Secrets of Bombardier beetle's superheated defensive spray revealed
The bombardier beetle has a unique defensive mechanism. It induces a chemical explosion inside its shell to create a boiling, toxic liquid which it sprays at its aggressor. Now researchers in the US have discovered how it does this, and they hope that further study of the conditions inside the beetle that allow it to produce the jet without harming itself may inform real world technologies.
Previously, onlyexternal observations had been made of bombardier beetles as theyproduced the superheated spray. However, a team of researchers fromMIT, the University of Arizona, and the Brookhaven NationalLaboratory were able to use high-speedsynchrotron X-ray imaging to observe theintricacies of the process taking place inside the half inch beetle.
The boiling, superheated spray known as benzoquinone is createdby combining two chemicals in a protective blast chamber located inthe hindquarters of the beetle. The resultant chemical reaction boilsthe mixture, simultaneously creating the pressure required to expelit at a predator.
The pulsing nature ofthe spray appears to be generated passively, and may be the key as tohow the bug survives the internal chemical explosions. The rate thatthe chemicals can be mixed is governed by the movement of a flexiblemembrane and a valve, which open and close aninternal passage that connects a second chamber holding the precursorliquid to the blast chamber.
When the passagewayallows the precursor liquid to flow through, the resultant explosionas it mixes with the chemical in the blast chamber stretchesthe membrane of the blast chamber, forcing the valve to close. Oncethe pressure is released via the expulsion of the newly createdbenzoquinone, the valve opens once more, allowing for the nextexplosion. By pulsing the spray, the bombardier beetle allows theblast chamber time to cool, preventing it from overheating andinflicting damage upon itself.
The bombardier beetle'ssophisticated internal defense mechanism represents a stunningexample of the complexity and beauty of natural evolution, but the team believes that continued observation of theprocess may reap real world technological benefits such as improved blast protection systems, and even the creation of new types of propulsion systems.
Check out the videobelow for footage of the bombardier beetle in action.