Centipedes are vicious predators. Rather than opting to tackle prey smaller than themselves, as the majority of predators do, the multi-legged assassins are experts at taking down much larger critters using powerful venom, with some species even venomous enough to kill a human.
How exactly the centipede's venom is able to do this has not been fully understood, until now. Researchers have been looking into just how the golden head centipede (Scolopendra subspinipes mutilans), which is found across East Asia and through into Australia, is able to tackle mice up to 15 times its size in just 30 seconds. The trick, it turns out, lies in a specific toxin found in its unusual and highly potent venom.
The study, published in The Proceedings of the National Academy of Sciences, details how the team managed to isolate the cocktail of toxins that the arthropods produce. They then tested them one by one to see exactly what they did, and the effect they had on their prey. They found that one toxin in particular, which has been named Ssm Spooky Toxin (the "Ssm" part comes from the centipede's Latin name, don’t ask us about the "Spooky" part), was responsible for the deadly results.
It turns out that the toxin works by blocking the flow of potassium in and out of a mammal's cells. Specifically, it targets the channels that belong to the KCNQ family, which are involved in a wide array of essential physiological systems. They are needed for cardiac action, for example, as well as keeping the muscles that are used in breathing from seizing up.
The toxin, it seems, disrupts the cardiovascular, respiratory, muscular, and nervous systems all at the same time. This is thought to be the first time that a venom has been found with such molecular action.
But not only have the team uncovered exactly how the venom gets to work when killing a centipede's prey, they have also figured out exactly how to stop it. They note that a particular drug called retigabine, which is normally used to treat epilepsy, has the opposite effect as Ssm Spooky Toxin, in that it opens up the very same potassium channels that the toxin closes.
This provides a pretty solid basis for the development of an anti-venom that should be pretty effective at neutralizing any centipede envenomation.