new state record

First collecting trip of the season!

/ Ted C. MacRae / 7 Comments

Last week I went on the first collecting trip of the 2023 season, which was actually the second phase of a study initiated last year to evaluate the efficacy of “jug traps” and baits for trapping longhorned beetles (family Cerambycidae). In the first year of the study, I set out 24 traps at 12 locations across southern Illinois and Missouri—one trap at each location baited with “pure” (99.5%) ethanol (EtOH), and the other baited with a 50:50 mixture of ethanol and sweet red table wine (SRW). The traps proved to be highly effective at trapping not only a diversity of Cerambycidae, but also Cetoniidae and Elateridae. Additionally, and in what was a bit of a surprise, the 50:50 mixture (EtOH/SRW) proved to be much more efficacious than EtOH alone. The reasons for this are not clear—-perhaps SRW contains other volatiles besides EtOH that are also attractive to the beetles, or possibly the sugars in SRW permit additional fermentation and, thus, extended volatilization of EtOH. Either way, the ability to substitute at least a portion of relatively expensive EtOH with cheap SRW without negatively impacting trap efficacy (actually improving it) allows cost savings and begs the question: how effective are traps baited with SRW alone?

To answer that question, I decided to conduct a second season of trapping, this time comparing three possible baits: SRW alone, 50:50 SRW/EtOH, and EtOH alone. I also wanted to conduct the study in a different area where a different longhorned beetle fauna might be expected to increase the diversity of species shown to be attracted to the traps, and for that I could not think of a better place than northwestern Oklahoma. The insect fauna of the area is decidedly more “western” than southern Missouri, and in fact I have collected several species of beetles in the area that represent new records for the state—most of which are more typically found further southwest in New Mexico and/or Arizona (manuscripts containing these records are currently in progress). Most importantly, I can reach the area from my home near St. Louis, Missouri in less than a day of driving, allowing me to make the repeated visits over the course of the season that will be necessary to service the traps and collect the data. Since three traps will be deployed at each location (instead of two as in 2022), fewer locations (six) were chosen, resulting in 18 total traps. The traps were set out May 16–18, during which time my good friend and collecting buddy Rich Thoma joined me, and I will return every five weeks to check the traps until early October, when they will be taken down.

Note: all field identifications are preliminary pending confirmation.

Day 1—Gloss Mountain State Park (Major Co.)
This is one of my favorite spots in northwestern Oklahoma, though not quite west enough to be considered part of the “panhandle.” The gypsum-capped mesas atop red clay soils have a decidedly “New Mexican” look, and I have collected several beetles here that represent new state records for Oklahoma, including Plionoma suturalis, Chrysobothris octocola, C. quadrillineata, and Paratyndaris prospopis. I decided to set two set of jug traps here because of the two distinctly different habitat types: one on/near the top of the mesa in copses of gum bumelia, netleaf hackberry, soapberry, and/or eastern red-cedar, and another in the mesquite chaparral along south border in isolated mesquite trees.

Ethanol-baited “jug trap” hanging in honey mesquite tree in mesquite chaparral.

Things were still a bit early in the season, and I did not spend anytime beating the newly leafed out trees, but I did find one Phyllophaga cribrosa on the ground and several Plionoma suturalis (gave a mating pair to Rich), one Trichodes bibalteatus, and one Monophylla terminalis on living Neltuma glandulosa [= Prosopis glandulosa].

Phyllophaga cribrosa (family Scarabaeidae) atop gypsum-capped mesa.
Plionoma suturalis (family Cerambycidae) mating pair on Neltuma glandulosa [= Prosopis glandulosa] (honey mesquite) in mesquite chaparral.

Other sightings of interest were an eastern collared lizard (Crotaphytus collaris) at the edge of the mesa and a Manduca quinquemaculata (five-spotted hawkmoth) getting an early start on its evening pollination rounds on still unopened Oenethera macrocarpa (Missouri primrose) blooms.

Eastern collared lizard (Crotaphytus collaris) atop gypsum-capped mesa.
Manduca quinquemaculata (five-spotted hawkmoth, family Sphingidae) nectaring in flight at flower of Oenethera macrocarpa (Missouri primrose) in mesquite chaparral.

Day 2—Alabaster Caverns State Park (Woodward Co.)
There is no camping at Gloss Mountain State Park, and we were hungry as well, so we drove to Woodward to grab some dinner and backtracked up to Alabaster Caverns State Park. Arriving at the campsite after sunset and setting up a new, never-before-erected tent in the dark was an interesting experience; however, the tent went up quickly enough that Rich and I were able to relax and enjoy a beer and conversation before turning in for the night. In the morning, after getting a good look at the canyon forest, I decided this might be a good spot to hang one of my Lindgren funnel traps before hanging the jug traps further up in Cedar Canyon. There are many very large gum bumelia trees in addition to hackberries and red-cedars—surprising to me given the riparian nature of the forest, and I found a nice secluded spot to hang the trap, which was baited with 50:50 SRW/EtOH, before breaking camp and heading to Raptorroost Trail to access the upper reaches of Cedar Canyon.

Morning sun over Cedar Canyon.

Cedar Canyon represents a collapsed cave system, now appearing as a jagged, forested gash cutting deeply into the gently rolling gypsum landscape. The area first came to my attention in 2009, when I “discovered” a healthy population of Cylindera celeripes (swift tiger beetle)—then considered one of North America’s rarest tiger beetles—living in the sparsely-vegetated gypsum exposures above the canyon. Checking in with the park office to show them our permit, we were surprised to learn that I should have also contacted them ahead of time to apply for a “separate, park-specific” permit, which after a bit of wrangling and cajoling we were able to convince them to grant on the spot (the vagaries of state park permits, where “some” park managers have a tendency to want to demonstrate the fact that they have ultimate authority over their piece of the earth). While we waited, we enjoyed looking at the Saurophaganax maximus skull found somewhere in northwestern Oklahoma and on display in the park office. A relative of the smaller but better-known Allosaurus, S. maximus lived during the late Jurassic (150 mya) and was, at that time, the largest meat-eating dinosaur in North America.

Saurophaganax maximus was the largest meat-eating dinosaur in North America during the late Jurassic (150 mya). This skull was found somewhere in northwestern Oklahoma.

After receiving our “re-permit,” we headed for Cedar Canyon to hang three jug traps in the canyon forest. This was eventually done, with traps hung at three points in the forest of mostly red-cedar, hackberry, and gum bumelia. Hanging the traps in the canyon was quite difficult—the trail into and out of the canyon was steep and technical, and finding places to hang the traps where they were unlikely to be seen and disturbed by park visitors while still being accessible to me was even harder. Before accessing the canyon via Raptorsroost Trail and hanging the traps, however, we quickly became distracted by goings on in the gypsum/red clay shortgrass prairie above the canyon. We first noted Moneilema armatum (cactus beetles) on Opuntia macrorhiza (prairie pricklypear cactus), collecting about a dozen individuals.

Moneilema armatum (family Cerambycidae) on pad of Opuntia macrorhiza (prairie pricklypear cactus) in gypsum/red clay shortgrass prairie.

As we searched the cactus and the morning sun warmed things up, I also began noticing adults of Acmaeodera tubulus coming to the flowers in bloom, mostly Tradescantia occidentalis (western spiderwort) but also Pyrrhopappus pauciflorus (smallflower desert-chicory) and a yellow-flowered Oenethera sp. (primrose). I was rather surprised to see this eastern U.S. species occurring this far west in such a decidedly “western” habitat—surely this must be near the western limit of distribution for the species!

Acmaeodera tubulus (family Buprestidae) on flower of Tradescantia occidentalis (western spidorwort) in gypsum/red clay shortgrass prairie.

At any rate, hanging the traps and indulging our distractions burned about three hours (and finding/photographing a beautiful female collared lizard [Crotaphytus collaris] and a few other interesting things burned even more time), so we went back down to our previous night’s campsite, ate a quick lunch, and then headed towards our next stop.

Eastern collared lizard (Crotaphytus collaris) atop gypsum exposure.
Band-winged grasshopper (family Acrididae, subfamily Oedipodinae, tribe Hippiscini) nymph in gypsum/red clay shortgrass prairie.
Escobaria missouriensis missouriensis (Missouri foxtail cactus) in gypsum/red clay shortgrass prairie.

Beaver Dunes City Park (Beaver Co.)
Beaver Dunes is a former state park, now a city park managed by the nearby city of Beaver primarily for ORVs. Despite the impacts on the dunes, there remain vast areas of the dunes that are closed to traffic and, thus, not impacted by ORV traffic and boasting a unique dune flora and fauna. Bordering the dunes on the east is a riparian zone boasting large Populus deltoides (eastern cottonwood) trees and smaller Celtis reticulata (netleaf hackberry) and Robinia pseudoacacia (black locust) trees. Notably, some years ago I collected a nice series of Poecilonota cyanipes (family Buprestidae) off the stunted cottonwoods in and around the tent campground—the only time I have collected this species other than a single individual up in Michigan even more years ago. We first drove through the tent campground and then the picnic area to scope out a camping spot and decide exactly where I wanted to hang the traps. Ultimately, I decided neither location was suitable for the traps as the wooded areas were adjacent to either dunes or prairie with little woody vegetation and where prevailing winds were likely to carry most of the scent emanating from the traps. Instead, I decided to hang them in a strip of woodland stretching north off the RV campground (Pioneer Campground).

Afterwards we explored the dunes, immediately finding several Batyle ignicollis apparently bedded down on the inflorescence of Styllingia sylvatica (Queen’s delight). I have seen this species doing the same thing on a previous visit some years ago, and in that case many individuals were found on many plants. In this case, however, beyond the three individuals seen on this first plant (two of which escaped as I tried to photograph them!), only one more individual on one other plant was seen.

Batyle ignicollis (family Cerambycidae) on inflorescence of Styllingia sylvatica in sand dune.

A couple of tenebrionids crossing the road were picked up before working our way to the picnic area and exploring the dunes in their vicinity. There was surprisingly little in bloom—primarily S. sylvatica and just a few sparsely blooming Penstemon fendleri (Fendler’s penstemon). We checked the former, finding only a few Euphoria kernii (all three color forms), one E. sepulchralis, and the one additional B. ignicollis on the former and nothing on the latter. The only other insects seen, or at least collected, were a large(ish) weevil on a grass stem and a Cicindela formosa (big sand tiger beetle). After exploring for a while and not seeing much activity, it seemed that further searching was “beating a dead horse,” so we started back towards the car. Along the way, I decided to beat once again the Celtis reticulata (netleaf hackberry) trees dotting the roadside and, unlike my earlier (limited) attempts, was immediately rewarded with a couple of Chrysobothris purpureovittata (family Buprestidae). Further beating continued to produce additional specimens as well as a few Agrilus lecontei and/or A. paracelti, and by the time I finished beating the last tree I had collected perhaps 12–15 C. purpureovittata and 6–8 Agrilus spp. I felt this was a happy note on which to end the day’s collecting, and we decided to run into town to look for dinner (we ended up bringing carry-out pizza back to the campground and enjoying it with a beer!).

Day 3—Beaver Dunes City Park (cont.)
Overnight it rained heavily (which I did not hear, despite being in a tent), so before heading off to the Black Mesa area we checked out the dunes to see if we could find fresh tracks. We found a few deer tracks, a nice long stretch of wild turkey tracks, and some small tracks that most likely belong to red fox.

Morning sun over the dunes.
Fresh tracks in the sand—possibly red fox.

Black Mesa State Park (Cimarron Co.)
Black Mesa State Park and Preserve are tucked into the extreme corner of northwestern Oklahoma, and it is here where “east” truly turns to “west.” Miles of shortgrass prairie suddenly give way, shortly before the park, to chaparral dotted with Cylindropuntia imbricata (cholla) and Juniperus monosperma (one-seed juniper). Arriving in the park after our 3½-hour drive straight west, we checked in at the office to show our permit (no hassle or “extra” permit needed), reserved our spot in the tent campground, and ate a quick lunch before heading to the Scenic Overlook where I’d planned to hang a set of traps in the hackberry/soapberry wooded ravine below the overlook. This was eventually done, but again we were distracted right off the bat when we noticed plants abundantly in flower around the parking lot. I quickly found a few Acmaeodera that I could not immediately identify—obviously members of the A. mixta/pulchella/immaculata group, but they are tiny, much smaller than any of those species! Most were on flowers of Tetraneuris acaulis (stemless four-nerve daisy), a few were on flowers of Melampodium leucanthum (blackfoot daisy), and one was on flower of Xanthisma spinulosum (spiny goldenweed). I’ll be anxious to get a better look at them once I return home. Traps successfully hung, we then headed to the next spot a short drive north of the state park.

A species in the Acmaeodera mixta/pulchella/immaculata group (family Buprestidae), but tiny! On flower of Tetraneuris acaulis (stemless four-nerve daisy) in shortgrass prairie.

1.6 mi E Kenton on Hwy 325 (Cimarron Co.)
I’ve visited this sandstone outcropping colonized by an interesting oak identified on iNaturalist as Quercus × undulata (wavyleaf oak)—a naturally occurring hybrid between Q. gambelii and Q. turbinella and that occurs more typically in Utah and the Intermountain West. This seems to be the easternmost occurrence of this hybrid, and while I’m in no position to vouch for the veracity of the identification, I do think there could be some interesting beetles associated with it. The outcropping is also colonized by two other decidedly western trees—Pinus edulis (Colorado pinyon) and Juniperus monosperma (one-seed juniper), both of which seem to be at their eastern natural limit here and which could host some interesting western insects as well. Unfortunately, my previous visits (early May through mid-June) all seemed to be at the wrong season (too dry), although on my last visit (early June last year) I did manage to collect a nice number and variety of Acmaeodera, including a new state record (A. quadrivittatoides)! Once again, there seemed to be little going on—just a few Nemognatha blister beetles and some tiny flies on the various yellow composite flowers found in bloom—despite the series of Acmaeodera collected down the road within the state park. Perhaps it was more due to the thick cloud cover with distant rain showers that had moved into the area than the time of season, but the oaks very recently leafed out and just now flowering still suggests it is early in the season here. Nevertheless, I hung the last set of traps in the oak/pine/juniper woodland atop the outcropping and look forward to seeing what might turn up in them later this season.

View from atop sandstone outcrop.
Nemognatha nigripennis? (family Meloidae) on flower Xanthisma spinulosum (spiny goldenweed) in shortgrass prairie.

Dinosaur Tracks (Cimarron Co.)
Hanging traps at the state park and the sandstone outcropping just north of the park took a few hours but still left us with some time to explore the area and I wanted to show Rich the famous dinosaur tracks found just across the road from Black Mesa Preserve. There is no signage, and 10 years having passed since the last time I saw them, so I wasn’t sure I would be able to find them. Fortunately, a little Google sleuthing paid off and we came right to the spot. The tracks—apparently made by a theropod (one of the carnivorous groups)—were discovered in the early 1980s and are on private land but are open to the public during daylight hours. We were fortunate that it had rained the previous night, which filled the tracks with water and made them especially visible in the sandstone rock at the bottom of the creek in which they were exposed. The largest, deepest, and best-preserved of the dozen or so tracks that are still visible (many are covered by mud) measure approximately 16” across and clearly show the 3-toed footprint typical of theropod dinosaurs. Given their size, perhaps they were made by Saurophaganax maximus!

Dinosaur tracks (likely a therapod) in creek bed near Black Mesa Preserve.

Black Mesa Preserve (Cimarron Co.)
I had considered hanging a set of traps adjacent to this location, but I saw little suitable habitat in the area, save possibly for the ribbon of large cottonwoods lining nearby Carrizo Creek. Regardless, since I had already placed two other sets at the nearby sandstone outcropping and a bit further south at the state park, I felt my coverage of the area was sufficient. To pass the remaining time, Rich and I hiked through the juniper chaparral on the north side of the mesa. The area still had an “early spring” feel to it, with yucca and cholla barely beginning to throw up or develop their flower stalks/buds and the whole area looking like it needed a good rain. Correspondingly, there was almost no insect activity to speak of—we found lone individuals of Leptinotarsa decemlineata (Colorado potato beetle) and Eleodes sp. (clown beetle) crawling on the trail, and I collected a single Omorgus sp. (skin beetle). Whatever thoughts we had of ascending the mesa and hiking to the High Point Monument were dashed when our legs—already tired from the day’s previous hikes—began to protest and cried “Enough!” Turning around before the kiosk leading to the mesa top turned out fortuitous, as suddenly plummeting temperatures and the threat of rain caused us to make our way back to the car with some sense of urgency. It began raining as soon as we reached the car, and we were ecstatic to find “The Merc” open and serving up dinner in nearby Kenton (the only Oklahoma City in the Mountain Time Zone!).

Juniper chaparral below Black Mesa.
Leptinotarsa decemlineata (Colorado potato beetle, family Chrysomelidae) in juniper chaparral.
Dinner at Mercantile Cafe (“The Merc”) in Kenton—the only city in Oklahoma in the Mountain Time Zone.

After dinner, we returned to the campground and enjoyed what turned out to be only a brief respite from the rain—long enough to enjoy a beer—before getting chased into the tent as it picked back up again. It would rain most of the night and all the next day as we made the long drive back to St. Louis, but with 18 traps hung in six distinct habitats and some interesting beetles in the bottles it was hard to be disappointed. Stay tuned for updates as I begin checking the traps next month.

©️ Ted C. MacRae 2023

The ever-increasing diversity of Oklahoma beetles

/ Ted C. MacRae / 8 Comments

My idea to return to Oklahoma’s Gloss Mountains this spring actually began taking shape during last year’s fall visit to the area, when I found a single Chrysobothris octocola adult on a dead mesquite (Prosopis glandulosa) branch. While common across the southwestern U.S. in association with this plant, its occurrence in the Gloss Mountains represented a northeastern range extension and new state record for Oklahoma! On that same trip I also collected an interesting beetle in the family Rhipiphoridae representing the species Toposcopus wrightii—also not previously recorded in the literature from Oklahoma. Combined with finding Acmaeodera macra here the previous year, it was becoming clear to me that area held good potential for other more typically southwestern species of wood boring beetles. Although I had by then visited the area several times, most of these visits were more focused on tiger beetles rather than wood boring beetles. If I could find such interesting species of wood boring beetles when I wasn’t focused on them, imagine what I might find if I timed a visit in late spring when such species should be at their peak of adult activity.

Chrysobothris quadrilineata | Gloss Mountains State Park, Major Co., Oklahoma

Chrysobothris quadrilineata | Gloss Mountains State Park, Major Co., Oklahoma (new state record).

Of course, success came quickly during this early June visit. I immediately found C. octocola common on the mesquite and would collect a nice series of voucher specimens before the day was over, and the second species I encountered, also on mesquite, was the longhorned beetle Plionoma suturalis—another new state record! I spent a bit of time working the mesquite, and when I had collected a sufficient series of both species, I turned my attention to the eastern red-cedars (Juniperus virginiana) in the area. Actually, I had had my eye on the red-cedars since last fall, when I noticed that nearly every tree had dead branches mixed in amongst the living branches. Closer examination revealed the workings of jewel beetle larvae in all of these dead branches, and a few larvae typical of the genus Chrysobothris were cut from one of the branches. A common species in the Great Plains associated with Juniperus is C. ignicollis, but these larvae looked rather big to represent that species, so I bundled up some dead branches and brought them back home for rearing but forgot to check on them before I left on this trip. At any rate, I walked up to one of the red-cedars, placed my beating sheet under a dead branch, gave the branch a whack with the handle of my net, and onto the sheet fell a rather robust Chrysobothris that I didn’t immediately recognize. I knew it wasn’t C. ignicollis, a much smaller species that I have collected on numerous occasions, so I thought maybe it could be C. texana, another western Juniperus-associate that I’ve collected less commonly. Still, the robust body and broad, distinct elytral and pronotal ridges had me second guessing that identification (especially after I found some individuals that looked more like what I remembered C. texana looking like). Over the next two days I beat hundreds (literally!) of dead juniper branches, finding many C. ignicollis but every now and then getting also one of these big, robust individuals.

Chrysobothris quadrilineata

Adults were beaten from dead branches on live Juniperus virginiana (new adult host).

After returning home, I checked my heavily annotated copy of Fisher (1942) and quickly determined the robust specimens as representing C. quadrilineata—a rather uncommon species and one that I’d never collected before. Described by LeConte in 1860 from New Mexico and recorded early in the 20th century from Arizona, Nevada and California, it has in more recent years been found to occupy a rather wide distribution across the western U.S., including Texas (Barr & Westcott 1976), Colorado, Oregon, South Dakota (Nelson et al. 1982), and Utah (Nelson 1987). Notice one state that is not in that list—Oklahoma! That’s right, another new state record! I later found photographs of this species on BugGuide taken in the very same area a year earlier (7 June 2012).

Chrysobothris quadrilineata

Adults also emerged from dead J. virginiana branches collected Sept. 2012 (first reported larval host).

When I returned home, I also checked the rearing cans and found several adults had emerged from the branches I collected last September. The only host associations that have been recorded for this species are adults collected on Juniperus californica (Linsley & Ross 1940) and J. pachyphloea [= J. deppeana] (Barr & Westcott 1976). Thus, J. virginiana not only represents a new host record for the species but is also the first known larval host. Considering how broadly distributed across the western U.S. this species is, it seems likely that it utilizes a number of Juniperus spp. throughout its range.

REFERENCES:

Barr, W. F. & R. L. Westcott. 1976. Taxonomic, biological and distributional notes of North American Chrysobothris, with description of a new species from California (Coleoptera: Buprestidae).  The Pan-Pacific Entomologist 52(2):138–153.

Fisher, W. S. 1942. A revision of North American species of buprestid beetles belonging to the tribe Chrysobothrini. U. S. Department of Agriculture, Miscellaneous Publication 470, 1–275.

Linsley, E. G. & E. S. Ross. 1940. Records of some Coleoptera from the San Jacinto Mountains, California.  The Pan-Pacific Entomologist 16(2):75–76.

Nelson, G. H. 1987. Additional notes on the biology and distribution of Buprestidae (Coleoptera) in North America, II.   The Coleopterists Bulletin 41(1):57–65.

Nelson, G. H., D. S. Verity & R. L. Westcott. 1982. Additional notes on the biology and distribution of Buprestidae (Coleoptera) of North America.  The Coleopterists Bulletin 35(2) [1981]:129–152.

Copyright © Ted C. MacRae 2013

Plionoma suturalis in Oklahoma—a new state record!

/ Ted C. MacRae / 11 Comments

When I returned from my vacation/insect collecting trip to western Oklahoma two weeks ago, most people upon learning where I went responded with a funny look that said, “Why would you want to go to Oklahoma?” Even entomologists familiar with my inclination for beetles merely assumed I went there to collect tiger beetles and were surprised to learn that, for this trip, I was actually targeting jewel beetles (family Buprestidae) and longhorned beetles (family Cerambycidae). Jewel beetles and longhorned beetles, of course, are largely associated with dead wood, and western Oklahoma is smack dab in the middle of the Great Plains. However, this does not mean that there are no trees in the area, or that whatever trees do exist are merely western examples of pedestrian eastern species with a depauperate beetle fauna. In fact, I came to this area precisely because previous visits had seemed to indicate high potential for interesting species of woodboring beetles. On my September 2011 visit, passing through on my way back from Colorado, I found several individuals of the unusual fall-active Acmaeodera macra (representing a northern range extension), and during last year’s fall visit I found a single Chrysobothris octocola adult on a dead mesquite (Prosopis glandulosa) branch—a northeastern range extension and new state record for Oklahoma! Interesting records for other species of beetles over the past few years also supported the idea that western Oklahoma was understudied and held the promise of more interesting new records for anyone willing to spend time in the area.

Plionoma suturalis (male) | Gloss Mountains, Major Co., Oklahoma

Plionoma suturalis (male) on mesquite (Prosopis glandulosa) | Gloss Mountains, Major Co., Oklahoma

Nearly all of these interesting records have been found in the Gloss Mountains, a fascinating system of gypsum capped, red clay mesas in Major Co. I now regard the Gloss Mountains State Park as my “portal” to northwestern Oklahoma and can’t imagine traveling to or through the area without stopping and spending time knocking around this fascinating, brick-red landscape. Such was the case during this year’s trip, and while I had decided to spend at least the first field day in and around the State Park, the collecting was so good that I stayed for a second day and returned for a third later in the week. The beetle shown in these photos is part (and only part) of the reason why. Arriving in the morning of the first day in the field, I headed straight for the mesquite tree on which I had found the C. octocola adult last fall. It’s a common species in the southwestern U.S. that normally wouldn’t warrant any special attention, but since the Oklahoma record was based on a single specimen I wanted to see if I could find additional individuals to confirm that the species was actually established in the area and that last year’s record wasn’t just a one-off. I whacked a dead branch, and onto my beating sheet fell a C. octocola adult! I whacked another dead branch, and off fell another adult! As it was, I would find the species as abundantly here, in strict association with mesquite, as I have seen it at other locations further to the southwest. Soon after collecting the first few C. octocola adults, however, I whacked a live branch on the same mesquite tree, and off fell two large, colorful longhorned beetles that I recognized instantly as representing the species Plionoma suturalis.

Plionoma suturalis (female) | Gloss Mountains, Major Co., Oklahoma

Plionoma suturalis (female) on mesquite flowers | Gloss Mountains, Major Co., Oklahoma

Plionoma suturalis belongs to the great tribe Trachyderini. Beetles in this tribe are known for the bright colors, attraction to flowers, and diurnal (day-active) tendencies, and while we have a few species in the eastern U.S. they are far more diverse in the southwestern states. Plionoma suturalis and another U.S. species (P. rubens) are known to occur from Texas west to California and south into northern Mexico, but I immediately had the feeling that finding this species in Oklahoma was a significant record. The beetles were abundant on the mesquite trees that lined the parking lot and dotted to landscape below the main mesa, with many observed feeding on the flowers (the trees were in full bloom) and numerous mating pairs also observed. Considering its abundance at the site and possible significance of the record, I collected several dozen specimens to serve as vouchers (not to mention I had only collected a handful of specimens in all of my previous years of collecting). Checking my database later that evening (I never leave home without my computer!) confirmed my suspicions—Oklahoma was not only a new state record, but a significant northeastern range extension. In fact, the closest previous record was by Lingafelter & Horner (1993), who recorded eight specimens from Wichita Co., Texas—just over 200 miles to the south! Further, the Wichita Co. specimens were all collected in 1956, and subsequent collecting had yielded no additional specimens, leading the authors to consider the status of this species in north-central Texas as doubtful.

The female feeds on flowers of mesquite (Prosopis glandulosa)

Large number of individuals were seen feeding on mesquite flowers.

Plionoma suturalis is one of only a handful of North American longhorned beetle species in which the adults exhibit bimodal seasonal activity, with adults appearing during the spring months, disappearing during the summer, and reappearing in the fall (see  for a previous example from Missouri) (Linsley 1962). In the Lower Rio Grande Valley of south Texas (where the activity of many species of longhorned beetles and other insects is distinctly bimodal to coincide with moderate temperatures and increased precipitation during spring and fall), this species has been found on fresh-cut mesquite and huisache (Acacia farnesiana) in the fall months and on the blossoms of fabaceous trees during spring and early summer (Hovore et al. 1987).

REFERENCES:

Hovore, F. T., R. L. Penrose & R. W. Neck. 1987. The Cerambycidae or longhorned beetles of Southern Texas: a faunal survey. Proceedings of the California Academy of Science 44(13):283–334, 20 figs.

Lingafelter, S. W. & N. V. Horner. 1993. The Cerambycidae of north-central Texas. The Coleopterists Bulletin 47(2):159–191, 7 figs.

Linsley, E. G. 1962. The Cerambycidae of North America. Part III. Taxonomy and classification of the subfamily Cerambycinae, tribes Opsimini through Megaderini. University of California Publicatons in Entomology 20:1–188, 56 figs.

Copyright © Ted C. MacRae 2013

Why are this beetle’s elytra outstretched?

/ Ted C. MacRae / 4 Comments

Toposcopus wrightii on dead branch Juniperus virginiana | Major Co., Oklahoma

I’ve puzzled over the beetle in the above photo since I first saw it back in September on Day 2 of this year’s Annual Fall Tiger Beetle Trip. I encountered it on a dead branch of eastern red-cedar (Juniperus virginiana) on top of the main mesa at Gloss Mountain State Park in northwestern Oklahoma. At about 8 mm in length, it immediately struck me as possibly something in the family Ripiphoridae (wedge-shaped beetles). Still, the full-length elytra covering the abdomen made me doubt that identification, so I collected the specimen to get a better look at it when I returned home. Later that same day, while scanning the base of another mesa across the highway from the park at night, I came upon another individual that seemed to represent the same species—this time on a dead branch of fragrant sumac (Rhus aromatica). That individual is seen in the photo below, and two things are immediately apparent: 1) the beetle is a female in the act of oviposition, and 2) it is holding its elytra outstretched in a most curious way.

Another female oviposits on a dead branch of Rhus aromatica.

A quick browse through BugGuide’s ripiphorid images quickly showed a likely match with the genus Toposcopus, and consulting the original description of both the genus and its only included species—T. wrightii (LeConte 1868) showed agreement with the key diagnostic character (eyes divided into two lobes connected by a slender line of smooth, non-faceted corneous membrane). These two females differ from the male by their much less flabellate antennae (presumably the male uses these organs to detect female-emitted pheromones). LeConte described this species from New Mexico, and Rivnay (1929) also saw specimens from Texas and Arizona when he reviewed the North and Central American species of the family. Although the species is listed on Don Arnold’s Checklist of the Coleoptera of Oklahoma, the listing seems to be based only on the presence of specimens in the Oklahoma State University insect collection, while published records of its occurrence in the state are, as far as I can tell, still lacking. This species, thus, seems to be, along with Acmaeodera macra and Chrysobothris octocola (both family Buprestidae), an example of a typically southwestern U.S. species whose distribution extends northeast into the Red Hills Region of northwestern Oklahoma. Considering that Cylindera celeripes (Swift Tiger Beetle) and Amblycheila cylindriformis (Great Plains Giant Tiger Beetle) also have only recently been discovered in this area, it would seem that this part of the state is still undersampled and has the potential to yield additional interesting southwestern U.S. species.

Why is this female holding her elytra outstretched while ovipositing?

Regarding the outstretched elytra, I’ve not seen this type of behavior before with a beetle in the act of oviposition. While several groups of insects in other orders may hold their forewings outstretched as part of threat displays, I’ve not seen a beetle hold its elytra outstretched for any reason at all other than flight and don’t recall seeing such behavior mentioned in the literature either. Thus, I’m at a loss to explain why the beetle is doing this. If you have any ideas I would love to hear them.

One thing that I enjoy immensely about 19th Century taxonomic literature is the rich, often effusive prose that frequently accompanies the descriptive portions of the text. (I also lament that such colorful writings are nearly universally frowned upon my modern editors. Perhaps as taxonomy advances more fully into electronic-only publishing the concerns about space will dissipate and taxonomic authors will no longer be constrained to such sterile, uniform, precisely formatted writings.) The naming of this species provides an especially colorful example of the embellishments permitted to 19th Century authors:

I desire in the name of this beautiful and interesting addition to our fauna, to commemorate the ability of Gen. W. W. Wright, the Chief Engineer and Commander of the Survey in which the species in the present memoir were collected. His attention to the comfort and safety of the party while traveling through a hostile Indian country will not soon be forgotten by any of his companions; while the skill with which the more difficult portions of the route were examined, and the labors of his assistants directed to the most easy methods of surmounting the difficulties, will commend itself to every admirer of correct engineering.

John L. LeConte is widely regarded as the father of North American coleopterology. I don’t think there is anybody from the 19th Century, save perhaps Charles Darwin, that I would have more liked to meet.

REFERENCES: 

LeConte, J. L. 1868. New Coleoptera collected on the survey for the extension of the Union Pacific Railway, E. D. from Kansas to Fort Craig, New Mexico. Transactions of the American Entomological Society 2:49–59.

Rivnay, E. 1929. Revision of the Rhipiphoridae of North and Central America (Coleoptera). Memoirs of the American Entomological Society 6:1–67, 3 plates.

Copyright © Ted C. MacRae 2012

Just repanda… er, wait a minute…

/ Ted C. MacRae / 7 Comments

Update 10/7/12, 10:41 a.m.—Thanks to Ben Coulter, who pointed out my rather silly misidentification of these beetles that actually represent Cicindelidia ocellata rectilatera (Reticulated Tiger Beetle). I have only my failure to even consider the possibility of a southwestern species to blame for the error, as the evidence was staring me right in the face (the lack of any trace of lateral connecting band and, most obviously, the reddish parts on the underside). No wonder the habitat didn’t seem quite right! I was not aware of the occurrence of this species east of Texas, so I’ll have to dig a little bit to see if this is an unusual record. Pearson et al. (2006) show the northeastern limit of distribution coming very close to but not actually reaching the southwestern corner of Arkansas, and the closest records given by Graves & Pearson (1973) are in western Louisiana and adjoining Texas. It would be immensely rewarding should this turn out to be a new state record (though there are many sources still to check to confirm this)—not to mention the irony of it in view of the post title (call it a double “er, wait a minute”!). At any rate, I should have been a lot more excited when I saw it than I was.

After a fun-filled day of photographing the Limestone Tiger Beetle in northern Texas, it was time to start working my way back to Missouri. I had one last goal that I wanted to accomplish before spending my last day in our state’s White River Hills, and that was to find and photograph the unbelievably gorgeous Cicindela formosa pigmentosignata. Dubbed the “Reddish-green Sand Tiger Beetle” by Erwin & Pearson (2008), this brilliant violaceous and nearly immaculate subspecies of the Big Sand Tiger Beetle is restricted to sandy areas of open pine forests in eastern Texas, southwestern Arkansas, and northwestern Louisiana (Pearson et al. 2006). I had a few specific localities that I’d gleaned from colleagues and the literature and targeted the two “best” (specificity of location, recent occurrence, and reasonably “on the way” back to Missouri) for Day 7 of the trip. The first site in Texas looked perfect—deep, dry sandy 2-tracks leading through open pine/oak forest, and I was actually surprised when I’d searched a mile or so of track and hadn’t yet seen one (the habitat just looked that good). Still, I spent quite a bit more time searching, thinking that numbers could be low and it might take such an effort. Sadly this was all in vain, and the time came to give up and try again at the second locality in Arkansas. The story was largely the same at this second locality also, and by late afternoon I had come to accept that this was one challenge that I was going to lose (for now at least).

Cicindela duodecimguttata Cicindelidia ocellata rectilatera | Nevada Co., Arkansas

As I searched one bit of potential habitat at the Arkansas location, I noted the presence of Cicindela repanda (Bronzed Tiger Beetle). This species is dreadfully common throughout much of the eastern U.S. in just about any near-water habitat, which told me I was probably too close to water to find the higher, drier-ground preferring Big Sand Tigers. I’ve seen millions of C. repanda through the years (this may not be an exaggeration), and since they show so little polytopism (geographically-based variation), at least in the parts of its distribution that I have visited, I hardly pay them mind anymore. As I was walking, however, something caused me to take a closer look—some of them didn’t seem quite “right.” Of course, you can’t just walk up to a tiger beetle and stoop down for a good look at it. Stalking is required, usually of several individuals before finding one that you can approach closely enough to see the necessary characters, and when I did this I realized most of the C. “repanda” I was seeing were actually a different species—Cicindela duodecimguttata (12-spotted Tiger Beetle)!

Even tiger beetles get bored during sex—this female preening her antennae seems oblivious to the male engaging her.

I get the impression from literature sources that 12-spotted Tiger Beetles are quite common further east, especially in the northeastern U.S. and southeastern Canada. However, here in the central U.S. they are not commonly encountered. In fact, these are the first of the species that I have seen since I began photographing tiger beetles more than 3 years ago. In Missouri the few instances that I have seen them were along creeks and small rivers with banks composed of sand and a fair bit of dark clay. This makes sense, given their generally darker coloration compared to Bronzed Tiger Beetles, and it is this character that first stands out amongst the hoardes of C. repanda with which it usually co-occurs.  Once the darker coloration draws the eye, the markings of the elytra—reduced and broken into six spots (usually) on each one—confirm its identity. Despite the similarity of appearance to C. repanda, this species is actually more closely related to Cicindela oregona (Western Tiger Beetle), an exceedingly common species found from the Rocky Mountains to the Pacific Coast and north deep into Alaska. In fact, the two species are so closely that they have formed a hybrid zone where they come into contact along the front range of the Rockies—one could almost argue that they are only subspecifically distinct because of this. 

A male pauses briefly while hunting for prey (or mates).

That I found them in this particular habitat was a bit of a surprise to me. I mentioned that in Missouri I’ve seen them on darker creek and river banks, but the creek bank at this location was quite lightly colored and seemed to consist almost entirely of sand. There were a few C. repanda mixed in with this small population. In all, it was a welcome consolation prize that made up for not finding C. formosa pigmentosignata—sort of!

Habitat for Cicindela duodecimguttata Cicindelidia ocellata rectilatera along Mill Creek, Nevada Co., Arkansas.

REFERENCES:

Erwin, T. L. and D. L. Pearson. 2008. A Treatise on the Western Hemisphere Caraboidea (Coleoptera). Their classification, distributions, and ways of life. Volume II (Carabidae-Nebriiformes 2-Cicindelitae). Pensoft Series Faunistica 84. Pensoft Publishers, Sofia, 400 pp.

Pearson, D. L., C. B. Knisley and C. J. Kazilek. 2006. A Field Guide to the Tiger Beetles of the United States and Canada. Oxford University Press, New York, 227 pp.

Added: Graves, R. L. & D. L. Pearson. 1973. The tiger beetles of Arkansas, Louisiana, and Mississippi (Coleoptera: Cicindelidae). Transactions of the American Entomological Society 99(2):157–203.

Added: Pensoft

Copyright © Ted C. MacRae 2012

Josef Knull was wrong!

/ Ted C. MacRae / 11 Comments

A few weeks ago I received an email from Kyle Schnepp, an entomology student at Purdue University.  Kyle has taken on the rather ambitious project of developing an illustrated key to the Buprestidae of eastern North America, for which he has been spending the past year acquiring material for photographs.

During his examination of specimens in the Field Museum of Natural History, Kyle came across two examples of an extraordinarily rare species of Buprestidae, Agrilus audax Horn.  Although described more than 100 years ago from specimens collected in Texas (Horn 1891), few records have been published in the years since.  Chamberlin (1926) reported the species also from Arizona and Illinois but without further details, causing Fisher (1928), in his revision of the genus (woefully out-of-date now, but still the only comprehensive resource for identifying the North American species), to regard at least the Illinois record as probably erroneous (common for many of Chamberlin’s records).  The first undisputed report of this species from outside of Texas was by Josef Knull (1934), who reported the species emerging from living, wind-thrown branches of slippery elm (Ulmus rubra) collected in western Missouri.  More than half a century would pass before the species would turn up again – first in Oklahoma (Nelson and MacRae 1990) and twice again in Missouri through the efforts of Gayle Nelson and myself (MacRae 1991, MacRae and Nelson 2003). All but one of these specimens were beaten from bur oak (Quercus macrocarpa).

Agrilus audax Horn, 1891 – male (L) and female (R)

While the rarity of this species makes Kyle’s find significant enough, there is an even more significant – and interesting – aspect to his discovery.  Both of the specimens, one male and one female, were collected in Ohio, which is a rather extraordinary geographical range extension. Additionally, the specimens were collected by none other than Josef Knull.  To students of North American Buprestidae, the name Josef Knull is as familiar as Carl Linnaeus, Charles Darwin, or Thomas Say. A Professor of Entomology at The Ohio State University from 1934-1962, Knull published nearly 200 papers on the taxonomy, biology, and distribution of these and other families of beetles (Davidson and Bellamy 2002).  Although he lacked a Ph.D., he was an indefatigable collector and describer of beetles – to his fellow colleagues and students, he was known as “Professor” or “Doctor” as a show of respect.  He spent many of his summers traveling through the southwestern U.S. with his wife Dorothy Knull (herself an entomologist specializing in leafhoppers), and by the time he died in 1975 he had described 233 species and subspecies of beetles (as well as one species of Fulgoridae).  He was, and is, an icon among North American beetle collectors.

Curiously, Knull did not recognize these specimens for what they were, instead identifying them as the similar and much more widespread species, Agrilus vittaticollis.  Curious, because Knull collected these specimens in 1949 and 1953 – after first reporting the species in Missouri.  Agrilus audax belongs to a small group of species that look very similar to each other by way of their large size and striking coloration – black elytra and a red pronotum with a densely pubescent median channel.  Agrilus vittaticollis is the most common of these (though still not as commonly encountered as many other species in the genus), and the much less common A. benjamini also belongs to this group.  Kyle had sent me the above photo in an attempt to confirm their identity, but true confirmation would require examination of characters of the face and ventral surface.  Kyle quickly took additional photographs of these characters and sent them to me – they are shown below and leave no doubt as to the identity of these specimens.

Agrilus vittaticollis prosternum – note sides bent downward to sharp points.

Agrilus audax prosternum – sides normal, not bent downward to sharp points.


Agrilus audax frons is moderately depressed and uniformly pubescent (deeply depressed & pubescent only on lower half in A. benjamini).

Agrilus audax male sternite – the deep, smooth, elongate depression is diagnostic (A. benjamini males have only an obsolete depression).


Finding a new state record buprestid in Ohio – the land of Knull – based on specimens collected by Knull himself is nothing short of remarkable (almost like proving E. O. Wilson wrong¹). The occurrence of A. audax in Ohio also lends some credibility to Chamberlin’s record of the species in Illinois. Kyle is graciously allowing me to include these new records in a forthcoming publication; my thanks to him for this and also for allowing me to use his fine photographs in this post.  Kyle did also mention that these were the only misidentified specimens he saw in the Knull collection at the Field Museum of Natural History. For those interested in acquiring reprints of Knull’s papers, pdfs of the 50 papers he published in the Ohio Journal of Science may be found at this link.

¹ The title of this post is a play on the title of a recent post by Alex Wild at Myrmecos. No true disrespect is intended to Josef Knull, who’s legacy (with the possible exception of his frustratingly vague label data) is rightfully held in high regard by all who knew him or know of his work.

REFERENCES:

Chamberlin, W. J. 1926. The Buprestidae of North America, exclusive of Mexico, a catalogue including synonymy, bibliography, distribution, type locality and hosts of each species. W. J. Chamberlin, Corvallis.

Davidson, J. M., and C. L. Bellamy.  2002. The entomological contributions of Josef Nissley Knull (1891-1975).  Zootaxa 37:1-24.

Horn, G. H. 1891. The species of Agrilus of Boreal America. Transactions of the American Entomological Society 18:277-366.

Knull, J. N. 1934. Notes on Coleoptera, No. 4. Entomological News 45(10):207-212.

MacRae, T. C. 1991. The Buprestidae (Coleoptera) of Missouri. Insecta Mundi 5(2):101–126.

MacRae, T. C., and G. H. Nelson. 2003. Distributional and biological notes on Buprestidae (Coleoptera) in North and Central America and the West Indies, with validation of one species. The Coleopterists Bulletin 57(1):57–70.

Nelson, G. H., and T. C. MacRae. 1990. Additional notes on the biology and distribution of Buprestidae (Coleoptera) in North America, III. The Coleopterists Bulletin 44(3):349–354.

Copyright © Ted C. MacRae 2010

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North America’s largest robber fly

/ Ted C. MacRae / 20 Comments

Female Microstylum morosum perched on fragrant sumac (Rhus aromatica) bush

Female Microstylum morosum perched on fragrant sumac (Rhus aromatica)

A few days ago, I featured Promachus hinei, one of the so-called “giant robber flies” and a common inhabitant of the glades and grasslands that dot Missouri’s largely forested landscape. That individual was seen at Long Bald Glade Natural Area in Caney Mountain Conservation Area, one of the many limestone glades that are a prominent feature of extreme southwestern Missouri’s White River Hills, as it snacked on a small carpenter bee (Ceratina sp.) and posed obligingly for a series of super close-up photographs. Promachus and its congeners are impressively large; however, I would see an even larger robber fly that day. I didn’t know what it was at the time, but I knew that never before had I seen such a magnificent fly, with its large, shimmering, emerald eyes, streamlined body almost devoid of setae (hairs), and ludicrously large size. These monsters were actually quite common at the glade, so I failed to appreciate the significance of what I was seeing as I chased one after another – more intent on securing photographs than specimens. This was not an easy task – they were extremely wary, rarely allowing me to approach within 12 feet no matter how cautiously and slowly I moved. Not one to back down from such a challenge (remember, I stalk tiger beetles), I persisted, traversing the rough, rock-strewn terrain amidst clumps of big bluestem (Andropogon gerardii), Indian grass (Sorghastrum nutans), and fragrant sumac (Rhus aromatica) until, at last, I got within striking distance of the impressive female shown in these photos. Taking flight before I felt assured of a good shot, I followed her repeated long, loping escape flights until I was able to get another few shots and she disappeared for good.

Same individual as in previous photo after flying to another perch.

Same individual as in previous photo after flying to another perch.

It didn’t take long after I returned home to figure out what I had seen, as there is really nothing that can be mistaken for Microstylum morosum, North America’s largest robber fly (Back 1909)¹. At 35–40 mm of length, this individual didn’t quite match the astounding 50-mm upper body length for the species (that’s 2 inches, folks!). Nonetheless, it was an impressive beast indeed! It is not surprising that North America’s largest robber fly should be a species of Microstylum, as it is this same genus that contains the world’s largest robber fly – the aptly named M. magnum from Madagascar, with a body length of 60 mm and an almost preposterous wingspan of up to 84 mm (that’s over 3 inches folks!). I don’t know if any flies exist that are larger than this, but certainly none can be more imposing.  While I’m happy with the photos that I did obtain, I must confess some disappointment that I wasn’t able to get more than these basic lateral profile shots.  Of the several photographs of this species that can be found on the web, this female, photographed by Greg Lavaty of Houston, Texas, is (in my humble opinion) certainly the most stunning.

¹ Puzzled by the use of the prefix “micro” in the genus name – hardly seeming appropriate for such an enormous fly – I asked Eric Fisher (retired, California Department of Food and Agriculture) about the name’s derivation, to which he replied, “The name refers to the quite small ‘stylus’ of the antenna apex; Macquart specifically mentions this character in his 1838 original description of the genus. (This is not a very helpful diagnostic character, as many asilids share this feature…).”

Even more significant than its size, however, was its very occurrence on this glade. Like Ospriocerus abdominalis, which I had seen just a few weeks earlier in the Loess Hills of extreme northwestern Missouri, M. morosum is a denizen of the Great Plains, and also like that species it has until now not been known from Missouri. That’s right – another new state record!  Unlike O. abdominalis, however, the Missouri occurrence of M. morosus represents a significant northeastern extension of its known range.  The species was long considered a Texas endemic until Beckemeyer and Charlton (2000) confirmed its occurrence in southeastern Arizona and documented significant range extensions into Oklahoma, Kansas, extreme southeastern Colorado, and extreme northeastern New Mexico.  Its eastern distributional limit was thought to occur along a north-south line from Douglas County, Kansas to Mayes County, Oklahoma to Brazoria County, Texas; however, Warriner (2004) documented its occurrence some 200 miles east of this line in the blackland prairies of southwestern Arkansas.  The occurrence of M. morosum in the White River Hills of Missouri represents yet another significant eastern extension of its known range – Long Bald Glade lies 185 miles NNE of the collection site in Arkansas and 155 miles ENE of the nearest known record in Mayes County, Oklahoma (Locust Grove), making it the easternmost known locality for this species.

As in Arkansas, where the collection site represents one of the highest quality blackland prairie remants in the state, Long Bald Glade represents a high quality remnant of the limestone glades that once occurrred much more extensively within Missouri’s White River Hills.  Like the blackland prairie of Arkansas, the limestone glades of the White River Hills have been dramatically reduced since EuroAmerican settlement due to land use conversion, and fire suppression and overgrazing of the remaining tracts have resulted in significant woody encroachment – chiefly by eastern red-cedar (Juniperus virginiana) – and loss of vegetational diversity. This has caused dramatic reductions in populations of the many Great Plains plant and animal species that are found here and nowhere else in the state.  Considering the overall distribution of M. morosum, it is unlikely that it occurs more extensively within Missouri than the White River Hills, emphasizing the importance of continued conservation and restoration activities in this unique part of Missouri.  However, since the White River Hills extend into northwestern Arkansas, M. morosum may occur in that part of Arkansas as well as the southwestern part of the state.

I thank Eric Fisher and Herschel Raney for confirming the identity of this species and its status as a new record for Missouri.

Photo details: Canon 100mm macro lens on Canon EOS 50D (manual mode), ISO-100, 1/250 sec, f/10-11, MT-24EX flash 1/2 power through diffuser caps.

REFERENCES:

Back, E. A. 1909. The robberflies of America, north of Mexico, belonging to the subfamilies Leptograstrinae and Dasypogoninae. Transactions of the American Entomological Society 35:137–400.

Beckemeyer, R. J. and R. E. Carlton.  2000.  Distribution of Microstylum morosum and M. galactoides (Diptera: Asilidae): significant extensions to previously reported ranges.  Entomological News 111(2):84–96.

Warriner, M. D.  2004.  First Arkansas record of the robber fly Microstylum morosum (Diptera: Asilidae).  The Southwestern Naturalist 49(1):83–84.

Copyright © Ted C. MacRae 2009

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Ospriocerus abdominalis

/ Ted C. MacRae / 18 Comments

Photo details: Canon 100mm macro lens on Canon EOS 50D, ISO 100, 1/250 sec, f/14, MT-24EX flash 1/4 power w/ diffuser caps.

Photo details: Canon 100mm macro lens on Canon EOS 50D, ISO 100, 1/250 sec, f/14, MT-24EX flash 1/4 power w/ diffuser caps.

My dipteran digression continues with this photograph of the robber fly, Ospriocerus abdominalis (Diptera: Asilidae).  More than just a pretty picture, this represents yet another apparently new state record that I and my colleague Chris Brown discovered a few weeks ago during our 2-day survey of Missouri’s critically imperiled hilltop prairies in the extreme northwest corner of the state.  Like the previously discussed Cylindera celeripes (swift tiger beetle) and Beameria venosa (a prairie-obligate species of cicada), O. abdominalis has not previously been recorded further east than Nebraska, Kansas, Oklahoma and Texas. This large fly is a grassland denizen that ranges over western North America and into Mexico (Cannings 1998, as Ospriocerus aeacus). It is somewhat suggestive of a mydas fly, although its short antennae immediately identify it as a robber fly (mydas flies have elongate clubbed antennae).  It also reminds me of the magnificent western robber fly Wyliea mydas by its mimetic, wasp-like coloration – presumably modeled after spider wasps of the genus Pepsis and Hemipepsis (Hymenoptera: Pompilidae) – but is distinguished by its black body and wings with red dorsal coloration on the abdomen (W. mydas has the abdomen wholly black and the wings red).  While not quite as handsome as W. mydas, it is impressive nonetheless.

The dry hilltop prairie remnants in which O. abdominalis, B. venosa, and C. celeripes were found are associated with the Loess Hills, a unique landform along the western edge of Iowa that reaches its southern terminus in extreme northwest Missouri.  Due to their extreme rarity and vulnerability to woody encroachment and anthropogenic degradation, these remnant habitats are considered one of Missouri’s most critically imperiled natural communities. Only about 50 acres of original habitat remain, and of this only half is in public conservation ownership.  Many of the plants and animals found in these habitats represent hypsithermal relicts that migrated eastward during a dry and warm period after the last ice age and were then “left behind” in pockets of relictual habitat as a return to cooler, wetter conditions forced the main populations back to the west.  More than a dozen plants and two vertebrates occurring in these prairies are listed as species of conservation concern.  As is typically the case, the flora and vertebrate fauna of these remnant habitats have been fairly well characterized, while precious little attention has been given to the vastly more diverse invertebrate fauna.  As we begin to study the insects of these habitats more carefully, we are almost sure to find a great many species that are more typically found further to the west and that live nowhere else in Missouri.  Their continued presence in the state will be wholly dependent upon the critically imperiled habitats in which they live, making conservation and restoration of the remaining loess hilltop prairie remnants in Missouri all the more important.

My thanks to Eric Fisher and Herschel Raney for confirming the identity of O. abdominalis.

REFERENCES:

Cannings, R. A. 1998. Robber Flies (Insecta: Diptera: Asilidae), in Smith, I. M., and G. G. E. Scudder, eds. Assessment of species diversity in the Montane Cordillera Ecozone. Burlington: Ecological Monitoring and Assessment Network.

Copyright © Ted C. MacRae 2009

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