Physics in the animal world: the bombardier beetle and its "weapon"

The bombardir beetle of the species Brachinus crepitans (photo: beatlename.ru)

The scorer beetles are represented by the subfamily Brachininae and Paussinae (ground beetle family). There are scorers everywhere, there are none except in Antarctica. More famous is the subfamily Brachininae. His representatives, scientists have studied the best.

The size of the beetles of this subfamily is very different. The maximum size of the bombardier beetle is 3 cm. They usually look, there are neither bright elytra, nor especially large mandibles. But there is something else - the ability to shoot at the enemy with a poisonous liquid, the temperature of which reaches 100 ° C. The liquid itself is remarkable, not to mention the process of "shot".

What is this liquid?

Beetles are shot with a mixture of hydroquinones and hydrogen peroxide. This mixture is produced by two symmetric glands of internal secretion. Substances produced by the glands enter a special reservoir with fortified walls. There are also smaller tanks containing catalase and peroxidase. Their walls are also reinforced, and they are connected to the central reservoir. The muscles that are responsible for opening and closing the "trunk" are tightly compressed. Reagent chambers are similarly closed. When the beetle is calm, the fluids do not mix, all the “flasks” are tightly closed.

As soon as the beetle needs to be fired, the walls of the large tank are compressed, and substances from the smaller chambers are squeezed into the main “reactor”. Here, the enzymes react with hydrogen peroxide, resulting in the formation of atomic oxygen. It is a very strong oxidizing agent that reacts with hydroquinones, oxidizing them to quinones (scientists managed to find out the chemical composition of these substances - this is 2-methyl-1,4-benzoquinone).
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Both reactions take place with the release of large amounts of heat - the mixture is heated to 100 ° C. Do not forget that all this happens not in a glass vessel like a flask or test tube, but in the organism of a living being. As soon as oxygen also appears in the main chamber, the volume of the substance increases, and the whole mixture is ejected through the openings at the tip of the abdomen of the insect. Individual shots are controlled by a special membrane. If the pressure in the tank exceeds a certain level, the membrane opens, the mixture is released, the pressure decreases. The membrane closes. After this, the process is repeated, and so on until the complete exhaustion of the reagents in the chambers of the abdomen of the beetle. The pulsation is necessary so that the tank, where the main reaction takes place, has time to cool down before the moment of a new shot.

The tip of the abdomen of the insect is very mobile. When “shooting” due to this mobility, the beetle can aim, and very accurately. He is able to "shoot" for himself, for himself, above his head, to the right, to the left and up. The bombardier of a number of species shoots liquid not with a jet, but with a series of shots, the duration of each is from 8 to 17 ms. The velocity of ejection of fluid reaches 10 m / s. Remembering that the enemy of the beetle is usually very close, we can say that the “shell” catches the enemy almost instantly. An ant, a larger beetle, or even a frog, who are going to grab the scorer, usually have no time to do anything.



In order to study the process of "shooting", Eric Arndt (Eric Arndt) and his colleagues at the Massachusetts Institute of Technology used a complex system . It consists of a synchronous x-ray emitter and a high-speed camera that can capture up to 2000 frames per second.

Other bugs can also throw away the scaring liquid. In particular, ground beetles of a number of species are able to throw away corrosive liquid in different directions. But no reaction takes place inside their abdomen - this fluid is produced by special glands. Neither heating to high temperature, nor significant pressure in this case.

Another interesting fact is that males and females of scorers can “shoot” equally accurately. But they have somewhat different adaptations for shots, although the reaction itself, the tanks and everything else are absolutely the same.

How does the scorer survive?

This is a difficult question to which entomologists (and not only them) have tried to find an answer for more than one year. The thing is that the reagent chambers and the main tank are covered with a special cloth. This fabric is not only resistant to the promotion of all chemicals involved in the reaction, but also withstands high temperatures. Plus, its thermal conductivity is small, so that heat does not spread throughout the beetle’s body, only the main reservoir is heated. The tank during the "shot" does not stretch.

Bombardier beetle and aircraft

The system of organs of the beetle, where chemical reaction and release of fluid is carried out, can be important for humans. First, data from studying the process of the impulse “shot” of the beetle can be useful to engineers who design various engines, including jet engines for aircraft. Perhaps, the technology of accurate and fast injection will help ensure the recovery of the engine after it accidentally stops.

Scientists still have much to figure out, now the main attention of specialists is concentrated on the chamber where the reaction of oxidation of the reactants takes place. Studying the structure of this chamber can help create a heat-resistant material that is resistant to the action of active chemicals. It is useful in industry, science, military affairs.

What else?

The bombardier beetle is very much liked by creationists . They argue that such a complex specialized system could not appear in the process of evolution. Well, if so, then the bug appeared suddenly and immediately as a divine creation. Now scientists have been able to find intermediate links in the evolution of the bombardier beetle, where the “tool” is gradually becoming more and more complex. Yes, and modern members of subfamilies scorers "armed" in different ways. Some beetles are guided by the elytrice, and not the abdomen. Other scorers emit only a slightly heated liquid, and a number of species in general emit only corrosive liquid without heating. They also differ in their cameras — one can trace the development of a “laboratory” from a simple system to a complex one. So there can be no talk of any "divinity" of the beetle.