---
title: "What the sources say about the Bombardier Beetle | AnimalTracks.wiki"
description: "46 claims from the Bombardier Beetle profile, each beside the words of the source that backs it."
image: "https://animaltracks.wiki/images/animals/bombardier-beetle-1.webp"
canonical: "https://animaltracks.wiki/animals/bombardier-beetle/sources/"
---

# What the sources say about the Bombardier Beetle (*Brachinus crepitans*)

> 46 claims from the Bombardier Beetle profile, each beside the words of the source that backs it. A "..." marks a cut in a quote and [brackets] an insertion.

Profile: [Bombardier Beetle](https://animaltracks.wiki/animals/bombardier-beetle/)

## Vogel et al. (2025). Molecular basis of the explosive defence response in the bombardier beetle Brachinus crepitans. Royal Society Open Science.

https://doi.org/10.1098/rsos.241823

| The page says | The source says |
| :--- | :--- |
| Brachinus crepitans has been recorded in Germany, where researchers studying its chemistry collected live specimens from Nordrhein-Westfalen | Adult bombardier beetles (B. crepitans) were collected from Nordrhein-Westfalen, Germany, with permission from the Nature Conservation Agency in Koblenz |
| A pair of glands sits in its abdomen | which forcibly expel a hot spray of noxious p-benzoquinones from their paired abdominal defensive glands when attacked by vertebrate or invertebrate predators |
| each with a reservoir holding a solution of roughly 25 percent hydrogen peroxide and 10 percent hydroquinones, carried in an oily, non-reactive solvent | an aqueous solution of approximately 25% hydrogen peroxide and approximately 10% p-hydroquinones along with approximately 10% n-alkanes as a non-reactive second liquid phase acting as a solvent (note: 'oily' glosses n-alkanes for the audience; the paper's 'approximately' is kept as 'roughly'.) |
| Muscles around the reservoir squeeze that mixture through a one-way valve into a second, armor-walled chamber that researchers think is lined with cells producing catalase and peroxidase enzymes | these muscles contract to force the stored chemicals ... through a one-way valve into the rigid-walled, sclerotized RXC lined with cells that are thought to secrete catalases and peroxidases (note: The 2025 paper hedges the enzyme lining ('although this has not been confirmed'), so the page hedges it too, even though the older UTEP page states it flatly.) |
| Mixing the two sets off an explosive reaction that turns the hydroquinones into benzoquinones, releasing oxygen, water and 48.5 kilocalories of heat per mole of benzoquinone made | Mixing initiates an explosive exothermic reaction that produces p-benzoquinones, free oxygen and water, also generating 48.5 kcal of thermal energy per mol p-benzoquinones |
| The spray leaves the beetle at up to 100°C, moving as fast as 10 meters a second, and it can land up to 30 centimeters away | at temperatures of up to 100°C, at speeds of up to 10 m s−1 and over distances of up to 30 cm |
| The pressure cannot push back through the one-way valve, and the discharge leaves as what researchers call a pulsed jet | The high overpressure in the RXC results in an explosive secretory discharge that cannot pass back through the valve into the RC [10]. It is therefore ejected as a noxious pulsed jet |
| a rapid series of bursts aimed at the point where something is touching the beetle | The defence secretion is ejected as a jet of fine mist without visible dissipation ... in a rapid series of consecutive pulses. ... Higher magnification highlights the precision with which the beetle orientates the jet towards the contact point with forceps (note: Figure 1 caption, and it is B. crepitans: this is the species-level support for 'rapid pulses', which the 500-per-second figure (another species) is not.) |
| warming collected secretions to 90°C for ten minutes barely slowed the catalase enzymes down | we mixed the defensive secretions collected from 30 beetles with 30% hydrogen peroxidase at different temperatures for different durations, and used bubble formation to quantify enzyme activity. Even exposure to 90°C for 10 min did not significantly inhibit the formation of bubbles, confirming the outstanding thermal resistance of the catalases (note: The experiment tested the enzymes, not the chamber lining, so the sentence credits the chemistry.) |
| Emptied by repeated firing, the glands need about 13 hours to refill completely, and the spray then returns to normal | The glands still produced defensive secretions after 3 h (four rounds of stimulation), but they were depleted after 6 h (seven rounds of stimulation). After a rest period, the spray count and duration in response to stimulation returned to normal, indicating complete replenishment of the MGS after 13 h (note: The 13 h is the refill after repeated stimulation emptied the glands, not the recovery from a single discharge.) |
| Explosive Chemical Spray Up To 100°C | ejected as a noxious pulsed jet ... at temperatures of up to 100°C (note: stats.superpower; 'Up To' restored: the label previously read a flat '100°C', which is stronger than the source.) |
| Fired in Rapid Pulses | The defence secretion is ejected as a jet of fine mist without visible dissipation ... in a rapid series of consecutive pulses (note: stats.superpower; figure 1 caption, B. crepitans, so 'rapid pulses' is species-level and does not lean on the Stenaptinus figure.) |
| blasts attackers with a chemical spray up to 100°C | It is therefore ejected as a noxious pulsed jet ... in the direction of the perceived threat ... at temperatures of up to 100°C (note: tagline; 'up to' restored, matching the source.) |
| fired in rapid pulses | The defence secretion is ejected as a jet of fine mist without visible dissipation ... in a rapid series of consecutive pulses (note: tagline; B. crepitans figure 1 caption.) |
| Chemical pressure builds in a sealed reaction chamber until it fires in rapid, explosive pulses | Mixing initiates an explosive exothermic reaction ... The high overpressure in the RXC results in an explosive secretory discharge that cannot pass back through the valve into the RC ... It is therefore ejected as a noxious pulsed jet (note: vibe.reason; 'sealed' is the rigid-walled chamber whose discharge cannot pass back through the valve, and 'until it fires' is the paper's own sequence: overpressure builds in the chamber and therefore the discharge is ejected. 'rapid pulses' is figure 1's 'a rapid series of consecutive pulses' for B. crepitans.) |
| It mixes two stored chemicals when it needs to. | Glandular secretions enter the CD and accumulate in the RC ... When the beetle is provoked, these muscles contract to force the stored chemicals ... through a one-way valve into the rigid-walled, sclerotized RXC (note: FAQ 1 framing sentence: the two chemicals are stored in the reservoir and combine in the reaction chamber only when the beetle is provoked.) |
| The beetle keeps hydrogen peroxide and hydroquinones in a reservoir chamber, then squeezes them through a one-way valve into a second chamber that is thought to be lined with catalase and peroxidase enzymes. | these muscles contract to force the stored chemicals—an aqueous solution of approximately 25% hydrogen peroxide and approximately 10% p-hydroquinones ... through a one-way valve into the rigid-walled, sclerotized RXC lined with cells that are thought to secrete catalases and peroxidases (note: FAQ 1; the source's 'thought to' is kept verbatim, because the 2025 paper says the enzyme lining 'has not been confirmed'.) |
| The mixing sets off an explosive reaction that produces benzoquinones, oxygen and water, and the mixture leaves the beetle's abdomen at up to 100°C. | Mixing initiates an explosive exothermic reaction that produces p-benzoquinones, free oxygen and water ... It is therefore ejected as a noxious pulsed jet ... at temperatures of up to 100°C |
| The chamber walls are rigid and hardened, and a one-way valve stops the blast pushing back into the reservoir. | through a one-way valve into the rigid-walled, sclerotized RXC ... The high overpressure in the RXC results in an explosive secretory discharge that cannot pass back through the valve into the RC (note: FAQ 2, rewritten: the old answer's premise (releasing the pressure at once) was not in any source, and its ref did not state the mechanism it claimed.) |
| Both chambers are lined on the inside with cuticle, the tough material an insect's shell is made of, which protects the cells underneath from the chemicals and the heat. | The luminal surfaces of the chambers are lined with cuticular material to protect the underlying cells from the chemicals and heat (note: FAQ 2; 'the tough material an insect's shell is made of' defines cuticle for the audience.) |
| Even the enzymes cope: secretions collected from Brachinus crepitans and held at 90°C for ten minutes still worked. | To evaluate the thermal resistance of the catalase from B. crepitans, we mixed the defensive secretions collected from 30 beetles with 30% hydrogen peroxidase at different temperatures for different durations, and used bubble formation to quantify enzyme activity. Even exposure to 90°C for 10 min did not significantly inhibit the formation of bubbles |
| Not Evaluated | the bombardier beetle Brachinus crepitans (note: stats.conservationStatus. No reference in the profile states a Red List status; this quote anchors the species name only. GBIF's copy of the Red List returns NOT_EVALUATED for Brachinus crepitans (Linnaeus, 1758), usage key 4474861 (https://api.gbif.org/v1/species/4474861/iucnRedListCategory), checked 2026-09-17, and source:prefetch found no Crossref assessment DOI (2026-09-15). The house convention for an unassessed species is to carry no status reference (#596).) |

## Dean et al. (1990). Defensive Spray of the Bombardier Beetle: a Biological Pulse Jet. Science.

https://doi.org/10.1126/science.2349480

| The page says | The source says |
| :--- | :--- |
| A different bombardier beetle, Stenaptinus insignis, was recorded spraying in pulses about 500 times a second, a firing pattern researchers compared to the pulse-jet engine of a World War Two flying bomb | The defensive spray of the bombardier beetle Stenaptinus insignis is ejected in quick pulses (at about 500 pulses per second) rather than as a continuous stream. ... The ejection system of the beetle shows basic similarity to the pulse jet propulsion mechanism of the German V-1 "buzz" bomb of World War II. (note: Different species from B. crepitans; the body names Stenaptinus insignis explicitly rather than generalizing the pulse rate to the profile's species.) |

## Sugiura & Sato (2018). Successful escape of bombardier beetles from predator digestive systems. Biology Letters.

https://doi.org/10.1098/rsbl.2017.0647

| The page says | The source says |
| :--- | :--- |
| In one bombardier beetle at least, the weapon works from inside a predator | Our experiment showed that P jessoensis ejected hot chemicals inside the toads, thereby forcing the toads to vomit. (note: Scoped to the studied species: the result is Pheropsophus jessoensis, not B. crepitans, and the next sentence names it.) |
| In a laboratory study of a related species, Pheropsophus jessoensis, toads (Bufo japonicus and B. torrenticola) swallowed the beetles, and 43 percent of the toads vomited them back up between 12 and 107 minutes later, every one still alive and active | we investigated how the bombardier beetle Pheropsophus jessoensis escapes from two toad species, Bufo japonicus and B torrenticola, under laboratory conditions. ... Although all toads swallowed the bombardier beetles, 43% of the toads vomited the beetles 12-107 min after swallowing them. All the vomited beetles were still alive and active. |
| the chemical spray having gone off inside the toad's own stomach | Our experiment showed that P jessoensis ejected hot chemicals inside the toads, thereby forcing the toads to vomit. |
| In a laboratory study of a related species, Pheropsophus jessoensis, toads (Bufo japonicus and B. torrenticola) swallowed the beetles whole, and 43 percent of the toads vomited them back up between 12 and 107 minutes later. | we investigated how the bombardier beetle Pheropsophus jessoensis escapes from two toad species, Bufo japonicus and B torrenticola, under laboratory conditions. ... Although all toads swallowed the bombardier beetles, 43% of the toads vomited the beetles 12-107 min after swallowing them. |
| Every vomited beetle was still alive and active. | All the vomited beetles were still alive and active. |
| The beetles had fired their hot chemical spray inside the toads' stomachs, forcing them to vomit. | Our experiment showed that P jessoensis ejected hot chemicals inside the toads, thereby forcing the toads to vomit. |

## Saska & Honek (2008). Synchronization of a Coleopteran Parasitoid, Brachinus spp. (Coleoptera: Carabidae), and Its Host. Annals of the Entomological Society of America.

https://doi.org/10.1603/0013-8746(2008)101[533:soacpb]2.0.co;2

| The page says | The source says |
| :--- | :--- |
| Lab work showed the larvae of B. crepitans and its relative B. explodens are ectoparasitoids, insects that grow attached to the outside of a host and eventually kill it, and that they develop on the pupae of another ground beetle, Amara | Laboratory experiments have shown that larvae of ectoparasitoids Brachinus explodens Duftschmid and Brachinus crepitans (L.) (Coleoptera: Carabidae) develop on pupae of spring breeding species of the genus Amara (Coleoptera: Carabidae). (note: 'ectoparasitoids' defined in-text for the young audience; the quote carries the term for both species' larvae.) |
| In the field, Brachinus females lay their eggs as Amara larvae are about to pupate, and the bombardier larvae hatch just as Amara pupae become available | Brachinus adults arrived later than their hosts, and females started to oviposit when Amara larvae were just about to pupate, and Brachinus larvae hatched when Amara pupae became available. (note: The field half of the study is reported at genus scope ('Brachinus'), so the sentence says Brachinus, not B. crepitans.) |
| tags: parasitoid | Laboratory experiments have shown that larvae of ectoparasitoids Brachinus explodens Duftschmid and Brachinus crepitans (L.) (Coleoptera: Carabidae) develop on pupae of spring breeding species of the genus Amara (Coleoptera: Carabidae). (note: moved from the sea lamprey (#777), which feeds on blood and has filter-feeding larvae; the beetle's larvae develop on and kill Amara pupae.) |

## Ivanič Porhajašová & Babošová (2022). Impact of arable farming management on the biodiversity of Carabidae (Coleoptera). Saudi Journal of Biological Sciences.

https://doi.org/10.1016/j.sjbs.2022.103371

| The page says | The source says |
| :--- | :--- |
| in Slovakia, where a three-year farmland survey found it was one of the dominant ground beetles in pitfall traps | We studied the composition of carabids in ecological and integrated farming, in three different crops in southern Slovakia. The ground beetles were caught using pitfall traps during a period of three years, from 2018 to 2020. ... Brachinus crepitans also dominated |
| reaching 16.47 percent of one year's catch on the organically farmed plots | The open land species Brachinus crepitans was also dominant. Its dominant occurrence was limited to 2019 within the integrated management system (5.98%) and to 2020 in the ecological system (16.47%) (note: 16.47% is the 2020 figure for the ecological system alone, not a range across the three crops. The paper calls that same system organic elsewhere ('The crop rotation in the organic farming system was as follows', and '4 784 were in organic and 3 017 in integrated farming', which the abstract reports as ecological management). The 5.98-16.47% range the abstract prints is across farming systems and years, and the species sat at 3.12-9.84% in the other system-years, so the range is not quoted.) |
| Farmland | The open land species Brachinus crepitans was also dominant. (note: stats.habitat; B. crepitans dominated farmland pitfall-trap catches in this three-year study.) |
| tags: agricultural | The open land species Brachinus crepitans was also dominant. (note: Replaces the `savanna` tag (#596), whose definition is "expansive tropical grasslands ... following migrating herbivore herds". This is three years of pitfall trapping in arable crop fields (alfalfa, winter wheat and pea) under organic and integrated farming at Nitra-Dolna Malanta, Slovakia, where B. crepitans reached 16.47 percent of one year's catch; the tag reads "Foraging across farm pastures, crop fields, and grain silos". The `woodland` tag stays on the UTEP line "Bombardier beetles of all types generally live in temperate zone woodlands or grasslands".) |

## Bombardier Beetle (Tribe: Brachini). University of Texas at El Paso, Centennial Museum, Chihuahuan Desert Homepage.

http://museum2.utep.edu/chih/theland/animals/invertebrates/insects/bombardier.htm

| The page says | The source says |
| :--- | :--- |
| 4 to 15 millimeters long | The only genus, Brachinus (described in 1983), 4-15 mm in length, contains about 40 species which occur over much of North America. (note: Genus-level figure (Brachinus), not species-specific to B. crepitans; worded at genus scope in the body.) |
| a family whose adults tend to live several weeks | Ground beetles tend to live for several weeks, during which they have ample opportunity to mate and pass on their genes (note: Stated for ground beetles (family Carabidae) generally, not Brachinus; the source's 'tend to' and 'several weeks' both kept. The only lifespan any source in the pack gives.) |
| At night they come out to hunt smaller insects | like most other ground beetles, tends to come out at night to prey on smaller insects |
| Brachinus, like nearly all ground beetles, eats a number of insects farmers count as pests | Brachinus, like nearly all the species in the family Carabidae, is a predator, and eats a number of other insects that are agricultural pests |
| It fires only when something actually makes contact | Defense Mechanism: The Beetle will only fire only when directly contacted |
| Beetles in the genus can also swivel the tip of the abdomen through about 270 degrees, and can spray in whatever direction a predator comes from | the beetle can rotate the end of its abdomen 270 degrees in any direction, which allows for an impressive "firing range." In effect, the beetle can spray in whatever direction the predator comes from (note: 270 degrees, not the 360 the pre-rewrite draft claimed; genus-level source, worded at genus scope.) |
| Grasslands | Bombardier beetles of all types generally live in temperate zone woodlands or grasslands (note: stats.habitat; genus/tribe-wide statement. The label drops the source's 'generally', which a compressed field cannot carry, and does not strengthen it.) |
| Woodland | Bombardier beetles of all types generally live in temperate zone woodlands or grasslands (note: stats.habitat; was 'Woodland Margins', which the source does not say: it says woodlands.) |
| Insects, Including Agricultural Pests | Brachinus, like nearly all the species in the family Carabidae, is a predator, and eats a number of other insects that are agricultural pests (note: stats.diet; genus-level source. The label drops 'nearly all the species in the family', which qualifies which beetles are predators, not what they eat.) |

## Bombardier beetles. National Geographic.

https://www.nationalgeographic.com/animals/invertebrates/facts/bombardier-beetle

| The page says | The source says |
| :--- | :--- |
| dangerLevel: Medium | hot enough to burn and stain human skin (note: The tier is a capability: Medium is "Can injure, but rarely seriously". A burn and a stain from a 4 to 15 mm beetle that fires only on contact is exactly that, and no cached source reports a serious human injury or a death. The page covers bombardier beetles at subfamily scope (Brachininae and Paussinae) and opens on a photo captioned "The common bombardier beetle ( Brachinus crepitans )", the same group scope as the UTEP reference already in the profile. Settled in #596.) |