Strategic Strikes by Mantis Shrimp Smash Shells Selectively

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Strategic strikes by mantis shrimp smash shells selectively

point of their attack to the apex of the long Cerithinum shells after failing to penetrate the open end.

Wondering whether the crustaceans were deliberately targeting the most fragile regions of the shell, Crane and Cox assaulted the shells with a mantis shrimp robot – affectionately known as Ninjabot, which Cox had built previously with David Schmidt, Yahya Modarres-Sadeghi and Patek – to test A mantis shrimp setting up a shell by tapping with its antennules before striking. which portions of each shell were most Photo credit: courtesy of the Patek Lab. vulnerable. However, the team quickly realised that the crustacean’s shell- For a tiny crustacean, Caribbean rock crustaceans – which weren’t averse to positioning ritual was far more mantis shrimp (Neogonodactylus bredini) taking a swipe – as the animals were so sophisticated than they had thought. pack a ferocious punch. Bludgeoning the small, although Crane recalls that they ‘Settinguptinyshellstobestruck[by shells of snails and other crustaceans to could draw blood if they unfurled their Ninjabot] at exactly the desired angle gain access to the sweet meat within, dactyl spears. against a complex substrate was mantis shrimp flick their cudgel-like exceptionally frustrating and time claws at accelerations approaching those Back at Duke, Crane and Samantha consuming’, Crane recalls. Eventually, of a bullet exiting a gun. Yet, Rachel Kisare tempted the stomatopods with she and Cox confirmed that the central Crane from Stanford University, USA, snails ranging from squat-shelled Nerita portion of the shell, which the mantis explains that the ballistic shrimp is the odd versicolor to long helical-shelled shrimp avoid striking, is the most robust one out in the world of snail and Cerithium atratum to catch the mantis while the opening and apex regions are crustacean demolishers: ‘Animals like shrimp in the act. ‘We have endless hours more fragile. They also realised that the crabs and fish slowly crush shells’. of video footage of mantis shrimp doing resourceful animals only resorted to However, despite the wealth of high- pretty much everything besides eating’, hammering on the pointy end of the speed information about mantis shrimp chuckles Crane, but the team’s patience longest and slimmest shells when they pulverising attacks, little was known was eventually rewarded as they caught were no longer able to chip away at the about the stomatopod’s overall strategies. the animals carefully rotating the shells opening, because the thick ridges that Would the smashing crustaceans strike into position with their maxillipeds, run across the whorls prevented the shells haphazardly or would they before placing their antennules on the damage from penetrating further. precisely pinpoint their assaults? And shell and delivering the first of as many as could they change their plan of attack if 460 blows. And when Crane and Kisare So, mantis shrimp target specific regions thwarted? Intrigued, Crane and her PI, teamed up with Suzanne Cox to analyse of a shell and they can adapt their Sheila Patek from Duke University, USA, the strike pattern, it was clear that mantis strategies to suit, but there are still many began investigating the feisty creatures’ shrimp primarily focused their attack on more tantalising mantis shrimp mysteries striking strategy. the opening of the shorter squat shells, to resolve. chipping away to gain access to the snail ‘Collecting these mantis shrimp is usually within. However, Crane admits that she 10.1242/jeb.183590 easy’, recalls Crane, describing how the was blown away when she and Kisare Crane,R.L.,Cox,S.M.,Kisare,S.A.and animals live in shallow clear water and are watched a crustacean dine on longer Patek, S. N. (2018). Smashing mantis shrimp conspicuous when they poke their eyes skinny Cerithium snails. Explaining that strategically impact shells. J. Exp. Biol. 221, and antennules out of their burrows. the mantis shrimp in Patek’s lab usually doi:10.1242/jeb.176099. Fortunately, the inquisitive scientists’ consume squat-shelled snails, she was Kathryn Knight fingers were at little risk from the spirited astonished when the animals switched the [email protected]

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