Month: September 2011

Cicindela formosa gibsoni… or not!

/ Ted C. MacRae / 11 Comments

Last Friday I began the 2011 Annual Fall Tiger Beetle Trip™. This year’s edition was actually a last-minute change—my original plans to collect wood for rearing wood-boring beetles in south Texas thwarted by that state’s long and continuing drought (along with the unwillingness of some of the area’s federal wildlife refuge managers to grant my research study permits despite the work I’ve done there in past years—apparently only institutional and not personal research is now deemed credible by these courageous individuals who are doing their best to protect the natural resources in their charge). My travel funds are limited, and rather than throw good money at a bad situation, I decided to pursue greater chances of success and make the trip that I have wanted to do for some time now—the Great Sand Dunes tour through the Rocky Mountains and Great Basin. The target species include many of the classic western sand dune species, and I hope to feature most of them in the days and weeks after the conclusion of the trip this coming weekend.

Cicindela formosa gibsoni | nr. Maybell, Colorado

The first of these target species that I encountered is the subject of this post, Cicindela formosa gibsoni (Gibson’s Big Sand Tiger Beetle).  This large, robust, and gorgeously marked subspecies is highly restricted in occurrence, curiously to two areas separated by more than 1,000 km—the Maybell Sand Dunes in northwestern Colorado (Moffat County) and the Great Sand Dunes of southwestern Saskatchewan.  It is distinguished from the nominate form and other subspecies by having the white markings of the elytra so expanded in most individuals that they coalesce and cover nearly the entire elytral surface.  The result of such a large white surface with contrasting red-purple head, thorax, and elytral sutural area is one of North America’s most spectacularly marked tiger beetle species.  The individual photographed here was one of many observed a few days ago on the Maybell Sand Dunes¹, and I feel truly lucky to have been able to personally witness these striking beetles flying powerfully across the dunes in their small home range, landing far away with the comical bounce and tumble that is characteristic of this and the other subspecies.

¹ In the interest of full disclosure, these photos were taken later in the day using subjects confined in a terrarium of native substrate. I had intended to photograph them in the field; however, they unexpectedly began digging burrows around 2 p.m., and my efforts to stalk the last few stragglers before they disappeared were not successful.


An interesting situation occurs regarding the taxonomy of this subspecies.  Despite the nearly identical appearance of adults from both the Saskatchewan and Colorado populations, logic and differences in larval coloration suggest that these two populations have arisen independently, their common appearance a result of convergence rather than shared ancestry.  Molecular studies are in progress to determine more conclusively whether this is true (hopefully augmented with material collected during this trip).  The subspecies was originally described based on specimens collected in Saskatchewan, thus, if convergence is confirmed the Maybell population will find itself needing a new name.

Congratulations to Doug Taron, who narrowly beat perennial heavyweight Ben Coulter, Tracy Mormon and Mr. Phidippus for the ID Challenge #12 win.  The overall standings remain unchanged, with Ben still in the lead with 65 points, Mr. Phidippus 2nd with 54 points, and Roy completing the podium at 39 points.  The final standings may seem like a lock, but there will still be one more challenge in the session—anything can happen!

Copyright © Ted C. MacRae 2011

ID Challenge #12

/ Ted C. MacRae / 29 Comments

This should be a relatively easy ID Challenge compared to previous editions—2 points each for the correct order, family, genus, species, and subspecies.  Additional points will be awarded on a discretionary basis for relevant natural history comments.  Standard challenge rules apply, including moderated comments during the challenge period (you don’t have to be first to score points), early-bird points to those who do arrive at the correct answer before others, etc.  Ben Coulter maintains a commanding lead in BitB Challenge Session #4, but with this and one more challenges left in the current session is his lead secure?

Copyright © Ted C. MacRae 2011

My Canon 8X Macro Lens

/ Ted C. MacRae / 37 Comments

For the past few months I have started routinely using extension tubes with my 100mm macro lens for photographing tiger beetles. I do this primarily because for most tiger beetles and other insects in the smallish to medium-sized range I need the capability to go both above and below 1X magnification, meaning that I must constantly switch between my Canon 100mm lens (1X maximum) and MP-E 65mm lens (1X minimum). With a full extension tube set (68mm), my 100mm macro lens effectively becomes a 0.7–2.0X macro lens, a nice range of magnifications for most of the photographs that I take. There is a secondary benefit to this in that the subject-to-lens distance is decreased somewhat, allowing me to get the MT-24EX flash heads closer to the subject for better lighting.

Lately I’ve been wondering what the magnification capabilities would be if I added extension tubes to the 65mm lens.  With a maximum magnification of 5X, it hardly seems that even more magnification would ever be needed, but who knows what uses one might find if the capability exists.  In theory, it seemed like it should work—after all extension tubes are simply tubes with no glass (in fact, the 65mm lens itself is simply a macro lens with a very expensive, built-in bellows).  The only consideration was whether the focal plane would remain outside of the lens.  Tonight I finally decided to sit down and try it out, and the results were really quite stunning.  The three photos below show an ordinary pencil lead, the first with the 65mm lens alone set at 1X, the second with the lens set at 1X plus full extension tubes, and the third with full extension tubes and the lens set at 5X.  The full extension tube set provides an additional ~1.7X magnification, making the 65mm lens effectively a 1.7–8.0X macro lens!

Canon MP-E 65mm lens @ 1X

Canon MP-E 65mm lens @ 1X + 68mm extension tubes (= 1.7X)

Canon MP-E 1-5X macro lens @ 5X + 68mm extension tubes (= 8X)

The subject-to-lens distance is indeed quite short—only about 38mm or so.  However, having at my disposal an 8X macro lens suddenly opens up a whole new world of ideas for insect macrophotography.  Knowing that the combination of 65mm lens and extension tubes is possible, I just had to try this out on a living subject—like now!  I happened to have in a terrarium a subject from the day’s collecting, so I tried it out—again with the 65mm lens fully extended to result in 8X magnification.  Shown below is a example of this lens combination at full magnification, completely uncropped—can you name the subject?

Canon MP-E 65mm lens @ 5X + 68mm extension tubes (= 8X)

Copyright © Ted C. MacRae 2011

A cicindelophilic wish list

/ Ted C. MacRae / 3 Comments

  • Cicindelia obsoleta vulturina disjuncts bolting across lichen-covered sandstone balds.
  • Cicindela scutellaris yampae—red, white and blue in all its glory!
  • Big, bold, hugely white Cicindela formosa gibsoni bouncing across the sand.
  • Cicindela arenicola dancing across the St. Anthony dunes.
  • Hugely-mandibled male Cicindela waynei riding the backs of their lovers.
  • The almost pure white Cicindela albissima in its own tiny little corner of Utah.
  • Cicindela theatina, perhaps most colorful of the western sand dune species.

In a perfect world, I will make it to every one of these locations and encounter each and every species in the list. More realistically, it would be presumptuous to expect complete success on such a quickly planned, last minute trip—I’ll be happy to make it to at least some of these sites and find what I’m looking for. Beyond the above species there should also be the more reliable Cicindela lengi, C. tranquebarica, and the nominate forms of C. formosa and C. scutellaris—classic denizons of the west. When I get a chance to take a look in alkaline flats, perhaps I’ll also be able to add C. willistoni or C. parowana to the bounty list. When I can take specimens, I will (responsibly), and when I can’t I’ll hopefully take acceptable photos. Really though, this is mostly about getting out and seeing a huge swath of the country that I’ve never seen before during the most gorgeous time of year. I’ll see it my way—up close and personal and not just blasting by at 70 mph. Sometimes life just doesn’t get any better!

Copyright © Ted C. MacRae 2011

Not all Florida tiger beetles are rare

/ Ted C. MacRae / 6 Comments

Tetracha carolina (Carolina Metallic Tiger Beetle) | Dixie Co., Florida

I fear my recent series of posts from Florida might leave readers with the impression that all of that state’s tiger beetle species are rare endemics occurring in tiny remnants of relictual habitats and encountered only by the most intrepid collectors enduring the harshest of conditions.  While it’s true that Florida has its share of such species (perhaps more than any other state in the country), it is also home to numerous species that most cicindelophiles would consider rather common—even pedestrian.  “Common” is a relative term, however, depending on where you live, and featured here is a species that until recently would have been for me just as exciting a find as Cicindelidia scabra or Habroscelimorpha striga.

Purple reflections and expanded apical lunules on the elytra distinguish this species from T. floridana

Tetracha carolina (Carolina Metallic Tiger Beetle) is one of the most widely distributed tiger beetle species in the Western Hemisphere, occurring not only across the southern U.S. but also the West Indies and south through Mexico, Central America, and the west coast of South America to Chile.  It was only during the past 10 years, however, that I actually saw the species for myself in Missouri, as it is restricted to the Mississippi Alluvial Plain in the extreme southeastern corner of the state (the so-called “Bootheel”).  Not much was known about the status of this species in Missouri the first time I encountered it under building lights at the University of Missouri Delta Research Center in Portageville.  It was my first experience with “nocturnal tiger beetling,” and you can imagine my excitement at seeing these green and purple beauties glittering in the light of my headlamp.  We now know that the species, despite its restricted occurrence in Missouri, is actually quite common in a variety of habitats in that part of the state, including even agricultural fields where they hide during the day under irrigation pipes (Fothergill et al. 2011).

I simply can't resist these tiger beetle face shots!

The individual in the photographs shown here was seen at the famed “Road to Nowhere” site in a remote part of the Florida Gulf Coast—one of eight total species of tiger beetles that I’ve seen at this site during my two August visits (2009 and this year).  This site is actually one of a few places in Florida where this species co-occurs with T. floridana (Florida Metallic Tiger Beetle), an endemic species restricted to estuarian habitats in the southern half of the Florida peninsula, and until recently considered a subspecies of T. carolina (Naviaux 2007).  The brilliant purple reflections in the basal half of the elytra clearly distinguish this individual as T. carolina, as did its occurrence up on the drier sandy roadside rather than down in the salty mud flats preferred by T. floridana.  Also seen at this site up along the road were numerous adults of the broadly distributed T. virginica (Virginia Metallic Tiger Beetle), making this one of the few sites in the country where three of the four U.S. species of Tetracha can be found (the fourth, T. impressa—Upland Metallic Tiger Beetle, is a Neotropical species that reaches the U.S. only in the Lower Rio Grande Valley of south Texas).

REFERENCE:

Fothergill, K., C. B. Cross, K. V. Tindall, T. C. MacRae and C. R. Brown. 2011. Tetracha carolina L. (Coleoptera: Carabidae: Cicindelitae) associated with polypipe irrigation systems in southeastern Missouri agricultural lands. Cicindela 43(3): in press.

Naviaux R. 2007. Tetracha (Coleoptera, Cicindelidae, Megacephalina): Revision du genre et descriptions de nouveaus taxons. Mémoires de la Société entomologique de France 7:1–197.

Copyright © Ted C. MacRae 2011

Two things I love about glades during fall…

/ Ted C. MacRae / 9 Comments

…prairie dock (Silphium terebinthinaceum) in bloom…

Prairie dock (Silphium terebinthinaceum) in bloom | Caney Mountain Cons. Area, Ozark Co., Missouri

…and prairie tiger beetles (Cicindelidia obsoleta vulturina) on the prowl…

Prairie tiger beetle (Cicindelidia obsoleta vulturina) | Caney Mountain Cons. Area, Ozark Co., Missouri

On the last weekend of August I made another trip to the White River Hills of north-central Arkansas in a last gasp effort to confirm the occurrence in the area of the swift tiger beetle (Cylindera celeripes).  Records of this species include a single individual collected in 1996 at a site near Calico Rock, but two trips to the area this past June had already failed to reveal its presence.  I didn’t really expect that I would find it this time either, and such was the case.  However, what I was expecting/hoping to see was the beginning of the fall emergence of the prairie tiger beetle.  The Missouri/Arkansas disjunct population of this handsome species is perhaps my favorite tiger beetle of all, not only because of its good looks but because of the many spectacular fall collecting trips I’ve taken through the White River Hills to look for it.  In this regard I had success, although only two individuals were seen all day long.  The area around Calico Rock seemed dry, apparently having been missed by the thunderstorms that rolled through the area a week earlier and that would have surely triggered full bore adult emergence. 

Long Bald Glade Natural Area, Caney Mountain Cons. Area, Ozark Co., Missouri

The following day I returned to Caney Mountain Conservation Area on the Missouri side, where last fall I had finally found prairie tiger beetles after years of searching what must be the extreme northeasternmost limit of its distribution.  Fresh evidence of recent rains was seen, and accordingly the beetles were out in fairly decent numbers in the same area where I found them last fall.  I took the opportunity to photograph a few individuals (which I had not done last year) and then turned my attention to looking for other insects.  I had my eye out for the spectacularly beautiful bumelia borer (Plinthocoelium suaveolens) and eventually found one.  I hoped also to see the marvelously monstrous Microstylum morosum (North America’s largest robber fly), which I found at this site in 2009 as a new state record and was rewarded with two individuals (these will serve as vouchers for the state record, since I didn’t collect it in 2009).  Temperatures were rather warm and both of these latter species are traditional “summer” species; however, the presence of prairie tiger beetles, the tawny tinge to the prairie grasses, and the noticeably longer shadows under a deep blue sky told me that fall was, indeed, on the way.

Prairie tiger beetle (Cicindelidia obsoleta vulturina) | Caney Mountain Cons. Area, Ozark Co., Missouri

While prairie tiger beetles are (at least for me) the most iconic harbinger of fall in the White River Hills, another classic fall sight was the thick stands of prairie dock plants with their tall, bolting flower spikes.  In Missouri this plant serves as a larval host for the longhorned beetle Ataxia hubbardi.  In my early years of collecting in Missouri’s glades, I delighted in finding adults of these beetles clinging to the flower stalks during fall—presumably laying eggs from which larvae would hatch and bore down into the tap-root.  Although commonly regarded as a pest in sunflower in the southern Great Plains, individuals associated with prairie dock in Missouri’s glades seem different—smaller, narrower, and darker—than those found on sunflower and other more common hosts.  Additional material will be needed to make a final assessment on whether these individuals represent a distinct taxon; however, I have not been able to find this species on prairie dock in Missouri since I moved back to the state nearly 16 years ago.  The reason for this sudden disappearance remains a mystery, and perhaps it is purely coincidental that the Missouri Department of Conservation began managing all of their glades with prescribed burns during my previous 5-year absence from the state.  In the meantime, I will continue to examine prairie dock stems every fall in the hopes that once again I will find the beetles and be able to come to a decision about their taxonomic status.  Perhaps I should re-focus my efforts in “low quality” (i.e., never-burned) gladey roadsides rather than our state’s “high quality” (i.e., high floral diversity) natural areas.

Copyright © Ted C. MacRae 2011

Crazy Eyes

/ Ted C. MacRae / 70 Comments

Spissistilus festinus | Stoneville, Mississippi

Spissistilus festinus (three-cornered alfalfa hopper) is one of the few truly economic pests in the otherwise bizarre and innocuous family Membracidae (treehoppers).  Its common name alludes to one of the crops it affects, but my encounters with this species are most often in soybean (I am, after all, a soybean entomologist).  Damage in this crop is caused by both adults and nymphs, whose piercing/sucking mouthparts cause girdling and breakage of the stem—often just a few inches above the soil.  This individual was seen during my travels last week in a soybean field in Stoneville, Mississippi, where numbers throughout the season were especially high this year.  Although I have seen innumerable S. festinus adults, I have never noticed their crazy, zig-zag patterned red and white eyes until I managed this closeup face shot (click on photo for best view).

This slightly cropped photo was taken with a 100mm macro lens and full extension tube set, resulting in slightly more than 2X magnification.  One of the lessons I took from was the need to pay more attention to background and value contrast.  By placing the subject a few inches in front of the dark green soybean foliage I was able to achieve a much more pleasing background than the typical black background one gets with full flash photos at high magnification.  Although both the subject and the background are green, there is still sufficient difference in shade to create contrast between them.  Light-green is one of the more difficult colors to work with when full flash is used with high shutter speeds and small apertures to maximize crispness and detail (in this case, 1/250 sec and f/16).  However, increasing ISO to 400 and lowering flash exposure compensation to -2/3 can reduce the amount of flash needed to illuminate the subject with such settings, making it easier to achieve a properly exposed and true-colored subject.

Copyright © Ted C. MacRae 2011

Mini-review of the Cicindelidia abdominalis species-group

/ Ted C. MacRae / 8 Comments

Now that I have seen and photographed in the field all four species of the Cicindelidia abdominalis species-group, I thought some might find it useful to have a summary of each species with comparisons, photographs and a key to distinguish the four species. The key presented below is based on that found in Brzoska et al. (2011), which itself is a modification of couplet 8 in the key to the species of Common Tiger Beetles (Cicindela) found in Pearson et al. (2006). Following the key are comparative notes for each species that discuss key characters and give specific information about their distribution, along with field photographs to illustrate the distinguishing characters.

Key to the Cicindelidia abdominalis species-group

1. Elytral surface covered with deep punctures, pronotum with dense decumbent setae (old specimens may have the setae rubbed off and the presence of setal punctures should be checked), usually with 6 labral setae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

— Elytral surface (excluding presutural foveae) relatively smooth, with shallow punctures, pronotum glabrous or with fine pronotal setae, usually with 4 pronotal setae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2(1) Elytra black, with a post median marginal spot, usually with a vestige of a middle band, restricted to peninsular FL north of Miami-Dade County . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. scabrosa (Schaupp)

— Elytra green or bronze-green, rarely with a post median marginal spot, and without evidence of a middle band, restricted to Miami-Dade County, FL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. floridana (Cartwright)

3(1) Pronotum, and mes- and metepisternum glabrous, restricted to Polk and Highlands Counties, FL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. highlandensis (Choate)

— Pronotum with fine decumbent setae, and mes- and metepisternum with decumbent setae, widespread across southeastern U.S. Coastal Plain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C . abdominalis (Fabricius)

Cicindelidia scabrosa—Scabrous Tiger Beetle

This species is largely limited to oak/pine scrub habitats in peninsular Florida north of Miami-Dade Co., although it does just sneak north of the border into souutheastern Georgia. From Cicindelidia abdominalis and C. highlandensis it can be distinguished by the distinctly punctured rather than smooth elytra and the presence of dense white setae along the lateral margins of the pronotum. From C. floridana it can be distinguished by the black rather than coppery-green coloration and the usual presence of a post-median spot along the lateral elytral margins. More information about this species can be found in my post, “The (almost) Florida-endemic Cicindelidia scabrosa.”

Cicindelidia scabrosa
Cicindelidia scabrosa | Levy Co., Florida

Cicindelidia floridana—Miami Tiger Beetle

Only recently rediscovered after being thought extinct for nearly a century, this species is most similar to C. scabrosa but is restricted to pine rockland habitat in Miami-Dade Co. where C. scabrosa does not occur. Like that species it exhibits the distinctly punctured rather than smooth elytra and dense white setae along the lateral margins of the pronotum that distinguish both species from C. abdominalis and C. highlandensis; however, its coloration is brilliant coppery green rather than black like C. scabrosa, especially in living individuals seen in the wild. More information about this species can be found in my posts, “Rediscovery of Cicindela scabrosa floridana” and “Photographing the Newly Rediscovered Cicindelidia floridana.”

Cicindelidia floridana
Cicindelidia floridana | Miami-Dade Co., Florida

Cicindelidia highlandensis—Highlands Tiger Beetle

This species is most similar to C. abdominalis, sharing with it the smooth elytra and glabrous pronotum that distinguish both species from C. scabrosa and C. floridana. Unlike that more widespread species, however, C. highlandensis is found only along a narrow band of sand scrub habitats on the Lake Wales Ridge in Polk and Highland Cos., central Florida, and it can be distinguished from it by the lack of white setae on the pronotum and mes- and metepisterna (lateral portions of the thorax above the middle and hind legs). More information about this species can be found in my post, “Highlands Tiger Beetle.”

Cicindelidia highlandensis
Cicindelidia highlandensis | Polk Co., Florida

Cicindelidia abdominalis—Eastern Pine Barrens Tiger Beetle

This is the only relatively broadly distributed species of the group, occurring in a variety of dry sand habitats along the southeastern U.S. Coastal Plain from New Jersey west to Louisiana and south into the northern half of Florida. Aside from its non-endemic distribution, this species can be distinguished from C. scabrosa and C. floridana by its smooth elytra and lack of dense white setae along the lateral pronotal margin, and from it’s most similar relative C. highlandensis by the presence of fine, decumbent (lying down) setae on the pronotum and on the mes- and metepisterna above the middle and hind legs. More information about this species can be found in my post, “Tiger Beetles Agree—It’s Hot in Florida!.”

Cicindelidia abdominalis
Cicindelidia abdominalis | Withlacoochee Co., Florida

REFERENCES:

Brzoska, D., C. B. Knisley, and J. Slotten. 2011. Rediscovery of Cicindela scabrosa floridana Cartwright (Coleoptera: Cicindelidae) and its elevation to species level. Insecta Mundi 0162:1–7.

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