Bombardier Beetle Research Articles

The bombardier beetle

The chemistry behind the bombardier beetle's chemical defenses illustrates the principles of reaction rates, catalysis, and laboratory safety.

Discharge by a Female Ground Beetle, Pterostichus lucublandus (Coleoptera: Carabidae), Used as a Defense against Males1

Many species of insects are known to discharge fluids from the end of the abdomen to repel predators such as snakes, birds, rodents, or even other insects. When such a defensive substance is expelled as a gas or liquid onto a pursuing enemy, it usually distracts or incapacitates the attacker long enough for the intended victim to escape, (iround beetles of the genus Brachinus, commonly called bombardier beetles, are most noted for this tactic (Eisner 1958), but many carabid species in other genera are also capable of expelling a deterrent substance (Eisner 1958, Ball 1960, Eisner et al. 1963, Schildknecht 1970). Schildknecht and his colleagues (Schildknecht 1970) examined the fluids from the pygidial glands of 20 species of carabids, including 5 species of the genus Pterostichus, and found 19 of them to be mostly methacrylic and tiglic acids, both of which they designated as cytotoxins which function in defensive mechanisms. However, the literature does not indicate that the predator suffers more than a temporary disabling, and most recover within a few minutes. Insects normally cease attacking and spend 15–30 sec vigorously trying to clean their antennae and mouth parts with their feet or by rubbing them on the ground (Eisner and Meinwald 1966). Some experience an immediate and brief period of seizures during which their legs are so convulsed that locomotion is impossible, which suggests that the spray acts as a transient poison (Eisner 1958).

The Defensive Chemistry of Land and Water Beetles

AbstractWherever life forms have arisen, they have had to defend themselves, even on the lowest levels, against their own kind. Darwin called this the struggle for life. The following discussion shows that this struggle can be carried on chemically with compounds of widely differing classes. Examples of defensive substances found are hot quinones in bombardier beetles, and weak and strong carboxylic acids, phenols, terpenes, steroids, and alkaloids in other Adephaga.

Biochemistry at 100°C: Explosive Secretory Discharge of Bombardier Beetles ( Brachinus )

The defensive chemical spray of bombardier beetles is ejected at 100 degrees C, with a heat content of about 0.2 calorie per milligram.

The protective role of the spray mechanism of the bombardier beetle, Brachynus ballistarius Lec.

Bombardier beetles, Brachynus ballistarius Lec., subjected to controlled traumatic stimuli or to predator attacks, always responded instantly by ejecting a spray from the tips of their abdomens. The spray was not directed at random, but through rotation of the end of the abdomen was always aimed accurately toward the particular appendage or quarter of the body that had been stimulated. More than 20 consecutive discharges could often be elicited from a single bombardier. All of the predators tested, including certain ants, carabids, mantids, and spiders, were almost invariably repelled by the spray before they could inflict noticeable injury. Following impact of the spray, the ants and carabids showed transient behavioural abnormalities, probably attributable to the toxicity of the secretion.

Researches upon the defensive glands of Bombardier beetles

(1899). Researches upon the defensive glands of Bombardier beetles. Annals and Magazine of Natural History: Vol. 4, No. 22, pp. 315-316.