entomology

When is an ant not an ant? When it’s a jumping spider, of course!

/ Ted C. MacRae / 12 Comments

Peckhamia sp.

This past weekend my good friend and long-time collecting partner Rich and I visited one of our favorite insect collecting spots in all of Missouri – Victoria Glades Conservation Area. Together with an adjacent parcel owned by The Nature Conservancy, these represent one of the finest remaining examples of the glades – more properly called xeric limestone prairies – that once extended in an arc through Jefferson Co. south of St. Louis on south and west facing exposures of dolomitic limestone1.

1 For a more detailed description of the geology and natural history of these glades, see my post The Glades of Jefferson County.

Spring was late this season, with cool and wet conditions persisting into the early part of May. During the past two weeks, however, it has warmed and dried considerably (too much, almost), and thus the cacophony of life has begun in earnest. Still, despite the heat, we found the abundance of insects rather sparing, which in combination with the suite of wildflowers that were seen in bloom gave a feel of early spring (I mentioned to Rich that it “seemed like May 10th”). There were a few good species to be found though, the first being a single Agrilus fuscipennis, beaten off of its host persimmon (Diospyros virginiana). Continued beating of persimmon turned up little else, at which point I turned my attention to the post oak (Quercus stellata) trees lining the margins of the glades. The first couple of branches that I whacked turned up little of interest, but an “ant” that fell on my sheet from the third branch gave me pause – it was a little “too big”, and the manner it which it scampered across the sheet was a little “too urgent” and “too halting”. When I looked at it more closely, I realized that it was, of course, not an ant at all, but a jumping spider (family Salticidae), and more specifically a species in one of several genera within the family that are known for their striking mimicry of ants.

I have long wanted to photograph one of these gems, having seen them once or twice before but thus far not successful in photographing them. In this particular case, I had the advantage of somebody to help me, so I coaxed the spider onto a stick and had Rich hold it while I got my camera ready. Unfortunately, the ant… er, spider just kept running up and down the stick from one end to the other, forcing me to repeatedly grab the stick on alternating ends with one hand after the other (and quickly or it would run onto my hands!) and never really having an opportunity to attempt some shots. After a time of this, I decided to coax it onto a leaf instead to see if the larger, flatter surface might be of some help. It really didn’t, though, as the ant JUST. WOULD. NOT. STOP. RUNNING! Eventually, I resorted to simply trying to track the spider through the lens – holding the camera with my right hand and the leaf with my left, and firing shots whenever I thought the spider might be even close to in focus. I can be patient when photographing insects (and their kin), but this spider certainly tested my limits, and I eventually ended the session not at all confident that I had any usable photos. To my surprise, I managed to get one image (above) that wasn’t half bad and another that was at least serviceable (below – focus a bit too much in “front”).

Peckhamia sp.

As far as I can tell, this individual is a species of the genus Peckhamia, which Cutler (1988) distinguishes from the related genus Synageles by the carapace being more convex in the cephalic area and sharply declivous (downward sloping) behind the third row of eyes. The individual in these photos seems to agree with these characters, if I am interpreting them correctly. He also mentions the habit of species in these two genera to hold their second pair of legs aloft to give the illusion of them being antennae, which we noted for this individual and can attest to its effectiveness!

For more about ant mimics that I have found in Missouri, see my previous posts Flower ants? Check again! and North America’s itsiest bitsiest longhorned beetle.

REFERENCE:

Cutler, B. 1988. A revision of the American species of the antlike jumping spider genus Synageles (Araneae, Salticidae). Journal of Arachnology 15(3) [1987]:321–348 [pdf].

© Ted C. MacRae 2018

Ellipsoptera lepida – ghost tiger beetle

/ Ted C. MacRae / 7 Comments

In the early 2000s, Chris Brown and I were beginning our general survey of Missouri tiger beetles. Our goal was to characterize the occurrence and distribution of all species within the state. At the time, 22 species were known to occur in Missouri, and our work would uncover the presence of two more—one being a vagrant occurrence of the widespread Cicindelidia trifasciata ascendens (ascendent tiger beetle) (Brown & MacRae 2005); the other being the rare Cylindera celeripes (swift tiger beetle) (MacRae & Brown 2011). Of the species already known from the state, however, some were known from only a few records and hadn’t been seen in the field by either Chris or myself. One such species was Ellipsoptera lepida (ghost tiger beetle), an almost pure white species known to occur in deep, dry sand habitats over most of central North America (Pearson et al. 2015). At that time, I had still seen only the more common species in Missouri, and the combination of its name and unusual, mostly-white color put this species high on my “must see” list.

Ellipsoptera lepida (ghost tiger beetle)

My first experience would come quickly. In June 2001, Chris and I visited a recent addition to Weldon Spring Conservation Area on the north side of the Missouri River in St. Charles Co. called Darst Bottoms. The area at one time was productive farmland, but the “Great Floods” of 1993 and 1995 left deep deposits of sand over the area. While no longer suitable for agriculture, the process of succession allowed valuable wildlife habitat to develop, and the area was purchased and added to the Conservation Area. By the time of our visit in 2001, early succession had resulted in young forests of mostly eastern cottonwood (Populus deltoides) surrounding a vast central plain of white sand. Chris and I didn’t know what to expect on that first visit, both of us being in the early stages of our survey of Missouri tiger beetles, but we figured we would find something interesting.

Ellipsoptera lepida (ghost tiger beetle)

I still remember the moment I first saw E. lepida and realized what it was. We had already found Cicindela formosa generosa (eastern big sand tiger beetle)—the first time I had seen that species in Missouri outside the southeastern lowlands (we would eventually find it at many sites along the Missouri and Mississippi Rivers and a few smaller interior rivers)—and were searching for additional specimens. We were in a small opening adjacent to the larger central plain when I thought I saw something move near my feet. I stopped to look down but didn’t see anything, so I began walking again while scanning the ground ahead of me. Again, I thought I saw movement nearby and stopped to look, this time pausing a little longer and doing so a little more carefully. That’s when I saw it, and even though I had seen only photographs of the species and museum specimens I recognized it instantly for what it was and yelled out “lepida!” Chris came over to see for himself, and we marveled at the effectiveness of their camouflage—they seemingly were able to disappear right before our eyes even though we were looking right at them.

Sand plain habitat for Ellipsoptera lepida (ghost tiger beetle).

Over the next few years, Chris and I found the species at several sites along or not too distant from the Missouri and Mississippi Rivers—always on sand deposits deep enough to become dry. We never found them in great numbers, sometimes just single individuals while other sand residents were abundant, and not at all sites where we did find more reliable species such as C. f. generosa and C. tranquebarica (oblique-lined tiger beetle). Pearson et al. (2015) mention that despite the broad distribution of this species across central North America that its actual occurrence is rather spotty and localized and that it has disappeared from many sites where it was previously known to occur. This was our experience in Missouri as well, as many of the museum records we had gleaned for the species no longer appeared to support populations of the beetle. This is likely due, at least in part, to the ephemeral nature of the habitats on which the species depends, at least those along the big rivers that are vulnerable to revegetation and succession back to bottomland forest.

Ellipsoptera lepida (ghost tiger beetle)

Of course, all of this occurred long before I took up insect macrophotography in 2009, and while I had managed to photograph most of the tiger beetle species in Missouri in the years that followed, E. lepida was one that I continued to lack. In the summer of 2015 I decided to rectify that situation and, when the time was right, returned to Darst Bottoms in hopes of finding and photographing this species. Imagine my surprise when I hiked into the area and, instead of young cottonwood stands surrounding a vast, barren sand plain, I found mature cottonwood forests surrounding a thickly vegetated sand prairie with only isolated patches of barren sand. Needless to say, with such little suitable habitat for the beetles they were neither abundant nor even common. In fact, the only evidence I found that told me they were still there at all was coyote scat containing unmistakable remains of the adult beetles. Skunked on my first effort, I decided to try another spot where we had seen good populations of the beetle—Overton Bottoms Conservation Area along the Missouri River in Cooper and Monteau Counties in central Missouri, now Overton Bottoms South Unit and part of the Big Muddy National Wildlife Area. Like Darst Bottoms, this area had experienced revegetation and succession in the decade+ since my previous visit; however, unlike the former there still remained a vast central plain that, while vegetated, was sparsely vegetated enough to continue providing suitable habitat for the beetle. It took some work, but I eventually found the beetles localized in one part of the sand plain (see photograph #3), and there were enough of them out at the time of my visit that I succeeded in getting the series of photographs shown in this post.

Ellipsoptera lepida (ghost tiger beetle)

I have fond memories of all 24 tiger beetle species in Missouri—each one presenting a unique collection of experiences that will fuel my love affair with the group for years to come. With E. lepida, the jubilance and excitement of that first, unexpected encounter remains near the top of the list for me.

REFERENCES:

Brown, C. R. & T. C. MacRae. 2005. Occurrence of Cicindela (Cicindelidia) trifasciata ascendens (Coleoptera: Cicindelidae) in Missouri. Cicindela 37(1–2):17–19 [pdf].

MacRae, T. C. & C. R. Brown. 2011. Historical and contemporary occurrence of Cylindera (s. str.) celeripes (LeConte) (Coleoptera: Carabidae: Cicindelinae) and implications for its conservation. The Coleopterists Bulletin 65(3):230–241 [pdf].

Pearson, D. L., C. B. Knisley, D. P. Duran & C. J. Kazilek. 2015. A Field Guide to the Tiger Beetles of the United States and Canada. 2nd Edition. Oxford University Press, New York, 264 pp. [Oxford description].

© Ted C. MacRae 2017

Cicindela scutellaris flavoviridis (chartreuse tiger beetle)

/ Ted C. MacRae / 5 Comments

In previous posts I have discussed some Texas subspecies of Cicindela scutellaris (festive tiger beetle) and C. formosa (big sand tiger beetle)—two widespread and geographically variable species that occur broadly across eastern North America and that segregate into several distinctive and geographically restricted subspecies (Pearson et al. 2006). With the former species, I actually found two of its Texas subspecies, the second being C. s. flavoviridis (dubbed the “chartreuse tiger beetle” by Erwin & Pearson, 2008). This subspecies occurs in a narrow band from north-central Texas south to central Texas and apparently does not intergrade with rugata (which I featured previously) to the east (Pearson et al. 2006) and minimally with subspecies lecontei to the north (Vaurie 1950).

Cicindela scutellaris flavoviridis

Cicindela scutellaris flavoviridis

This beautiful subspecies usually lacks maculations, at most possessing two tiny ivory white spots along the outer edge of the elytra, and the shining metallic upper body surface is the most stunning shade of greenish-yellow, or chartreuse, color that I have ever seen. It shares with C. s. rugata a more wrinkled pronotum and smoother head than other C. scutellaris subspecies, but the latter is distinguished by its darker blue to blue-green dorsal coloration. Vaurie (1950) regarded C. s. flavoviridis to be intermediate between rugata and scutellaris but more closely related to the latter due to their shared yellow/coppery reflections on the elytra. Cicindela s. flavoviridis 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 C. scutellaris subspecies only males have a white labrum and females have a dark/black labrum.

Cicindela scutellaris flavoviridis

Cicindela scutellaris flavoviridis

Like all of the other C. scutellaris subspecies, this one occurs in deep, dry sand habitats such as dunes, blowouts, and road cuts. I found this population along a tributary of the Red River known as Cobb Hollow” in Montegue Co., Texas in early October 2015, where they occurred in small numbers on deep sand bars alongside the small creek. I actually made two visits to this site one week apart—failing the first time in my efforts to obtain good, in situ field photographs but succeeding on the second visit.

Cicindela scutellaris flavoviridis

Cicindela scutellaris flavoviridis

I am quite satisfied with these photos, especially the first one above that gives a good lateral view of an adult striking an interesting pose on sloped sand, although I would have liked to have gotten at least one with some foliage in the photo to add a bit of perspective. Nevertheless, having now succeed in photographing the four “western” subspecies of C. scutellaris (rugata and flavoviridis in Texas, nominate scutellaris in the Great Plains, and yampae in northwestern Colorado), I am now motivated to get good photographs of the three “eastern” subspecies: lecontei proper (there are populations in northern Missouri), rugifrons along the North Atlantic coast, and unicolor in the southeastern U.S. (although I have photographed an interesting lecontei × unicolor intergrade population in southern Missouri).

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 2017

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 / 7 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! My hi

/ 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.

Bulnesia retama – 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. [Edit 12/15/25: This plant has been identified from a photograph posted to iNaturalist as Bulnesia retama—ID #330427306.] 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

Super duper June bugs

/ Ted C. MacRae / 11 Comments

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

North America’s most recognizable longhorned beetle

/ Ted C. MacRae / 25 Comments

One of the more impressive insects that we found during our visit to Sand Hills State Park in south-central Kansas last June was Plectrodera scalator, the cottonwood borer. Large and robust (in fact, the only larger species in the family are the prionid root borers and their kin), their striking checkered pattern of white pubescence on a glossy black body makes them perhaps the most recognizable of all North American longhorned beetles (Linsley & Chemsak 1984). The very robust body of this individual, along with the relatively shorter antennae (only about as long as the body) identify it as a female—males are generally smaller and less robust with the body slightly tapering and the antennae distinctly longer than the body.

Plectrodera scalator

Plectrodera scalator (Fabricius, 1792) | Sand Hills State Park, Kansas

The white coloration on the body of these beetles is not a cuticular pigment (which is rather rare in beetles and is most often associated with species found in white sand habitats, e.g., certain tiger beetles), but instead a result of dense mats of microscopic white setae. The patterns formed by these mats are apparently as unique to each individual as fingerprints are to humans (Yanega 1996), making these beetles at once immediately recognizable as a species yet distinctive as individuals.

Plectrodera scalator

Adults of this species are found most often on cottonwood.

These are said to be common beetles in their range across the eastern two-thirds of the country, especially so in the Great Plains where their favored host, cottonwood (Populus deltoides), is especially abundant. Despite this, I have encountered this species only a handful of times in more than 3o years of searching. I know they’re out there, even in my home state of Missouri where I recorded 154 specimens collected in the state and deposited in various collections (MacRae 1994). It was not until around 2000 that I even saw my first ones (on a cottonwood tree in a homeowner’s yard just across the Mississippi River in Illinois), and in fact this one was actually found by Mary Liz Jameson, who had accompanied us to the field that day. It makes me wonder if their coloration, so strikingly conspicuous when isolated against a clean, blue sky background, might actually afford some type of cryptic protection against the normal backdrop of foliage and branches on which they are normally found—a phenomenon that I call “conspicuous crypsis” and which I have noted for other longhorned beetles (e.g., Acanthocinus nodosus). Perhaps, with this species at least, I have not yet set my search image to notice them.

Plectrodera scalator

Large, robust size and a distinctive checkered pattern of black and white makes these beetles among the most recognizable longhorned beetles in North America.

REFERENCES:

Linsley, E. G. and J. A. Chemsak. 1984. The Cerambycidae of North America, Part VII, No. 1: Taxonomy and classification of the subfamily Lamiinae, tribes Parmenini through Acanthoderini. University of California Publications in Entomology 102:xi + 1–258. [preview]

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

Yanega, D. 1996. Field Guide to Northeastern Longhorned Beetles (Coleoptera: Cerambycidae). Illinois Natural History Survey Manual 6, x + 174 pp. [preview]