Tierra de Oro Laboratory

Physiology and Ecology in the Pinyon-Juniper Savannah

Eleodes obscura

Large black beetle held in fingers.
Eleodes obscura. This subspecies, E. o. dispersa is distinguished by the relatively low ridges on the elytra with many irregularly spaced punctures.

Eleodes obscura is a large, common, and widespread Tenebrionid beetle. It may be the most well-studied species of Eleodes, with more than two dozen papers describing its taxonomy, behavior, ecology, and metabolism.

Identification (Triplehorn et al., 2009, 2015):

Size: 28-35 mm.

Subfamily: Blaptinae

Tribe: Amphidorini

Subgenus: Eleodes.

Anterior angles of the pronotum are obtuse. Elytra sides are rounded and without marginal bead (compared to, e.g., E. acutus). In the local subspecies (E. o. dispersa) elytra are irregularly and muricately punctate. Profemora are dentate in males, sinuate in females.

Range

Eloeodes obscura comprises four subspecies, and is widespread throughout western North America.

References

Bernett, A. (2008). The Genus Eleodes Eschscholtz (Coleoptera: Tenebrionidae) of Eastern Colorado. Journal of the Kansas Entomological Society 81, 377–391.

Brown, K. W. (1971). A population approach to computer taxonomy with applications in the genus Gonasida. Ph.D Thesis. U.C. Riverside.

Hetz, M. and Slobodchikoff, C. N. (1988). Predation pressure on an imperfect Batesian micicry complex in the presence of alternative prey. Oecologia 76, 570–573.

Hetz, M. and Slobodchikoff, C. N. (1990). Reproduction and the energy cost of defense in a Batesian mimicry complex. Oecologia 84, 69–73.

Johnston, M. A., Fleming, D., Franz, N. M. and Smith, A. D. (2015). Amphidorini Leconte (Coleoptera: Tenebrionidae) of Arizona: Keys and Species Accounts. The Coleopterists Bulletin 69, 27–54.

Kaiser, A., Klok, C. J., Socha, J. J., Lee, W.-K., Quinlan, M. C. and Harrison, J. F. (2007). Increase in tracheal investment with beetle size supports hypothesis of oxygen limitation on insect gigantism. Proc. Natl. Acad. Sci. U.S.A. 104, 13198–13203.

Kenagy, G. J. and Stevenson, R. D. (1982). Role of Body Temperature in the Seasonality of Daily Activity in Tenebrionid Beetles of Eastern Washington. Ecology 63, 1491–1503.

Lease, H. M., Klok, C. J., Kaiser, A. and Harrison, J. F. (2012). Body size is not critical for critical PO2  in scarabaeid and tenebrionid beetles. Journal of Experimental Biology 215, 2524–2533.

Marino, P. C. (1986). Activity Patterns and Microhabitat Selection in a Desert Tenebrionid Beetle (Coleoptera: Tenebrionidae). Annals of the Entomological Society of America 79, 468–471.

McIntyre, N. E. (1999). Use of Pogonomyrmex nest-sites by Tenebrionid beetles (Coleoptera: Tenebrionidae) for oviposition and thermoregulation in a temperate grassland. The Southwestern Naturalist 44, 379–382.

Schilman, P. E., Kaiser, A. and Lighton, J. R. B. (2008). Breathe softly, beetle: Continuous gas exchange, water loss and the role of the subelytral space in the Tenebrionid beetle, Eleodes obscuraJournal of Insect Physiology 54, 192–203.

Sheldon, J. K. and Rogers, L. E. (1984). Seasonal and Habitat Distribution of Tenebrionid Beetles in Shrub-Steppe Communities of the Hanford Site in Eastern Washington. Environmental Entomology 13, 214–220.

Slobodchikoff, C. N. (1978). Experimental Studies of Tenebrionid Beetle Predation By Skunks. Behav 66, 313–322.

Slobodchikoff, C. N. (1979). Utilization of Harvester Ant Debris by Tenebrionid Beetles. Environmental Entomology 8, 770–772.

Slobodchikoff, C. N. (1983). Water Balance and Temperature Preferences, and Their Role in Regulating Activity Times of Tenebrionid Beetles. Oikos 40, 113.

Slobodchikoff, C. N. and Wismann, K. (1981). A Function of the Subelytral Chamber of Tenebrionid Beetles. Journal of Experimental Biology 90, 109–114.

Slobodchikoff, C. N., Vaughan, T. A. and Warner, R. M. (1987). How Prey Defenses Affect a Predator’s Net Energetic Profit. Journal of Mammalogy 68, 668–671.

Stapp, P. (1997). Microhabitat Use and Community Structure of Darkling Beetles (Coleoptera: Tenebrionidae) in Shortgrass Prairie: Effects of Season Shrub and Soil Type. American Midland Naturalist 137, 298.

Tanner, V. M. and Packham, W. A. (1965). Tenebrionidae beetles of the Nevada Test Site. Brigham Young University Science Bulletin 6, 1–41.

Thomas, D. B., Smith, A. D., Triplehorn, C. A. and Aalbu, R. A. (2014). Walker’s Eleodes (Coleoptera: Tenebrionidae). Zootaxa 3835, 583–592.

Triplehorn, C. A., Thomas, D. B. and Riley, E. G. (2009). The Genus Eleodes Eschscholtz (Coleoptera: Tenebrionidae) in Texas. The Coleopterists Bulletin 63, 413–437.

Triplehorn, C. A., Thomas, D. B. and Smith, A. D. (2015). A Revision of Eleodes Subgenus Eleodes Eschscholtz (Coleoptera: Tenebrionidae). Transactions of the American Entomological Society 141, 156–196.

Uhey, D. A., Riskas, H. L., Smith, A. D. and Hofstetter, R. W. (2020). Ground-dwelling arthropods of pinyon-juniper woodlands: Arthropod community patterns are driven by climate and overall plant productivity, not host tree species. PLoS ONE 15, e0238219.

Uhey, D. A., Bowker, M. A., Haubensak, K. A., Auty, D., Vissa, S. and Hofstetter, R. W. (2022). Habitat Type Affects Elevational Patterns in Ground-dwelling Arthropod Communities. Journal of Insect Science 22, 9.

Whicker, A. D. and Tracy, C. R. (1987). Tenebrionid beetles in the shortgrass prairie: daily and seasonal patterns of activity and temperature. Ecological Entomology 12, 97–108.

Wise, D. H. (1981). Seasonal and Yearly Patterns in the Densities of Darkling Beetles (Coleoptera: Tenebrionidae) in a Montane Community. Environmental Entomology 10, 350–358.