Insects That Fart
Farting is not an exclusive trait of vertebrates. Many insects also produce intestinal gases — partly as a by-product of digestion, partly as an active survival strategy. The insect world offers some of the most fascinating and loudest examples of intestinal gas in the animal kingdom, even if the anatomical details differ fundamentally from those of humans.
Do Insects Actually Have a Gut?
Yes — insects possess a complete digestive tract from mouth to anus (the so-called proctodeum), with specialised foregut, midgut, and hindgut structures. In the hindgut of many species live symbiotic microorganisms that ferment plant material — especially cellulose and hemicellulose. This fermentation produces the same gases as in humans: carbon dioxide, hydrogen, methane, and sulphur compounds. Whether insects actively 'release' these gases or whether they passively diffuse through the cuticle depends on the species. What is clear: gas exchange takes place.
Cockroaches: The Methane Producers
American cockroaches (Periplaneta americana) and various cockroach species are among the best-studied gas-producing insects. Studies have measured that a single cockroach can release up to 35 milligrams of methane per day — an impressive figure relative to its body mass. Methane-producing archaea live in the hindgut of cockroaches — the same group of microorganisms that also produce methane in the human gut and in the rumen of cattle. Since cockroaches occur in enormous population densities and are globally widespread, some models estimate their contribution to global methane emissions at measurable fractions of a percent.
Termites: The Underestimated Climate Force
Termites are the insects with the greatest global relevance regarding methane production — so significant that they deserve their own article. Short version: termites live in colonies of millions of animals, feed almost exclusively on cellulose, and their digestive community of bacteria, protozoa, and archaea produces enormous amounts of methane and CO₂. Estimates suggest termites are responsible worldwide for 2–4 percent of atmospheric methane production — a figure that is becoming increasingly relevant in the climate change discussion.
Bombardier Beetles: The Loudest Defence
No article about insect gas production would be complete without the bombardier beetle (Brachinus species). Strictly speaking, their defence weapon is not a fart — but the mechanism is fascinatingly related. In the abdomen of the bombardier beetle are two separate reservoirs: one with hydroquinone, one with hydrogen peroxide. When threatened, the beetle mixes both substances in a specialised reaction chamber, where an explosive exothermic reaction takes place. The result: a loud bang, a temperature of up to 100°C, and a precisely aimed spray. The beetle can fire its 'fart cannon' up to 500 times per second and aim in almost any direction — thanks to moveable discharge openings on the abdomen.
Did you know?
- A single cockroach can produce up to 35 mg of methane per day — more than a cow relative to body mass.
- Termites are responsible for 2–4% of global methane emissions.
- The bombardier beetle fires an explosive chemical from its abdomen — up to 500 times per second.
- The same methane-producing archaea that live in cattle rumens also live in cockroach hindguts.
Fun Fact
The bombardier beetle survived an experiment in which it was swallowed by a toad: it fired its chemical weapon inside the toad's stomach — whereupon the toad regurgitated it after 44 minutes. The beetle survived unharmed. This event was documented in a scientific study in 2012.
Sources
- Hackstein, J.H.P. & Stumm, C.K. (1994). Methane production in terrestrial arthropods. PNAS, 91(12), 5441–5445.
- Suarez, F.L. et al. (1999). Fermentation and gas production in the cockroach hindgut. Insect Biochemistry.
- Dean, J. et al. (1990). Defensive spray of the bombardier beetle. Science, 248, 1219–1221.
- Mahaney, W.C. (2002). Atlas on the human environment. Springer.