Beetles are insects that belong to the largest order — taxonomic category — in the animal kingdom. This order contains a third of all known insects, and includes over 300,000 species worldwide and some 30,000 species in North America.
Beetles are easily recognized by the tough, armor-like forewings that cover the membranous hind wings used for flying. Chewing mouthparts with well-developed mandibles, enable beetles to eat a broad range of materials. Many beetles are predators, others are scavengers and a few are parasites.
Females lay eggs that hatch into larvae that feed on their special food source. Here, they grow and eventually form a pupal stage from which a new adult emerges.
Carrion beetles are very interesting insects that form a taxonomic group of more than 100 species and includes a few species referred to as burying beetles. Some of the larger burying beetles dig a cavity under the carcass of a small dead animal such as a mouse. They do this until the animal falls into the hole produced and is actually buried. The decaying animal then serves as a food source for the larvae that hatch from eggs the female deposits in the corpse.
Burying beetle parents tend the carcass where their brood of larvae are growing and maturing. The larvae feed on the carcass from the inside out eventually leaving the tail, the skull, and a few pieces of skin and a host of new adult flies.
One might think that this would be a rather messy and very smelly situation. However, it has been found that as the larvae grow, the parents regularly refresh a dark microbial film on the inside of the dead animals body cavity with oral and anal secretions. The microbes making up this film resembles the parent beetles gut microbiomes. A rather peculiar smell is emitted, but it is not an obnoxious one. In addition, both the parents and the larvae produce antimicrobial substances that serves to restructure the microbial community and control the odor.
Research has shown that the film produced by the parents also helps the offspring grow more efficiently. It seems that the larvae also add secretions that influences the cavity and larval growth.
Larrie Stone is a retired Dana College science professor.