The bombardier beetle produces an internal explosion that is then expelled as a superfast boiling liquid toward attackers. Science is a journal that explains the work of scientists from MIT and Arizona. All over the globe, except Antarctica, are Bombardier Beetles. Because of their highly effective defense system, they have almost no enemies predators. Scientists have long been puzzled at the ability of this half-inch beetle to expel and produce boiling toxic spray, without causing any harm. The bombardier beetle expelled benzoquinone. It is then superheated, and expelled as a powerful, pulse-generating jet. Image: MIT. Dr. Wah Keat Lee of Brookhaven National Laboratory, Eric Arndt (a graduate student at MIT), Christine Ortiz, professor of materials science at MIT and Wendy Moore assistant professor of entomology, conducted a study to find out the reason. According to Mr. Arndt, “Their defense mechanism is extremely effective – invulnerable most vertebrates and invertebrates — except for very specialized predators who have developed countermeasures to the noxious Spray.” The study was conducted by Dr. Wah-Keat Lee, of Brookhaven National Laboratory; Eric Arndt, a graduate student at MIT; Christine Ortiz, professor of materials science and engineering at MIT; Wendy Moore, assistant professor in entomology, benzoquinone This beetle’s unique ability to heat the liquid with superheat and then expel it is what makes them so special, according to Mr. Arndt. This is because the beetles can synthesize chemical right away by mixing chemical precursors inside a protective chamber at their rear. The irritant is formed when the two materials are mixed together. This heat raises the temperature of the liquid to almost boiling point. The pressure that is required to expulse the liquid in a jet also results from this process. Professor Ortiz described the process inside a live beetle, saying: “For decades the complicated mechanism by which the bombardier is able to achieve spray pulsation for chemical defense has been poorly understood because only external observations have been used.” The latest study used high speed synchrotron Xray imaging at the Argonne Laboratory, where they literally ‘look inside’ the abdomens and exploded bomber beetles. These detailed images showed for the first-time how this process worked. The action was captured by a camera at 2 ,000 frames each second. The explosion was captured by X-rays. The passageway that connects two chambers within the beetles’ bodies controls the spray pulse. This process is controlled by two structures, a flexible membrane (or valve), and an internal passageway. This passageway opens and closes between the one chamber that holds the explosive liquid and another. The valve is closed when there’s an explosion. The membrane returns to its initial state after the liquid has been ejected and then the passage opens again, which allows the next pulse of energy to form. This happens so quickly within the insect, that it was not possible to observe the entire process. The bombardier beetle’s explosive method is not only super fast, but also emits a much higher temperature liquid than other insects using the same chemical. It also expels it five times quicker. Arndt said that both the heat and speed make this spray more effective against predators. Researchers believe that the spray’s pulsing action protects the reaction chamber structure, allowing the walls to cool down before it explodes again. Professor Ortiz stated that “Understanding beetles’ ability to survive intense internal blasts may aid in designing blast protection systems.” This could be used to design propulsion systems. Scientists believe that the dynamic of spray generation can provide useful information for the design and construction of propulsion systems. R. Jeffrey Dean is a professor of biology at Cleveland State University. He studies the defence mechanisms of the bombardier honey beetle and said that this study “is a (wonderful confirmation) of the passive qualitative ‘pulsejet’ model first suggested by his group. While the results aren’t surprising, they amaze me at the rapid advances in techniques.” This study was supported by the National Science Foundation and National Security Science and Engineering Faculty Fellowship. The Department of Defense (through US Army Research Office) and the Department of Energy. Citation: “Mechanistic origins in bombardier beetle explosion-induced defensive spray pulsesation,” Eric M. Arndt and Wendy Moore. Science. 2015. Published 1 May. DOI: 10.1126/science.1261166. MIT Video – How Bombardier Beetles Bomb This MIT video explains how the bombardier beetles explode their super-hot, noxious substance.
Scientists explain why the Bombardier Beetle explodes boiling water from its bottom.
