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Mycotrupes lethroidesLarge Mycotrupes
Federal Protection: No US federal protection
State Protection: No Georgia state protection
Global Rank: GNR
State Rank: S1S2
SWAP High Priority Species (SGCN): Yes
Element Occurrences (EOs) in Georgia: 7
Habitat Summary for element in Georgia: Sandhills
Adults are fairly large, 20 mm [0.8 inch] long and robust in form. Oval, convex, with a distinctly granular surface, this flightless beetle is a dull black (not shiny) in color. Elytral grooves are practically absent. Anterior part of pronotum with a pronounced apical depression (in males, as large or larger than the head) lending it a dimpled appearance. Clypeus of male with a small horn.
Easily distinguished by the fused elytra and the absence of metathoracic wings. May be differentiated from Mycotrupes cartwrighti by its larger size and allopatric range.
Xeric longleaf pine-turkey oak sandhills.
The diet of adult M. lethroides includes fungi, acorns, dung and other arthropods. Food of larvae unknown.
The flightless adults dig vertical burrows (typically 8-25 cm) in deep, sandy soils. Burrows are used by feeding and resting beetles, and adults provision cells within the burrows for larval development. There is typically a single individual per burrow, the burrow entrances are marked by a prominent mound of sand (i.e., “push-up”) that may be several inches high. These beetles may stridulate when handled. Activity is diurnal and highly seasonal (confined to the cooler months; November through March). The larva is undescribed.
A study examining the historic, and current, distribution of this Georgia-endemic beetle has never been attempted. This species is easy to survey for, thus an effort to finely map the entirety of the species distribution is warranted. The species may be collected from September-March in large numbers using pitfall traps baited with fermenting malt or molasses. Adults may be collected by excavating burrows.
Endemic to Georgia, this sandhill specialist is restricted to the upper Atlantic Coastal Plain and Fall Line regions, close to Augusta. The genus Mycotrupes is a small group comprised of five species (all earth-boring and flightless, with ranges corresponding to ancient shorelines) with non-overlapping Coastal Plain distributions that, collectively, extend from South Carolina to central Florida (two species are known from Georgia).
Loss, degradation and fragmentation of naturally-functioning longleaf pine sandhills threaten the future of this species.
Locally distributed. Documented from approximately 12 sites in Georgia. There are significant populations present on several protected lands, including Fort Gordon. Additional studies addressing this beetle status are needed.
Conduct additional surveys for the beetle throughout its presumed Georgia range. Habitats supporting populations of this beetle may be managed and enhanced through the use prescribed burns. Careful evaluation of herbicides used in sandhills inhabited by this species is recommended. Inasmuch as these beetles often utilize and dig burrows in primitive sand roads and similar “two-tracks”, paving or profound disturbance to such areas should be avoided when possible.
Beucke, K.A. 2009. Phylogenetics, niche modeling and biogeography of Mycotrupes (Coleoptera: Geotrupidae). Ph.D. dissertation. University of Florida, Gainesville.
Beauke, K.A., and P. Choate. 2009. Notes on the feeding behavior of Mycotrupes lethroides (Westwood) (Coleoptera: Geotrupidae). Coleopterists Bulletin 63(2):228−229.
Howden, H.F. 1963. Speculations on some beetles, barriers, and climates during the Pleistocene and pre-Pleistocene periods in some non-glaciated portions of North America. Systematic Zoology 12(4):178−201.
Jameson, M.L. 2002. Geotrupidae, Latreille 1802. Pp. 23−27, In R.H. Arnett, Jr., M.C. Thomas, P.E. Skelley, and J.H. Frank (eds.). American Beetles, Volume 2 – Polyphaga: Scarabaeoidea through Curculionoidea. CRC Press, Boca Raton, FL.
Olson, A.L., T.H. Hubbell, and H.F. Howden. 1954. The burrowing beetles of the genus Mycotrupes. Miscellaneous Publications of the Museum of Zoology, University of. Michigan 84:1−84.
Woodruff, R. E. 1973. The Scarab Beetles of Florida. Arthropods of Florida and Neighboring Land Areas Vol. 8. Florida Dept. of Agriculture and Consumer Services, Division of Plant Industry, Gainesville, FL. 200 pp.
Dirk J. Stevenson
1 December 2018