Seven new species of katydids are among the largest and bulkiest insects in the world, a new study says.

Found only on the island of Madagascar, the bugs have the "biceps" of a bodybuilder and can be very aggressive—both surprising traits for katydids.

“If you get anywhere near them, they will try to grab you with their powerful forelegs and pull your finger toward their mandibles to give you a nasty bite,” says study co-author George Beccaloni, former curator of katydids and related insects at London’s Natural History Museum. (Beccaloni avoided such injuries by using long forceps to grasp the katydids.)

“I haven’t seen that defensive behavior in any other katydids."

Beccaloni and colleagues identified the new species based on museum specimens