Cicindela formosa generosa | Castlewood State Park, Missouri.
Last fall I took my younger daughter to the Al Foster Trail on the western side of Castlewood State Park, just a few miles down the road from my house. As we walked the trail through typical bottomland forest next to the Meramec River, I noticed what appeared to be open ground on a rise to the north of the trail. When I went up to investigate, I saw a rare sight for Missouri—dry sand! Obviously a deposit from some past flood event, the post oaks established around its perimeter and native warm season grasses sparsely dotting its interior suggested it had been laid down many years ago. Such sights were likely common along the big river systems of pre-settlement Missouri, as natural flooding cycles laid sand deposits up and down the river courses, each deposit gradually succumbing to vegetation as new deposits were laid down elsewhere. Today, with channelization and levees for flood control, the Missouri and Mississippi Rivers are just narrow, hemmed-in shadows of their former selves, unable to lay down such deposits in most years until, at last, catastrophic flooding occurs on a grand scale (as is occurring now). Feeding into the Mississippi River just south of the Missouri River is the Meramec River—as the state’s only still-undamned undammed river system, it still has opportunity on occasion to lay down these interesting dry sand habitats.
The dark brown coloration of this rather ''dirty'' individual is typical of most Missouri populations.
When I see dry sand habitats in Missouri, three tiger beetle species immediately come to mind—Cicindela formosa (big sand tiger beetle), C. scutellaris (festive tiger beetle), and Ellipsoptera lepida (ghost tiger beetle). My colleague and co-cicindelophile Chris Brown and I have spent many a weekend traveling up and down the state’s river systems with these species in mind. None of them are rare in the state, but their fidelity to deep, dry sand habitats also makes them by no means common. It is always cause for celebration when a new site is discovered for one of these species somewhere in Missouri. Thus, it was in anticipation of one (or more) of these species that I returned to the spot last week on the first truly gorgeous spring day of the season. Could it really be that, after ten years of searching for these species throughout the state, I would find a population just a few miles down the road from my house?!
A number of individuals in this population show traces of the bright coppery red coloration more typical of nominotypical populations west of Missouri.
Walking onto the site, I began to see tiger beetles immediately. However, they were Cicindela tranquebarica (oblique-lined tiger beetle), a common species in Missouri that enjoys not only dry sand habitats, but also wet sand, wet mud, dry clay, and even concrete habitats—hard to get excited about such a habitat slut! Nevertheless, within minutes I began seeing more robust beetles that were unmistakably big sand tigers. Big, bold, and beautiful, the beetles were wary in the late afternoon heat and quickly launched into their powerful escape flights that ended comically some 20 yards away with a characteristic bounce and a tumble. Such behavior might seem to make them impossible to photograph, but I’ve been at this for awhile and know their behavior pretty well—a slow, cautious approach, crouching carefully at the right distance, and crawling deliberately on elbows and knees while peering from behind the camera until it shows up in the lens set to 1:3 (one-third life size). Then it’s a matter of even more slowly closing the distance and scooting around to get the desired angles and composition. Move slowly enough and they’ll forget you’re there and resume normal behavior—you’ll be richly rewarded with views of foraging, stilting, and other classic tiger beetle behaviors.
Coloration and markings may seem conspicuous but provide excellent camouflage against the pebbley-sand substrate.
Most of the big sand tiger beetle populations we have found in Missouri are typical of the eastern subspecies C. formosa generosa, distinguished from other named subspecies by the dark brown dorsal coloration and thick white markings that are separate dorsally and joined along the outer edges of the elytra (Pearson et al. 2006). This subspecies is predominantly midwestern and northeastern in distribution, while the typically bright coppery-red individuals assigned to the nominotypical subspecies are found further west in the Great Plains. There are, however, certain populations in Missouri that show more or less suffusion of coppery-red coloration. This is typically explained as hybrid influence, as Missouri lies on the western edge of the distributional range of subspecies generosa. However, we have only seen these coppery-red indications on the eastern side of Missouri, while populations on the western side of the state along the Missouri River exhibit typical dark brown coloration. The population here in St. Louis Co. is the third population we have found to show this coppery-red influence, and in fact most of the individuals I saw exhibited greater or lesser amounts of this coloration. My personal belief is that there is no genetic basis for this subspecific distinction, but that the differences in color are instead related to conditions of the soil in which they live—possibly pH. Sand habitats in the eastern United States are typically acidic, while alkaline soils abound in the Great Plains (formerly a vast sea bottom). Hey, it’s a thought!
Big sand tiger beetles remain one of my favorite beetle species in Missouri.
The combination of striking coloration and bold white markings exhibited by big sand tiger beetles might seem to make them quite conspicuous and vulnerable to predation—especially in the open, sparsely vegetated areas that they inhabit; however, against the textured sandy substrates on which they are found they are almost impossible to detect until they move. I’ve learned not to try to see them first and sneak up on them, as this is a lesson in futility. Rather, I simply walk through an area and fix my sights on individuals as they take flight, watching them as they fly and eventually land and then sneaking up to the spot where I saw them land. I generally need to stop about 8-12 feet out and study the spot carefully to pick them out, and then I can continue sneaking up on them.
Photo Details: Canon 50D w/ 100mm macro lens (ISO 160, 1/200 sec, f/16), Canon MT-24EX flash w/ DIY oversized concave diffuser. Typical post-processing (levels, minor cropping, unsharp mask).
REFERENCES:
Pearson, D. L., C. B. Knisley and C. J. Kazilek. 2006. A Field Guide to the Tiger Beetles of the United States and Canada. Oxford University Press, New York, 227 pp.
Copyright © Ted C. MacRae 2011
Beetles In The Bush 
Fantastic photos, Ted! This remains one of my favorite species.
Thanks, Ben. I never get tired of finding these guys – they just have so much personality.
Gorgeous critter, Ted.
I don’t think the nature and nurture explanations for the variation are necessarily mutually exclusive, may not even likely to be.
Perhaps, but of course it’s all speculation either way unless/until somebody starts doing some genetic work.
Bolstering the nurture side of the argument is the fact that one of these “red” Missouri populations occurs in the sand flats at St. Joe State Park. These are not natural sand flats made of milled quartz, but rather anthropogenic flats of pulverized limestone from lead mining operations that took place there in the past—likely very high pH, and some of the reddest individuals I’ve ever seen, yet only fairly recently could they have colonized the area. The other “red” population occurs along the Current River, which like the Meramec, is a small gravel-bottomed river with much different character than the two Big Muddies. Every other Missouri population we’ve found occurs along those larger river systems and exhibits the typical brown coloration. Combine those observations with the fact that these are robust, powerful fliers that use their excellent dispersive capabilities to exploit ephemeral habitats, and it just doesn’t seem that likely that the color differences upon which these subspecies are based are due in any significant way to insular genetic effects.
Great post, Ted!
When I give up insects for a career in rap music, I will definitely making use of the word “nominotypical”. I can probably get it to rhyme with “anteroclypeal”, or some such.
Thanks, Alex. I use that word whenever I get the chance!
Of course, “habitat slut” is the term that had me chuckling the most when I wrote it.
Hi Ted. Enjoyed the post. I noticed your pics of these guys included the entire beetle, at the last even from a bit of a distance, which seems to be in contrast from what you have done quite a bit in the past– adult tiger photos with a close-up of a well positioned body with little concern for inclusion of the legs. I’ve gone back a forth between these two things and I usually try to get both types of shots including occasional shots from a greater distance to also give some idea of the microhabitat, behavior, etc. Is this post indicative of you now leaning more towards shots of the entire beetle, legs and all?
Hi Chris. I think it reflects my growing interest in composition. From that perspective, my personal favorite is the last one (actually the most distant shot) because of the sense of scale and landscape created by the inclusion of the plantlets and the view over the small rise. In earlier days I might have cropped that photo down quite a bit. That’s not to say I’m no longer interested in close shots, but I usually do those with more purpose now than just to show the whole beetle as close as possible, e.g. frontal or oblique-frontal shots.
Any idea if the nifty other beetle in the photo of the brown one is a prey item?
I only noticed that other beetle when I was examining the photographs. I didn’t see the tiger beetle acting predaceous at the time, so I think the other beetle just happened to be sitting where the tiger beetle landed. I’ve been trying to identify the smaller beetle – looks sort of like a dermestid, but I don’t know.
I understand that these beetles are fairly large for cicindelini (usually around 25mm). Does their size have any correlation with flight behavior/ propensity to fly when an intruder gets too close? I unfortunately have only observed a few species ( Cicindela sexguttata, Cicindela dorsalis media, Cicindela scutellaris unicolor). Based on your observations would you say that some species are “bolder” than others and thus easier to photograph?
Hi Roy – different tiger beetles show different degrees of skittishness, although there aren’t many that I would say are all that tame. The bigger ones tend to be more difficult because they are often more powerful fliers and, thus, fly longer distances when disturbed. I’ve pretty much learned how to approach them and move to allow myself to get so close – only during the hottest part of the day with highly skittish species (e.g., Ellipsoptera hirtilabris) do I find it impossible to get as close as I want.