Burying Beetle feeding on rabbit carcass

A burying beetle feeds on a dead rabbit, which will rot slowly thanks to microbes that the beetle transfers from its gut to the carcass. Credit: Andy Sands/NPL/Getty

Zoology

A beetle’s secret sauce prevents its diet of carrion from liquefying

The burial beetle and its microbiome conspire to prevent cadavers from rotting.

A type of beetle that dines on dead animals enlists its own gut bacteria to keep its food fresh.

Burying beetles stash the cadavers of small animals underground for the beetle larvae to eat. To investigate how the insect prevents its prize from rotting, Shantanu Shukla and Heiko Vogel of the Max Planck Institute for Chemical Ecology in Jena, Germany, and their colleagues studied dead mice infested with a common burying-beetle species (Nicrophorus vespilloides), as well as beetle-free mouse cadavers.

After nine days, the beetle-free carcasses “emitted a strong putrefactive odor”, the authors write, and were laced with putrescine, a smelly toxic compound produced when bacteria break down amino acids. But the carcasses tended by beetles were free of odour and putrescine. These carcasses, unlike the control carrion, hosted high levels of bacteria found in the guts of N. vespilloides.

The beetles and their gut bacteria produce antimicrobial substances, which might help to suppress bacteria that decompose carrion, the authors say.