The American burying beetle (Nicrophorus americanus) is the largest carrion beetle, or silphid, in North America. This species reaches 1.0 to 1.8 inches (25 to 35 centimeters) in length, as documented by R.S. Anderson in 1982 and later by D.C. Backlund and G.M. Marrone in 1997. During the daytime, American burying beetles are believed to bury themselves under vegetation litter or into soil as J. Jurzenski documented in 2012.
At night, they fly to find carrion and are active from late spring through early fall. These beetles occupy a variety of habitats and bury themselves in the soil to hibernate for the winter. American burying beetles emerge from their winter inactive period when ambient nighttime air temperatures consistently exceed 59°F, as documented by A.J. Kozol and others in 1988 and later in 1990. J.C. Bedick and others later documented this in 1999 and agency biologists also documented in 2008.
Reproduction occurs in the spring to early summer after this emergence. New adult beetles or offspring, called tenerals, usually emerge in summer and overwinter, or hibernate, as adults. In 1998, A.J. Kozol and others noted that they comprise the breeding population the following summer M. Amaral and others later confirmed this in 2005.
The American burying beetle is native to at least 35 states in the United States, covering most of temperate eastern North America, as well as the southern borders of three eastern Canadian provinces. The species is believed to be extirpated from all but nine states in the United States and is likely extirpated from Canada. However, the current range is much larger than originally thought when the species was listed in 1989. Based on the last 15 years of surveys, the American burying beetle occurs in portions of Arkansas, Kansas, Oklahoma, Nebraska, South Dakota, and Texas; on Block Island off the coast of Rhode Island; and in reintroduced populations on Nantucket Island off the coast of Massachusetts and in southwest Missouri, where a nonessential experimental population was established in 2012 under section 10(j) of the Act (77 FR 16712; March 22, 2012). Reintroduction efforts are also under way in Ohio, and survival of reintroduced American burying beetles into the next year, after successful overwintering, was documented in 2019. American burying beetles have not been documented in Texas since 2008.
Risks such as habitat loss or alteration and artificial lights affect most populations. All remaining populations have some risks associated with areas of urban or suburban development, particularly in the New England Analysis Area, but most current American burying beetle populations are in rural areas and have potential risks associated with habitat loss due to agricultural land uses. All habitat alterations also have potential to affect carrion populations, competing scavenger populations, and carrion availability. Risks associated with the effects of changing climate, including increasing temperatures, are now the most significant threat for most populations. More detailed information is available in the Species Status Assessment Report that was published in 2019.
Reproductive activity for the American burying beetles usually begins in May or June, once night time air temperatures in the general area approach 59°F consistently and cease by mid-August in most of the range, as documented by A.J. Kozol in 1988 and again in 1990. Immediately upon emergence from their winter hibernation, American burying beetles begin searching for a mate and properly sized carcass for reproduction. Burying beetles are capable of finding a carcass between one and 48 hours following death of prey and at a distance of at least two miles (3.2 kilometers), but finding them after 24 hours is more typical, as documented by Conley in 1982. Success in finding carrion depends upon many factors including availability of optimal habitats for small vertebrates, as M.V. Lomolino and J.C. Creighton noted in 1996. D.S. Wilson and Knollenberg documented in 1984 that success also depends on the density of competing invertebrate and vertebrate scavengers, individual searching ability, reproductive condition. D.S. Wilson and others also noted in 1984 that nighttime air temperature played an important role. B.C. Ratcliffe later confirmed this in 1996. The American burying beetle has been shown to be attracted to an array of vertebrate carcasses including mammals, birds, as A.J. Kozol and others documented in 1988, and herptiles, as J.C. Bedick documented in 1997. A.J. Kozol and others also found no preference for avian verses mammalian carcasses in 1988. Consequently, it is widely believed that American burying beetles will use any carcass for reproduction, as long as it is within the favored weight class to maximize fecundity, but further investigation is required to determine the actual resource American burying beetles uses in situ.
While the American burying beetles has life history requirements similar to other carrion beetles, it is the largest Nicrophorus in North America and requires a larger carcass to raise a maximum number of offspring than the other burying beetles, as noted by A.J. Kozol and others in 1988, as well as S.T. Trumbo in 1992. Potential carrion sources for reproduction are carcasses weighing from 1.7 to 10.5 ounces (48 tp 297 grams), with an optimum weight of 3.5 to 7.0 ounces (80 to 200 grams), as documented by A.J. Kozol in 1988 and again in 1990. American burying beetles are nocturnal and must find and bury the carcass in one night. Once an appropriate carcass has been found for reproduction, inter- and intra-specific competition can occur until usually only a single dominant male and female burying beetle remain, as documented by B.P. Springett in 1967 and later by D.S. Wilson and J. Fudge in 1984, as well as M.P. Scott and Traniello in 1989. Carcasses that become available are not necessarily found and buried immediately by carrion beetles. Complete concealment may take from 2 to 24 hours, during which time the carcass could be discovered and appropriated by a competitor, as documented by D.S. Wilson and J. Fudge in 1884 and later by M.P. Scott in 1994. American burying beetles typically out-compete other burying beetles as a result of its larger size, noted by A.J. Kozol and others in 1988. Our 1991 recovery plan noted that once winning the battle for the rights to the carcass, the successful couple buries the carrion, usually in the first night. It is at this point that they copulate and construct a brood chamber around the carcass, although either sex is capable of burying a carcass alone, as A.J. Kozol and others documented in 1988.
Parental care in the genus Nicrophorus is unique because both parents participate in the rearing of young, as documented by E. Pukowski in 1933 and later in 1990 by I.A. Fetherston and others, as well as S.T. Trumbo in 1990, with care provided by at least one parent, usually the female. Parental care is critical for larval survival, as noted by D.S. Wilson and J. Fudge in 1984. Once underground, both parents strip the carcass of fur or feathers, roll the carcass into a ball and treat it with anal and oral secretions that form a brood chamber and retard growth of mold and bacteria. The female beetle lays eggs in the soil adjacent to the carcass, as documented by E. Pukowski in 1933, and later by M.P. Scott and J.F.A. Traniello in 1990, where the eggs incubate for about six days before hatching into altricial larva. Higher temperatures increase egg development rates and reduce incubation times. Studies suggest that females reproducing on smaller carcasses produce fewer eggs than females reproducing on larger carcasses, as noted by J.C. Creighton and others in 2009, and later confirmed by E. J. Billman and others in 2014. Just before eggs hatch and larvae reach the carcass, parents prepare the brood ball by opening a small feeding depression at the top that they treat with regurgitated oral fluids. Brood sizes of American burying beetles can sometimes exceed 25 larvae, but 12 to 18 is more typical, as documented by A.J. Kozol in 1990.
One or both of the parents may remain with the larvae for several days and at least one parent, usually the female, will remain until they pupate, as documented by M.P. Scott in 1990 and A.J. Kozol in 1995. Larvae beg and are fed by parents, as documented by E. Pukowski in 1933 and later I.A. Fetherston and others in 1990 and P.T. Smiseth and others in 2003, as well as D. Leigh and P.T. Smiseth in 2012, or they can feed directly from the treated carcass. Larvae of large Nicrophorus species, are extremely dependent on parental regurgitation and will die before they reach second instar, which is the second stage of larval development, if they receive no parental care, noted Scott in 1998. Additionally, American burying beetles will cull their brood through cannibalism to increase size and survival of larvae in response to a less than adequately sized carcass, as documented by E.J. Billman and others in 2014. The reproductive process from carcass burial to eclosure, or emergence from pupae, is about 30 to 65 days.
The life history of the American burying beetle is similar to that of other burying beetles, as noted by E. Pukowski 1933 and later by D.S. Wilson and J. Fudge in 1984, M.P. Scott and J.F. A. Traniello in 1987 and A.J. Kozol and others in 1988, p 173. The American burying beetle is a nocturnal species that lives for only about one year. American burying beetles are active from late spring through early fall, occupying a variety of habitats and where they bury themselves in the soil to hibernate for the duration of the winter.
Reproduction occurs in the spring to early summer after this emergence. New adult beetles or offspring, called tenerals, usually emerge in summer and over-winter, or hibernate, as adults. In 1998, A.J. Kozol and others noted that they comprise the breeding population the following summer M. Amaral and others later confirmed this in 2005. Adults and larvae depend on dead animals, called carrion, for food, moisture and reproduction.
The American burying beetle is a nocturnal species that lives for only about one year.
American burying beetles are active at night and are most active from two to four hours after sunset. In 1999, J.C. Bedick and others documented that no captures were recorded immediately after dawn and T.L. Walker and W. Hoback confirmed in 2007. Individual American burying beetles must fly to find food, a mate and an appropriately sized carcass on or near suitable soils for burial. This could require individuals to move considerable distances to fulfill these needs. Several researchers, including J.C. Bedick and others in 2004, documented that American burying beetles are nocturnal and have been reported moving distances up to 18 miles (29 kilometers) in a single night in Nebraska, in the direction of the prevailing wind. During the daytime, American burying beetles are believed to bury under vegetation litter or into soil, as documented by J. Jurzenski in 2012.
The American burying beetle (Nicrophorus americanus) is the largest carrion beetle, or silphid, in North America. This species reaches 1.0 to 1.8 inches (25 to 35 centimeters) in length, as documented by R.S. Anderson in 1982 and later by D.C. Backlund and G.M. Marrone in 1997
Length: 1.0 to 1.8 in (25 to 35 cm)
American burying beetles are black with orange-red markings. Their hardened elytra, or wing coverings, are smooth, shiny black, with each elytron having two scallop-shaped orange-red markings. The pronotum over the mid-section between the head and wings is circular in shape with flattened margins and a raised central portion, as described by B.C. Ratcliff in 1996. The most diagnostic feature of the American burying beetle is the large orange-red marking on the raised portion of the pronotum, a feature shared with no other members of the genus in North America, as noted in the 1991 recovery plan. The American burying beetle also has an orange-red frons, or the upper, anterior part of the head, and a single orange-red marking on the clypeus, which can be considered as the lower face located just above the mandibles. Antennae are large, with notable orange club-shaped tips for chemoreception.
When not involved with brood rearing, carrion selection by adult carrion beetles for food can include an array of available carrion species and sizes, as well as feeding through capturing and consuming live insects and eating fly larvae when encountered on a carcass, as documented by S.T. Trumbo in 1994. The American burying beetle has been shown to be attracted to an array of vertebrate carcasses including mammals, birds, as noted by A.J. Kozol and others in 1988, and as well as herptiles, as J.C. Bedick noted in 1997. Additionally, in 1998, A.J. Kozol and others found no preference for avian verses mammalian carcasses. Baited traps could be attracting American burying beetles for both feeding and potential reproduction, but reproduction includes feeding because adults and larvae feed on carcasses that are buried for reproduction.
The American burying beetle is considered a generalist in terms of the vegetation types where it is found, as the historical range include most of the eastern United States and has been successfully live-trapped in a wide range of habitats, including wet meadows, partially forested loess canyons, oak-hickory forests, shrub land and grasslands, lightly grazed pasture, zones, coniferous forest and deciduous forests with open understory as J.C. Creighton and others documented in 1993 and later by A.J. Kozol in 1995, as well as M.V. Lomolino and others in 1995. In 1997, A.K. Holloway and G.D. Schnell documented that individuals do not appear to be limited by vegetation types as long as food, shelter in suitable soils and moisture are available and have been recorded moving between and among these habitat types. This was later confirmed by J.C. Creighton and G. D. Schnell in 1998.
In 1997, A.K. Holloway and G. D. Schnell found at Fort Chaffee, Arkansas that trapping success of N. americanus was higher at sites where small mammals are more abundant, irrespective of habitat defined on the basis of general vegetative characteristics. The beetles occurrence in an area is widely believed to depend on the presence of small mammals, birds and other sources of carrion necessary for completion their life cycle, as documented by R.S. Anderson in 1982, E.L. Muths 1991 and additionally by agency biologists in the recover plan that was also published in 1991. M. Amaral and others later confirmed this in 1997.
Land on which the natural dominant plant forms are grasses and forbs.
A dense growth of trees and underbrush covering a large tract.
Environments influenced by humans in a less substantial way than cities. This can include agriculture, silvaculture, aquaculture, etc.
Nicrophorus americanus is probably most closely related to the similarly sized, Nicrophorus germanicus of the Old World. In its extant populations, the geographic distribution of Nicrophorus americanus overlaps with N. carolinus, N. marginatus, N. pustulatus, N. tomentosus and N. orbicollis, from which it differs physically in coloration and size. Within North American Nicrophorus, Nicrophorus americanus is most similar to N. orbicollis.
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