The Texas Prick

Recently my friend Kent Fothergill launched a series of posts ranting about discussing the difficulties associated with common names. The inaugural post featured the insect I show here, Dectes texanus, a member of the family Cerambycidae (longhorned beetles) that has gained attention in recent years as an occasional pest of soybeans, especially in the upper Mississippi Delta (Tindall et al. 2010). As is usual, when an otherwise obscure little insect suddenly begins costing somebody money people feel compelled to give it a common name. Rather than the uninspired “soybean stem borer” or ironically Latin-ish ”Dectes stem borer” monikers that seem to have taken hold for this species, Kent jokingly suggested that if people were serious about common names, this insect should actually be called the “Texas prick” as a direct translation of the scientific name.¹

¹ Actually, I couldn’t find any reference to the word “Dectes” as a Latin word or “prick” as its English translation. Rather, my copy of Brown (1956) lists dectes as a Greek word meaning “biter.” I think this must be what LeConte (1852) had in mind when he first coined the genus name, since he mentions among the characters that define the genus several features of the mandibles. If that is the case, then to be accurate the alternate common name for this beetle should be the “Texas biter.” However, that name causes nothing like the snicker that “Texas prick” elicits, and since common names are bound by no rules whatsoever, I choose levity over accuracy and stick with Kent’s proposed name.

Dectes texanus | Washington Co., Mississippi

Being the pedantic, anal retentive, taxonomist-type that I am, it may surprise you to learn that I actually don’t have a problem with common names. To be honest, however, I will admit that this is a fairly recent change-of-mind for me—for many years I was a die-hard “scientific-names-only” type of guy. I not only thought common names were useless (for all the reasons listed by everybody who opposes them), but I even refused to learn them—my geek passive aggression, I guess. In the years since I started this blog, however, I’ve not only grown less oppositional in my stance, but have actually learned to embrace common names for what they are—comfortable names that don’t intimidate the taxonomically disinclined. Labels is all they are, and if one common name can refer to several species or several common names refer to one species, it’s not the end of the world. Common names aren’t meant to replace scientific names—how could they? Scientific names fulfill a special set of needs for a select group of people (i.e., to reflect phylogeny), and despite its flaws the Linnaean system of nomenclature that has been in use for the past several hundred years has served this purpose better than any other system devised. The reason for this is because genus and species names also provide a convenient and relatively easily memorizable system of labels that allow scientists to actually talk about organisms in a way that makes sense. This is an advantage that the Linnaean system has over any numerical phylogenetic system, no matter how much more precisely the latter can indicate phylogeny. For scientists, scientific names, in effect, serve a dual purpose. Non-taxonomists, however, don’t need dual purpose names—they just want easy-to-say and easy-to-remember labels, and if common names engage more people in a discussion about nature and its inhabitants then I’m all for it.

Accepted common name: Dectes stem borer; BitB common name: ”Texas Prick”

This is not to say that I will ever give up scientific names. I love scientific names, and it is my goal in life to know as many of them as possible—even synonyms (I know, sick!). I also think that scientific names are not as scary as some people believe. Boa constrictor, for example (yes, that is both its common and scientific name), or gorilla (Gorilla gorilla)… or Dectes stem borer! To help bridge the gap, I have taken to mentioning, as a matter of practice, both the scientific name and—when one exists—the common name for the insects and other organisms featured on this blog. This applies not only at the species level, but families and other higher taxa also (e.g., “jewel beetles, family Buprestidae”). It is my way of talking science in a way that welcomes the interested lay person. Considering the increasingly anti-science din in our country by creationists, climate change denialists, knee-jerk GM critics, etc., I think the more we can get scientists and non-scientists comfortable talking to each other the better off we will be.

The insect featured in this post was found and photographed in a field of cultivated soybeans in northeastern Mississippi. It’s identification as Dectes texanus (other than its association with soybean) is based on the face being only slightly protruding and the relatively large lower lobe of the eye. There is one other species in the genus, D. sayi, also broadly distributed in the U.S. but distinguished from D. texanus by its distinctly more protruding face and small lower eye lobe (giving the impression of ”tall cheeks”). This species, too, is known to bore in the stems of soybean but is much happier doing so in common ragweed (Ambrosia artemisiifolia) (Piper 1978). The species name—sayi—was given to honor the 19th century entomologist Thomas Say, regarded by many as the ‘Father of American entomology.’ This species also has been called ”soybean stem borer” by some, which doesn’t do much to alleviate concerns about common names referring to multiple species. I am reluctant, however, for reasons of respect, to use the common name for D. sayi that results if one uses the same rationale used by Kent in coining his common name for D. texanus…

REFERENCES:

Brown, R. W. 1956. Composition of Scientific Words. Smithsonian Institution Press, Washington, D.C., 882 pp.

LeConte, J. L. 1852. An attempt to classify the longicorn Coleoptera of the part of America north of Mexico. Journal of the Academy of Natural Sciences Philadelphia (series 2) 2(1):99–112.

Piper, G. L. 1978. Biology and immature stages of Dectes sayi Dillon and Dillon (Coleoptera: Cerambycidae). The Coleopterists Bulletin 32(4):299–306.

Tindall K. V., S. Stewart, F. Musser, G. Lorenz, W. Bailey, J. House, R. Henry, D. Hastings, M. Wallace & K. Fothergill. 2010. Distribution of the long-horned beetle, Dectes texanus, in soybeans of Missouri, Western Tennessee, Mississippi, and Arkansas. Journal of Insect Science 10:178 available online: insectscience.org/10.178.

Copyright © Ted C. MacRae 2013

Crazy Eyes

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 BugShot 2011 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

Tracking Tetraopes texanus with Terry

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