January 8, 2011 29 Comments
In June 1994, I made my first insect collecting trip to Big Bend National Park. Both of my previous visits to Texas had been to the Lower Rio Grande Valley, so I was anxious to see what beetle treasures awaited me in this huge chunk of western Texas. For three days I sampled the astounding diversity of beetles found in the park’s low desert scrub, oak/juniper woodlands, and high pine forests, and on the final day I decided to visit the sotol grasslands – a transitional habitat between the desert and woodlands in the Chisos Mountains foothills. Sotol (Dasylirion wheeleri) is the host plant of jewel beetles in the genus Thrincopyge - exquisitely beautiful beetles of metallic blue or green and vivid yellow. Larvae bore through the plant’s dried flower stalks, while adults wedge themselves in the base of this agave-like plant, hidden from view by the plant’s long, strap-like, saw-toothed leaves. I had not yet seen these beetles for myself, so I began searching the through the plants – carefully prying apart the wicked leaves in hopes of seeing adults peering up from the base, and then using my foot-long forceps to extract them. It’s a painful process, as no amount of care completely prevents the plant’s stout, recurved spines from impaling and ripping forearm flesh while trying to grab and pull out the beetles!
While prying apart the leaves of one particular plant, I was startled by one of the most imposing-looking insects that I have ever seen as it jumped up on top of the foliage and assumed this decidedly aggressive posture. Although I recognized it as some type of katydid, it was unlike any I’d seen before - large and robust, vivid green and yellow with flashing red eyes, its short spotted hind wings outstretched, spiny forelegs held high, and huge jaws spread wide open. Her long dagger-like ovipositor only added to her impressiveness. So spectacularly terrifying was its threat display that I couldn’t resist the opportunity to collect it for eventual mounting in life-like position. I felt a little silly being scared of a katydid but nevertheless took great care to avoid getting my fingers anywhere near those jaws as I gingerly corraled it into a jar.
Neobarrettia spinosa is also known as the greater arid-land katydid or spiny bush katydid, but I prefer the name that has been coined by some – “red-eyed devil”! This species belongs to a small genus of primitive katydids largely restricted to northern Mexico, with only two species extending north into the south-central and southwestern U.S. The black front edge of the pronotum and (in life) red eyes identify this individual as N. spinosa (N. victoria, also occurring in Texas, has the pronotal front edge green and the eyes pale). Unlike most katydids, which have adopted omnivorous or hervivorous feeding habits, species of Neobarrettia and their subfamilial relatives are pure carnivores capable of capturing and consuming prey as large as themselves. Its bulging eyes, elongate and heavily spined forelegs, and massively robust mandibles on a large head (presumably for enlarged mandibular musculature) clearly represent adaptations for predation (Cohn 1965).
The painting above from Cohn’s revision of the genus shows the true colors of a living female and its threat display. I collected this specimen before the days of the internet or my own interest in photography, so I had nothing but my memory to guide me as I tried to recreate the threat display during mounting. I got it mostly right but missed on a few details – the wings should have been placed more vertically, and the insect also rears back more on its hind legs to display the brightly colored cephalic portion of its abdominal venter. I could try to relax and remount the specimen, but given its fragility and the fact that doing so would do little to make it any more imposing, I think the pose I have it in now is just fine.
This turned out to be a more difficult ID Challenge than I anticipated, but a record number of participants played along anyway. Dave wins this challenge with 11 pts on the basis of a correct identification and entertaining logic to accompany it. Ben Coulter was the only other person to correctly identify the genus and species, earning 9 pts for 2nd place, while BitB’s own James Trager and TGIQ share the final podium spot with 5 pts each. Ben continues to dominate the overall competition with 32 pts now, but the battle for 2nd place has really heated up – Janet Creamer (14 pts) and TGIQ (13 pts) have the edge, but Dave (11 pts), James Trager (11 pts), and Christopher Taylor (10 pts) are all within easy striking distance.
Cohn, T. J. 1965. The arid-land katydids of the North American genus Neobarrettia (Orthoptera: Tettigoniidae): their systematics and a reconstruction of their history. Miscellaneous Publications of the University of Michigan Museum of Zoology 126:1-179.
Copyright © Ted C. MacRae 2011