American Burying Beetle

Nicrophorus americanus

Description

Also known as the giant carrion beetle, the shiny black American burying beetle, Nicrophorus americanus, is identified by two pairs of scalloped red spots on the wing covers (elytra), red antenna stems with orange clubs, and a large orange-red pronotal disk (segment behind the head). It is the largest member of its genus, measuring 1-1.4 in (2.5-3.6 cm).

Behavior

A nocturnal beetle, it is attracted to carrion by smell. A number of beetles fight among themselves over a carcass until one pair—usually the largest male and female—takes possession. They then bury it, constructing a brooding chamber at the same time. The female lays eggs on the carrion, and both parents remain with the eggs until they hatch to tend the larvae. In general, the species exhibits one of the highest levels of parental care of any beetle in the insect order Coleoptera. It seems larvae cannot survive without parental care, although, it is unclear as to why. Brood sizes vary from three to 31, and a positive correlation between carrion weight and number of larvae has been observed. Larvae emerge as adults after about 50 days, and parents and young disperse. Adults burrow in the soil to overwinter. Occasionally, burying beetles capture live insects.

Habitat

Scientists speculate that the American burying beetle prefers mature, virgin forests, but its present New England habitat includes maritime scrub thickets, coastal grasslands, and pasture. The availability of deep humus and top soils suitable for burying carrion is essential. Further research is needed to clarify habitat requirements.

Distribution

This species was once found in 32 states and three Canadian provinces. Its range extended from Nova Scotia and Quebec south to Florida, and west to Texas and the Great Plains.

Since 1970, the range of the species has been documented from only six states including the extant population on Block Island in Rhode Island and occurrences in Oklahoma. More surveys are needed to determine whether populations exist in Kentucky, Arkansas, Missouri, and Nebraska. There is a single 1972 record from Ontario. The extant populations are located on private lands, with the exception of the Cherokee/Muskogee County population, which occurs on a jointly managed state wildlife management area and National Guard installation.

The American burying beetle is currently known to occur in Rhode Island, Oklahoma, Arkansas, and in Nebraska, where six American burying beetles were discovered on the Valentine National Wildlife Refuge in the summer of 1992.

The 1992 discovery indicated that a viable population of the beetles may exist on the refuge. Valentine National Wildlife Refuge is completely outside the previously known Nebraska range of American burying beetles; this was only the third collection of the rare beetle in Nebraska since 1970. Only 11 beetles have been collected in Nebraska since the 1880s.

A remnant population also may exist in Iowa. Wildlife officials have intentionally left the location of the New England population vague to deter collectors. Although no population estimate has been attempted, the species is considered to have experienced one of the most disastrous declines ever recorded for an insect species.

Threats

The cause of the precipitous decline of the range of the American burying beetle is unknown, although contamination by dichlorodiphenyltrichloroethane (DDT) and other pesticides is one possibility. In addition, the black lights on "bugzappers" are thought to attract and electrocute males. Because they participate in brood-rearing, burying beetle males are not considered surplus population, unlike those of many other beetle species. Although scientists fully expect to discover remnant populations in other states, the status of the species is considered critical.

Conservation and Recovery

In 1991, a pilot effort began to reintroduce this Endangered insect at historical habitat on Penikese Island, Massachusetts. Lab-reared beetles have been released over a period of several years, and trapping confirmed that some of the release stock has reproduced. In the summer of 1994, the U. S. Fish and Wildlife Service (FWS) secured protection for habitat on Block Island, Rhode Island, which is being managed as part of the Ninigret National Wildlife Refuge. One of the purposes of the new unit is to provide protection for the only known natural population of the American burying beetle in the eastern United States.

Effective captive breeding programs also are under way. In the 1992, the FWS reported that the Cincinnati Zoo Insectarium had successfully raised more than 300 larvae from 13 pairs of this Endangered insect that were on loan there. Re-pairings are being conducted to maximize the reproductive output of the short-lived adult beetles.

In 1995, the FWS and Oklahoma Biological Survey hosted the first rangewide recovery coordination meeting for the insect. FWS Region 5 has lead responsibility for recovery of the American burying beetle, although, adding to the challenge of coordinating protection and recovery efforts, all states in which the beetle is known to survive fall within different FWS administrative regions.

More than 40 participants attended the two-day meeting, including representatives of all five involved FWS regions, agency and university researchers from several states, federal agencies such as the Forest Service and Department of Defense, and large landowners such as the Weyerhauser Company. They discussed a wide variety of research and management issues. Although many questions remain about why the beetle disappeared from most of its range and what can be done to reverse the decline, substantial progress toward a better understanding of this unique creature is being achieved.

Contacts

Regional Office of Endangered Species
U.S. Fish and Wildlife Service
P.O. Box 1306
Albuquerque, New Mexico 87103
http://southwest.fws.gov/

Regional Office of Endangered Species
U.S. Fish and Wildlife Service
Federal Building
Ft. Snelling
Twin Cities, Minnesota 55111
http://midwest.fws.gov/

Regional Office of Endangered Species
U.S. Fish and Wildlife Service
1875 Century Blvd., Suite 200
Atlanta, Georgia 30345
http://southeast.fws.gov/

Regional Office of Endangered Species
U.S. Fish and Wildlife Service
300 Westgate Center Dr.
Hadley, Massachusetts 01035
http://northeast.fws.gov/

Regional Office of Endangered Species
U.S. Fish and Wildlife Service
P. O. Box 25486
Denver Federal Center
Denver, Colorado 80225
http://www.r6.fws.gov/

References

Anderson, R. S. 1982. "On the Decreasing Abundance of Nicrophorus americanus in Eastern North America." Coleoptera Bulletin 36(2):362-365.

Kozol, A. J., et al. 1987. "Distribution and NaturalHistory of the American Burying Beetle." Report. Eastern Heritage Task Force of The Nature Conservancy.

Schweitzer, D. F., and L. L. Master. 1987. "American Burying Beetle: Results of a Global Status Survey." Report. U.S. Fish and Wildlife Service, Newton Corner, Massachusetts.

U. S. Fish and Wildlife Service. 1991. "American Burying Beetle (Nicrophorus americanus) Recovery Plan." Newton Corner, Massachusetts.