Month: December 2016

Cicindela formosa pigmentosignata (the “reddish-green sand tiger beetle”)

/ Ted C. MacRae / 6 Comments

In my last post, I discussed Cicindela scutellaris rugata, the so-called “wrinkled fetiger beetle” (Erwin & Pearson 2008)—one of several geographically restricted subspecies of a more widespread and geographically variable species. This was not the only goal of the day, however, as I was also hoping to see a second geographically restricted subspecies—Cicindela formosa pigmentosignata, the “reddish-green sand tiger beetle (Erwin & Pearson 2008). The parent species of these two species show remarkably similar patterns of distribution, habits, and diversification—both occur most commonly as nominotypical subspecies in the Great Plains but have also expanded eastward and diverged there and around the periphery of their range into a number of distinctive subspecies; both favor deep, dry sand habitats without standing water; and both exhibit a “spring/fall” life history where sexually immature adults emerge in fall, pass the winter in burrows, and emerge again in spring ready to mate and lay eggs. In fact, these two species are so inextricably linked to each other that throughout most of their range, where one is found usually so is the other, and where one is represented by a distinctive subspecies so is the other. The main exception to this is in the far southeastern U.S., where C. scutellaris has established as the subspecies C. s. unicolor in sandy forest openings but C. formosa has not.

Cicindela formosa pigmentosignata

Cicindela formosa pigmentosignata W. Horn, 1930—Van Zandt Co., Texas

Cicindela formosa currently contains five recognized subspecies (Pearson et al. 2006)—the nominate subspecies (big sand tiger beetle) found west of Missouri (and which I’ve photographed in Nebraska), C. f. generosa (eastern sand tiger beetle) found in Missouri (photographed here and here) and further east, C. f. gibsoni (Gibson’s sand tiger beetle) found in Colorado and Manitoba (the consubspecificity of these two widely disjunct populations currently being the subject of debate), C. f. rutilovirescens (Mescalero sand tiger beetle) found in New Mexico (and which I’ve seen and collected a single specimen, but before my days as a photographer), and this one: C. f. pigmentosignata from eastern Texas and neighboring areas of Arkansas and Louisiana. Rumpp (1986) proposed that the parent species, C. formosa, radiated in central North America, adapting to barren sand conditions, dispersing along sand hills and major river systems into other areas, and ultimately diverging into the currently recognized subspecies.

Cicindela formosa pigmentosignata

Adults commonly exhibit “shade seeking” behavior during the hotter parts of the day.

As with C. s. rugata, I found this subspecies in a couple of old, rural cemeteries in eastern Texas (Henderson and Van Zandt Counties)—the photos shown here are from the second locality and were taken during the afternoon in the heat of the day. Because of this the beetles were quite wary and difficult to approach, but they also exhibited much more photogenic behaviors related to thermoregulation such as stilting and shade seeking. As I stalked the beetles through the deep, dry sand trying to get photographs, I was reminded yet again of why I love this species of tiger beetle so much—their bulk; their bulging eyes; their long, looping escape flights that end with a comical bounce and tumble, only to end up on their feet and facing their pursuer. These beetles are loaded with personality and behavioral charisma, and this particular subspecies with its brilliant and almost completely immaculate reddish-purple elytra and vividly contrasting blue-green legs and sides was an especially treasured sight to behold (especially after failing in my first attempt to find it back in 2012).

Cicindela formosa pigmentosignata

“Stilting” is another thermoregulatory behavior designed to raise the body up off the hot sand.

I am reasonably satisfied with these photos, although I would have liked to have gotten at least one without some part of the beetle obscured by foliage. That said, I now prefer some foliage in my tiger beetle photos, as I think it adds a bit of perspective, and when it is in the context of thermoregulatory behavior so much the better. And so, having now gotten good field photographs of this subspecies I am motivated more than ever to return to the Mescalero Sand Dunes in New Mexico and find and photograph C. f. rutilovirescens to complete my photographic “collection” of subspecies of the sand tiger beetle. Of course, by then I will probably be sufficiently dissatisfied with my existing photos of the other subspecies (already so with those of C. f. gibsoni due to excessively cropped compositions) that I will want to do the same with each of them as well. Such is the curse—and the blessing—of the insect photographer!

REFERENCES:

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

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

Rumpp, N. L. 1986. Two new tiger beetles of the genus Cicindela from western United States (Cicindelidae: Coleoptera). Bulletin of the Southern California Academy of Sciences 85(3):139–151 [Biodiversity Heritage Library pdf].

© Ted C. MacRae 2016

Cicindela scutellaris rugata (the “wrinkled tiger beetle”)

/ Ted C. MacRae / 9 Comments

During last year’s Fall Tiger Beetle Collecting Trip, I visited several rural cemeteries in northeastern Texas. No, this was not a diversion from my beetle collecting—cemeteries in rural areas can be great places to look for tiger beetles because they tend to be lightly managed parcels of land of low agricultural value, thus retaining to some degree the character of the original landscape. In this case, the cemeteries I visited were located in the northern part of Texas’ Post Oak Savannah, a transitional ecoregion with uplands characterized by deep sandy soils supporting native bunchgrasses and scattered post oaks. It is the open, sandy areas in this region where distinctive subspecific populations of two more broadly distributed tiger beetles can be found—Cicindela scutellaris rugata and Cicindela formosa pigmentosignata. One location where I looked for them was an old cemetery in Henderson County. Within minutes of stepping out of the car, I found the first subspecies—unmistakable by its solid shiny blue coloration.

Cicindela scutellaris rugata

Cicindela scutellaris rugata Vaurie, 1950—Henderson Co., Texas

Cicindela scutellaris rugata, dubbed the “wrinkled tiger beetle” by Erwin & Pearson (2008), is one of seven recognized subspecies of this widely distributed species that shows greater geographical variation than any other species of tiger beetle in North America (Pearson et al. 2006). Across its range the species is found in deep, dry sand habitats that are fully exposed to the sun and lack any standing water. Except in the far southeastern U.S., this species is often found in association with C. formosa (although in Missouri I have noted that C. scutellaris occurs slightly earlier in the spring and slightly later in the fall—perhaps at least in part to avoid direct competition with and possibly even predation by that larger species).

Cicindela scutellaris rugata

The “wrinkled tiger beetle” exhibits solid blue to blue-green coloration with no maculations.

This subspecies is similar in appearance to C. s. unicolor, distributed across the southeastern U.S. and separated from C. s. rugata by the Mississippi River floodplain—both are shiny blue to blue-green in coloration and exhibit no maculations on the elytra. However, C. s. rugata has a more wrinkled pronotum (hence, the subspecific epithet) and smoother head, while C. s. unicolor has a smoother pronotum and more wrinkled head. Another subspecies, C. s. flavoviridis, shares this surface sculpturing but differs in having the elytra colored lighter yellow-green—in this sense C. s. rugata can be considered intermediate between C. s. unicolor to the east and C. s. flavoviridis to the west (Vaurie 1950). Cicindela s. rugata can also be confused with immaculate forms of C. sexguttata (six-spotted tiger beetle), but the latter is less robust with a more tapered posterior, and both sexes of C. sexguttata have a whitish labrum (in all subspecies of C. scutellaris only males have a white labrum, while females have a dark to black labrum).

Cicindela scutellaris rugata

The more wrinkled pronotum and smoother head distinguishes C. s. rugata from C. s. unicolor.

As I have noted for other C. scutellaris subspecies that I have encountered (nominate as well as C. s. lecontei, C. s. yampae, and Missouri’s intergrade population of C. s. unicolor x C. s. lecontei), adults were fairly abundant during the late morning hours but largely disappeared during the afternoon, probably having dug into their burrows to escape the midday heat (although I did not search for the burrows and dig them out as I have done for the other mentioned subspecies). I did see a very few individuals at another sandy cemetery in neighboring Van Zandt Co. that I visited later in the afternoon (and at both locations I found the stunning C. formosa pigmentosignata—that will be the subject of another post).

REFERENCES:

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

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

Vaurie, P. 1950. Four new subspecies of the genus Cicindela (Coleoptera, Cicindelidae). American Museum Novitates 1458:1–6 [AMNH Digital Library pdf].

© Ted C. MacRae 2016

The “black bringer of light”

/ Ted C. MacRae / 6 Comments

During last year’s Fall Tiger Beetle Collecting Trip, I spent a day visiting cemeteries in the Post Oak Savannah region of northeastern Texas to look for tiger beetles associated with open sand in and around the cemeteries. It had been a good day, and I thought I would try to squeeze in one more visit to a locality I had visited earlier in the day. By the time I arrived at Sand Flat Cemetery in Henderson Co., however, it was almost 6 p.m.—the sun was still up, but the shadows were long and no tiger beetles were found. Not all insects, however, are so quick to turn in as tiger beetles, so I lingered for awhile and eventually found an area where several large bee flies (family Bombyliidae) were seen flying and briefly perching on the ground or the tips of plains snakecotton (Froelichia floridana). Since this was the last stop of the day and there were no tiger beetles to demand my attention, I spent a fair bit of time trying to photograph these very skittish flies and ended up with photos of two different individuals that I was happy with.

Poecilanthrax lucifer

Poecilanthrax lucifer (Fabricius, 1775)—Sand Flat Cemetery, Henderson Co., Texas

Alex Harman was the first to suggest they might represent the species Poecilanthrax lucifer based on a quick iPhone photo that I posted on Facebook, a hunch that was eventually confirmed by Bishop Museum dipterist Neil Evenhuis based on these photos sent to him by e-mail. Poecilanthrax  is a strictly North American (sensu lato) genus that, at the time of its last revision by Painter & Hall (1960), contained 35 species. Although distributed from Canada south through Central America, the greatest abundance of species and individuals is found in the Great Basin region, and, so far as is known, the larvae develop as parasites inside caterpillars of various cutworms and armyworms (family Noctuidae).

Poecilanthrax lucifer

Adults were found perching on the flowers of plains snakecotton (Froelichia floridana)

Poecilanthrax lucifer is one of the more widely distributed species in the genus, occurring predominantly in the West Indies and southern Gulf States but also ranging south into Central America and north into Arkansas and southern Illinois. It is distinguished from other species in the genus by its conspicuous black and yellow tomentose (densely covered with short matted woolly hairs) crossbands on the abdomen and the bases of the larger veins yellow or tan and contrasting with the remainder of the wing color pattern.

Poecilanthrax lucifer

Black and yellow tomentose abdominal bands and yellow/tan larger wing veins distinguish this species.

Like other species in the genus, P. lucifer is known to parasitize noctuid caterpillars, having been reared from fall armyworm (Spodoptera frugiperda) and exhibiting parasitism rates of up to 25%. This species is unique in the genus, however, in that it has also been reported as a hyperparasite (parasite of a parasite) of Myzine haemorrhoidalis (family Tiphiidae), a primary parasite of white grubs (genus Phyllophaga) in Puerto Rico. The life histories of many species in the genus remain unknown, however, so perhaps other species in the genus will eventually be found to act as hyperparasites as well. All species of Poecilanthrax appear to be univoltine (one generation per year) in natural habitats; however, P. lucifer and a few others that frequent agricultural areas have been found to become facultatively bivoltine or multivoltine due to the extended seasonal availability of pest caterpillars that often occur in these situations.

Poecilanthrax lucifer

“Satanic deadly disease” or “black bringer of light”?

The scientific name of Poecilanthrax lucifer is perhaps one of the more ominous sounding names I’ve encountered. “Anthrax” is, of course, commonly associated with the often deadly infectious bacterial disease caused by Bacillus anthracis, while “lucifer” is none other than Satan himself! However, I suspect that the name of the genus refers not to the disease, but rather its original Greek meaning of “charcoal” in reference to the often black color of the adult flies. Likewise, the original Latin meaning of the word “Lucifer” is “morning star” or “Venus” when used as a noun and “light-bringing” when used as an adjective—only after a series of corruptions through repeated transcriptions and translations of the Bible did it become a name synonymous with the Devil. Thus, a name that could be interpreted as “Satanic deadly disease” might actually mean the “black bringer of light”.

REFERENCE:

Painter, R. H. & J. C. Hall. 1960. A monograph of the genus Poecilanthrax (Diptera: Bombyliidae). Kansas State University of Agriculture and Applied Science, Agricultural Experiment Station, Technical Bulletin 106, 132 pp. [HathiTrust pdf].

© Ted C. MacRae 2016

Fun with eucraniines!

/ Ted C. MacRae / 2 Comments

During my February/March 2015 visit to Argentina, I had the opportunity to travel to west-central provinces of San Juan and San Luis with Federico Ocampo for a weekend of insect collecting. Up to that point most of my collecting in Argentina had been limited to the northeastern provinces (Chaco, Corrientes, and Misiones), so I was excited for the chance to explore a radically different biome. West-central Argentina represents a transition zone from the flat, wet, treeless plains of the Humid Pampas in east-central Argentina (Buenos Aires, Santa Fe, and Córdoba Provinces) to the massive Andes Mountains running along the western edge of South America. This area is home to the Monte, a desert biome characterized by volcanic sediments, piedmont plains, large mountain blocks and dry salt lakes. Conditions in the Monte are generally more hospitable than in the neighboring Atacama and Patagonian Deserts lying north and south of the Monte, respectively. As a result, the flora and fauna in the Monte is relatively rich and characterized by a diversity of shrubs, grasses, and cacti.

Dunas de Encón

Encón Dunes, San Luis Province, Argentina

Of the several sites we visited in the area, the most remarkable was “Las Dunas de Encón” (the Encón Sand Dunes) in San Luis Province. Belonging to a larger system covering some 250,000 hectares—the largest in South America (and, thus, sometimes called the “Argentinian Sahara”)—the dunes are thought to have formed some 100–200K years ago as a result of dry conditions brought on by Quaternary glaciations. I find sand dune systems endlessly fascinating due to their unique and often endemic plants and animals and have visited many systems in North America (Bruneau, Coral Pink, Glamis, Great, Medora, St. Anthony, and others), but this was the first sand dune system I’ve had the opportunity to see outside of the U.S. Federico, a scarab specialist, shares that fascination and has, in fact, described a number of species in the scarabaeine tribe Eucraniini—endemic to South America—that utilize these very sand dunes (Ocampo 2005, 2007, 2010). He was hoping one or more of them might be out and about; I was hoping to see anything, really.

Host for Lampetis spp.

Parkinsonia praecox? – adult host plant for Lampetis baeri and L. corinthia.

One of the first plants that caught my attention was a woody, fabaceous shrub that looked very much like what I would have previously called Cercidium, now Parkinsonia, and which after a bit of digging I conclude is likely Parkinsonia praecox. Woody, fabaceous shrubs in desert habitats are a sure bet to host jewel beetles, so I began paying special attention to each shrub as I wandered by. It wasn’t long before I saw a large, brilliant metallic green jewel beetle sitting on an outer branch of one of the shrubs—it was one of the most beautiful jewel beetles I have ever seen out in the field with my own eyes! I managed to catch it, and over the next few hours I collected not only several more of this species but also several individuals of an even larger, more somber-colored species. I was able to identify them as Lampetis baeri (Kerremans, 1910) and L. corinthia (Fairmaire, 1864), respectively, when I compared them to material in the collections at Fundacion Miguel Lillo, Instituto de Entomologia, Tucuman, Argentina [IFML]) during my visit there the following week (see photos below).

Lampetis baeri (Kerremans, 1910)

Lampetis baeri (Kerremans, 1910) [IFML]


Lampetis corinthia (Fairmaire, 1864)

Lampetis corinthia (Fairmaire, 1864) [IFML]

As a jewel beetle enthusiast, you would think that was the highlight of my day. In fact, the fun had only started. For a time after our arrival, Federico pointed out burrows likely made by eucraniine adults, but we didn’t see any evidence of activity at first. It wasn’t long, however, before we found the first adult—a fine Eucranium beleni Ocampo, 2010, the largest of the three species occurring at this site (about the size of our North American Deltochilum). One of the more obvious features of eucraniines is their enormously enlarged forelegs and pronotum to hold the musculature required to carry—that’s right, carry!—provisions to the larval burrow (in contrast with the more commonly seen habit among members of the subfamily of using the hind legs to push provisions to the burrow). This unusual morphology gives these beetles not only an amusing, shuffling gait but also a rather comical method for turning themselves upright (as seen in this video narrated by Federico). There are other dung beetles that pull, rather than push, larval provisions (e.g., Sisyphus spp., which stand on highly elongate hind legs and walk backwards while pulling the dungball), but eucraniines seem to be the only ones that actually lift provisions off the ground to carry them. In the case of E. beleni, this involves carrying pieces of dung with the forelegs held out in front of the head while walking forward on the middle and hind legs (Ocampo 2010). I didn’t get to see that behavior with E. beleni, but I did see it with one of another of the eucraniines we found that day (see below). In the E. beleni photo below, note the brushy middle and hind tarsi—an adaptation for walking on loose sand.

Eucranium belenae

Eucranium belenae Ocampo, 2010 walks on its middle/hind legs while holding its forelegs aloft.

Eucranium belenae burrow

Eucranium belenae burrow plugged with a piece of dung.

The second species in the group that we encountered was Anomiopsoides cavifrons (Burmeister, 1861). This species is much smaller than E. beleni (about the size of a large Onthophagus), and unlike E. beleni—and, in fact, most other dung beetles—the larvae of A. cavifrons develop on plant matter rather than dung. Both males and females provision the larval burrows with pieces of plant debris that they pick up with their front legs and carry back to the burrow while walking on their other four legs. This rather amusing video shows a male bringing a piece of debris back to his burrow, then exiting to find and retrieve another piece of debris to bring back to the burrow. The molar region of their mandibles is heavily sclerotized for masticating the plant fibers in preparation for the larvae. There are a couple of other species in the tribe that opportunistically include plant matter in their diet, but A. cavifons seems to be the only one known to utilize dry plant matter in desert habitats almost exclusively (Ocampo 2005). Anomiopsoides cavifrons was far more abundant in the dunes than E. beleni, and by early to mid-afternoon they were encountered with such regularity that I stopped even looking at them.

Anomiopsoides cavifrons male at burrow

Anomiopsoides cavifrons (Burmeister, 1861) male at burrow entrance.

We also were fortunate to see a few individuals of the third species known from these dunes, Anomiopsoides fedemariai Ocampo, 2007. This species is intermediate in size between the extremes represented by E. beleni and A. cavifrons and utilizes pellets of the plains viscacha (Lagostomus maximus), a species of rodent in the family Chinchillidae, for food (Ocampo 2007).

REFERENCE:

Ocampo, F. C. 2005. Revision of the southern South American endemic genus Anomiopsoides Blackwelder, 1944 (Coleoptera: Scarabaeidae: Scarabaeinae: Eucraniini) and description of its food relocation behavior. Journal of Natural History 39(27):2537–2557 [pdf via DigitalCommons].

Ocampo, F. C. 2007. The Argentinean dung beetle genus Anomiopsoides (Scarabaeidae: Scarabaeinae: Eucraniini): description of a new species, and new synonymies for A. heteroclyta. Revista Sociedad Entomología Argentina 66(3–4):159–168 [pdf via SciELO Argentina].

Ocampo, F. C. 2010. A revision of the Argentinean endemic genus Eucranium Brullé (Coleoptera: Scarabaeidae: Scarabaeinae) with description of one new species and new synonymies. Journal of Insect Science 10:205, available online: insectscience.org/10.205 [pdf via DigitalCommons].

© Ted C. MacRae 2016