Bombardier Beetle

• GeneralIt fires a chemical jet at 100°C from its abdomen with an audible crack.
• In an armoured chamber it mixes hydroquinones and hydrogen peroxide with enzymes that set off an explosive reaction, in pulses of hundreds per second.
• It can swivel the tip of its abdomen and aim the discharge in almost any direction, even forwards by bouncing it off its elytra.
• Toads have been filmed swallowing a bombardier beetle and vomiting it up alive minutes later: the beetle was still detonating inside the stomach.
• It is the only animal known to be able to sustain an explosion of hot substances inside its own body.
• It stores 25% hydrogen peroxide and 10% hydroquinones separately; when they are mixed in a rigid-walled chamber with catalases and peroxidases, the reaction shoots out a jet of benzoquinones at 100 °C.
• It does not fire a continuous jet but a very rapid series of pulses, and aims the nozzle precisely at the exact point where it is being attacked.
• Two of the key ingredients, the benzoquinones and the peroxide, are potent cytotoxins: part of the mystery is how it stores them without harming itself.
• A 2025 study finally identified the enzymes involved and found that glucose is the stable precursor of both the peroxide and the hydroquinone.

Skeleton type

Invertebrate - chitin exoskeleton (insect)

Habitat and environment

Farmland, grassland and under stones on damp soil

Sexual maturity

The larva is an obligate ectoparasitoid of the pupae of other ground beetles, mainly of the genus Amara; the size of the adult depends on the size of the pupa it has consumed

Gestation / incubation

Full post-embryonic development takes about 24 days at 24.7 °C; the third-instar larva attaches to the host pupa and consumes it entirely in about two days

Litter / clutch size

The females lay the eggs in the soil or inside protective mud cells; the first-instar larva actively searches for a host pupa

Sources consulted: Vogel et al. (2025), Royal Society Open Science · Aneshansley y Eisner (1969), Science · Saska & Honek 2004, Journal of Zoology · ficha de especie · Saska & Honek 2004, Journal of Zoology, desarrollo de Brachinus explodens y B. crepitans · Worcestershire Biological Records Centre · ficha de especie de Brachinus crepitans · Saska & Honek, sincronizacion con Amara

Best time: Adults active in spring and summer, under stones and leaf rosettes in dry grassland on limestone; breeding is synchronised with the host's pupation, between June and early July