Even the
tiniest organisms can make it to the big leagues. The number one fastest animal
movement in the world now belongs to an ant no bigger than the tip of your
finger.
Ominously
named the Dracula ant (Mystrium camillae), this minuscule species is shy and
elusive, a subterranean predator that enjoys sucking the blood from its own
hapless larvae in a practice fondly known as "nondestructive
cannibalism".
It's also
wicked fast. A new study has found that the jaws on this rare and mysterious
species can snap shut five thousand times quicker than the blink of an eye.
Using a
high-speed camera, scientists at the Smithsonian have now caught this
remarkable movement in action for the first time.
The
mechanism works sort of like a finger snap, except at a meteoric pace, one thousand
times faster than what human hands are capable of.
Pressing the
tips of its mandibles together, pressure between the ant's jaws begins to
build, until at last it reaches a breaking point, eventually releasing one of
the mandibles so it slides across the other.
From start
to finish, the action takes 0.000015 seconds, going from zero to around 320
km/h (198 mph) in a fraction of an instant.
This
particular species of Dracula ant has now taken the gold medal for the fastest
known animal appendage and the fastest known biological manoeuvre ever.
The genus
Mystrium has been called the "most mysterious group within the bizarre
Dracula ants", and scientists are still not sure why this cryptic ant has
evolved such special mandibles.
Although, in
the animal kingdom, when it comes to catching prey and avoiding predators,
speed is extremely important. Today, the fastest known movements are behaviours
based on hunting and defence, and these quick twitches are commonly observed in
arthropods like mantis shrimp, froghoppers and trap-jaw ants.
Among these
creatures, energy is stored up in the muscles and then released via a latch
that lets the energy loose through some sort of elastic spring. By
incorporating latches and springs, these animals are saved from overworking
their muscles, and this allows creatures like the Dracula ant to forage for
food and defend themselves against predators in the most efficient way
possible.
Even
compared to other trap-jaw ants, however, the Mystrium Dracula ant reigns
supreme. Currently, we know at least six lineages of ants that have similar
power-amplified mandibles, but the Mystrium camillae has a unique morphology
that makes it especially quick.
Unlike other
ants with trap-jaws, the mandibles on these fellas start from a closed position
and then slide across each other. What's more, the spring and latch mechanisms
that allow the jaw to slam closed are embedded within the mandible itself.
This unique
structure is probably what gives this genera such speed. In trap-jaw ants like
the Odontomachus and Myrmoteras genera - where the spring, latch and trigger
structures are separated - it takes three to sixty times longer for the jaws to
close. And even at peak velocity, this movement is still ten to twenty times
slower than what Mystrium camillae is capable of.
The authors
of the paper think that maybe these special jaws developed alongside this ant's
unique underground habitat - in the tropics of South East Asia and Australia -
where open jaws are not really an option.
"The
foraging and nesting habits of Mystrium are also restricted to confined tunnels
in logs and in the soil, and this may favour this type of amplification system
where the ant cannot open its jaws widely as seen in trap-jaw ants which
largely forage in open spaces," the authors propose.
But we still
can't be sure. These creatures are like buried treasure, and more research will
be needed if we want to know why they have developed such expeditious
trap-jaws.
This study
was published in the Royal Society Open Science.
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