2014 Great Plains Collecting Trip iReport

During the past year or so I’ve followed up my longer (one week or more) insect collecting trips with a synoptic “iReport”—so named because they are illustrated exclusively with iPhone photographs. It may come as a surprise to some, but iPhones actually take pretty good pictures (especially if you pay attention to their strengths and weaknesses), and their small, compact size makes it easy to take lots of photos while trying to use time in the field wisely. I find the iPhone to be a great tool for documenting the general flavor of a trip and for taking quick photos of subjects before getting out the big rig. I will, of course, feature photographs taken with the ‘real’ camera in future posts.

For this trip, I teamed up with Jeff Huether for the third time since 2012. Our quarry for this trip was longhorned beetles (family Cerambycidae) in the genus Prionus. Larvae of these beetles are subterranean, with some species feeding on roots of woody plants and others on roots of grasses and other herbaceous plants. Among the latter are an array of species occurring in the Great Plains, many of which have been very uncommonly collected. However, in recent years lures have been produced that are impregnated with prionic acid—the principal component of sex pheromones emitted by females in the genus. Originally produced for use in commercial orchards (which are sometimes attacked by P. laticollis in the east and P. californicus in the west), these lures are proving themselves to be useful for us taxonomist-types who wish to augment the limited amount of available material of other, non-economic species in the genus. While Prionus was our main goal, rest assured that I did not pass on the opportunity to find and photograph other beetles of interest.

I began the trip by driving from St. Louis to Wichita, Kansas to meet up with Jeff, who had flown there from his home in upstate New York. Our plan was to visit sites in southeastern Colorado and northeastern New Mexico, where several of the Prionus spp. that we were looking for were known to occur. Before doing this, however, we stopped in Hardtner, Kansas to see “Beetle Bill” Smith and tour his amazing natural history tribute, Bill and Janet’s Nature Museum.

"Beetle" Bill Smith, founder of Bill & Janet's Nature Museum, Hardtner, Kansas.

“Beetle Bill” Smith, founder of Bill & Janet’s Nature Museum, Hardtner, Kansas.

After the tour (and a delicious lunch at his house of fried crappie prepared by his wife Janet), we headed west of town and then south just across the state line into Oklahoma to a spot where Bill had found a blister beetle (family Meloidae) that Jeff was interested in finding. During lunch I mentioned a jewel beetle (family Buprestidae) that I had looked for in the area several times, but which had so far eluded me—Buprestis confluenta. Emerald green with a dense splattering of bright yellow flecks on the elytra, it is one of North America’s most striking jewel beetles and is known to breed in the trunks of dead cottonwoods (Populus deltoides). Bill mentioned that he had collected this species at the very spot where we were going, and when we arrived I was enticed by the sight of a cottonwood grove containing several large, dead standing trunks—perfect for B. confluenta.

Buprestis spp. love large, dead, barkless cottonwood trunks.

Buprestis spp. love large, dead, barkless cottonwood trunks.

I searched for more than one hour without seeing the species, though I did find a few individuals of the related (and equally striking) B. rufipes on the trunks of the large, dead trees. Once that amount of time passes I’m no longer really expecting to see what I’m looking for, but suddenly there it was in all of its unmistakable glory! It would be the only individual seen despite another hour of searching, but it still felt good for the first beetle of the trip to be one I’d been looking for more than 30 years!

Buprestis (Knulliobuprestis) confluenta, on large, dead Populus deltoides trunk | Woods Col., Oklahoma| USA: Oklahoma

Buprestis confluenta, on the trunk of a large, dead cottonwood (Populus deltoides) | Woods Col., Oklahoma| USA: Oklahoma

I usually wait until near the end of a collecting trip to take the requisite selfie, but on this trip I was sporting new headgear and anxious to document its maiden voyage. My previous headgear of choice, a vintage Mambosok (impossible to get now), finally disintegrated after 20 years of field use, and on the way out-of-town I picked up a genuine Buff® do-rag. I know many collectors prefer a brim, but I don’t like they way brims limit my field of vision or get in the way when I’m using a camera. Besides, I’m usually looking down on the ground or on vegetation, so sun on my face is not a big issue. And do I be stylin’ or wut?

A "selfie" makes the trip official.

A “selfie” makes the trip official.

We made it to our first locality in southeast Colorado by noon the next day—the vast, dry grasslands north of Las Animas. Jeff had collected a blister beetle of interest here on an earlier trip, but as I looked out across the desolate landscape I wondered what on Earth I could find here that would be even remotely interesting to me.

Shortgrass prairie habitat for Prionus integer.

Shortgrass prairie habitat for Prionus integer.

Letting Jeff have some time to look for his blister beetle, I started down the roadside and after a short time found a live female Prionus sp. (later determined to represent P. integer). The only female Prionus I had ever collected before was P. heroicus, a giant species out in Arizona, and that was almost 30 years ago, so I wasn’t immediately sure what it was. Eventually I decided it must be Prionus, and a quick stop to kick the dirt while Jeff looked for his beetle turned into an intense search for more Prionus that surely were there. I did find two male carcasses shortly thereafter, and then nothing more was seen for the next hour or so.

Prionus integer male | Bent Co., Colorado

Prionus integer male (found dead) | Bent Co., Colorado

During the time that I was searching, however, I started noticing strange burrows in the ground. I excavated a few—they were shallow but contained nothing. Nevertheless, they matched the size of the beetles perfectly—surely there was a connection?

Prionus integer adult burrow.

Prionus integer adult burrow.

I wondered if Jeff knew about the beetles occurring here, but when I showed him what I had found the surprised look on his face told me this was not the case. I showed him the burrows, and we both agreed they had to be connected. I got the shovel out of the truck and walked back to the area where I had seen the live female, then sunk the shovel deep into the ground next to one of the burrows and pried up a chuck of the soil containing the burrow in its entirety. As we broke apart the soil another female was revealed, and we immediately decided to set out some traps baited with prionic acid lures. We expected the beetles to become active during dusk, so we went into town to get something to eat and then check out another nearby locality before returning to the site at dusk. While we were gone it rained heavily at the site, so we weren’t sure if or how this would affect beetle activity and their possible attraction to the traps. However, as we approached the site (slipping and sliding on the muddy 2-track), we could actually see beetles crawling on the road from afar. What we found when we got out of the car was nothing short of mind-blowing—the beetles were everywhere, crawling on the road, crawling through the grass, and overflowing in the flooded traps! The vast majority were males, as expected, but we also found a fair number of the much more rarely collected females. This was significant, as the chance to observe mating and oviposition behavior made the encounter far more informative than if we had only found and collected the much more numerous males.

Prionus integer mating pair.

Prionus integer mating pair.

The following day we headed south into northeastern New Mexico to look at some shortgrass prairie sites near Gladstone (Union Co.) where two species of Prionus had been collected in recent years: P. fissicornis (the lone member of the subgenus Antennalia) and P. emarginatus (one of eight species in the poorly known subgenus Homaesthesis, found primarily in the Great Plains and Rocky Mountains). Fresh off of our experience the previous day, we were on the lookout for any suspicious looking “burrows” as we checked the roadsides at several spots in the area but found nothing, and while a few blister beetles piqued the interest of Jeff at one site, the complete absence of woody vegetation or flowering plants in general in the stark grassland landscape made the chances of me finding any other woodboring beetles remote. Eventually I became distracted by the lizards that darted through the vegetation around us, including this lesser earless lizard (Holbrookia maculata) and a collared lizard (better photos of both forthcoming).

Holbrookia maculata (lesser earless lizard) | Union Co., New Mexico.

Holbrookia maculata (lesser earless lizard) | Union Co., New Mexico.

Despite no clues to suggest that Prionus beetles were active in the area, we set out some traps at two sites with soil exposures that seemed similar to those seen the day before. As Jeff set the last pair of traps in place, my distraction with saurian subjects continued with a dusty hognose snake (Heterodon nasicus gloydi). While photographing the animal I looked down to my side, and what did I see but a male Prionus fissicornis crawling through the vegetation! I called out to Jeff, and for the next half an hour or so we scoured the surrounding area in a failed attempt to find more. We would not be back until the next morning to check the traps, so our curiosity about how abundant the beetles might be would have to wait another 18 hours. We cast an eye towards the north and watched late afternoon thunderstorms roll across the expansive landscape and decided to check out the habitat in nearby Mills Rim.

Thunderstorms over shortgrass prairie.

Thunderstorms over shortgrass prairie.

The rocky terrain with oak/pine/juniper woodlands at Mills Rim was a dramatic contrast to the gently rolling grasslands of the surrounding areas. We came here mostly out of curiosity, without any specific goal, but almost immediately after getting out of the car a huge Prionus male flew up to us—almost surely attracted by the scent of the lures we were carrying. Within a few minutes another male flew in, and then another. Because of their huge size and occurrence within oak woodland habitat, we concluded they must represent P. heroicus, more commonly encountered in the “Sky Islands” of southeastern Arizona. We stuck around to collect a few more, but as dusk approached we returned to the surrounding grasslands to set out some lures to see if we could attract other Prionus species. The frontal system that had waved across the landscape during the afternoon had left in its wake textured layers of clouds, producing spectacular colors as the sun sank inexorably below the horizon.

Sunset over shortgrass prairie.

Sunset over shortgrass prairie.

This attempt to collect grassland Prionus beetles would not be successful, and as dusk progressed we became distracted collecting cactus beetles (Moneilema sp., family Cerambycidae) from prickly pear cactus plants (Opuntia sp.) before darkness ended our day’s efforts. This did not mean, however, that all of our efforts were done—there are still night active insects, and in the Great Plains what better nocturnal insect to look for than North America’s largest tiger beetle, the Great Plains giant tiger beetle (Amblycheila cylindriformis, family Cicindelidae—or subfamily Cicindelinae—or supertribe Cicindelitae, depending on who you talk to)?! We kept our eyes on the headlamp illuminated 2-track as we drove back to the highway and then turned down another road that led into promising looking habitat. Within a half-mile of the highway we saw one, so I got out to pick it up and then started walking. I walked another half-mile or so on the road but didn’t see anything except a few Eleodes darkling beetles (family Tenebrionidae), then turned around and walked the habitat alongside the road on the way back. As I walked, tiny little rodents—looking like a cross between a mouse and a vole—flashed in and out of my headlight beam as they hopped and scurried through the vegetation in front of me. Most fled frantically in response to my attempted approach, but one, for some reason, froze long enough under my lamp to allow me this one photo. When I posted the photo on my Facebook page, opinions on its identity ranged from kangaroo rat (Dipodomys sp.) silky pocket mouse (Perognathus flavus) to jumping mouse (Zapus sp.). Beats me.

silky pocket mouse? Zapus sp., jumping mouse? | Union Co., New Mexico.

Kangaroo rat? Silky pocket mouse? Jumping mouse? | Union Co., New Mexico.

Almost as if by command, it rained during the early evening hours where we had set the traps, and the following morning we were rewarded with traps brimming with Prionus fissicornis males. Not only were the traps full, but males were still running around in the vicinity, and we even found a few females, one of which was in the act of ovipositing into the soil at the base of a plant.

Prionic acid-bated traps w/ Prionus fissicornis males.

Prionic acid-bated traps w/ Prionus fissicornis males.

Prionic acid-bated traps w/ Prionus fissicornis males.

Prionic acid-bated traps w/ Prionus fissicornis males.

Prionus fissicornis male | Harding Co., New Mexico.

Prionus fissicornis male | Harding Co., New Mexico.

Prionus fissicornis oviposition hole.

Prionus fissicornis oviposition hole.

Eventually P. fissicornis activity subsided, and we decided to go back to the area around Mills Rim to see what beetles we might find in the woodland habitats. We also still were not sure about the Prionus beetles we had collected there the previous day and whether they truly represented P. heroicus. The scrubby oaks and conifers screamed “Beat me!”, and doing so proved extraordinarily productive, with at least a half-dozen species of jewel beetles collected—including a nice series of a rather large Chrysobothris sp. from the oaks that I do not recognize and a single specimen of the uncommonly collected Phaenops piniedulis off of the pines.

Oak/juniper woodland at Mills Canyon, habitat for Prionus heroicus.

Oak/juniper woodland at Mills Canyon, habitat for Prionus heroicus.

Not only is the scenery at Mills Rim Campground beyond spectacular, it also boasts some of the most adoringly cute reptiles known to man—such as this delightfully spiky horned lizard (I prefer the more colloquial name “horny toad”!). I’m probably going to regret not having photographed this fine specimen with the big camera.

Phrynosoma cornutum (Texas horned lizard) | Harding Co., New Mexico.

Phrynosoma cornutum (Texas horned lizard) | Harding Co., New Mexico.

Fresh diggings beside a rock always invite a peek inside. You never know who might be peeking out.

Who's home?

Who’s home?

Peek-a-boo!

Peek-a-boo!

The trip having reached the halfway point, we debated whether to continue further south to the sand dunes of southern New Mexico (with its consequential solid two-day drive back to Wichita) or turn back north and have the ability to collect our way back. We chose the latter, primarily because we had not yet had a chance to explore the area around Vogel Canyon south of Las Animas, Colorado. We had actually planned to visit this area on the day we encountered P. integer in the shortgrass prairie north of town, and a quick visit before going back to check the traps that evening showed that the area had apparently experienced good rains as shown by the cholla cactus (Cylindropuntia imbricata) in full bloom.

Cylindropuntia imbricata | Otero Co., Colorado.

Cylindropuntia imbricata | Otero Co., Colorado.

Whenever I see cholla plants I can’t help myself—I have to look for cactus beetles (Moneilema spp.). It had rained even more since our previous visit a few days ago, and accordingly insects were much more abundant. Several Moneilema adults were seen on the cholla, one of which I spent a good bit of time photographing. The iPhone photo below is just a preview of the photos I got with the big camera (which also included some very impressive-sized cicadas—both singing males and ovipositing females). The cactus spines impaled in the camera’s flash control unit serve as a fitting testament to the hazards of photographing cactus insects!

Moneilema sp. on Cylindropuntia imbracata } Otero Co., Colorado.

Moneilema sp. on Cylindropuntia imbracata } Otero Co., Colorado.

The hazards of photographing cactus beetles.

The hazards of photographing cactus beetles.

Later in the afternoon we hiked down into the canyon itself, and while insects were active we didn’t find much out of the ordinary. We did observe some petroglyphs on the sandstone walls of the canyon dating from the 1200s to the 1700s—all, sadly, defaced by vandals. Despite the rather uninspiring collecting, we stayed in the area for two reasons: 1) Jeff wanted to setup blacklights at the canyon head in hopes of collecting a blister beetle that had been caught there on an earlier trip, and 2) I had noted numerous Amblycheila larval burrows in the area (and even fished out a very large larva from one of them) and wanted to search the area at night to see if I could find adults. Jeff was not successful in his goal, and for a time I thought I would also not succeed in mine until we closed up shop and started driving the road out of the canyon. By then it was after 11 p.m. and we managed to find about a half-dozen A. cylindriformis adults. This was now the third time that I’ve found adults of this species, and interestingly all three times I’ve not seen any beetles despite intense searching until after 11 p.m and up until around midnight.

Lithographs on canyon wall | Mills Canyon, Colorado.

Lithographs on canyon wall | Mills Canyon, Colorado.

The next morning we found ourselves with two days left in the trip but several hundred miles west of Wichita, where I needed to drop Jeff off for his flight back home before I continued on home to St. Louis. I had hoped we could make it to the Glass Mountains just east of the Oklahoma panhandle to see what Prionus species might be living in the shortgrass prairies there (and also to show Jeff this remarkable place where I’ve found several new state records over the past few years). As we headed in that direction, I realized our path would take us near Black Mesa at the western tip of the Oklahoma pandhandle, and having been skunked on my first visit to the area last year due to dry conditions but nevertheless intrigued by its very un-Oklahoma terrain and habitat I suggested we stop by the area and have a look around before continuing on to the Glass Mountains. We arrived in the area mid-afternoon and headed straight for a rock outcropping colonized by scrub oak (Quercus sp.) and pinyon pine (Pinus sp.)—very unusual for western Oklahoma—that I had found during my previous trip.

The author looks pensively out over the Black Mesa landscape.

The area around Black Mesa couldn’t be more unlike the perception that most people have of Oklahoma.

I wanted to beat the oaks for buprestids—surely there would be a state record or two just sitting there waiting for me to find them, but as I started walking from the car towards the oaks the approach of a loud buzz caught my attention. I turned around to see—would you believe—a large Prionus beetle circling the air around me and was fortunate to net it despite its fast and agile flight. I hurried back to the car to show Jeff what I had found; we looked at each other and said, “Let’s collect here for a while.” The beetle had apparently been attracted to the lures in the car, so we got them out, set them up with some traps, and went about beating the oaks and watching for beetles to fly to the lure. Sadly, no  jewel beetles were collected on the oaks, although I did find evidence of their larval workings in some dead branches (which were promptly collected for rearing). Every once in a while, however, a Prionus beetle would fly in, apparently attracted to the lure but, curiously, never flying directly to it and falling into the trap. Many times they would land nearby and crawl through the vegetation as if searching but never actually find the trap. However, just as often they would approach the trap in flight and not land, but rather continue circling around in the air for a short time and before suddenly turning and flying away (forcing me to watch forlornly as they disappeared in the distance). Based on their very large size, blackish coloration and broad pronotum, we surmised (and later confirmed) these must also be P. heroicus, despite thinking (and later confirming) that the species was not known as far east as Oklahoma. Not only had we found a new state record, but we had also recorded a significant eastern range extension for the species. And to think that we only came to Black Mesa because I wanted to beat the oaks!

Prionus heroicus male

Prionus heroicus male

Bite from Prionus heroicus male.

Proof that Prionus heroicus males can bite hard enough to draw blood!

We each collected a nice series of the beetles, and despite never witnessing the beetles actually going to the traps a few more were found in the traps the next morning after spending the night in a local bed & breakfast. I also found a dove’s nest with two eggs hidden in the vegetation, and as we were arranging for our room at the bed & breakfast a fellow drove up and dropped off a freshly quarried dinosaur footprint (the sandstone, mudstone, and shale deposits around Black Mesa are the same dinosaur fossil bearing deposits made more famous at places like Utah’s Dinosaur National Monument).

Dove's nest w/ eggs.

Dove’s nest w/ eggs.

Dinosaur fossil footprint

Freshly quarried dinosaur fossil footprint

By the way, if you ever visit the area, the Hitching Post at Black Mesa is a great place to stay. A longhorn skull on the barn above an authentic 1882 stagecoach give a hint at the ambiance, and breakfast was almost as good as what my wife Lynne can do (almost! 🙂 ).

Longhorn skull on barn at our Bead and Breakfast.

Longhorn skull on barn at our Bead and Breakfast.

132-year-old stagecoach - model!

132-year-old stagecoach – model!

After breakfast we contemplated the long drive that lay between us and our arrival in Wichita that evening—our longer than expected stay in the area had virtually eliminated the possibility to collect in the Glass Mountains. Nevertheless, there was one more thing that I wanted to see before we left—the dinosaur footprints laying in a trackway along Carrizo Creek north of the mesa. I only knew they were in the area based on a note on a map, but as there were no signs our attempt to find them the previous day was not successful. Armed with detailed directions from the B&B owners, however, we decided to give it one more shot. Again, even after we found the site I didn’t see them immediately, I suppose because I was expecting to see distinct depressions in dry, solid rock. Only after the reflections of light from an alternating series of small puddles—each measuring a good 10–12″ in diameter—did I realize we had found them. Recent rains had left the normally dry creek bed filled with mud, with the footprints themselves still filled with water.

Dinosaur tracks | vic. Black Mesa, Oklahoma.

Dinosaur tracks | vic. Black Mesa, Oklahoma.

It is not surprising that I would be so excited to find the tracks, but what did surprise me was the effect they had on me. Seeing the actual signs of near mythical beasts that lived an incomprehensible 100 million years ago invites contemplation and reminds us that our time here on Earth has, indeed, been short!

Dinosaur tracks | vic. Black Mesa, Oklahoma.

Dinosaur tracks | vic. Black Mesa, Oklahoma.

By this time, we had no choice but to succumb to the long drive ahead. We did manage to carve out a short stop at the very first locality of the trip in an effort to find more Buprestis confluens (finding only a few more B. rufipes), but otherwise the day was spent adhering to our goal of reaching Wichita before nightfall. Jeff was home and sipping tea before lunchtime the next day, while I endured one more solid day of driving before making it back to St. Louis in time for dinner with the family. At that point, the trip already could have been considered a success, but how successful it ultimately ends up being depends on what beetles emerge during the next season or two from these batches of infested wood that I collected at the various spots we visited.

Wood collected for rearing wood-boring beetles.

Wood collected for rearing wood-boring beetles.

If you like this Collecting Trip iReport, you might also like the iReports that I posted for my 2013 Oklahoma and 2013 Great Basin collecting trips as well.

© Ted C. MacRae 2014

Sunset beetles

Acmaeodera immaculata? | vic. Vogel Canyon, Colorado.

Acmaeodera immaculata? (family Buprestidae) | vic. Vogel Canyon, Colorado.

Regular readers of this blog know that I am fond of natural sky backgrounds for insects found during the day on flowers and foliage. Not only does the sky provide a clean, uncluttered background that allows the subject to stand out, it also gives the photo a more appropriate temporal flavor—i.e., photographs of diurnal insects should look like they were taken during the day. It’s a little bit tricky setting the camera to allow flash illumination of the subject while still allowing the sky to register as well, but I find such photographs more pleasing and interesting than those with a jet-black background, typical in flash macrophotography, and far more pleasing than those with a jumble of sticks and weeds cluttered behind the subject. These days my daytime insect photos almost always incorporate a blue-sky background (examples here and here) unless: 1) I actually photographed the subject at night (examples here and here); or 2) I wish to highlight an intensely white or delicately structured subject (examples here and here).

Aulicus sp. | vic. Black Mesa, Oklahoma

Trichodes oresterus? (family Cleridae) | vic. Black Mesa, Oklahoma

But what about in between day and night—specifically, sunset? Incorporating a sunset sky into a flash-illuminated macrophotograph is even trickier than incorporating a blue midday sky because the central problem—low light levels—is magnified. Blue sky photographs challenge the fast shutter speeds and high f-stops usually needed for macrophotographs, but relatively minor adjustments to ISO, shutter speed, and f-stop are usually sufficient to allow the sky to register while still being able to maintain depth of field and minimize motion blur. At sunset, however, because there is much less illumination of the sky, more aggressive settings are often required to allow the sky to register on the camera sensor—settings that can sometimes result in too much motion blur or insufficient depth of field. These problems can be mitigated to some degree with the use of a tripod (and very cooperative subjects), but for dedicated “hand-held” enthusiasts like myself this is not an option. Why bother? Because the results can be spectacular! The setting sun often creates stunning colors not seen at other times of the day and offer a change of pace from blue skies, which, like black backgrounds, can start looking rather monotonous if used exclusively in one’s portfolio.

Linsleya convexa | vic. Vogel Canyon, Colorado

Linsleya convexa (family Meloidae) | vic. Vogel Canyon, Colorado

The photos featured in this post were taken during several sunsets on a trip earlier this past summer through Colorado and Oklahoma. I especially like the jewel beetle (Acmaeodera immaculata?) photograph—technically it has good focus and depth of field and a pleasing composition, but I really like the color coordination between the beetle, flower, and sky. The checkered beetle (Trichodes oresterus?) photograph is also very pleasing, especially the detail on the beetle, although the color of the sky is only somewhat different than a more typical daytime blue. The blister beetle (Linsleya convexa) photograph is probably the most problematic technically due to slight motion blur and being slightly off-focus at the eye—not surprising since of the three this photo had the lowest light conditions. However, the color contrast between the sky and subject make this a nevertheless striking image.

If you have experience with ambient light backgrounds in flash macrophotography, your comments on approaches you’ve taken to deal with reduced light situations will be most welcome.

© Ted C. MacRae 2014

Seminar on Oklahoma’s Glass Mountains

Earlier this week I gave a seminar to the Entomology Group of the Webster Groves Nature Study Society. Founded in 1920 and known locally as “WGNSS”, the organization seeks “to stimulate interest in nature study on the part of adults and children, to cooperate with other organizations in nature study, and to encourage amateur research in the natural science.” I’ve been an active member in the society’s Entomology Group since the early 1980s, and for almost five years now I have also served as editor for the society’s newsletter, Nature Notes (see this archive of recent issues). Occasionally they invite me to talk—sometimes to just the Entomology Group and other times to the Society as a whole—about my entomological exploits. This time I chose to focus on my several visits to the Glass Mountains in northwestern Oklahoma over the past few years, which readers of this blog may remember has been the source of an inordinate number of new state records and other significant finds for the beetles I study. The presentation provided an overview of the insects I’ve encountered during these visits, and for those who might be interested a PDF version of the presentation is posted here. 

Natural History of Oklahoma’s Glass Mountains…

Copyright © Ted C. MacRae 2014

What was that insect?

Yesterday I posted an identification challenge of a different sort. The main subject in the photo was a jewel beetle (family Buprestidae), but there was also another insect in the photo—a small parasitic wasp sitting on the branch below the beetle. Some of you saw it—Charley Eiseman was the first and correctly guessed it was a member of the family Encyrtidae, earning 5 pts, and Wikispecies editor gets 5 pts for further identifying it as a member of the genus Metaphycus. Honestly, I took several shots of the beetle and never saw the wasp until I examined the photograph during processing. I’m not certain, but I think the small object next to the wasp could be a scale insect (family Coccidae), which are known hosts of Metaphycus spp.

Of course, there is still the jewel beetle, and it wouldn’t be fair for me to award points for the wasp but not the beetle. Heath gets 5 pts for first identifying the beetle in the genus Agrilus; however, nobody was able to identify the species as A. granulatus—commonly associated with cottonwood and poplar (Populus spp.) across North America. Since Charley was the only person to mention both the beetle and the wasp, I’m going to give him a tie-breaking bonus point and declare him the challenge winner.

Populations of A. granulatus have been assigned to several subspecies—the beetle shown here (photographed June 2013 at Beaver Dunes, Oklahoma) represents the nominate form—restricted to the U.S. east of the Rocky Mountains, where it breeds in native eastern cottonwoods (P. deltoides) and introduced Lombardy poplars (P. nigra var. ‘Italica’). Agrilus granulatus is often confused in collections with A. quadriguttatus, but that species is associated with willow (Salix spp.) and can be further distinguished by the less dense pubescence of the lower face not obscuring the surface; the pronotum with the lateral margins evenly rounded and not strongly sinuate at the base, the median channel less distinct, and the lateral depressions scarcely pubescent; and the elytra more gradually narrowed posteriorly with the tips more acutely rounded and more coarsely serrulate and the pubescent spots less distinct (Fisher 1928).

Here are a few more photographs of the jewel beetle (without the wasp):

Agrilus granulatus granulatus on Populus deltoides | Beaver Dunes, Oklahoma

Agrilus granulatus granulatus on Populus deltoides | Beaver Dunes, Oklahoma

Agrilus granulatus granulatus on Populus deltoides | Beaver Dunes, Oklahoma

Agrilus granulatus granulatus on Populus deltoides | Beaver Dunes, Oklahoma

Agrilus granulatus granulatus on Populus deltoides | Beaver Dunes, Oklahoma

Agrilus granulatus granulatus on Populus deltoides | Beaver Dunes, Oklahoma

REFERENCE:

Fisher, W. S.  1928. A revision of the North American species of buprestid beetles belonging to the genus Agrilus.  U. S. National Museum 145, 347 pp.

Copyright © Ted C. MacRae 2014

Pop! goes the beetle

Alaus oculatus (eyed elater) | Beaver Dunes State Park, Oklahoma

Alaus oculatus (eyed elater) | Beaver Dunes State Park, Oklahoma

Last June while collecting beetles from cottonwood trees at Beaver Dunes State Park, Oklahoma, I came across one of my favorite beetles—Alaus oculatus, or eyed elater (family Elateridae, or click beetles). Large by click beetle standards, the most striking feature of eyed elaters is, of course, their false eye spots, which are not eyes at all but patches of pubescence—black surrounded by a narrow ring of white—intended to look like eyes and located prominently on the prothorax rather than the head. A handful of related species are also found in various parts of the U.S., all of which exhibit variations on this same eye spot theme. Undoubtedly these spots serve to frighten would-be predators, much like the false eye spots on the thorax of many lepidopteran caterpillars. The true eyes, of course, are much smaller and are located on the head in front of the “false eyes.” In contrast to the prominently visible eye spots, pubescence on the rest of the body seems to function in cryptic coloration. The mottled patterning blends in with the bark of trees where these beetles usually hang out for effective concealment.

Look into my eye(spot)s!

Look into my eye(spot)s!

If either of those first two lines of defense don’t work, the beetles exhibit “thanatosis” by lying still with legs and antennae appressed to the body to fool the would-be predator into thinking that they are already dead.

A ventral look at the clicking mechanism between the pro- and mesosterna.

Adults exhibit “thanatosis” (play dead)  when disturbed.

Their most remarkable defensive behavior, however, is their ability to snap or “click” their bodies with enough force to free themselves from the grasp of a novice predator (or careless entomologist). The click is produced by a large prosternal spine and mesosternal notch on the beetle’s underside. To click, the beetle arches back its head and pronotum to retract the spine from the notch cavity, the tip of which is then pressed against the edge of the notch. Muscles within the thorax contract, storing elastic energy, and as the flexible hinge between the pro- and mesothoraces moves, the spine slides until its tip passes over the edge of the notch, releasing the elastic energy stored in the thoracic musculature and snapping the spine back into the notch cavity with enough force to produce an audible click.

A large spine on the prosternum fits into a groove on the mesosternum.

A large spine on the prosternum fits into a groove on the mesosternum.

This clicking ability also comes in handy if the beetle frees itself from the grasp of a predator and lands on its back. While the beetle’s legs are too short to right itself, its click is capable of launching the beetle high into the air. By tumbling while in the air, the beetle has a 50% chance of landing on its feet (thus, several attempts may be required). When jumping from a hard surface, the beetle is actually capable of launching itself to a height that is several times its body length and can tumble several times while in the air. This raises an interesting question, since theoretically an elevation of only one body length and half of a body revolution are all that is needed for an upside-down beetle to right itself. The power of the click, thus, grossly exceeds the minimal requirement for righting, yet the beetles seem incapable of moderating the force of the click. Furthermore, the 50% probability of landing suggests that they are also incapable of controlling the orientation of their body during the jump and landing. Did the clicking mechanism initially evolve to combat the grasp of predators and was then co-opted for use in jumping, or was the ability to jump the selective pressure that drove its evolution?

Locked and loaded—the mechanism is primed for the click.

Locked and loaded—the mechanism is primed for the click.

Ribak & Weihs (2011) used biomechanical analyses with Lanelater judaicus to support the idea that the click evolved primarily as a mechanism for vertical jumping. They reason that the excessive vertical distance of the jumps ensures sufficient height when jumping from soft substrates such as foliage or loose soil. A followup study evaluating the effect of natural substrates (Ribak et al. 2012) found that jump height was dramatically reduced (by ~75%) when the beetles jumped from leaves that covered approximately half of the study site and that the reduction in jump height was directly correlated with the amount of work absorbed by the substrate. This provides further evidence that the beetles do not moderate their jumping force and instead simply aim to jump “as high as possible” and rely on random chance for landing back on their feet.

After clicking, the spine returns to its resting position out of the groove.

After clicking, the spine returns to its resting position within the groove.

REFERENCE:

Ribak, G., S. Reingold & D. Weihs. 2012. The effect of natural substrates on jump height in click-beetles. Functional Ecology 26(2):493–499 [abstract].

Ribak, G. & D. Weihs. 2011. Jumping without using legs: The jump of the click-beetles (Elateridae) is morphologically constrained. PLoS ONE 6(6):e20871. doi:10.1371/journal.pone.0020871 [full text].

Copyright © Ted C. MacRae 2014

Hairy milkweed beetle

Across the Great Plains of North America, sand dune fields dot the landscape along rivers flowing east out of the Rocky Mountains. Formed by repeated periods of drought and the action of prevailing south/southwest winds on alluvium exposed by uplifting over the past several million years, many of these dunes boast unique assemblages of plants and animals adapted to their harsh, xeric conditions. Some are no longer active, while others remain active to this day. Among the latter is Beaver Dunes in the panhandle of northwestern Oklahoma.

Beaver Dunes, Oklahoma

Beaver Dunes State Park, Beaver Co., Oklahoma

As I explored the more vegetated areas around the perimeter of the dunes, I spotted the characteristically hairy, fleshy, opposite leaves of Ascelpias arenaria. Known also as “sand milkweed,” this plant is associated with sand dunes and other dry sandy soil sites throughout the central and southern Great Plains. I always give milkweeds a second look whenever I encounter them due to the association with them by longhorned beetles in the genus Tetraopes. It wasn’t long before I spotted the black antennae and red head of one of these beetles peering over one of the upper leaves from the other side.

Tetraopes pilosus on Asclepias arenaria

Tetraopes pilosus on Asclepias arenaria | Beaver Dunes State Park, Oklahoma

This was no ordinary Tetraopes, however. Its large size, dense covering of white pubescence, and association with sand milkweed told me immediately that this must be T. pilosus (the specific epithet meaning “hairy”). Like its host, this particular milkweed beetle is restricted to Quaternary sandhills in the central and southern Great Plains (Chemsak 1963), and also like its host the dense clothing of white pubescence is presumably an adaptation to prevent moisture loss and overheating in their xeric dune habitats (Farrell & Mitter 1998).

Tetraopes pilosus

Species of Tetraopes have the eyes completely divided by the antennal insertions—thus, “four eyes.”

Tetraopes is a highly specialized lineage distributed from Guatemala to Canada that feed as both larvae and adults exclusively on milkweed (Chemsak 1963). Larval feeding occurs in and around the roots of living plants, a habit exhibited by only a few other genera of Cerambycidae but unique in the subfamily Lamiinae (Linsley 1961). Milkweed plants are protected from most vertebrate and invertebrate herbivores by paralytic toxins, commonly termed cardiac glycosides or cardenolides. However, a few insects, Tetraopes being the most common and diverse, have not only evolved cardenolide insensitivity but also the ability to sequester these toxins for their own defense. Virtually all insects that feed on milkweed and their relatives have evolved aposematic coloration to advertise their unpalatability, and the bright red and black color schemes exhibited by milkweed beetles are no exception.

Species of the genus Tetraopes are characterized by the completely divided eyes.

Adult beetles, like the leaves of their hosts, are clothed in white pubescence.

As  noted by Mittler & Farrel (1998), variation in coloration among the different species of Tetraopes may be correlated with host chemistry. Milkweed species vary in toxicity, with more basal species expressing simpler cardenolides of lower toxicity and derived species possessing more complex and toxic analogs. Most species of Tetraopes are associated with a single species of milkweed, and it has been noted that adults of those affiliated with less toxic milkweeds on average are smaller, have less of their body surface brightly colored, and are quicker to take flight (Chemsak 1963, Farrell & Mitter 1998). Thus, there seems to be a direct correlation between the amount of protection afforded by their host plant and the degree to which the adults advertise their unpalatability and exhibit escape behaviors. Asclepias arenaria and related species are the most derived in the genus and contain the highest concentrations of cardenolides. In fact, they seem to be fed upon only by Tetraopes and monarchs while being generally free from other more oligophagous insect herbivores such as ctenuchine arctiid moths and chrysomelid beetles that feed on less derived species of milkweed (Farrell & Mitter 1998). Accordingly, T. pilosus is among the largest species in the genus and has the majority of its body surface red. Also, consistent with it being more highly protected than others in the genus, I noted virtually no attempted escape behavior as I photographed this lone adult.

Asclepias arenaria

Asclepias arenaria (sand milkweed) growing at the base of a dune.

In addition to metabolic insensitivity to cardenolides, adult Tetraopes also exhibit behavioral adaptations to avoid milkweed defenses (Doussard & Eisner 1987). The milky sap of milkweed is thick with latex that quickly dries to a sticky glue that can incapacitate the mouthparts of chewing insects that feed upon the sap-filled tissues. Adult Tetraopes, however, use their mandibles to cut through the leaf midrib about a quarter of the way back from the tip. This allows much of the sticky latex-filled sap to drain from the more distal tissues, on which the beetle then begins feeding at the tip. Leaves with chewed tips and cut midribs are telltale signs of feeding by adult Tetraopes.

REFERENCES:

Chemsak, J. A. 1963. Taxonomy and bionomics of the genus Tetraopes (Coleoptera: Cerambycidae). University of California Publications in Entomology 30(1):1–90, 9 plates.

Doussard, D. E. & T. Eisner. 1987. Vein-cutting behavior: insect counterploy to the latex defense of plants. Science 237:898–901 [abstract].

Farrell, B. D. & C. Mitter. 1998. The timing of insect/plant diversification: might Tetraopes (Coleoptera: Cerambycidae) and Asclepias (Asclepiadaceae) have co-evolved? Biological Journal of the Linnean Society 63: 553–577 [pdf].

Linsley, E.G. 1961. The Cerambycidae of North America. Part 1. Introduction. University of California Publications in Entomology 18:1–97, 35 plates.

Copyright © Ted C. MacRae 2013

Why did it take 30 years to collect these beetles?

Poecilonota cyanipes

Poecilonota cyanipes (eastern poplar jewel beetle) | Beaver Dunes State Park, Oklahoma

This is the best known of the American species of Poecilonota, and the one most commonly collected east of the Rocky Mountain.—Evans (1957)

I’ve been interested in insects since I was a kid, but I didn’t really become a dedicated coleopterist until after I’d finished graduate school and started working as a field entomologist with the Missouri Department of Agriculture. It was a perfect job for a young entomologist with a bent for collecting—being outside all day inspecting nursery stock and driving the back roads checking insect traps. It wasn’t long before I found myself focusing on wood-boring beetles, due initially to their horticultural importance but eventually to their astounding diversity and intrinsic beauty. So began my formal survey of the families Buprestidae and Cerambycidae in Missouri, and I spent the next eight years collecting them in all corners of the state and examining every insect collection, public and private, that I could find that might contain Missouri representatives of these families. In the end, I documented a cool 350 species and subspecies in the two families combined, more than a fifth of which represented new state records (MacRae 1991, 1994).

Poecilonota cyanipes

The specific epithet ‘cyanipes‘ refers to the blue feet

One species, however, that I had expected to find almost completely eluded me. This, despite the quote above by Evans (1957) in his revision of the genus Poecilonota in North America. Although it had been recorded from much of North America east of the Rocky Mountains in association with poplars (Populus spp.) and willows (Salix spp), I never actually encountered P. cyanipes in the field and found just two specimens labeled simply “Mo” in the insect collection at the University of Missouri in Columbia. This puzzled me, as I had beaten countless branches of cottonwood (Populus deltoides) and willow in search of this species and found many of the other known poplar/willow associates. I had even already collected two specimens of its much rarer congener, P. thureura, off of a redbud tree at the entrance to the Entomology Building on campus while still in graduate school!

Poecilonota cyanipes

This species can be recognized by its coppery color and elongate, distinctly reddish elytral apices,

As is often the case, good comes to those who wait, and I’ve finally gotten my chance during the past two seasons to encounter this species in numbers—last year as prey taken from nest sites of the buprestid-specialist crabronid wasp, Cerceris fumipennis, and this past June on cottonwood trees in northwestern Oklahoma at Beaver Dunes State Park. The individual in these photos was the first one I found—beaten from the lower branch of a small, living cottonwood exhibiting significant branch dieback, and over the course of the next two days I managed to beat close to three dozen specimens from the small, stunted cottonwoods that dotted the park. I suspect that the combination of good timing—buprestids of many types were common on a number of woody plant species in the area—and susceptible hosts with abundant branch dieback due to protracted drought conditions over the past few years was the reason I was able to find so many of the beetles. A perfect storm for wood-boring beetles, so to speak!

Poecilonota cyanipes

The non-angulate pronotal sides distinguish this species from another eastern species, P. ferrea.

As suggested above, larvae of this species are associated exclusively with dead or dying branches of Populus and Salix (both in the family Salicaceae), often in association with galls made previously by other species of wood-boring beetles, e.g., Saperda concolor in poplar (Knull 1920) and Agrilus criddlei in willow (Wellso et al. 1976). In fact, with one exception (P. viridicyanea on Chilopsis linearis) all members of the genus seem to be associated exclusively with plants in these two genera. However, in addition to these plants, Nelson et al. (2008), in their catalogue of the Buprestidae of the U.S. and Canada, also included black locust (Robinia pseudoacacia) in the family Fabaceae as a larval host for P. cyanea. I am convinced that this record represents at best a mere incidental adult association, and there are other examples of such in the catalogue (the final preparation of which was completed after the untimely death of the senior author). This is unfortunate, since erroneous records in such ‘standard’ references tend to be propagated in subsequent literature, which already seems to have happened in the case of black locust as a larval host for P. cyanipes (Paiero et al. 2012).

REFERENCES:

Knull, J. N. 1920. Notes on Buprestidae with description of a new species (Coleop.). Entomological News 31(1):4–12 [BioStor].

MacRae, T. C. 1991. The Buprestidae (Coleoptera) of Missouri. Insecta Mundi5(2):101–126 [pdf].

MacRae, T. C. 1994. Annotated checklist of the longhorned beetles (Coleoptera: Cerambycidae and Disteniidae) known to occur in Missouri. Insecta Mundi 7(4) (1993):223–252 [pdf].

Nelson, G. H., G. C. Walters, Jr., R. D. Haines, & C. L. Bellamy.  2008.  A Catalogue and Bibliography of the Buprestoidea of American North of Mexico.  Coleopterists Society Special Publication No. 4, The Coleopterists Society, North Potomac, Maryland, 274 pp. [description].

Paiero, S. M., M. D. Jackson, A. Jewiss-Gaines, T. Kimoto, B. D. Gill & S. A. Marshall. 2012. Field Guide to the Jewel Beetles (Coleoptera: Buprestidae) of Northeastern North America. 1st Edition. Canadian Food Inspection Agency, 411 pp. [pdf].

Wellso, S. G., G. V. Manley & J. A. Jackman. 1976. Keys and notes on the Buprestidae (Coleoptera) of Michigan. The Great Lakes Entomologist 9(1):1–22.

Copyright © Ted C. MacRae 2013