A New Sampling Protocol for the Endangered American Burying Beetle, Nicrophorus Americanus Olivier (coleoptera: Silphidae)

The endangered American burying beetle, Nicrophorus americanus Olivier, presently occurs in small and widely scattered areas on the periphery of its former range. As part of the recovery plan for this insect implemented by the U.S. Fish and Wildlife Service (USFWS), we conducted surveys in Nebraska to ascertain its presence. Additionally, we examined various trapping methods and procedures in the course of our survey work. We compared the effectiveness of different trap designs, trap placement, timing of trapping, types and amounts of bait, and monitoring traps. We also developed methods to reduce beetle mortality in traps. Our work offers more effective sampling procedures for N. americanus and suggests the current USFWS sampling protocol should be modified. New procedures include larger traps, moist soil substrate, a soil berm to the edge of the trap, longer trapping season, and increased distances between traps. A moist soil substrate, in combination with a shade-giving rain cover, precludes the necessity of servicing all traps by 9 AM each day (as mandated in the current protocol), a task that is logistically difficult or impossible if there are many traps. The sampling procedures we have identified as most appropriate for N. americanus will also improve sampling for other silphid species. Throughout the 1990s, numerous surveys (many unpublished) were conducted in many states to locate remnant populations of the endangered American burying beetle, Nicrophorus americanus Olivier. This species was formerly distributed throughout 35 states and three Canadian provinces in eastern North America from Nova Scotia to western Nebraska and from the upper peninsula of Michigan to Texas (U.S. Fish and Wildlife Service 1991). In the last century it has disappeared from over 90% of its historic range (Lomolino et al. 1995). The beetle now occurs in only seven states: Block Island off the southern coast of Rhode Island (Kozol 1989, 1991), Penikese and Nantucket Islands in Massachusetts (Muths and Scott 2000), eastern Oklahoma and western Arkansas (U.S. Fish and Wildlife Service 1991; Creighton et al. 1993; Lomolino et al. 1995), central Nebraska (Ratcliffe 1996; Ratcliffe and Jameson 1992; Bedick et al. 1999), southern South Dakota (Backlund and Marrone 1997), and southeastern Kansas (Miller and McDonald 1997). Because of the precipitous decline in the distribution of N. americanus, it was proposed as an endangered species (Recce 1988) and placed on the endangered species list in August 1989. Various ideas have been postulated to explain the decline of this species, but no clear answer has emerged; see Bedick et al. (1999) for a summary of various hypotheses and associated literature. The USFWS, in cooperation with the scientific community, formulated a recovery plan (U.S. Fish and Wildlife Service 1991) that is now being implemented. One goal of the recovery plan is to locate undocumented populations of N. americanus. As a part of this plan, the USFWS published 57 The Coleopterists Bulletin, 58(1):57–70. 2004.