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What a move! Watch ants use their spring-loaded jaws to somersault to safety

Scientists at the University of Illinois dropped trap-jaw ants into antlion pits, which bury themselves and lie in wait to hunt hapless insects
Trap-jaw ants use their mandibles to somersault to safety as a last resort
Used this method to escape from antlions around 15 per cent of the time
Mandibles are usually used to hunt and can whip shut at speeds over 40 metres per second, which is the equivalent of 89mph (144km/h)

By Sarah Griffiths for MailOnline and Mailonline

Published: 04:52 EST, 15 May 2015 | Updated: 04:52 EST, 15 May 2015

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As dramatic exits go, the trap-jaw ant has one of the most impressive out there.

The insects use their spring-loaded mandibles to somersault to safety and evade the jaws of predators hiding in sand, a new study reveals.

The move is the last resort for the ants, which usually use their jaws to attack and consume prey.

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These jaws were made for jumping: Trap jaw ants use their spring-loaded mandibles to somersault to safety (pictured) and evade the jaws of predators hiding in sand, a new study reveals

The mandibles of the trap-jaw ant Odontomachus brunneus can whip shut at speeds over 40 metres per second, which is the equivalent of 89mph (144km/h) instantaneously maiming a prey insect or enemy ant.

They also are used for more routine tasks, such as digging nests or tending to eggs and larvae.

While previous studies have shown that trap-jaw ants sometimes jump with their jaws, it was a mystery why.

Fierce: The mandibles of the trap-jaw ant Odontomachus brunneus (shown) can whip shut at speeds over 40 metres per second, which is the equivalent of 89mph (144km/h) instantaneously maiming a prey insect or enemy ant

The great escape: The athletic move is the last resort for the ants, which usually use their jaws to attack and consume prey. This set of images from the study show the escape jumps of O. brunneus during interactions with the antlion. The location of the pit is marked with a black arrow and the trap-jaw any with a white arrow

INCREDIBLE TRAP-JAW ANTS

Odontomachus brunneus - a type of trap-jaw ant - is found in the south eastern US, Central America and West indies.

It has large, straight mandibles which it can open 180 degrees and snap shut on prey at speeds of over 40 meters per second, which is the equivalent of 89mph (144km/h).

The jaw is triggered when sensory hairs on the inside of the mandibles are touched.

They can also be used for slower and gentler tasks such as building nests and tending to larvae.

University of Illinois graduate student Fredrick Larabee, said: ‘It was unknown whether this behaviour was meant to help them get away from a predator, and it wasn’t clear that it actually improved their odds of surviving an encounter with a predator.’

Now, the study, published in the journal Plos One, claims that the mandibles aid the ants’ survival by allowing them to catapult themselves out of a dangerous situation, such as the territory of pit-building antlions.

The fearsome predators dig conical pits in the sand and bury themselves at the bottom of them to wait for victims.

‘If an ant falls into the pit, it tries to run away, but the sand crumbles beneath its feet,’ Larabee said.

‘This pulls it closer to the centre of the pit where the antlion is waiting.’

But the antlion sometimes hurls sand at an ant, causing a tiny avalanche that further destabilises its target.

Incredible ants avoid predators with mandible-powered jumps

Mission impossible? While previous studies have shown that trap-jaw ants (pictured a) sometimes jump with their jaws, it was a mystery why. Now experts have confirmed that ants jump from antlion pits (c) to escape the clutches of the fierce predator (b) around 15 per cent of the time, according to their experiments

ANTLION’S HUNTING TECHNIQUE

Antlion larva, sometimes known as doodlebugs, can grow up to one-and-a-half inches (4cm) long and are found in arid and sandy habitats around the world.

They mainly eat ants and hunt with the help of sand pit traps.

The average pit is two inches (5cm) deep and three inches (8cm) wide at the edge.

When it is dug, the larva crawls backwards using its abdomen as a plough to move sand out of the way- burrowing downwards.

Using one of its front legs, it places loose particles over its head to disguise its hiding place below the surface of the sand or soil.

As the animal moves around, the pit gets deeper so that the angle becomes as steep as is possible.

It lies in wait with its wide-open jaws just above the surface.

The slippery slope draws careless ants into the centre where the antlion strikes.

Lucky ants try to run up the hill or perform a somersault to escape.

But the larva sometimes chucks sand to make the insect slip back down towards its jaws.

If the ant tumbles to the bottom of the pit and the antlion grabs it with its mandibles, the ant is doomed.

In order to explore how often the trap-jaw ants use their jaw-jumping manoeuvre to escape from a predator, the athletic insects were dropped into antlion pits in the lab.

The ants usually tried to run out of the pit, and sometimes were successful.

If that strategy failed, they sometimes jumped with their jaws.

‘The ants were able to jump out of the pits about 15 percent of the time in their encounters with antlions,’ Larabee said.

The researchers then glued the ants' mandibles shut before dropping them into the pits and found that they couldn’t jump at all, proving the occasional function and the power of the mandibles.

‘It cut their survival rate in half,’ he said.

Entomology professor Andrew Suarez said that previous research has shown that O. brunneus sometimes adopts an unusual body posture just before jumping.

The creature lowers its head, making contact with the ground, and occasionally raises a leg before deploying its mandibles to hurl itself into the air.

‘Based on our earlier studies, if the ant was striking a prey object, the distance between the ant and the prey was about the length of the trigger hairs that come off the mandibles,’ Suarez said.

‘But when they were jumping off a surface, you would often see the ants put their entire face against the surface, and it was more of a pushing behaviour than a striking behaviour.’

Larabee said that the study shows how a trait or capability that evolved for one purpose can be adapted for different uses.

‘In this case, a tool that is very good for capturing fast or dangerous prey also is good for another function, which is escape.'

ANTS' MOVEMENTS HIDE MATHEMATICAL PATTERNS

When ants go exploring in search of food they end up choosing collective routes that fit statistical distributions of probability, a team of mathematicians has found.

Their study is one of many in which experts are trying to unravel how birds, fish and ants organise themselves so well while moving collectively.

Researchers from Spain and the US studied Argentine ants and say their findings could be used to coordinate the movement of micro-robots in cleaning contaminated areas, for example.

When Argentine ants (pictured) go exploring in search of food they end up choosing collective routes that fit statistical distributions of probability, a team of mathematicians has found

They analysed the insects' movements while they explored a petri dish and modelled how they formed their routes.

The study, which is published in the journal Mathematical Biosciences, began by looking at individuals, before focusing on group movements.

Experts recorded all these movements to detect that the random changes in direction of the insects follow mathematical patterns.

María Vela Pérez, of the European University in Madrid explained: 'To be more specific, they are a mixture of Gaussian and Pareto distributions, two probability functions which are commonly used in statistics, and that in this case dictate how much the ant "turns" at each step and the direction it will travel in.'

Experts analysed the insects' movements while they explored a pertri dish and modelled how they formed their routes. These images show the concentration of pheromones (shown in red from left to right) after 10,000 time steps, 20,000 time steps and 40,000 time steps

The scientists had already verified in previous studies that the 'persistence' of ants, or rather, their tendency not to change their direction while there are no obstacles or external effects, together with the 'reinforcement' occurring in areas which they have already visited - thanks to the pheromone trail that they leave - are two factors which determine their routes as they forage.

Using all the data they created a model describing the collective movements of ants on a surface, which bolster that was seen in the petri dishes.

The advances could be applied in diverse technological fields.

'For example, they could be used to design the coordination of a group of micro-robots or small robots to clean a contaminated area or other tasks,' Vela Pérez said.