Carrion beetles (family Silphidae) are widely known for specializing in the decomposition of dead animals. While consuming decaying animals is central to their existence, the overall diet of these insects is much more diverse. This broader feeding spectrum includes several non-carrion food sources that support their survival and reproductive success, allowing them to thrive in various ecosystems and overcome competition for their main resource.
Primary Role and Consumption of Carrion
The consumption of decomposing animal matter is the foundational feeding habit for most species within the Silphidae family. This diet includes the remains of vertebrates (mammals, birds, and reptiles) and large invertebrates. Specialized senses allow adult carrion beetles to locate a fresh carcass quickly, sometimes within hours, to claim the resource before competitors arrive. Both adult and larval life stages rely on this decaying matter for sustenance and growth. Larvae feed directly on the flesh, accelerating the breakdown of animal remains and recycling nutrients like nitrogen and phosphorus back into the soil.
Secondary and Opportunistic Food Sources
Beyond the carcass, carrion beetles exhibit opportunistic feeding behaviors that supplement their diet. A common non-carrion food source is the mass of fly larvae (maggots) that colonize the decaying flesh. Adult carrion beetles, particularly those in the Silphinae subfamily, actively prey on these maggots and their eggs. This predatory behavior provides protein to the adults and reduces competition for the carcass, ensuring more food remains for their developing larvae.
Certain species also consume fungi and decaying plant matter found in moist, rich environments. For instance, the American Carrion Beetle (Necrophila americana) occasionally feeds on rotten fruit or fungi, utilizing other available organic materials as needed. A few species are known to prey on small, living invertebrates like snails or caterpillars, further diversifying their nutritional intake.
Specialized Diets of Burying Beetles
The genus Nicrophorus, commonly known as burying beetles, demonstrates a unique and specialized feeding strategy. These beetles locate small vertebrate carcasses, such as a mouse or a shrew, and bury them beneath the soil. The parents strip the carcass of its fur or feathers, treat the flesh with antimicrobial secretions, and mold it into a compact, defensible ball.
This prepared “brood ball” serves as a preserved nursery and food source for their offspring. Once the larvae hatch, the parents provide elaborate direct care, a rare behavior among insects, by regurgitating pre-digested carrion directly into the mouths of the young. This parental provisioning dramatically increases the survival rate and growth speed of the larvae. The adults regulate the microbial decay of the meat and defend the food source for the entire two-week larval period.