The beetles that blast their way out of their predators

Even when they’re in the stomachs of a satisfied toad, bombardier beetles don’t give up the fight

Bombardier beetles are formidable insects, named after the member of a military bomber crew responsible for aiming and releasing bombs from aircraft. When the beetles are provoked they combine chemicals in a reinforced chamber within their abdomen, producing a volatile boiling mixture. The beetles shoot the explosive cocktail out of their back ends and onto their aggravators.


In a new study, scientists at Kobe University in Japan put these fiery beetles to the test by placing them in tanks with Japanese common toads and Japanese stream toads. Much larger and with tongues that can catch prey with deadly speed and accuracy, the toads easily caught the beetles and swallowed them whole.


At first, the amphibians seemed quite content following their meal, but then things took a turn; some of the toads started to convulse before opening their mouths and ejecting the mucus-covered beetles. Setting off their explosive chemical defence allowed almost half of the ingested victims to induce vomiting and, remarkably, escape from the toads alive. The escape artists had to play a waiting game, because it took between 12 and 107 minutes for their plan to take effect, but it was worth it – almost all of the survivors lived for over two weeks after being vomited up, with one lasting over a year and half.


To check that the explosion was definitely the key to their getaway, the scientists annoyed another set of beetles so that they released all of their defensive spray before the toads were let loose on them. These beetles didn’t make it out.


Researchers don’t know how the beetles survived for so long inside the toads’ digestive systems, but they do now know that their chemical defences are potent enough to help them wriggle free from the jaws of death. It’s not pretty, but if you want to see the bombardier beetles in action then watch the video below:



Feature image: Patrick Coin/Wikipedia/Creative Commons License BY-SA 2.5