The toad’s reaction to the explosion deep in its stomach is not instantaneous. But in time the body shakes, the mouth opens, and the culprit is expelled: a mucus-covered beetle that will live to fight another day.
Japanese scientists captured footage of the great escape during lab tests that pitted the walking powder kegs that are bombardier beetles against hungry toads of different species and sizes. So effective were the beetle’s defences against being eaten alive that even the researchers were taken aback.
“The escape behaviour surprised us,” said Shinji Sugiura, an agricultural scientist who performed the studies with Takuya Sato at Kobe University. “An explosion was audible inside several toads just after they swallowed the beetles.”
From a chemical standpoint, bombardier beetles are among the most unstable animals on the planet. When threatened, they mix chemicals in their hindquarters, hydrogen peroxide and hydroquinones, to produce an explosion of searing benzoquinone irritant. The boiling spray repels most predators the beetles encounter.
