Last June Jeff Huether and I made a trip out to a system of sand the dunes just south of Medora, Kansas. These dunes have been a popular historical collecting site since the late 1800s, when Warren Knaus first called attention to the area as “an interesting and profitable” locality for collecting insects (Knaus 1897). Knaus was a newspaper publisher in McPherson County, Kansas from 1886–1938, but his true passion was collecting beetles—an activity that took him throughout the Great Plains and Desert Southwest for nearly 50 years and earned him stature as one of Kansas’ most highly regarded coleopterists (Dean 1938). Despite his travels, Knaus remained enamored with the sand hills near his home and eventually published an annotated account of the rarer and more interesting beetles that he had encountered there over the years (Knaus 1926). One of the beetles mentioned in that paper was a “new species of Strigodermella…taken by sweeping in 1923 and 1925″. Those specimens soon became the type series for Strigodermella knausi (now Strigoderma knausi), named such by its describer (Brown 1925) in honour of its collector.
I suppose it is only fitting, then, that one of the first beetles that we encountered that day was this species. Actually, we couldn’t have missed them if we tried, they were so numerous! At first I assumed they were Strigoderma pygmaea, a species I had seen only once many years ago in Florida. Fortunately, we were in the company of Mary Liz Jameson, Associate Professor of Entomology at Wichita State University and an expert on scarab beetles. Mary Liz informed us of the beetle’s true identity, noting its rarity and relatively restricted distribution and that this was the type locality for the species.
At first the beetles were merely bycatch in our sweep nets as we looked for more ‘interesting’ beetles (i.e., jewel beetles for me, blister beetles for Jeff, and longhorned beetles for both of us). I tend to have trouble remaining so singularly focused, however, especially when the jewel and longhorned beetles aren’t out in numbers, and before long I found myself observing, and eventually photographing, these diminutive little scarabs. They were especially abundant at the south edge of the dunes, where they were hanging out on grasses and other low vegetation. A closer look revealed that almost every individual was perched in a rather characteristic pose, clinging to the vegetation with the middle and hind legs but extending them so that the beetle was nearly horizontal with the front legs held free and the segments of the antennal club spread widely apart. One can only presume that these were all males and that they were adopting this pose in an attempt to “smell” sex pheromones emitted by the unseen females. Mary Liz mentioned that the females are very rarely seen, and indeed among the nearly 100 specimens examined by Bader (1992) in his revision of the genus was but a single female.
Bader (1992) notes that S. knausi has been taken by sweeping grasses and cotton and taken by light traps in Kansas and Oklahoma with a few records from northern Texas. I mentioned earlier the resemblance of this species to S. pygmaea (Fabricius, 1798), which, like S. knausi, also seems to prefer sandy habitats and can be taken at lights or by sweeping low vegetation (Bader 1992). That species, however, occurs more broadly across the southeastern U.S., being especially common in Florida and along the Atlantic coast as far north as Long Island, New York. The two species can be distinguished by, among other characters, the presence (S. knausi) or absence (S. pygmaea) of a median sulcus (furrow) on the front part of the pronotum (easily seen in the second photo above).
Bader, A. M. 1992. A review of the North and Central American Strigoderma (Coleoptera: Scarabaeidae). Transactions of the American Entomological Society 118(3):269–330 [JSTOR].
Brown, W. J. 1925. A new species of Strigodermella. Bulletin of the Brooklyn Entomological Society 20:200–201.
Dean, G. A. 1938. Warren Knaus. Journal of the Kansas Entomological Society 11(1):1–3 [JSTOR].
Knaus, W. 1897. Collecting notes on Kansas Coleoptera. Transactions of the Annual Meetings of the Kansas Academy of Science 16:197–199 [JSTOR].
Knaus, W. 1926. The Coleoptera of the Sandhill Region of Medora, Reno County, Kansas. Entomological News 37(8):262–266 [Biostor].