Month: July 2011

Speaking of Graphisurus…

/ Ted C. MacRae / 3 Comments

Graphisurus fasciatus | Sam A. Baker State Park, Missouri.

Graphisurus fasciatus is the commonest of the three species in this North American genus. It is easily distinguished from  by its smaller, narrower form, more mottled coloration, and lack of distinctive triangular-shaped black markings on the elytra. However, it can easily be confused with the third species in the genus G. despectus, which is nearly identical in size and coloration. From this latter species, G. fasciatus may be distinguished by the slightly darker ground color of the elytra (in G. despectus the elytra are more uniformly grayish) with the post-median dark marking of the elytra not very conspicuous (in G. despectus this marking and contrasts distinctly with the grayish elytra). Also, the tips of the elytra are distinctly emarginate (concave) in G. fasciatus but more subtruncate in G. despectus, and the scutellum in the former is pubescent (hairy) but glabrous (lacking hairs) in the latter.

Host plant is also a clue as to the identity of this individual (a male, as distinguished by its very long antennae and lack of distinctly elongate ovipositor extending from the tip of the abdomen), as it was found on the trunk of a very large, recently wind-thrown black oak (Quercus velutina)—its preferred host genus.  Graphisurus despectus, in contrast, appears to be associated almost exclusively with hickory (genus Carya).  Both species, despite their relatively modest size (generally 10–15mm in length, excluding the female ovipositor), seem to prefer dead wood from the trunk and main branches of larger trees for larval development, mining just beneath the bark rather than in the wood itself.

Copyright © Ted C. MacRae 2011

Graphisurus triangulifer in Missouri

/ Ted C. MacRae / 11 Comments

Graphisurus triangulifer | Sam A. Baker State Park, Missouri

Of the three species of the genus Graphisurus occurring in Missouri, G. triangulifer is both the most attractive and the least commonly encountered.  Back when I surveyed the Cerambycidae of Missouri (MacRae 1994), I examined only 45 specimens of this species in the major public and private collections of the state, compared to slightly more of the equally uncommon G. despectus and a whopping 271 of the übercommon G. fasciatus.  Nearly all of the specimens I examined of this species were encountered at lights, and it has been in this manner almost exclusively that I have seen the species for myself.

The species is named for the dark triangular markings on the elytra.

The individual in these photos was seen at Sam A. Baker State Park in the southeastern Ozark Highlands of Missouri during early July, and—like most of the others I have seen—it was attracted to my blacklight. I really don’t like photographing insects directly on the white landing sheet that I use for blacklighting, so I moved the beetle to the trunk of a nearby boxelder tree (Acer negundo) for a more natural looking background. There are a few reports of the species utilizing Acer for larval development (Lingafelter 2007), so this could be a very natural setting; however, I have not seen any actual records of the species being reared from that host. More often the species has been recorded breeding in dead sugarberry (Celtis laevigata). While I have conducted many rearings from Celtis, I’ve not yet succeeded in rearing this species—I suspect it probably breeds in larger diameter branches given its relatively large size (12–17 mm in length).  This idea is bolstered by the fact that the one adult that I did not encounter at lights was found on the trunk of a large, dead sugarberry near San Antonio, Texas.  Hoffman et al. (2002) noted that the species exhibits a southern, lowland distribution extending from Long Island to central Georgia, thence west to Texas and northward in the interior as far north as Ohio and Indiana (it has also been recorded from Kansas and, of course, Missouri).  This distribution pattern agrees largely with that of Celtis laevigata in the eastern U.S., suggesting that this plant may indeed be its primary host.  A fairly restricted host range for G. triangulifer would not be unexpected, since each of the other two species in the genus also exhibits a fair degree of host fidelity—G. despectus breeds almost exclusively in hickory (Carya spp.), while G. fasciatus breeds primarily in oak (Quercus spp.).

REFERENCES:

Hoffman, R. L., S. M. Roble, and W. E. Steiner, Jr. 2002. Thirteen additions to the known beetle fauna of Virginia (Coleoptera: Scirtidae, Bothrideridae, Cleridae, Tenebrionidae, Melyridae, Callirhipidae, Cerambycidae, Chrysomelidae). Banisteria 20:53–61.

Lingafelter, S. W. 2007. Illustrated Key to the Longhorned Woodboring Beetles of the Eastern United States. Coleopterists Society Miscellaneous Publications, Special Publication No. 3, 206 pp.

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.

Copyright © Ted C. MacRae 2011

Elytrimitatrix at my window

/ Ted C. MacRae / 7 Comments


This evening as I was sitting in my comfy chair, I noticed Stitch (one of the cats) pawing at the window. We live in the woods, so it is common for insects to land on the outsides of the windows after dark, attracted to the lights from within our home. Stitch was especially interested in a rather large beetle crawling frantically on the window, which I recognized quickly as the cerambycid beetle, Orthosoma brunneum. This big brown beetle is a member of the root-boring subfamily Prioninae, and although it is perhaps one of the commonest longhorned beetles in our area during July and August, I’ve not yet photographed it. As I debated whether to do so, I noticed the distinctive silhouette of another cerambycid beetle sitting quietly lower down on the window—smaller than O. brunneum but still decent-sized. I opened the window a crack (to keep all the other insects from rushing in), reached my hand through the crack, grabbed the beetle and in pulled it inside. It was a fine specimen of what is now known as Elytrimitatrix undata. I forgot all about the Orthosoma beetle and decided to photograph Elytrimitatrix instead.

While a member of the longhorned beetle family Cerambycidae, the group to which this species belongs (subfamily Disteniinae) has long been treated as sort of the “red-headed stepchild” of the family due to disagreement about its affinities to other cerambycid groups. It has at times been considered a tribe of the subfamily Lepturinae, a tribe of the subfamily Cerambycinae, a subfamily of its own, and even a separate family. Much of this disagreement focuses on details of its morphology despite the great superficial resemblance of the adults to other cerambycids. For now, it seems most workers are satisfied to regard the group as a distinct subfamily within the Cerambycidae, even though its exact relationships to other subfamilies still remain unclear.

Despite numerous representatives in the Neotropics, E. undata is the only member of the subfamily in the U.S., occurring broadly across the eastern and central states. For many years it was known as “Distenia” undata but was recently split out of that genus by Santos-Silva & Hovore (2007). Larvae have been recorded breeding in the dead wood of a variety of hardwoods as well as pine (the ultimate generalist), and adults are regular visitors at lights during the warm, muggy months of summer. I have also taken the species in numbers in traps baited with fermenting liquid (1 part molasses, 1 part beer, 8 parts water, and a packet of dry yeast) (MacRae 1994).

REFERENCE:

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.

Santos-Silva, A. & F.T. Hovore. 2007. Divisão do gênero Distenia Lepeletier & Audinet-Serville, notas sobre a venação alar em Disteniini, homonímias, sinonímia e redescrições (Coleoptera, Cerambycidae, Disteniinae). Papéis Avulsos de Zoologia 47:1–29.

Hook-faced Conehead – Pyrgocorypha uncinata

/ Ted C. MacRae / 5 Comments

Pyrgocorypha uncinata at UV lite | Lake Norfork, Arkansas

I had high hopes as I setup the blacklights in the pine/oak-hickory forest at Jordan Recreation Area on Lake Norfork in north-central Arkansas. The late June timing  and warm, humid conditions with no moon were perfect for wood boring beetles, and as dusk settled in I awaited their expected arrival.  But the beetles never came, and as dusk waned to full darkness I knew it was going to be one of those inexplicably mediocre nights.  If I’d had a hotel room waiting for me, I would’ve closed up shop as soon as this became apparent and headed on back.  This night, however, I was camping so there was really nothing else to do but see what else came to the lights anyway.  One of the more interesting was this conehead katydid, whose bizarre hook-shaped cone immediately identify it as the hook-faced conehead, Pyrgocorypha uncinata.  There are a number of coneheads in the eastern U.S., but I couldn’t recall ever seeing one with such a bizarre-shaped cone before.  There is good reason for this, as Singing Insects of North America shows this southeastern U.S. species to be at the limit of its distribution in northern Arkansas.

Looking at the above photo at home, I couldn’t help but notice the “face” formed by the eyes and cone, with the gap between the cone and the rest of the frons forming the “mouth” and the cone itself the “nose”—it looked to me like some weird, garrishly grinning fish!  Thus was born Super Crop Challenge #7, and since four participants correctly identified the individual in the photo down to species this challenge was decided on bonus points.  Max Barclay (Natural History Museum) earned the most (11) to win the challenge, while Patrick Coin and Sam Heads each earned 10 to round out the podium with a 2nd-place tie.  This was the last challenge of the BitB Challenge Session #3, so we can now crown a winner.  Today’s win vaults Max Barclay from 4th place in the overalls to the top spot with 29 pts—congratulations (and contact me for your loot).  Tim Eisele‘s 5 points in this challenge gave him a total of 24 pts, which was just enough to edge out former front-runner Troy Bartlett for 2nd place by a single point.  Troy keeps a foot on the final podium ahead of Dave with 23 points, also by a single point.

My thanks to the record 27 participants who took part in BitB Challenge Session #3.  The final overall standings are shown below, and look for the first challenge of BitB Challenge Session #4 coming up.

Place Participant IDC #8 SSC #5 SSC #6 IDC #9 Bonus 7/9 SSC #7 Total
1 Max Barclay 8     10   11 29
2 Tim Eisele 3 6 6 4   5 24
3 Troy Bartlett     11 12     23
4 Dave   11 3 8     22
5 Mr. Phidippus       11   4 15
6 Patrick Coin         2 10 12
7 Dennis Haines        11     11
8 Josh Basham       10     10
  Sam Heads           10 10
10 Alex Wild 9           9
  James Trager  1  4    4     9
  Brady Richards       9     9
13 Roy     5 3     8
  FlaPack           8 8
15 Traci       6     6
16 Johnson Sau       5     5
17 Annie Ray       4     4
  The Ozarkian       1   3 4
19 David Winter 3           3
  Ani       3     3
  Laurie Knight       2   1 3
22 Bob Cochran   2         2
  dragonflywoman     2       2
  Chris Grintter       2     2
25 David Rentz 1           1
  Anne McCormack   1         1
  Mike       1     1

IDC = ID Challenge; SCC = Super Crop Challenge.

Copyright © Ted C. MacRae 2011

Super Crop Challenge #7

/ Ted C. MacRae / 21 Comments

Who is this smiling critter?  Usual challenge rules apply, including moderated comments (to give everyone a chance to take part) and possible bonus points for beating others with the first correct answers, additional relevant information, or any suitably humorous quips.  I’ll give 2 points each for order, family, genus and species.  This is the last challenge of the current BitB Challenge Session, so the current leaders are playing for all the marbles!

Copyright © Ted C. MacRae 2011

T.G.I.Flyday – Triorla interrupta

/ Ted C. MacRae / 5 Comments

Triorla interrupta (male) | Calico Rock, Arkansas

While I was visiting the glades near Calico Rock, Arkansas this past June, I went into town to look along the White River.  With the amount of sandstone bedrock in the area, I thought there I might find sandy loam deposits along the river of the type preferred by Cylindera cursitans (ant-like tiger beetle).  While I didn’t find any of the beetles, I did see this robber fly (managing only this single shot before it flew off), which I take to be the male of Triorla interrupta based on the pattern of abdominal coloration (the first two segments partially black, followed by two almost wholly black segments).  According to BugGuide, this is the only North American species of the genus (a second occurring from Panama to Argentina), and Herschel Raney considers it to be the most common robber fly in Arkansas.

Copyright © Ted C. MacRae 2011

Lined Jewel Beetle

/ Ted C. MacRae / 3 Comments

Buprestis lineata mating pair on lower trunk of Pinus echinata | vic. Calico Rock, Arkansas

Here is another of the several wood-boring beetle species that I encountered during my June trips to the sandstone glade complex near Calico Rock in north-central Arkansas.  Shortleaf pines (Pinus echinata), the only native pine in this region, are common on and around the glades due to their acidic soils, and this mating pair of Buprestis lineata (family Buprestidae) was found near the base of the trunk of one of the larger trees.  These were actually the first of a number of different wood-boring beetles that I found on this particular tree, others being Xylotrechus sagittatus, Chalcophora virginiensis, and the sumptuously beautiful Acanthocinus nodosus.  All of these species are classic pine-associates in the southeastern U.S.  After photographing this couple, I observed numerous other individuals flying to the tree, landing on its trunk and searching nervously for mates, then fleeing if I approached too close (except the unfortunate early few that I conscripted as ‘vouchers’).  The tree was a veritable singles bar for wood-boring beetles!

Despite their abundance in the area, the pines do not grow well on the glades due to the thinness of the soils (that is, where there is soil!).  Not only do the trees grow slowly, but they suffer reduced longevity and high turnover, producing an abundance of stressed and dying trees that wood-boring beetles in the families Buprestidae and Cerambycidae are only too happy to utilize.  Most species in these families (with notable exceptions such as the emerald ash borer, Agrilus planipennis) prefer dead or dying trees for larval development, largely because healthy trees are quite capable of fending off attacks by bleeding and overwhelming newly hatched larvae as they attempt to bore into the tree.  Adults are able to detect these stressed trees through chemoreception of host plant volatiles, thus, the presence of numerous wood boring beetle adults on an otherwise healthy-looking tree is a clue that the tree’s days are numbered.  I don’t know what it was about the tree that caught my attention and made me go over to take a look at it—perhaps just its large size, but it proved to be a fruitful detour.

Copyright © Ted C. MacRae 2011

More on ‘Conspicuous Crypsis’

/ Ted C. MacRae / 16 Comments

Acanthocinus nodosus on trunk of Pinus echinata | vic. Calico Rock, Arkansas

In my previous post (), I used the term ‘conspicuous crypsis’ to describe the sumptuously beautiful lichen grasshopper, Trimerotropis saxatilis, as an example of an insect that, despite strikingly conspicuous colors/patterns, blends in perfectly with its native surroundings. I don’t think this is a formally recognized ecological concept (and a quick search of the web and my limited ecology literature didn’t turn up anything about it) with any real biological/ecological relevance, but rather just a little irony that personally I find interesting.

The same individual in the above photograph in its original resting spot.

The photographs in this post were also taken during one of my June trips to the sandstone glade complex around Calico Rock, Arkansas and show another insect that I would describe as conspicuously cryptic. This is Acanthocinus nodosus, in my opinion one of eastern North America’s most attractive longhorned beetles (family Cerambycidae). This species occurs across the eastern U.S. (just sneaking up into southern Missouri), where the larvae mine the phloem beneath the bark of dead and dying pines (Linsley and Chemsak 1995). BugGuide describes it as “subtle, yet beautiful” with an antennal span in males reaching a spectacular 120 mm (that’s 5 inches, folks!). Perhaps others have encountered this beetle more commonly further south, but I have previously seen only single individuals on just three occasions—twice in the Ozark Highlands of southern Missouri (one at lights and another searching the trunk of a standing, decadent pine tree at night) and another at lights in Alabama. As a result, I was quite excited to find this individual clinging during the day to the trunk of a large shortleaf pine (Pinus echinata). The tree appeared healthy, but I found adults of several other wood boring beetles crawling on its trunk as well, suggesting that maybe the tree was stressed or in the initial stages of decline.

Subtle, yet beautiful!

I must confess that the first photograph above was staged—I had moved the beetle from its original resting spot and placed it on a part of the trunk where the bark color contrasted more strongly with the beetle to increase its visibility.  The second and third photos above and left show the beetle in its original resting spot and illustrate just how cryptic the beetle is when resting on older, more weathered pine bark.  Admittedly, the somber coloration of this species is not as extraordinary as the lichen-green of the lichen grasshopper, but I nevertheless find the slate gray with velvet black markings quite beautiful.  When mounted on pins and lined up neatly in a cabinet, individuals of this species are as attractive as any dead insect can be.  It was not until I saw this individual in Arkansas—and tried to photograph it during the day—that the cryptic function of its coloration and patterning became truly apparent to me.  Most species in the tribe Acanthocini (to which this species belongs) also exhibit somber coloration with variable black markings or mottling, although only a handful can be considered as ‘conspicuously cryptic’ as this one.

REFERENCE:

Linsley, E. G. and J. A. Chemsak.  1995. The Cerambycidae of North America. Part VII, No. 2: Taxonomy and classification of the subfamily Lamiinae, tribes Acanthocinini through Hemilophini. University of California Publications in Entomology 114:1–292.

Copyright © Ted C. MacRae 2011