2015 Texas Collecting Trip iReport—Fall Tiger Beetles

This is the fourth in a series of “Collecting Trip iReports”—so named because I’ve illustrated them exclusively with iPhone photographs. As I’ve mentioned in previous articles in this series (2013 Oklahoma2013 Great Basin, and 2014 Great Plains), I tend to favor my iPhone camera for general photography—i.e., habitats, landscapes, miscellaneous subjects, etc.—during collecting trips and save my full-sized dSLR camera only for those subjects that I want high-quality macro photographs of. iPhones are not only small, handy, and quick but also capable (within reason) of quite good photographs (see this post for tips on making the most of the iPhone camera’s capabilities). This keeps the amount of time that I need to spend taking photos at a minimum, thus allowing more time for the trip’s intended purpose—collecting! Those photos form the basis of this overall trip synopsis, while photos taken with the ‘real’ camera will be featured in future posts on individual subjects.

Last year during late September and early October I travelled to eastern and central Texas. This trip was all about fall tiger beetles, in particular certain subspecies of the Festive Tiger Beetle (Cicindela scutellaris) and Big Sand Tiger Beetle (Cicindela formosa) found in that area that I had not yet seen. I enjoy all collecting trips, but fall tiger beetle trips are among the most enjoyable of all—cooler temperature, a changing landscape, and charismatic subjects that are both fun and challenging to find and photograph. This trip was no different, with spectacular weather during the entire week and, for the most part, great success in finding the species/subspecies that I was after. At this point I’d like to acknowledge the help of several people—David Hermann (Ft. Worth, Texas), David Brzoska (Naples, Florida), and Steve Spomer (Lincoln, Nebraska), who generously provided information on species and localities. My success at finding these beetles was due in large part to the information they provided.


Day 1 – Cobb Hollow

My car

Little question about what I am doing out here.

After driving 700 miles from my home near St. Louis, I arrived at the first stop of trip—Cobb Hollow in north-central Texas. This small creek lined with deep, dry sand is close to Forestburg (Montegue County)—the type locality of Cicindela scutellaris flavoviridis, a beautiful, all-green subspecies with the elytra suffused golden-yellow.  The habitat looked very promising from the start, and it wasn’t long before I found the first tiger beetle of the trip—a gorgeous, red nominate Big Sand Tiger Beetle (Cicindela formosa formosa). Not long after that I found the first Cicindela scutellaris flavoviridis, and over the next few hours I would find a total of nine individuals. Despite the extensive habitat along the creek the beetles were quite localized, occurring primarily in two dry sand areas within a mile west of the bridge. This spot is actually near the northern limit of the subspecies’ distribution, and several of the individuals showed varying influence from nominate scutellaris with the elytra tending to be more red than yellow-green. There was a diversity of other tiger beetles here as well—C. formosa formosa was the only one that was common, but I did find also a few individuals each of Tetracha carolina, Cicindelidia punctulata, Cicindela splendida, and C. repanda. A very cool place.

Cobb Hollow from bridge

View of Cobb Hollow east from the bridge

Sand bar along creek

Dry sand deposits line the creek.

Robber fly with bumble bee prey

I watched this robber fly snag a bumble bee in mid-flight.

Ted MacRae at Cobb Hollow

Looking down onto the creek from the bridge.


Day 2 – Stalking the Limestone Tiger Beetle

Today was all about looking for the Limestone Tiger Beetle, Cicindelidia politula. I have collected this species previously at several sites in Erath and Somervell Counties, Texas (west of Ft. Worth) and featured photographs from that trip. However, since I would be passing through the area on my way south I decided to spend a day looking for it again and, hopefully, collecting a few more specimens. Cicindelidia politula is related to the much more common and widespread Punctured Tiger Beetle, C. punctulata, but is shiny blue-black with the elytral markings absent or limited to the apices and the abdomen red. I visited several localities—two new ones for me in Erath County and another I had visited previously in Somervell County, with habitats that ranged from rocky clay to white limestone exposures along roadsides and even limestone gravel.

I found a fair number of individuals at the first site (1.7 mi SW Bluff Dale, Jct US-377 & FM-1188), which had a finely ground limestone substrate. Most of the individuals were flushed from the base of clumps of bunch grass and captured when they landed in more exposed situations.

Limestone habitat for Cicindelidia politula

Cicindelidia politula habitat—1.7 mi SW of Bluff Dale.

The beetle had also been reported along the roadsides at the second location (0.4 mi E Jct FM-2481 on CR-539), but the only individual I saw here was on a very coarse crushed limestone 2-track leading off of the main road.

Limestone habitat for Cicindelidia politula

Cicindelidia politula habitat—0.4 mi E Jct FM-2481 on CR-539.

The species was most numerous at the third site in Somervell County (3.4 mi SE Jct US-67 on CR-2013). I collected ten individuals and saw probably that many more on white limestone exposures along the roadside and along a dirt road cut along the base of the hill to the NE side of the highway. Most of the beetles in the latter area were seen along the scraped dirt road (at left in 2nd photo below), although presumably the beetles also utilized the undisturbed, surrounding habitat.

Limestone habitat for Cicindelidia politula

Cicindelidia politula habitat on white, limestone exposures along the roadside.

Limestone habitat for Cicindelidia politula

Cicindelidia politula habitat on white limestone hillside and scraped dirt road.

Catching the beetles at this last locality was challenging—the adults are fast and flighty, and the rough, rocky habitat made it difficult to clamp the net over the beetle and pounce on top of the rim before they were able to find a gap and escape. With practice I found my catch efficiency increased a little bit if I slowly approached the beetle and then made an assertive swing with the net right when the beetle began to fly—the trick is learning how to tell when they are ready to fly (and “assertive” is the key word!). Tiger Beetle Stalker; however, does not quit!

Tiger beetle stalker!

Tiger Beetle Stalker!


Day 3 (Part 1) – Pedernales Fall State Park

This was another locality where Cicindela scutellaris flavoviridis had been recorded. I came here to find this subspecies even though I had seen it two days previously at Cobb Hollow, because that latter population showed some slight intergradation of characters from nominate C. scutellaris and I wanted to get field photographs of a “pure” population. I was pretty excited when I saw extensive dry sand habitat lining the upper bank area along the Perdenales River; however, I found no tiger beetles of any kind after extensive searching through that habitat. I did note the area seemed dry and reasoned that perhaps timely rains had not yet triggered emergence of C. scutellaris, C. formosa, and other sand-loving fall tiger beetles. I did find a small area of wet sand right along the water’s edge where three species of Cicindelidia could be seen: C. ocellata rectilatera, C. trifasciata ascendens, and C. punctulata. I’ve photographed all of these species before, so I didn’t try to spend any time doing so here. However, combined with the species seen the previous two days, this made a total of ten species seen on the trip so far. Although I didn’t find the beetle I was looking for, I marveled at the beauty of the area, especially the Pedernales River with its hard, conglomerate bedrock and mini shut-ins and spent quite a bit of time here taking photographs.

Perdenales River

The Perdenales River is the centerpiece of the state park.

Schistocerca americana or nitens

Schistocerca americana or S. nitens (ID courtesy of Matt Brust).

Perdenales River

Shut-ins are extensive along the Perdenales River.

Poecilognathus sp.

Bee flies (family Bombyliidae), prob. Poecilognathus sp. (ID courtesy Rob Velten).


Day 3 (Part 2) – Lick Creek Park

Another of the Festive Tiger Beetle subspecies that I wanted to look for was Cicindela scutellaris rugata. I had several localities from which this solid blue-green subspecies has been recorded, and this site was the nearest of those that I planned to visit. The drive from Pedernales State Park was longer than I anticipated, so I didn’t get to this spot until close to 6 p.m. At first I worried that I wouldn’t have enough time to even find suitable habitat, but that was no problem as I quickly found the Post Oak Trail and its perfect open, post oak woodland with deep sand substrate. By all accounts the beetles should have been all over the trail but they weren’t. As with the previous site, the area was quite dry as evidenced by the wilted plants along the trail side, and I also note that the previous record from here was on Oct. 23rd—more than three weeks later. Despite the fact that I didn’t find any tiger beetles, I did see a young timber rattle snake (Crotalus horridus) crossing the trail late in the hike—I took a quick shot with the iPhone (see below) and then broke out the big camera and was able fire off a few shots before it left the trail and headed for cover. (Several people walking the trail came upon us, and they were all—happily—more than willing to oblige my requests to stay away until I was finished.)

Sand woodlant habitat for Cicindela scutellaris rugosa

Post oak woodland with dry sand substrate seems to be perfect for Cicindela scutellaris rugata.

Wilted American beautyberry (Callicarpa americana)

Wilted American beautyberry (Callicarpa americana).

Timber rattlesnake (Crotolus horridus)

A youngish (prob. ~32″ in length) timber rattlesnake (Crotolus horridus) was a treat to see.


Day 4 – East Texas cemeteries

Cemeteries are often great places to look for tiger beetles because they tend to be located on parcels of land with low agricultural value that were donated by landowners to local churches. Older cemeteries especially tend not to be highly maintained and, thus, offer excellent habitat for tiger beetles. My goals for this day were Cicindela scutellaris rugata and the gorgeous Cicindela formosa pigmentosignata. I had records of both from a couple of cemeteries in eastern Texas (Sand Flat Pioneer Cemetery in Henderson and Morris Chapel Cemetery in Van Zandt Counties) and found good numbers of both along sandy 2-tracks and sparsely to moderately vegetated sand exposures in and around the cemetery grounds. I don’t have any iPhone photographs to share of either of these species, but I did spent a lot of time with the big camera and got a number of photos of each that I am quite pleased with—I’ll share those in future posts. The cemeteries themselves were haunting and poignant, with some headstones dating back to the late 1800s.

Sandy 2-track habitat for Cicindela scutellaris rugata & C. formosa pigmentosignata

Sandy 2-track habitat for Cicindela scutellaris rugata & C. formosa pigmentosignata at Sand Flat Pioneer Cemetery, Henderson County, Texas.

 

Ant mound

Pogonomyrmex sp. poss. barbatus tend their nest entrance (ID courtesy of Ben Coulter).

Sand Flat Pioneer Cemetery

Oldest section of Sand Flat Pioneer Cemetery.

Died Nov 10, 1874

Fallen, but not forgotten—yet (died Nov 10, 1874).

Oldest headstones (late 1800s)

Oldest headstones (late 1800s) at rest under the shade of huge, red-cedar trees.

Oldest person (106 yrs old)

The oldest person died at 106 years of age (born in 1804).

At Morris Chapel Cemetery I found C. formosa pigmentosignata and C. scutellaris rugata on sparsely vegetated deep dry sand 2-track north of the cemetery. I did also manage to get field photos of the former before it got too hot and they became too active. There were also a few of the latter in the open sandy ground just outside the northwestern edge of the cemetery. As with Sand Flat Pioneer Cemetery, I spent a bit of time in the cemetery proper to look at the headstones—the oldest headstone also being the most poignant; a one and a half-year old boy who died in 1881.

Sandy 2-track habitat for Cicindela scutellaris rugata & C. formosa pigmentosignata

Sandy 2-track habitat near Morris Chapel Cemetery.

Morris Chapel Cemetery

A large, spreading post oak shades pioneers at rest.

Died 1881 (age 1½ yrs)

A poignant headstone (died 1881 at 1½ years of age).

After finishing up at Morris Chapel Cemetery I returned to Sand Flat Cemetery to see if I could get more field photographs before the beetles bedded down for the night. The sun was still up when I arrived a little before 6 p.m., but the shadows were long and no beetles were seen. Not one to waste an opportunity, I broke out the big camera anyway and started photographing a large species of bee fly (family Bombyliidae) that was perching on the ground and on the tips of plains snakecotton (Froelichia floridana).

Undet. bee fly

Bee fly (family Bombyliidae), poss. Poecilanthrax lucifer? (ID courtesy Alex Harman).


Day 5 (Part 1) – Cowtown Bowman Archery Club

With both specimens and good field photos of Cicindela scutellaris rugata and C. formosa pigmentosignata in hand, I returned my attention to C. scutellaris flavoviridis. Again, I did already have specimens in hand from Cobb Hollow, but most of them showed some degree of intergradation with nominate C. scutellaris and I was hoping to see some “pure” individuals. Failing to find it at the more southerly locations (Pedernales State Park and Lick Creek Park), I had one more location in Tarrant County where the subspecies had been recorded—a sand borrow pit near the entrance of Cowtown Bowman Archery Club. Once again I searched the area thoroughly for a couple of hours during mid-morning but did not see the subspecies or any other tiger beetles. Conditions were overcast and cool (72°F), but I do not think this explains the absence of adults. Rather, I think I was on the early side of the season and they just hadn’t started emerging at this site.

While I was at the site I found several tiger beetle larval burrows in a moderately vegetated area near the deeper sand deposits that were occupied by Tetracha carolina, so I used the “stab” or “ambush” method to collect several 3rd instars for an attempt at rearing. For those of you who are not familiar with this technique, a knife is set at a 45° angle with the tip in the soil about 1″ from the edge of the burrow. Then you wait, sometimes for quite a while, until the larva reappears at the top of the burrow and STAB the knife assertively into the soil to block the larva from retreating. The larvae are extremely wary with excellent vision and will usually drop back down immediately when they see you, so you have to be ready and act quickly. Once the retreat is blocked, a simple twist of the knife to expose the larva is all that is needed. I prepared larval habitats by placing native soil with as intact a top layer as possible in plastic critter carriers, made a starter hole for each larva with a pencil, dropped each larva into one of the holes, and then pushed the soil to seal the burrow entrance. This prevents the larvae from crawling right back out of the starter burrow, which can result in them encountering and fighting each other. The larvae will eventually reopen the burrow entrance, but after being sealed inside for a while they usually accept the burrow and further modify it to suit their needs.

 

Sandy grassland habitat for Tetracha prob. carolina

Sandy grassland habitat for Tetracha carolina.

Larval burrows (lower left) can be recognized by their clean, almost perfectly round, beveled edge. The presence of fresh soil diggings cast to one side (upper right) indicates the burrow is occupied by an active larva.

Tetracha prob. carolina larval burrow

Tetracha carolina larval burrow with cast soil diggings.

Using the “stab” or “ambush” method to collect larvae. One must have patience to successfully use this method.

"Stab 'n; grab" method to collect tiger beetle larvae (Tetracha prob. carolina)

Using the “stab” or “ambush” method to collect tiger beetle larvae.


Day 5 (Part 2) – Cobb Hollow (epilogue)

Although I had found Cicindela scutellaris flavoviridis at this site on the first day of the trip, I had not taken any field photographs in hopes of finding a more “pure” population at one of the more southerly locations. That did not happen, so I returned to Cobb Hollow on this last day in the field to get field photographs from the population there. Temperatures were a bit cooler (mid-70s) and cloud cover was variable, actually sprinkling when I arrived mid-afternoon but eventually clearing. This seemed to have no detrimental effect on adult presence, and it may have actually helped as I was able to photograph the very first individual that I found to my heart’s content. I collected that individual and the next three that I saw by hand and found two more over the next hour—all on the same deep, dry sand bars west of the bridge where I had seen them previously. Curiously, Cicindela formosa was strangely absent from these same areas where they had been so numerous a few days earlier.

Habitat for Cicindela formosa formosa and C. scutellaris flavoviridis

Deep, dry sand deposit where most of C. scutellaris flavoviridis were seen.

On the east side of the bridge I collected two more Tetracha carolina in the same moderately vegetated sandy clay spot as last time, then went on to the furthest dry sand bar where I found and photographed (but did not collect) a single C. formosa (only one shot before it took off). I also found a female green lynx spider (Peucetia viridans) sitting on her egg mass and got some nice macro photos as well as this iPhone shot (talk about a face only a mother could love!).

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Female green lynx spider (Peucetia viridans) atop her egg mass.


I hope you’ve enjoyed this collecting trip iReport. Stay tuned for true macro photographs of the tiger beetles and other insects/arthropods that I photographed on this trip in more subject-specific posts. You are also welcome to leave feedback in the comments below.

Ted MacRae w/ field collecting equipment & camera

© Ted C. MacRae 2016

Super duper June bugs

Last June, after spending the day collecting insects at Sand Hills State Park in south-central Kansas with Mary Liz Jameson, Jeff Huether and I setup our blacklights at the edge of the dunes. We were hoping to attract males of the genus Prionus, following a hunch that maybe the dunes—a popular historical collecting site—would prove to be the habitat for the enigmatic Prionus simplex (known only from the type specimen labeled simply “Ks.”). We knew it was a long shot, made even longer by a bright moon and the unseasonably cool temperatures that settled over the dunes as the sun dipped below the horizon, and in the end no Prionus would be seen. We did see, however, some other interesting insects, one of the more interesting being males of Hammond’s lined June beetle—Polyphylla hammondi. Almost immediately after sunset a number of these large, chunky-bodied beetles resembling super-sized versions of their far more diverse and commonly encountered relatives in the genus Phyllophaga (May beetles) began arriving at the lights—each one noisily announcing its visit by its loud, buzzing, flight and bumbling thud onto the ground nearby.

Polyphylla hammondi

Polyphylla hammondi | Sand Dunes State Park, Kansas

I’ve encountered beetles in the genus Polyphylla only occasionally over the  years, almost always at night as a result of their attraction to lights. The genus is most diverse in the southwestern U.S., and many species are found only in specific sand dune habitats (Young 1988, LaRue 1998). Their large size, relatively more restricted distributions, and less common occurrence make them interesting enough, but what made this encounter particularly interesting for me was the way the beetles—all males—held their fan-like antennae splayed out. Male Polyphylla have greatly enlarged antennae that they use to detect sex pheromones emitted by the female (Lilly and Shorthouse 1971). Many female Polyphylla are flightless, especially those restricted to sand habitats, and are rarely collected, and for some species they still remain unknown. In fact, the best way to find females is to listen for the sound of the males hitting the ground or vegetation once they have located a female (Skelley 2009).

Polyphylla hammondi

Male with antennae splayed to detect female pheromone.

It was clear to me that these males were actively searching for females. The greatly elongated antennomeres provide lots of surface area for sensory pores to detect female pheromones at low concentrations. I’d not seen this before and didn’t know how long it would last—many beetles have narrow windows of activity for mating that can be affected or restricted further by environmental cues such as temperature. I figured I’d better get some photographs on the spot while I could, and this was a smart decision as it wasn’t too long after I took these photos that the males stopped coming to the lights and those that were already there became inactive and no longer held their antennae so impressively splayed.

Polyphylla hammondi

Males cease activity after sunset.

In a recent paper describing a new western species of the genus, La Rue (1998) provided detailed notes on behavior that probably pertain to other sand dune inhabiting species as well. Males were observed to begin flying in late afternoon, making rapid, irregular flights several meters above the sand surface. However, as dusk approached, their flights became less erratic and more purposeful as they flew rapidly upwind and then returned in a slow zig-zag flight (indicative of osmoclinotaxic orientation). Mating occurred after they located a female sitting on the sand and alighted within a few centimeters of her. Several males were attracted to each female, further supporting the use of pheromones by the female to attract males. Males were also attracted abundantly to lights after dusk and ceased activity shortly to several hours after sunset, presumably because females cease releasing pheromone to attract them and burrow back into the sand.

REFERENCES:

LaRue, D. A. 1998. Notes on Polyphylla Harris with a description of a new species (Coleoptera: Scarabaeidae: Melolonthinae). Insecta Mundi 12(1–2):23–37 [pdf].

Lilly, C. E. & J. D. Shorthouse. 1971. Responses of males of the 10-lined June beetle, Polyphylla decemlineata (Coleoptera: Scarabaeidae), to female sex pheromone. The Canadian Entomologist 103:1757–1761 [abstract].

Skelley, P. E. 2009. A new species of Polyphylla Harris from peninsular Florida (Coleoptera: Scarabaeidae: Melolonthinae) with a key to species of the pubescens species group. Insecta Mundi 0085:1–14 [pdf].

Young, R. M. 1988. A monograph of the genus Polyphylla Harris in America north of Mexico (Coleoptera: Scarabaeidae: Melolonthinae). Bulletin of the University of Nebraska State Museum 11(2):vi+115 pp. [BioQuip preview].

© Ted C. MacRae 2016

A suitable ode to Warren Knaus

Last June Jeff Huether and I made a trip out to a system of sand the dunes just south of Medora, Kansas. These dunes have been a popular historical collecting site since the late 1800s, when Warren Knaus first called attention to the area as “an interesting and profitable” locality for collecting insects (Knaus 1897). Knaus was a newspaper publisher in McPherson County, Kansas from 1886–1938, but his true passion was collecting beetles—an activity that took him throughout the Great Plains and Desert Southwest for nearly 50 years and earned him stature as one of Kansas’ most highly regarded coleopterists (Dean 1938). Despite his travels, Knaus remained enamored with the sand hills near his home and eventually published an annotated account of the rarer and more interesting beetles that he had encountered there over the years (Knaus 1926). One of the beetles mentioned in that paper was a “new species of Strigodermella…taken by sweeping in 1923 and 1925″. Those specimens soon became the type series for Strigodermella knausi (now Strigoderma knausi), named such by its describer (Brown 1925) in honor of its collector.

"Medora" Dunes

Sand Hills State Park, in southcentral Kansas | a.k.a. “Medora” Dunes

I suppose it is only fitting, then, that one of the first beetles that we encountered that day was this species. Actually, we couldn’t have missed them if we tried, they were so numerous! At first I assumed they were Strigoderma pygmaea, a species I had seen only once many years ago in Florida. Fortunately, we were in the company of Mary Liz Jameson, Associate Professor of Entomology at Wichita State University and an expert on scarab beetles. Mary Liz informed us of the beetle’s true identity, noting its rarity and relatively restricted distribution and that this was the type locality for the species.

Strigoderma knausi

Strigoderma knausi males were abundant on low vegetation | Sand Hills State Park, Kansas

At first the beetles were merely bycatch in our sweep nets as we looked for more ‘interesting’ beetles (i.e., jewel beetles for me, blister beetles for Jeff, and longhorned beetles for both of us). I tend to have trouble remaining so singularly focused, however, especially when the jewel and longhorned beetles aren’t out in numbers, and before long I found myself observing, and eventually photographing, these diminutive little scarabs. They were especially abundant at the south edge of the dunes, where they were hanging out on grasses and other low vegetation. A closer look revealed that almost every individual was perched in a rather characteristic pose, clinging to the vegetation with the middle and hind legs but extending them so that the beetle was nearly horizontal with the front legs held free and the segments of the antennal club spread widely apart. One can only presume that these were all males and that they were adopting this pose in an attempt to “smell” sex pheromones emitted by the unseen females. Mary Liz mentioned that the females are very rarely seen, and indeed among the nearly 100 specimens examined by Bader (1992) in his revision of the genus was but a single female.

Strigoderma knausi

Almost every individual clung to the vegetation with the front legs free and antennae spread open.

Bader (1992) notes that S. knausi has been taken by sweeping grasses and cotton and taken by light traps in Kansas and Oklahoma with a few records from northern Texas. I mentioned earlier the resemblance of this species to S. pygmaea (Fabricius, 1798), which, like S. knausi, also seems to prefer sandy habitats and can be taken at lights or by sweeping low vegetation (Bader 1992). That species, however, occurs more broadly across the southeastern U.S., being especially common in Florida and along the Atlantic coast as far north as Long Island, New York. The two species can be distinguished by, among other characters, the presence (S. knausi) or absence (S. pygmaea) of a median sulcus (furrow) on the front part of the pronotum (easily seen in the second photo above).

REFERENCES:

Bader, A. M. 1992. A review of the North and Central American Strigoderma (Coleoptera: Scarabaeidae). Transactions of the American Entomological Society 118(3):269–330 [JSTOR].

Brown, W. J. 1925. A new species of StrigodermellaBulletin of the Brooklyn Entomological Society 20:200–201.

Dean, G. A. 1938. Warren Knaus. Journal of the Kansas Entomological Society 11(1):1–3 [JSTOR].

Knaus, W. 1897. Collecting notes on Kansas Coleoptera. Transactions of the Annual Meetings of the Kansas Academy of Science 16:197–199 [JSTOR].

Knaus, W. 1926. The Coleoptera of the Sandhill Region of Medora, Reno County, Kansas. Entomological News 37(8):262–266 [Biostor].

© Ted C. MacRae 2015

Spiney, scaley distractions

Those who have read this blog for any length of time know that single-mindedness is not one of my shortcomings. I call myself a coleopterist and even go on trips dedicated specifically towards their study, yet find it impossible to ignore the diversity of non-beetle insects that one finds on such trips. It doesn’t stop there—insect diversity is supported by plants, interesting in and of themselves but even more so in the ways they mix and match to form distinct natural communities. And, of course, natural communities are themselves a product of the landscape—soil and terrain, moisture and its timing, elevation and latitude and longitude. Field trips for me are a constant struggle between the inner specialist—wanting to know everything about my chosen niche (beetles)—and outer generalist—wanting to know something about everything else. But wait—that was a decidedly spineless perspective. There are also animals with spines out there. Not nearly as many as those without, mind you, but that just makes them special—more of a treat to be relished when seen, and among the spined it is the reptiles that get me most excited.

Holbrookia maculata (lesser earless lizard)

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

This post presents a trio of reptiles that distracted my attentions one day during last year’s Great Plains Collecting Trip. We were looking for promising habitat for Prionus longhorned beetles in northwestern New Mexico (Union Co.), where two species (P. fissicornis and P. emarginatus) had been collected recently in the area’s vast shortgrass prairie. Remembering our experience the previous day finding another species (P. integer) and its burrows, we were on the lookout for anything that looked remotely like a “burrow” but found nothing. The stark grassland landscape offered little woody vegetation that made the chances of finding any other woodboring beetles remote, and eventually I became distracted by lizards darting amongst the vegetation around us. The first was one I’d never seen before—the lesser earless lizard (Holbrookia maculata), rather small lizards that were extremely wary, difficult to approach, and quick to dash behind the nearest grass clump. I managed one fairly adequate iPhone photo, but I wanted better photos and had grown weary of finding no beetles so broke out the big camera.

Holbrookia maculata (lesser earless lizard)

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

I presume the first photo (two above) is a female while the second photo (immediately above) is a male based on the paler coloration and less distinct black markings of the former. The preferred habitat of “relatively level terrain with sparse, low-lying vegetative cover and loose, friable soils” (Degenhardt et al. 2005) describes perfectly the habitat in which we found them. They were extremely difficult to photograph due to their proclivity to hide behind vegetation, and the two photos shown here were about as far in the open as I could get them while trying to approach with the camera.

Crotaphytus collaris (common collared lizard)

Crotaphytus collaris (common collared lizard) | Union Co., New Mexico.

I have loved collared lizards ever since I first photographed a nice, big, colorful male Crotaphytus collaris (eastern collared lizard) in western Oklahoma back in 2009. When I saw this still striking but much less colorful individual, I didn’t know what species it was, but I didn’t think it was the eastern species that I had already encountered not only in Oklahoma but also several times on igneous glades in my home state of Missouri. To my surprise, however, the eastern species is the only one inhabiting New Mexico (Degenhardt et al. 2005)—other species distributed further to the west or south. I had better luck photographing this individual, for even though it occasionally ducked into the vegetation (allowing one charming shot of it peering above the “grass” line—see third photo below) it was also content to stay out in the open along the gently sloped road bank where I had found it and dart from spot to spot between suspicious glares. This particular individual was smaller than the big males I have seen, so I suspect it is either a female or a juvenile.

Crotaphytus collaris (common collared lizard)

Not shy about remaining fully exposed, it clambered atop a rack to watch more carefully.

Degenhardt et al. (2005) mention an interesting factoid about collared lizards regarding the fact that they, unlike many other lizards, do not readily lose their tails (autotomy). Collared lizards are fast runners, often rearing up on their two hing legs, for which an intact tail would be an important organ for maintaining balance. In the case of these lizards, the advantages of rapid locomotion probably outweigh benefits from tail autotomy.

Crotaphytus collaris (common collared lizard)

Peering charmingly above the “grass” line.

While two reptile species at one stop might seem doubly lucky, little did I know a hat-trick still awaited me. We still had no solid evidence to suggest that Prionus beetles were active in the area, but we set out two traps anyway because the soil exposures seemed similar to those we saw the day before and then moved just down the road to where the soils turned redder and seemed to have higher sand content to set one more trap. As Jeff set the trap, my distraction with saurian subjects continued when I ran into a marvelously camouflaged western hognose snake (Heterodon nasicus).

Hognose snake

Heterodon nasicus (western hognose snake) | Union Co., New Mexico.

Western hognose snakes are typically found in grassland habitats with sandy soils (Degenhardt et al. 2005), so the occurrence of this individual at this spot was no surprise. What was a surprise was how strikingly marked this individual looked compared to the other two individuals I’d seen to this point—the first a more subtly marked individual in a rare sand prairie in southeastern Missouri, and the second a more uniformly mottled individual in northwestern Oklahoma’s Salt Plains National Wildlife Refuge. This could be a result of subspecific differences—Missouri populations are assigned to the subspecies H. nasicus gloydi (dusty hognose snake), but I am unsure of the subspecific assignment of the Oklahoma individual. According to Degenhardt et al. (2005) only the nominate subspecies occurs in northern New Mexico (subspecies H. n. kennerlyi can be found in the southwestern part of the state, while intergrades with subspecies H. n. gloydi are said to occur in the extreme southeastern part of the state).

Hognose snake

The strongly upturned rostral (snout) is one character distinguishing the western from the eastern hognose snake.

All species of hognose snakes are famous for their well-choreographed sequence of defensive displays. While they are said to rear up cobra-like and strike out with their mouth open while hissing, I have never seen this behavior by any of the western or eastern hognose snakes that I’ve encountered. The first western individual I saw (in Missouri) insisted on continually trying to burrow into the deep, loose sand and made no other defensive display, while the eastern individual referenced above simply tried to run, although it did eventually barf up a half-digested frog! The individual shown here seemed reticent to do much of anything, remaining coiled up and watching and coiling even tighter as my molestations continued. At last, this one performed some theatrics by writhing in mock agony and then rolling over on its back and playing dead (a behavior called thanatosis). The Oklahoma snake also did this, adding further dramatic value by opening its mouth wide, allowing the tongue to protrude, and ejecting blood from the lacrymal glands while emitting musk from the cloaca. This one didn’t do too much with its mouth, but it did so much more with its cloaca (defecating!). If the idea of eating a snake isn’t revolting enough to begin with, then surely eating a snake covered in crap is!

Hognose snake

The ultimate in thanatotic displays—not only dead, but covered in crap!

In addition to the strongly upturned rostral (snout), best seen in the second photo above (the rostral is only moderately upturned in the eastern species), the black-checkered ventral coloration seen in the third photo confirms this as the western hognose species. The eastern hognose snake is distributed further east and does not occur in New Mexico (Degenhardt et al. 2005).

In an amusing twist to the search for Prionus at this site, while photographing the animal I happened to look down to my side and saw a male Prionus beetle crawling through the vegetation! I recognized the species immediately as P. fissicornis—represented in my cabinet by only a single specimen, and although Jeff and I would find no more after a through search of the area, our traps yielded a “bucket loads” of the beetles the next morning.

REFERENCE:

Degenhardt, W. G., C. W. Painter & A. H. Price. 2005. Amphibians and Reptiles of New Mexico. University of New Mexico Press, 507 pp. [Google Books].

© Ted C. MacRae 2015

Just how widespread is Prionus heroicus?

On our insect collecting trip to the western Great Plains last June, Jeff Huether and I encountered several species of beetles in the genus Prionus—longhorned beetles (family Cerambycidae) known commonly as “prionid root borers”. I’ve already recounted our experiences with two of them—P. integer in southeastern Colorado and P. fissicornis in northeastern New Mexico, both of which we encountered unexpectedly and by the “bucketload” using prionic acid baited traps in shortgrass prairie habitats. The third species we encountered was also rather unexpected, so much so that we were not even sure about its identity until we examined the collected specimens more closely. Unlike the two previously mentioned species, however, the behavior of this third species—P. heroicus, especially regarding its attraction to prionic acid, was quite different, and one of the localities where we found it raises some interesting questions regarding its recorded distribution.

Prionus heroicus male

Prionus heroicus male | Mills Canyon, Harding Co., New Mexico.

Prionus heroicus is among the largest species in the genus, and we first encountered it in northeastern New Mexico while searching for suitable habitat around the small town of Mills (Harding Co.) where several grassland-associated species in the genus had been found by other collectors. While we were searching we were intrigued by the USDA Forest Service road sign pointing to “Mills Canyon” and decided to head down the gravel road to see what it looked like. A few miles down the road the endless shortgrass prairie quickly changed to sandstone canyonland with oak/pine/juniper woodland. By now it was late afternoon, and the rich, pulsing buzz of cicadas filling the air as we drove slowly through the area suggested the potential for good insect activity. We stopped to take a closer look at things, and within minutes an enormous prionid beetle came flying up to the car—apparently attracted to the prionic acid lures inside!  We netted the beetle, and shortly afterwards another beetle flew into the vicinity… and another! We hurriedly set out some lure-baited traps, and over the next hour or so we collected close to a dozen beetles. Our first thought, based on their large size and the presence of 12 antennal segments, was that they might be P. californicus. This was a bit of a letdown, as our goal was to find little known and uncommonly encountered Great Plains species, not common and widespread western species like P. californicus. However, the blackish rather than reddish color and relatively broad pronotum eventually convinced us that we had actually found P. heroicus—not a rare species, but also not something we expected to see at this relatively northeastern location compared to its usual haunts in southeastern Arizona.

Prionus heroicus male

Males generally landed in the vicinity of the prionic acid lures but seemed unable to locate its precise whereabouts.

Interestingly, none of the beetles came directly to the lure-baited traps but, rather, flew to the vicinity and then either circled broadly in the air or landed some distance from the trap and ran rapidly on the ground as if searching. We missed a few that we tried to net in mid-air, which responded by immediate straight line flight far away into the distance. Those that we watched while on the ground searched for up to several minutes but seemed unable to locate the lure, eventually taking flight and flying away. This suggests that prionic acid is more important as a component of the female’s calling pheromones for long distance detection, but that other components might be necessary to allow the males to locate females in the immediate vicinity. We returned to the site the following day around noon and were surprised to see males flying to our lures immediately after our arrival, since we had observed P. integer and P. fissicornis activity to occur almost exclusively during the morning and evening hours. Linsley et al. (1961), however, also note that adults of this species fly during the day, as well as at night. Again, none of the beetles seemed capable of finding the precise location of the lure.

Prionus heroicus male

Males rapidly searched the ground after landing but seemed unable to locate the lures and eventually flew off.

The larval habits of P. heroicus are not known, but the closely related P. californicus feeds on roots of living oaks or occasionally in dead oak logs or stumps (Linsley 1962). Prionus heroicus may have similar habits, since adult females have been found in leaf litter at the bases of living oak trees and stumps (Hovore & Giesbert 1976, Skiles 1978). Presumably the Mills Canyon population is associated with Gambel oak (Quercus gambelii), which was the only oak species noted at this location. An interesting defensive behavior was observed for an adult beetle that I kept alive and photographed later in the hotel room. I had put the beetle on a light-colored tray, and while I was getting the camera ready to take some shots the beetle began crawling away. I picked it up and put it back into position, and for a brief period it assumed the rather comical-looking “standing-on-its-butt” pose shown in the accompanying photograph. It maintained this pose for some seconds and then gradually lowered itself in the front before beginning to crawl again. If I poked it before it finished lowering itself it immediately pushed its front all the way back up again and held the pose briefly before beginning to lower itself again. I did not encounter this behavior in the field—beetles on the ground immediately tried to flee when I handled them and took flight if allowed to.

Prionus heroicus male

Defensive posturing as a result of being disturbed.

The story does not end here, however, as this would not be our last encounter with the species. While we were traveling back towards the east, we decided to visit the area around Black Mesa in the extreme northwestern corner of the Oklahoma panhandle. I had been to this site the previous summer, and although conditions were very dry at the time the presence of Gambel oak in the area—perhaps the easternmost outpost of this western species—had me thinking about the possibility of the area serving as an unknown eastern outpost for western species of jewel beetles (family Buprestidae). Conditions were once again dry, and no jewel beetles were found, but this quickly became a moot point as not long after our arrival a large prionid beetle came flying up to me—again in the same manner as P. heroicus at Mills Canyon and in the middle of the afternoon. We decided these, too, represented P. heroicus and remained in the area for the rest of the day, counting at least a dozen males attracted to the vicinity of the lures that we’d set out. As with the males we observed in New Mexico, none seemed able to find the precise location of the lure, and some circling only briefly and then flew off without even landing. Unlike New Mexico, however, we did succeed in trapping a few males in lure-bated traps that we set out overnight and checked the next morning.

Prionus heroicus male

This Prionus heroicus male  near Black Mesa, Oklahoma confirms the presence of this species in the state.

Our capture of P. heroicus at Mills Canyon in northeastern New Mexico and near Black Mesa in northwestern Oklahoma not only seems to suggest an association of this species with Gambel oak, but also confirms the previously questionable occurrence of the species in Oklahoma. Alexander (1958) reported the species (under one of its synonyms, P. tetricus) from Payne Co. in north-central Oklahoma. This record is dubious, since Payne Co. is well east of the 100th meridian and has a decidedly eastern flora, including its oaks. That record has not been mentioned by any subsequent authors addressing the overall distribution of P. heroicus (Linsley 1962, Chemsak 1996). The presence of P. heroicus in the Black Mesa area, with its decidedly western flora, does not necessarily give credence to the Payne Co. record, but it does bring up the question of just how broadly distributed P. heroicus really is. Most records of this species are from mountainous areas of southern Arizona and New Mexico, but more recently it has been recorded from Texas (Big Bend National Park) by Van Pelt (1999, 2007) and extreme northwestern Colorado (Moffat Co.) by Heffern (1998). The latter record is particularly interesting, as this represents a considerable range extension from any previously recorded locality and begs the question regarding its occurrence in other parts of Colorado.

REFERENCES:

Alexander, D. R. 1958. A preliminary survey of the cerambycids (Insecta: Coleoptera) of Oklahoma. Proceedings of the Oklahoma Academy of Science 38:43–52 [pdf].

Chemsak, J. A. 1996. Illustrated Revision of the Cerambycidae of North America. Volume I. Subfamilies Parandrinae, Spondylidinae, Aseminae, Prioninae. Wolfsgarden  Books, Burbank, California, x + 149 pp., plates I–X [description].

Heffern, D. J. 1998. Insects of Western North America 1A Survey of the Cerambycidae (Coleoptera) or Longhorn Beetles of Colorado. Gillette Museum of Arthropod Diversity, Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, i + 32 pp., 1 color plate [summary].

Hovore, F. T. & E. F. Giesbert. 1976. Notes on the ecology and distribution of western Cerambycidae (Coleoptera). The Coleopterists Bulletin 30:350 [JSTOR].

Linsley, E. G. 1962. The Cerambycidae of North America. Part II. Taxonomy and classification of the Parandrinae, Prioninae, Spndylinae, and Aseminae. University of California Publications in Entomology 19:1–102, 1 plate [OCLC WorldCat].

Linsely, E. G., J. N. Knull & M. Statham. 1961. A List of Cerambycidae from the Chiricahua Mountain area, Cochise County, Arizona (Coleoptera). American Museum Novitates 2050:1–34 [pdf].

Skiles, D. D. 1976. Taxonomy and description of two prionine Cerambycidae from southern Arizona: a new species of Stenodontes and new status for Neomallodon arizonicus (Coleoptera). Proceedings of the Entomological Society of Washington 80:407–423 [Biodiversity Heritage Library].

Van Pelt, A. F. (ed.). 1999. Inventory of insects of Big Bend National Park, Texas. Big Bend Natural History Association, Big Bend National Park, and Texas.

Van Pelt, A. F. (ed.). 2007. Inventory of insects of Big Bend National Park, Texas. Report to Big Bend National Park, 204 pp.

© Ted C. MacRae 2015

Scorching plains, screaming cactus

One of my greatest pleasures with collecting insects is not only the sights of the habitats that I visit, but the sounds. How many a night I’ve spent camped out in the Ozarks and watched royal moths fluttering at the blacklight sheet while dueling katydids traded their raspy “ch ch ch“s in the tree branches above and a whip-poor-will sang it’s haunting, eponymous song off in the distance. What joy to be hiking the canyon-lands out west and hear the musical, descending “t-te-tee-teee-teew-teeew-teeeew-teeeeew” of the canyon wren echoing off the tall, sheer rock faces. Even large-treed urban parks offer the hypnotizing “wee-er, wee-er, wee-er, weeeeeeeee” of scissor grinder cicadas (Tibicen pruinosa) on a hot summer night. Ah—cicadas! Few other animals can match their ability to fill a landscape with song, and with more than 100 species in North America it’s a safe bet that no matter where you go you can hear cicadas.

Cacama valvata

Cacama valvata (Uhler, 1888) | New Mexico, Harding Co., 5 mi W of Mills

Scissor grinders were the cicadas of my urban youth in Kansas City; I was a teenager the first time I heard the rich, pulsing buzz of bush cicadas (Tibicen dorsata) in the prairies around my house farther east in Blue Springs; and I experienced my first periodical cicada (Magicicada spp.) event as a young adult in St. Louis with Brood XIX and their whirring, “flying saucer” chorus. More recently, I’ve made several trips to the western Great Plains, where particularly large cicadas known as “cactus dodgers” (Cacama valvata) perch on prickly pear (Opuntia spp.) and cholla (Cylindropuntia imbricata) cacti and sing their loud, distinctive songs in the scorching, mid-summer heat. The male song has been described as a high pitched “metallic zing” (Beamer & Beamer 1930) or as an intense shrill, often in short bursts (Kondratieff et al. 2002); however, to me it sounds like a dull-bladed table saw cutting through a piece of ironwood and hitting a nail!

Cylindropuntia imbricata | Otero Co., Colorado.

Cholla (Cylindropuntia imbricata, Otero Co., Colorado) is a preferred host for Cacama valvata.

Fast flying and alert, cactus dodgers often defy the attempts of collectors (Kondratieff et al. 2002) and have the amazing ability to usually land safely on their spined hosts without becoming impaled (although occasionally this does happen—see photo below). The perils of dodging cactus spines, however, seem to pale compared with the benefits of utilizing these widespread hosts, as the association appears to have facilitated the spread of the species into a wide variety of environments across the southern Great Plains and westward to California (Sanborn & Phillips 2013).

Cacama valvata female

This female has a cactus spine impaled on her head.

The photos in this post were taken during late June 2014 in the scorching, cholla-studded, shortgrass prairies of southeastern Colorado and northeastern New Mexico. Given their alertness and fast flying capabilities, they were a challenge to photograph before eventually finding the somewhat more cooperative subjects shown in the above photographs. Eventually, I was lucky enough to encounter two individuals sitting on a dead cholla stem in the mid-afternoon heat near Vogel Canyon, Colorado, one of which (the lower) was singing (and thus a male) and the other I surmised to be a female (this I confirmed once I got a better look through my camera viewfinder).

Cacama valvata male (bottom) & female (top)

A male Cacama valvata (bottom) sings to a female (top).

The male was creeping slowly towards the female as it sang, pausing occasionally and interrupting his song before resuming both. I presumed I was witnessing courtship singing, a behavior Kondratieff et al. (2002) have described in detail. They observed males perched on the ends of branches producing long, wavering, repeated shrills as they moved closer to the female. The song changed to a long shrill followed by shorter sequence of shrills as they made their final approach, which was followed by touching with the legs, mounting, and copulation.

Cacama valvata male singing

Cacama valvata male singing.

Unfortunately for this male, the female was already in the act of oviposition (poor male—wasting his time flirting with a married woman!). In cactus, females oviposit almost exclusively in dry, dead, skeletonized stems and rarely utilize green material (Beamer & Beamer 1930). The eggs laid by this female might remain in the dry stem for another three months or more, where they will await a fall rainstorm to wet the stem and ground and bring cooler temperatures to improve their chances of survival before hatching, dropping to the ground, burrowing into the soil, and searching for roots upon which they can feed.

Cacama valvata female ovipositing on dead cholla stem.

REFERENCES:

Beamer, L. D. & R. H. Beamer. 1930. Biological notes on some western cicadas. Journal of the New York Entomological Society 38(3):291—305 [pdf].

Kondratieff, B. C., A. R. Ellingson & D. A. Leatherman. 2002. Insects of Western North America 2. The Cicadas of Colorado (Homoptera: Cicadidae, Tibicinidae). Contributions of the C. P. Gillette Museum of Arthropod Diversity, Department of Bioagricultural Sciences & Pest Management, Colorado State University, Fort Collins, 63 pp. [pdf].

Sanborn, A. F. & P. K. Phillips. 2013. Biogeography of the Cicadas (Hemiptera: Cicadidae) of North America, North of Mexico. Diversity 5:166–239 (doi:10.3390/d5020166) [abstract].

© Ted C. MacRae 2014

How to catch “bucket loads” of Prionus fissicornis!

Fresh off our unexpected success at finding Prionus integer in the shortgrass prairie of southeastern Colorado, field mate Jeff Huether and I made our way down into northeastern New Mexico to see if the prionic acid lures we used to attract that species would bring us success with other species of Prionus. Several species in this genus are known to occur in the Great Plains, and we had records of three from the area around Gladstone (Union Co.). Based on our experience from the previous day, we stopped at several sites that had sandy/loam soil and searched exposures along the roadsides for burrows that bore any resemblance to those that we had found associated with P. integer. Frustratingly, we saw no such burrows or evidence of the presence of Prionus beetles in any of the spots that we searched.

Eventually, with day’s end drawing near, we decided to play a hunch and set traps at two sites with soil exposures that seemed most similar to those seen the day before. As Jeff set the last pair of traps in place, I occupied myself photographing a dusty hognose snake (Heterodon nasicus gloydi). While photographing the animal, I happened to look down to my side, and what did I see but a male Prionus crawling through the vegetation! I recognized the species immediately as P. fissicornis—represented in my cabinet by a single specimen. This species is distinguished by the highly segmented antennae (up to 30 segments or more) that place it in the monotypic subgenus Prionus (Antennalia). I called out to Jeff, and for the next half an hour or so we scoured the surrounding area; however, our searches were in vain as we failed to find another individual.

Prionus fissicornis male

Prionus (Antennalia) fissicornis male | 24 June 2014, Union Co., New Mexico

We cast an eye towards the north and watched late afternoon thunderstorms roll across the expansive landscape. Rain is normally a downer on an insect collecting trip. However, considering the numbers of P. integer that came to the traps after rain the previous day, we actually found ourselves hoping that the skies would open up. Whether they would and if this would lead to success with P. fissicornis (or other Prionus species), however, would have to wait until the next morning when we returned to check the traps.

Thunderstorms over shortgrass prairie.

Thunderstorms over shortgrass prairie.

Around 10 a.m. the next morning our reward was revealed—traps brimming with P. fissicornis males! Each trap contained more than a dozen individuals, and males were still actively crawling around in the vicinity of the traps as well.

Prionic acid-bated traps w/ Prionus fissicornis males

Prionic acid-bated traps filled w/ Prionus fissicornis males.

Prionic acid-bated traps w/ Prionus fissicornis males

Each trap contained more than a dozen males.

We spent about an hour at the site determining the extent of their occurrence, and like P. integer the previous day the males were found almost exclusively in a small area adjacent to (and upwind from) the traps. As we searched, we also found a few females, one of which seemed to be in the act of ovipositing into the soil at the base of a plant. I carefully excavated the hole into which the ovipositor had been inserted once the female withdrew it, but I was unsuccessful in finding an egg. Perhaps she was only probing to search for a suitable oviposition site and did not find this one to her liking.

Prionus fissicornis female

Prionus (Antennalia) fissicornis female | 24 June 2014, Union Co., New Mexico

There are some interesting similarities and differences with this species compared to our experience with P. integer the previous day. Males of both were highly attracted to the prionic acid lures that we used and were effectively trapped in cans over which the lures were suspended. It is also interesting that both species were found in rather large numbers directly after a rain event, and it seems logical to presume that rain might trigger adult emergence—as is the case with many insects that inhabit dry habitats with seasonal rains. However, we did not find P. fissicornis adults associated with burrows as with P. integer, making me even more intrigued with the burrowing behavior in the latter and its possible function. Also, it is interesting that we found P. fissicornis adults most active during the morning hours and P. integer most active during early evening, but since we did not visit both localities at both times of day it is not possible to say for sure that the two species differ in their adult daily activity.

© Ted C. MacRae 2014

My first experience with Prionus lure

Our quick stop in Hardtner, Kansas to see “Beetle Bill” Smith at the beginning of our Great Plains Collecting Trip had already produced one unexpected success—the long-sought-after Buprestis confluenta. However, our trip didn’t really begin in earnest until noon the next day when field mate Jeff Huether and I stopped in the middle of a vast, dry grassland north of Las Animas in southeastern Colorado. Even at this point we hadn’t gotten to the first of our planned localities a little further south where we were hoping to find longhorned beetles in the genus Prionus, the main objective of the trip, using recently developed pheromone lures. Jeff had, however, collected an interesting blister beetle at this spot on an earlier trip and wanted to take another look since we were in the area. I looked out across the desolate landscape and wondered what on Earth I could find here that would be even remotely interesting to me.

Shortgrass prairie, 10.5 mi N of Las Animas, Colorado.

Shortgrass prairie, 10.5 mi N of Las Animas, Colorado.

I was convinced there was no point for me to look around, but I wanted to let Jeff have some time to look for his blister beetle, so I milled around the vicinity of the car to look for any flowers that might be in bloom and hoped to maybe see a tiger beetle or two. As is often the case, plants were a little lusher and more diverse along the roadsides due to rain shedding by the road, so I decided to walk down the roadside and see what I might find. I hadn’t gone too far when I saw a big, brown beetle crawling along the edge of the road. My first thought while approaching it was ground beetle, but I quickly decided it was not that. Only when I crouched down and looked at the beetle, crawling with some urgency but making no attempt to fly, did I realize that it was a female Prionus (later identified as P. integer LeConte, 1851 in the subgenus Homaesthesis). I had, in fact, only once before ever seen a female Prionus, that being the ginormous species P. heroicus in southeastern Arizona almost 30 years ago. Incredible! We hadn’t even gotten to the first spot where we planned to look for Prionus, and I’d already found one. And a female, no less!

Prionus integer female

Prionus (Homaesthesis) integer LeConte, 1851 (female).

Jeff was out of ear-shot, so I resumed my walk along the roadside to look for more. Not long afterwards I found a male carcass laying on the ground, and then shortly afterwards I found another one. One of the carcasses was in pretty good condition still, giving me optimism that I would find a live one as well. Frustratingly, however, I saw nothing more during the next hour as I continued slowly down the road to a distance of nearly one mile from the car and then along the other side all the way back. During the time that I was searching, I noticed strange burrows in the ground. They were only along the roadsides and were especially numerous in the area where I had found the female and two male carcasses. The diggings looked fresh, so I tried excavating a few. They were no more than two inches deep, and I found nothing in any of the dozen or so burrows that I excavated. Nevertheless, I was convinced that the burrows were somehow associated with the Prionus beetles that I had found (even though I had never heard of burrows associated with adult Prionus beetles, nor have I been able to find anything in the literature since)—the size of the burrow matched that of the beetles perfectly, and the presence of fresh diggings meant something had made them recently. If the Prionus beetles didn’t make them, then what did?

Prionus integer burrow

Prionus integer adult burrow.

All the time as I was searching, I wondered if Jeff knew about the beetles occurring here. However, when we finally met up again near the car and I showed him what I had found, I could see by the surprised look on his face that this was not the case. I also showed him the burrows that I’d found, and we both agreed they had to be connected to the beetles. I decided to try using a shovel instead of my knife to excavate more burrows, thinking that maybe I wasn’t excavating deep enough, so we got the shovel out of the truck, walked to the area where I had seen the live female, 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 there it was—another female!

Prionus integer female

A female Prionus integer dug from her burrow (shovel in lower right).

We excavated more burrows in the vicinity, preferentially choosing those with the freshest-looking diggings, and while most were empty we did find several more females. We were beginning to think that only the females created the burrows, but eventually a male was dug from its burrow as well. By now it was clear that we needed to make the first schedule change of the trip (before even reaching the first planned locality!) and decided to set out lure-baited traps and check them later in the evening before resuming our plans the next day. We expected the beetles to become active during dusk, so we went into town to eat dinner and check out a nearby locality before returning to the site. While we were gone heavy rains moved through  the area, and 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—beetles were everywhere, crawling on the road, crawling through the grass, and overflowing in the flooded traps! The vast majority, as expected, were males—distinguishable by their smaller size and distinctly flabellate antennae—but we also found a fair number of the much more rarely collected females—most of them either mating or digging burrows.

Prionus integer mating pair

A male Prionus integer attempts to mate with a female.

It was tempting to focus on just collecting individuals, as we had clearly encountered an ephemeral emergence event. However, it was soon apparent that the number of individuals milling around and flying into the area was far greater than what we could possibly put in our bottles. As I gradually realized this, my focus shifted from collecting to observing—especially the females involved in mating and digging burrows. Most of the females that I saw digging burrows had their abdomens protruding from the burrow as they used their front legs to dig soil from the burrow, but eventually I noticed a burrow that had a female sitting completely within the burrow with her head just below and facing towards the burrow opening.

Prionus integer female

A Prionus integer female sits in her burrow.

I crouched down and watched the female closely (through the camera lens) and noticed a regular, almost rhythmic movement by the beetle as she sat in the burrow. I imagined perhaps the female was in the act of oviposition, although I now think it unlikely that this is the case (it doesn’t make sense for a female to make the energetic expenditure to dig a burrow large enough to contain the adult body when a simple probe of the ovipositor into the soil surface would accomplish the same thing. It also occurred to me that the female was emitting pheromone to attract males, but this begs the same question: why call for mates while enclosed within a burrow when doing so from the surface would be just as (and possibly more) effective. At any rate, the chance to observe mating and other behaviors made the encounter far more informative than if our focused had remained strictly on collecting the abundance that we had encountered.

Prionus integer female

Prionus integer female moving rhythmically in her burrow, but why?

Barr & Penrose (1969) give the only biological notes I am aware of for this species, noting that the larvae have been associated with the roots of sagebrush (Artemisia tridentata) and yellow rabbitbrush (Chrysothamnus viscidiflorus) and on two occasions finding larvae damaging newly planted beans or cutting underground stems of potato plants in southern Idaho. In both cases the fields had been recently cleared for cultivation, suggesting opportunistic feeding by larvae that were already present in the soil and feeding on native hosts when the land was cleared. At any rate, the site where we found the species was completely devoid of any rangeland shrubs, suggesting that herbaceous plants also may serve as suitable hosts for the species. We did observe small bunch grasses that were abundant in the area where both the beetles and their burrows were most numerous—in fact (although perhaps coincidentally), the burrows seemed most often to have been dug at the base of these grasses (see 3rd and 6th photos).

The sinking sun in the west and receding storm clouds in the east created conditions ripe for rainbows—a fitting exclamation point to our first (and completely unexpected) Prionus success of the trip. As the cloak of dusk descended, we packed up our gear and headed into town full of optimism about what other Prionus experiences lay ahead in the coming days.

Rainbow over shortgrass prairie

A rainbow hangs over the shortgrass prairie.

REFERENCE:

Barr, W. F. & R. L. Penrose. 1969. Notes on the distribution and bionomics of some Idaho Cerambycidae (Coleoptera). Great Basin Naturalist 29:88–95 [Biodiversity Heritage Library].

© Ted C. MacRae 2014