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The American Burying Beetle

Arkansas Natural Heritage Commission - Monday, February 13, 2012

The American burying beetle (Nicrophorus americanus) is the only endangered insect in the state of Arkansas. Also known as the giant carrion beetle, these insects have a specialized way of caring for their young—they provide growing larvae with carrion (dead animal flesh) to feed on. The beetles work at night in pairs to locate a suitable carcass then work together to bury it in the soil. Once the carcass is buried, the beetles strip away the fur or feathers and produce a compact ball. The female then lays eggs in a chamber created above the carcass. Both parents remain in the chamber to provide food for the larvae after they have hatched. Adults die soon after they stop providing food for their young.

A pair of American burying beetles with a bird carcass (left); beetles, larvae, and carrion in an underground chamber (right).

The American burying beetle is not the only carrion eating beetle in Arkansas, but is the largest member of its genus in North America—adults are approximately 1.5 inches long. The beetle has a black, glossy body with distinctive bright orange markings on the head shield, face, antennae, and wing coverings. Sometimes the beetles are found with swarms of orange-colored mites on their body, which help keep them clean. These beetles select larger carrion than other burying beetles, preferring carcasses that weigh at least 100 to 200 grams. They are even able to manipulate carcasses that weigh up to 200 times more than their own body.

Like so many other endangered species, the decline of the American burying beetle cannot be tied to one simple factor. Loss of habitat and habitat fragmentation are part of the problem, but very little information is available on specific habitat requirements for this species. The beetles appear to occupy a range of habitats, occurring in both grasslands and deciduous forests, usually with relatively little vegetation. The beetle’s decline may even be tied to the loss of other species, such as the passenger pigeon and prairie chicken. The young of these species provided the preferred carcass size at the right time of the year for beetle reproduction. As land was converted for agricultural uses, mice became more plentiful. But with an average weight of only 25 grams, mice are too small for the American burying beetle. Widespread cutting of forests increased edge habitat (the edge of the forest next to a more open field habitat), which led to more predators and scavengers such as foxes, raccoons, opossums, skunks and crows. All of these compete with the beetles for carrion.

Two ANHC natural areas, Cherokee Prairie and H.E. Flanagan Prairie, support populations of the American burying beetle. To learn about other nearby conservation efforts, check out this webpage from the St. Louis Zoo.

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