science

Diminishing Stag Beetle

/ Ted C. MacRae / 14 Comments

This past June I made a couple of trips to north-central Arkansas. They were my first real efforts to collect insects in Arkansas, despite hundreds (literally) of trips to various localities throughout the Ozark Highlands in adjacent southern Missouri. The similarities between the two areas were obvious, yet there was also the feeling of a brand new area just waiting for exploration. On the second trip, I found a campground that looked good for blacklighting to see what wood-boring beetles I might be able to attract amongst the surrounding pine/oak-hickory forest. The evening was warm (very warm!) and humid with no moon—typically ideal for blacklighting, but beetles were sparse at the sheets for some reason (perhaps deterred by the obnoxiously unrelenting yells of drunk Arkansans and their out-of-control offspring?!). The evening, however, was not a total loss—at one point an enormous stag beetle landed on the top of the sheet.  It was so big that I couldn’t even fit it into the viewfinder of my camera:

I fiddled with the camera and changed some settings.  I got a little more of the beetle in the viewfinder this time, but it was still just too big:

Additional fiddling with the camera allowed even more of the beetle to be seen:

As I took the photographs, I even began wondering if the beetle itself was actually shrinking:

Eventually, it turned out to be a normal-sized beetle after all:

This is a female of the common eastern North American species Lucanus capreolus.¹  I don’t seem to encounter female stag beetles as often as the males, so this was still a nice find on an otherwise frustrating night.

¹ Two bonus point in the current BitB Challenge session to the first person who correctly explains how I know this.  Overall contenders: here’s your chance to score an advantage as we enter the final stretch in the current Challenge session.

Copyright © Ted C. MacRae 2011

Four-humped Longhorned Beetle

/ Ted C. MacRae / 8 Comments

Acanthoderes quadrigibba | Chalk Bluff Natural Area, Arkansas.

On a recent collecting trip, I went over to Chalk Bluffs Natural Area in the Mississippi Alluvial Plain of northeastern Arkansas.  My quarry was a population of Cylindera cursitans (ant-like tiger beetle) that has been reported from the site—one of the only known sites for the species in Arkansas.  While I was there, I noticed some movement on the trunk of a tree, and a closer look revealed that what appeared to be a piece of bark was actually a beetle—a longhorned beetle to be precise.  The elevated gibbosities of the pronotum and white, transverse fasciae of the elytra immediately identify it as Acanthoderes quadrigibba, a not uncommon species in the eastern U.S., but one that I still get excited about whenever I encounter it.

Note the four pronotal ''humps'' in this dorsolateral profile view.

Judging by the number and diversity of plant genera that have been recorded as larval hosts for this species—Linsley and Chemsak (1984) recorded Acer, Betula, Carya, Castanea, Celtis, Cercis, Fagus, Ficus, Quercus, Salix, Tilia, and Ulmus—you could be forgiven for thinking that this is one of the most common and abundant species of longhorned beetle in North America.  I have not found this to be the case, and I don’t think it is because I’m simply missing it due to its cryptic appearance.  Longhorned beetles in the tribe Acanthoderini are, like many species in the family, quite attracted to lights at night, and I’ve done plenty of lighting over the years.  What I have noticed is that nearly all of my encounters with this species have been in the Mississippi Alluvial Plain—an area rich with wet, bottomland forests that contrast markedly from the dry to dry-mesic upland forests that cover much of the southern two-thirds of Missouri.  I’ve also reared the species a few times from Salix, one of the host genera recorded by Linsley and Chemsak (1984).  In both cases, the wood was not freshly dead (as is commonly preferred by many other longhorned beetles), but a little past its prime and starting to get somewhat moist and punky.  In the case of this beetle, I suspect that the nature of the host wood may be more important than the species, the preference being for longer dead wood in moister environments.  Of course, observations by another collector in another state may completely obliterate my idea, but for now it sounds good.

A closeup photograph of the elytral markings of this beetle was the subject of ID Challenge #9, to which a record 18 participants responded (thanks to all who played!).  Troy Bartlett takes the win with 12 points (and attention to detail), while Dennis Haines, Max Barclay, Mr. Phidippus, and Josh Basham all score double-digit points.  Troy’s win moves him into the top spot in the overall standings of the current BitB Challenge Session with 23 pts, but Dave is breathing down his neck with a deficit of just a single point.  Tim Eisele and Max Barclay have also moved to within easy striking distance with 19 and 18 points, respectively, and several others could make a surprise move if the leaders falter.  I think I’ll have one more challenge in the current session before deciding the overall winner—look for it in the near future. 

REFERENCE:

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 102:1–258.

Copyright © Ted C. MacRae 2011

ID Challenge #9

/ Ted C. MacRae / 62 Comments

Despite the super close-up nature of the photograph in today’s challenge, this is not a crop and is thus a straight up ID Challenge (making this either a very giant insect or maximum magnification of my 65mm lens).  I’ll award 2 pts each for order, family, genus, and species.  Standard challenge rules apply, including moderated comments (to give everyone a chance to take part) and possible bonus points for being the first to guess correctly (in the off chance multiple people offer the same correct answers), offering suitable relevant information, or just making me chuckle.  Reminder: nobody walks away with no points, so it pays to try even if you haven’t a clue!¹

¹ If you question the importance of this, just ask Dave, whose pity points in the last challenge helped him retain sole possession of 2nd place in the overall standings.

Who am I?

Copyright © Ted C. MacRae 2011

A “Giant” Pygmy

/ Ted C. MacRae / 10 Comments

Not long ago, I got an email from grasshopper expert David J. Ferguson confirming my identification of  (and also encouraging my recent fascination with band-winged grasshoppers (family Acrididae, subfamily Oedepodinae) and their marvelously cryptic nymphs).  He suggested that I might also find the “toad lubbers” (family Romaleidae) and pygmy grasshoppers (family Tetrigidae) interesting, since they too have many of those qualities I was finding attractive in band-winged nymphs, only on a very small scale.  It was a prescient comment, as I’d already started taking notice of the pygmies and even photographed one before ever getting his email.

Tettigidea lateralis | Shaw Nature Reserve, Missouri.

I take this individual to represent Tettigidea lateralis (black-sided pygmy grasshopper), which I saw at Shaw Nature Reserve during my May search for .  Actually, I’m not sure I would have even noticed this individual, as I walked along the trail going from open woodland through dry dolomite glade, had it not actually been sitting on my net rim.  I haven’t studied pygmies all that much, other than to note that they seem common around streams and other wet areas and are usually quite small.  This one, however, at close to 15mm in length seemed positively gigantic!  I placed it on the barren dolomite along the trail, expecting it to flee immediately.  Instead it just sat there—begging me to photograph it, so I did.

Bold, white femoral markings contrast nicely with its otherwise marvelously cryptic coloration.

This one appears to be a female with a short pronotum, but I can’t tell if it is an adult with short wings or still a nymph (it was certainly large enough to be an adult!).  Either way, I’m interested in the function of the bright white femoral marking on what is otherwise a very cryptically colored individual.

Copyright © Ted C. MacRae 2011

T.G.I.Flyday – Andrenosoma fulvicaudum

/ Ted C. MacRae / 19 Comments

Andrenosoma fulvicaudum | Stone Co., Arkansas

First, about the name. T.G.I.Flyday is my contribution to a collusional triad between dipterist Morgan Jackson, myrmecologist Alex Wild, and myself (uhm, beetles).  Although Alex blogs primarily about ants, he has long featured a “Friday Beetle Blogging” series.  I’ve also occasionally stepped on their toes with an ant or fly post, so Morgan and I thought it would be fun to complete the Friday switcheroo with a post about ants on his blog and one about flies on mine. Get it?… Oh well, it made me chuckle when we thought it up.  Anyway, here is my first T.G.I.Flyday contribution.

Among the flies (order Diptera), it is hard to pick anything but robber flies (family Asilidae) as the most charismatic group.  Several subfamilies of robber flies have candidates that vie for the most impressive species, mostly due to their enormous size combined with striking green eyes (e.g., Microstylum morosum, Diogmites neoternatus) or vivid, aposematic / mimetic coloration (e.g., Archilestris magnificus, Eccritosia zamon, Wyliea mydas).  However, my favorite subfamily is the Laphriinae—not because of the amazing bumble bee-like appearance of the nominate genus, but rather the larval food of all species in the subfamily; wood-boring beetle larvae.  Over the years, I have put up hundreds of batches of dead wood for rearing wood-boring beetles in the families Buprestidae and Cerambycidae, and not uncommonly do I find in one of the emergence containers—especially those containing dead pine—an adult of one of these impressive flies. Oftentimes their characteristic pupal cases will be found protruding from the emergence hole, in which case I pin it underneath the fly (just in case some ambitious dipterist examines my collection after I’m gone and finds that the pupal case of xx species is not yet described).  I’ve by now accumulated a rather decent little robber fly collection (especially considering that I’m really a coleopterist), graciously identified for the most part by world robber fly expert Dr. Eric Fisher (California Department of Food and Agriculture).

Last weekend I made the second in a series of trips I’ll be taking to the White River Hills region of north-central Arkansas in an effort to confirm the occurrence there of Cylindera celeripes (swift tiger beetle).  My efforts are focused on the area around Calico Rock, a marvelous system of acidic sandstone barrens interspersed amongst shortleaf pine and oak forests.  The occasional dead pines found in such areas are highly attractive to a variety of pine-associated buprestids and cerambycids (my first loves), and whenever I see a standing dead tree I make a beeline straight for it (the tiger beetles can wait).

This individual was sitting on the trunk of a dead shortleaf pine with a mirid bug for prey.

On this day, sitting on the trunk of the first dead pine that I approached was not a buprestid or cerambycid, but rather this laphriine robber fly.  Based on the reddish posteriodorsal markings of the abdomen and general gestalt, I take this to be Andrenosoma fulvicaudum, a widespread though never very abundant species that occurs across most of North America.  According to Bromley (1934), the species frequents dry, sandy locations where it rests on logs, stumps, or tree trunks exposed to the bright sunlight and is commonly observed preying on small hymenopterans.  These observations are quite consistent with mine, except this one was feeding on a true bug in the family Miridae (perhaps distracting it just enough to allow me these photographs).  Cannings (1998) notes that A. fulvicaudum is attracted to recently burned forests, which will provide a fresh supply of wood-boring beetle larvae on which its larvae can prey.  This is the only species of Andrenosoma occurring in eastern North America; four additional species are restricted to Texas and a fifth occurs only in the western U.S., but the genus reaches its greatest diversity in the Neotropics.

REFERENCES:

Bromley, S. W. 1934. The Laphriine Robber Flies of North America.  Ph.D. dissertation, Ohio State University, 358 pp.

Cannings, R. A. 1998. Robber flies (Insecta: Diptera: Asilidae), In I. M. Smith and G. G. E. Scudder [Eds.], Assessment of Species Diversity in the Montane Cordillera Ecozone, Burlington: Ecological Monitoring and Assessment Network.

Copyright © Ted C. MacRae 2011

Sugarcane Weevil in Brazil

/ Ted C. MacRae / 3 Comments

Sphenophorus levis (sugarcane weevil) | Conchal, Brazil.

Brazil is one of the world’s top producers of sugarcane, and they have the Middle East to thank for it.  While the U.S. was responding to the 1973 OPEC oil embargo by building bigger and bigger SUVs, Brazil aggressively developed an alternative fuels industry based on sugarcane for ethanol production.  Today, about half of Brazil’s sugarcane is milled for ethanol, yet despite this enough raw sugar is produced from the remaining sugarcane crop to rival India as the world’s top producer.

The large acreage devoted to sugarcane and tropical climate in which it is grown make Brazil’s crop especially vulnerable to infestation by insect pests—and there are many!  One of the most important is Sphenophorus levis (sugarcane weevil, or “bicudo da cana-de-açúcar”).  Larvae bore in the roots and crown of the plant, reducing biomass accumulation and longevity.  This feature of the insect’s biology also makes the larvae extraordinarily difficult to control, since they are largely protected from chemical applications by surrounding plant tissues.  This adult beetle was captured in a field trap placed in a sugarcane field in Conchal, approximately 175 km N of São Paulo.  The traps consist of split sugarcane stalks buried under debris within crop rows—adults are attracted to the cut surface of the stalks, where they congregate in numbers.  Traps are used not only to monitor beetle occurrence and abundance in fields, but also to provide a source of insects for laboratory rearing and evaluation of control test agents.

Copyright © Ted C. MacRae 2011

Tracking Tetraopes texanus with Terry

/ Ted C. MacRae / 12 Comments

Last month I traveled to Starkville, Mississippi to meet with an academic cooperator at Mississippi State University.  While arranging the trip, I contacted Terry Schiefer (no, not the fashion jewelry designer, but curator at the Mississippi Entomological Museum) to let him know I would be visiting.  Considering that late May should be pretty good insect collecting in that area, I wanted to see if he might be interested in doing a little beetle collecting after I finished up with my meetings.  Terry also specializes in Coleoptera and shares with me an interest in the taxonomy and faunistics of Cerambycidae and Cicindelinae.  I first met Terry some 13 years ago during my previous visit to MSU; I remember ogling at an impressive series of Aegomorphus morrisii, a spectacular species of longhorn beetle that was known at that time by precious few specimens and that he had recently found in Mississippi.  We hadn’t seen each other since but managed to keep in contact with occasional correspondence during the course of our longhorn studies.

Me & Terry Schiefer | Noxubee National Wildlife Refuge, May 2011.

Terry was more than happy to go beetle collecting with me, and among the possibilities that he mentioned when I arrived at the museum was nearby Noxubee National Wildlife Refuge.  I had done a little collecting there on my last visit, but I was especially intrigued when he mentioned the local population of an uncommon milkweed beetle species, Tetraopes texanus, that he had reported in one of the refuge’s prairie remnants (Schiefer 1998).  I have only seen this species once, up here in in east-central Missouri and which I reported as the species’ northernmost known population (MacRae 1994).  My more recent attempts to find this species have not been successful, so I was excited at the chance to see this longhorned species once again.

We arrived at the prairie with plenty of daylight to spare and began walking through the area where Asclepias viridis (its presumed host in Mississippi; in Missouri I found it on Asclepias viridiflora) was growing.  Typically milkweed beetles are quite approachable, having nothing to fear from predators by virtue of the cardiac glycosides that they sequester in their bodies from their milkweed foodplants and advertise so conspicuously with their bright red and black coloration.  Thus, we were looking for beetles sitting brazenly on the plants, but none were seen.  Eventually, Terry saw one in flight, and then I saw one in flight as well.  For some time, this was the only way we were seeing the beetles, and only by slowing down and scanning the prairie vegetation more carefully and deliberately did we begin to see the adults sitting on vegetation.  Interestingly, very few of them were seen actually sitting on milkweed plants.  Rather, they were on all manner of other plants, and they were very quick to take flight on our approach.  This was playing havoc with my desire to get field photographs of the beetles, especially field photographs on the host.  I decided that any photograph—host plant or not—was better than none, so I began attempting some shots.  My first one didn’t work out so well:


Finally I was able to get one of the beetle sitting on a plant, but the dorsal characters can’t be seen, nor is there anything about the photo that allows the species to be distinguished as T. texanus (the abruptly attenuate last antennomere distinguishes it from similar-appearing species):


Progress—more of the dorsal surface can be seen in the photo below, and the beetle is actually sitting on a milkweed plant.  However, the antennal tips are still frustratingly out of focus.  Note the completely divided upper and lower lobes of the eye—Tetraopes beetles give new meaning to the term “four-eyes”:


I chased beetle after beetle in flight, endlessly zigzagging across the prairie in what had to be a spectacle to any unknown observer.  Eventually, we found a beetle sitting on its host plant, and it remained calm during my deliberate approach.  I circled around for a good view of the dorsal surface and snapped off an apparent winner—everything in focus, good composition… but arghh, the antennal tips were clipped!


I kept at it and was about to back off a bit on the magnification and switch to landscape mode so I could get the full antennae in the frame when the beetle turned in a most fortuitous manner—nicely positioning its distinctive antennal tip right in front of a bright green leaf for contrast.  My friends, I present Tetraopes texanus on its presumed host plant, Asclepias viridis!


Terry and I were both puzzled by the flighty, nervous behavior that the beetles were exhibiting.  Neither of us had seen such behavior with milkweed beetles before, and I’m not sure I can offer any explanation for such.  I’d be interested in hearing any ideas you might have.

My thanks to Terry for showing me a few of his favorite spots (allowing me to collect a few choice species of longhorns), and to my co-worker/colleague Jeff Haines for indulging my desire mix a little beetle collecting into the business trip.  I hope they enjoyed it as much as I did.

REFERENCES:

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

Schiefer, T.L. 1998. Disjunct distribution of Cerambycidae (Coleoptera) in the black belt prairie and Jackson prairie in Mississippi and Alabama. The Coleopterists Bulletin 52(3):278–284.

Copyright © Ted C. MacRae 2011

Bichos Argentinos #14 – Flies!

/ Ted C. MacRae / 22 Comments

A few miscellaneous fly photos from La Reserva Ecológica Costanera Sur (Buenos Aires, Argentina)  taken last March.  I don’t have IDs except provisionally to family (let’s face it—flies are hard!).

I suppose something in the Tachinidae, based on the black and white striped coloration and distinct abdominal setae.


Definitely a robber fly (family Asilidae), but which one?


I suppose this is some kind of bottle fly (family Calliphoridae).


Nice eyes!


Copyright © Ted C. MacRae 20011