Beetle, American burying

Nicrophorus americanus

phylum: Arthropoda

class: Insecta

order: Coleoptera

family: Silphidae

status: Critically endangered, IUCN Endangered, ESA

range: USA (Arkansas, Massachusetts, Nebraska, Oklahoma, Rhode Island)

Description and biology

The American burying beetle, also known as the giant carrion beetle, is the largest of the North American carrion beetles (those that feed on carrion, or the decaying flesh of dead animals). This shiny black beetle reaches an average length of 1 to 1.4 inches (2.5 to 3.5 centimeters). It has bright orange or red spots on the plate covering its head, on the plate immediately behind, and on the plates covering its forewings.

These beetles often fight over carrion. Males fight males, and females fight females. When one male and one female remain, they form a couple. Working together, they dig out the soil beneath the carcass (dead body) until it is completely buried about 8 inches (20 centimeters) deep.

In the underground chamber, the beetles coat the carcass with secretions from their mouths and anuses. These secretions strip away the carcass's fur or feathers while preserving

what remains. In a passageway near the carcass, the female lays her eggs, and they hatch in a few days. The parents then feed the larvae (young) from the decomposing carcass for about 50 days, until the larvae develop into adults.

This complex parental teamwork—both in preparing the carcass and in raising the young—makes the American burying beetle unique among beetle species.

Habitat and current distribution

The American burying beetle is currently found in only four locations: on Block Island in Rhode Island, in a 14-county area of Oklahoma and Arkansas, in two counties in Nebraska, and on Nantucket Island in Massachusetts. The combined populations in Massachusetts and Rhode Island number less than 1,000. Total populations in the other areas are unknown.

These beetles inhabit grasslands, pastures, shrub thickets, and oak-hickory forests.

History and conservation measures

The American burying beetle had a range that once extended throughout the eastern and midwestern United States and eastern Canada. Since the 1960s, however, its numbers have been rapidly declining. The beetle has disappeared from 99 percent of its former range.

Scientists are unable to explain exactly why the beetle is vanishing. They believe it might be due to changes in its habitat and food supply. Small animals the beetle uses for food and reproduction, such as mice, are fewer in number. Meanwhile, competitors such as foxes, skunks, and raccoons have increased in number. Pesticides and insecticides, used primarily on farmland, may have also played a role in the decline of the American burying beetle, but no one is sure exactly how.

Scientists are currently studying the ecology and reproductive habits of the American burying beetle. Efforts to reintroduce the beetle into suitable habitat have begun. The population of American burying beetles on Nantucket Island is a reintroduced one.