Click beetles: Hatch’s click beetle (Eanus hatchi)
(Arthropoda: Insecta: Coleoptera: Elateridae: Dendrometrinae) Profile prepared by Sarah Foltz Jordan, The Xerces Society for Invertebrate Conservation
Eanus hatchi is endemic to Sphagnum bogs in the Puget Sound area of Washington. In the Seattle are, much of the available habitat for this species has been heavily altered or eliminated by urban development, and the species may be extirpated at both of the known sites (Chase Lake and Carkeek Park). This flight-capable species, however, is suspected to be more widespread than is documented, and springtime surveys of additional Sphagnum bogs in the region are needed.
Characteristic of the click beetle family (Elateridae), this species is elongate in shape, with the pronotum pointed on the posterior corners. The prosternum has a spinelike process that fits into a grove in the mesosternum, and the prothorax and mesothorax are loosely joined, enabling adults to arch, “click,” and flip over when they are upside down. This species is relatively small (7-9 mm, 0.28-0.35 in.) and has a metallic-bronze color which may reflect bright green or purple (reviewed in Martin 2003). The lack of flattening is one of the key field characters which distinguishes this species from other elaterids (Bergdahl 2009, pers. comm.).
Adults are most active in early spring, typically in April and May, although they may be encountered in June as well, particularly at mid-elevation (e.g. 450 m (1476 ft.)) bogs (Bergdahl 2009, pers. comm.). Although the larvae probably take multiple years to develop (Johnson 2008, pers. comm.), little is known about the seasonal activity of the larvae. The feeding habits of this species are unknown, but adults likely visit flowers and feed on honey dew, pollen, nectar, and floral structures. Extrafloral nectaries, including the exudates of new conifer growth, are another probable adult food source. Larvae probably predate on small insects (Johnson 2008, pers. comm.).
Washington: This species is endemic to the Puget Sound area of Washington. It was historically known from Sphagnum bogs in Snohomish and King counties, although the species may be extirpated at both of the Snohomish County sites (Chase Lake and Carkeek Park) in which case the only extant populations would be restricted to King County (Johnson 1984 and Bergdahl 2009, pers. comm.). Sphagnum habitat has been heavily altered by urban development at both sites, and survey attempts were not successful at locating this species or even Sphagnum habitat at the Carkeek Park site (Bergdahl 2008, pers. comm.). Records in King County are from three sites (Lake Marie, Snoqualmie Bog and Kings Lake Bog), although more recent survey work in the region by James Bergdahl revealed additional populations in southern King County at undisclosed localities (Bergdahl 2008, pers. comm.).
Oregon: This species has not been found in Oregon, although there is the possibility that it occurs in suitable habitat in the northwest part of the state (Bergdahl 2009, pers. comm.).
Federal Land: There are no known sites on of this species on federal land. Due to proximity of sites and habitat, the species may occur on the Mt. Baker/Snoqualmie National Forest (Bergdahl 2009, pers. comm.).
This species is found in low to mid elevation eutrophic Sphagnum bogs in forested areas, usually below 305 m (1000 ft.). Although this species has been found in relatively dry bogs, it is unknown if it prefers dryer habitats (J. Bergdahl in Martin 2003). Adults have been collected on low, floating mats of vegetation (Lane 1938), and may prefer the interface between Sphagnum mats and sedges (reviewed in Martin 2003). Additionally, adults spend at least some of their time higher up in bog vegetation, and tend to be found in association with Ledum groenlandicum and other flowering shrubs (reviewed in Martin 2003). The species has also been found on the foliage of hemlock (Tsuga spp.) (P. Johnson in Martin 2003). Larvae have been encountered above the water line near bog margins (Lane 1971), where they may inhabit decaying wood (P. Johnson in Martin 2003).
Inventory: Survey for new populations in lowland Sphagnum bog habitat. This flight-capable species is suspected to be more widespread than King County and to occur at many more bogs (Bergdahl 2008, pers. comm.). The main challenge with this species is that the adults are active only during a short period in early spring, which happens to be when few entomologists are in the field collecting insects (Bergdahl 2008, pers. comm.). Significant areas should be surveyed during the appropriate survey window (early spring). Among the six species in the Eanus genus, E. hatchi is the only one found in Sphagnum bogs at low elevation (less than 1000 m).
Management: Manage bog habitats to maintain water quality and quantity both at known and potential sites. Avoid application of pesticides or other chemicals in the proximity of such habitat.
Research: Studies designed to answer questions about the life history and ecology of this species are needed.
Bergdahl, J.C. 1997. Endemic Sphagnum bog beetles from the Puget Sound Region: Kings Land and Snoqualmie Bogs, King Co., Washington. Unpublished report for the Northwest Biodiversity Center.
Bergdahl, James. 2008. Personal communication with Sarah Foltz, Xerces Society for Invertebrate Conservation.
Bergdahl, James. 2009. Personal communication with Sarah Foltz, Xerces Society for Invertebrate Conservation.
LaBonte, J.R., D.W. Scott, J.D. McIver, and J.L. Hayes. 2001. Threatened, endangered, and sensitive insects in Eastern Oregon and Washington forests and adjacent lands. Northwest Science. 75:185-198.
Lane, M.C. 1938. A new species of the genus Eanus (Coleoptera Elateridae). Pan-Pacific Entomologist. 14(4): 188-191.
Lane, M.C. 1971. Key to the genus Eanus. in M.H. Hatch, Beetles of the Pacific Northwest. University of Washington Publications in Biology. 16: 28-29.
Johnson, 1984. Letter on file with the Washington Department of Wildlife, Nongame Division.
Johnson, Paul. 2008. Personal communication with Sarah Foltz, Xerces Society for Invertebrate Conservation.
Martin, R. 2003. Analysis Species Assessment: Hatch’s Click Beetle (Eanus hatchi). Baker River Terrestrial Working Group Analysis Species. Puget Sound Energy, Inc. Available at: http://www.pse.com/Hydro%20Licensing/baker/reports/TerrestrialWGStudies/T04%20Analysis%20Species/An_Sp_it_Review_HatchsBeetle_RM_Final%20Report_8_24_03.pdf. (Accessed 4 Dec. 2008).
NatureServe. 2008. “Eanus hatchi.” NatureServe Explorer: An online encyclopedia of life [web application]. Feb. 2008. Version 7.0. NatureServe, Arlington, Virginia. 15 Dec. 2008 .
U.S. Fish and Wildlife Service. 1989. Endangered and threatened wildlife and plants; animal notice of review. Federal Register, Department of the Interior. 54(4): 554-579.
Washington Department of Fish and Wildlife. 1991. Hatch’s click beetle. Available at: http://wdfw.wa.gov/archives/pdf/94025119.pdf. (Accessed 4 Dec. 2008).