicine ants in the tribe Dacetini.-Biology:Strumigenys form small nests in soil, under or between rocks, or in and under logs or under cattle dung. Some species nest in association with other ants such as Bothriomyrmex mayri or Rhytidoponera metallica. Although they are...
trigger is built from it upper lip. This type of evolution
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
would be deemed as convergent evolution
Convergent evolution
Convergent evolution describes the acquisition of the same biological trait in unrelated lineages.The wing is a classic example of convergent evolution in action. Although their last common ancestor did not have wings, both birds and bats do, and are capable of powered flight. The wings are...
and the trap jaw would be considered an analogy. This is because they are all similar features but involved independently rather than a common ancestor.
External links
- Pictures of Odontomachus bauri
- Ants of Costa Rica: Odontomachus bauri
- "The breakneck world of ants that bite fast and jump high" University of California Museum of Paleontology experiments include videos of Odontomachus bauri mandibles at work
- Encyclopedia of Life page
- AntWeb page
- UC Berkley News Press Release
- New Scientist News Article