Animals have evolved all sorts of tactics to ward off predators and avoid getting munched—but Asian bombardier beetles (Pheropsophus jessoensis) can hatch an escape plan even after they’ve been swallowed. Once inside a predator’s stomach, the beetles eject a hot chemical spray that induces vomiting. To find out just how effective that chemical spray is, scientists collected bombardier beetles from forests in central Japan, took them back to their lab, and fed them to two predators, the Japanese common toad and the Japanese stream toad. The toads snatched up the beetles in every single trial. But just moments later, a sound like an explosion burst from their bellies, in some cases followed by a beetle breakout. Nearly half—43%—of the toads vomited up the beetles they had swallowed. And the beetles walked away unscathed, some after bathing in the toad’s stomach juices for more than an hour, the researchers report today in Biology Letters. They say the chemical spray was key to the escape plan, because “pretreated” beetles—which had already sprayed out much of their chemical supply—were unlikely to survive. Only 5% came back from a trip down the toad’s gullet. So you don’t need to be a chameleon or a speed demon to escape the wrath of predators—you just need to be packing chemical heat.
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