Bioceramics power the mantis shrimp's famous punch

October 18, 2018, Cell Press
A peacock mantis shrimp attacking its prey with its dactyl clubs. Credit: Maryam Tadayon / Biological & Biomimetic Materials Laboratory

Researchers in Singapore can now explain what gives the mantis shrimp, a marine crustacean that hunts by battering its prey with its club-like appendages, the most powerful punch in the animal kingdom. In a paper publishing October 19 in the journal iScience, they show that a saddle-shaped structure in the mantis shrimp's limbs, which acts like a spring to store and then release energy, is composed of two layers made of different materials. Measuring the composition and the micro-mechanical properties of the layers—which are mostly bioceramic and mostly biopolymeric, respectively—allowed the researchers to simulate how the saddle stores such large amounts of elastic energy without breaking.

"Nature has evolved a very clever design in this saddle," says senior author Ali Miserez, a materials scientist who studies unique biological structures at Nanyang Technological University in Singapore. "If it was made of one homogeneous material, it would be very brittle. It would for sure break."

Previous research from the lab of biologist Sheila Patek had examined the mantis shrimp's dactyl clubs—the appendages they use to attack their prey—and suggested that muscles alone couldn't be creating the amount of force with which the crustaceans strike. Other research had hypothesized that the saddle might be used to store , but studying the structure and mechanical properties of the saddle was challenging. "The movement is so fast that people hadn't been able to focus just on the saddle itself, which is why we needed to study it by computer simulation," says Miserez.

His team analyzed the composition of the saddle, making micro-measurements of the materials' to develop a simulation of the mantis shrimp's strike. They found that the top layer of the saddle is composed mostly of a relatively brittle bioceramic similar to tooth or bone, while the underside contains a higher content of biopolymers, which are fibrous like a rope and therefore strong when pulled on. When the mantis shrimp's muscles and connective tissues load energy into the saddle, the top layer is compressed and the bottom layer is stretched, meaning that each layer is placed under the forces it is best able to withstand.

A mantis shrimp. Credit: Maryam Tadayon / Biological & Biomimetic Materials Laboratory
"If you asked a mechanical engineer to make a spring that can store a lot of elastic energy, they wouldn't think of using a ceramic. Ceramics can store energy if you can deform them, but they're so brittle that it wouldn't be intuitive," says Miserez. "But if you compress them, they're quite strong. And they're stiffer than metal or any polymer, so you can actually store a higher amount of than you could with those materials."

The researchers also performed a series of experiments using small strips of actual saddle structures that they cut with a powerful picosecond laser beam. They analyzed how forces were distributed when the strips were bent the way they are in the mantis shrimp and when they were bent the wrong way. When they were bent the wrong way, with the biopolymers compressed and the bioceramics stretched, the strips were less able to withstand strong forces, likely due to tiny fractures in the ceramic layer.

Miserez and his colleagues are continuing to study the structure of the mantis shrimp saddle and have even started 3-D-printing some -inspired springs of their own, which could potentially be used in microrobotics.

"From a fundamental science perspective, the mechanics of this structure are quite interesting," he says. "But what this design also shows is that you can make a very efficient spring—and you can make it out of ceramics, which are more efficient than other materials people are using now. You can use materials that you wouldn't have thought about based on your mechanical engineering knowledge."

How a bi-layered saddle structure made of bioceramics and biopolymers powers the mantis shrimp's famous punch. Credit: iScience

Explore further: How mantis shrimp evolved many shapes with same powerful punch

More information: Tadayon et al.: "Biomechanical Design of the Mantis Shrimp Saddle - A Biomineralized Spring Used for Rapid Raptorial Strikes," iScience (2018). DOI: 10.1016/j.isci.2018.08.022

Related Stories

Mantis shrimp roll their eyes to improve their vision

July 12, 2016

Imagine rolling your eyes to help you see more clearly. Although it wouldn't work for humans, new research published today in Nature Communications has shown mantis shrimp use eye rotations to enhance their polarization vision.

Strategic strikes by mantis shrimp smash shells selectively

June 15, 2018

For a tiny crustacean, Caribbean rock mantis shrimp (Neogonodactylus bredini) pack a ferocious punch. Bludgeoning the shells of snails and other crustaceans to gain access to the tasty snail within, mantis shrimp flick their ...

Extreme mobility of mantis shrimp eyes

May 1, 2018

New research, led by biologists from the University of Bristol, has uncovered fresh findings about the most mobile eyes in the animal kingdom - the eyes of the mantis shrimp.

Recommended for you

Multiple stellar populations detected in the cluster Hodge 6

February 18, 2019

Using ESO's Very Large Telescope (VLT), astronomers have found that the cluster Hodge 6 hosts multiple stellar populations. The detection could provide important hints on the formation and evolution of Hodge 6 and star clusters ...

Predicting sequence from structure

February 18, 2019

One way to probe intricate biological systems is to block their components from interacting and see what happens. This method allows researchers to better understand cellular processes and functions, augmenting everyday laboratory ...

Energetic particles can bombard exoplanets

February 18, 2019

TRAPPIST-1 is a system of seven Earth-sized worlds orbiting an ultra-cool dwarf star about 120 light-years away. The star, and hence its system of planets, is thought to be between five-to-ten billion years old, up to twice ...

Meteorite source in asteroid belt not a single debris field

February 17, 2019

A new study published online in Meteoritics and Planetary Science finds that our most common meteorites, those known as L chondrites, come from at least two different debris fields in the asteroid belt. The belt contains ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.