insects

An irresistible sight!

/ Ted C. MacRae / 24 Comments

One of the few highlights of my Memorial Day weekend collecting trip came in the earliest moments of my visit to Ha Ha Tonka State Park.  My destination was Ha Ha Tonka Savanna Natural Area, and a short walk through fire-restored woodland led me to the open glade where just a few years earlier a UMC student had collected the rare and little-known Agrilus impexus.  Entering the glade, I was all set to begin sweeping the vegetation along the woodland/glade interface, paying special attention to any honey locust (Gleditsia triacanthos) that I might happen to find in the area as a potential host for the beetle.  What I saw instead as the glade opened up in front of me was a sight that any collector of wood-boring beetles will find almost irresistable – a recent wind-throw!  In this case, it was a black oak (Quercus velutina) laying in full sun – its bright brown leaves suggesting that it had fallen within the past few weeks (and would thus still be emitting the volatiles that wood-boring beetles find so attractive).  I wanted to begin looking for A. impexus, but I knew there would be beetles actively crawling on the trunk and branches of that tree.  I couldn’t resist it – I dropped my sweep net and beating sheet and made my way to the tree (in the end it didn’t matter, since no other beetles – including A. impexus – would be seen that day).

I already had an idea what I might find.  Recent wind-throws are the domain of Chrysobothris, and if the tree is a deciduous species then this means members of the Chrysobothris femorata species-group.  I recently featured one of six newly described members (C. caddo) of this taxonomically challenging group (Wellso and Manley 2007), providing a synopsis of the now twelve species in the group and their primarily host preferences.  Fully half of these are associated primarily or exclusively with oaks – four occurring in Missouri (quadriimpressa, rugosiceps, shawnee, and viridiceps).  Of these, C. quadriimpressa is the most commonly encountered (although the others are by no means uncommon), and all of the nearly dozen or so beetles I found on this particular tree in fact represented that species. Confirmation of my ID would require microscopic examination of the female pygidium (which is shallowly impressed on each side of the middle) and male genitalia, but in general this species can be distinguished in the field by its smallish size (~10-12 mm in length – rugosiceps and shawnee tend to be larger) and the post-median pair of foveae (circular impressions) on the elytra being joined (they are distinctly separated in viridiceps).

As we’ve seen with other species of jewel beetles (e.g., C. caddo, Dicerca lurida, D. obscura), adults of C. quadriimpressa are incredibly cryptic and nearly impossible to see on the bark of their hosts – at least until they move.  They are notoriously difficult to approach – their large eyes and penchant for rapid escape flights suggesting excellent vision.  This is a useful capability for insects that must expose themselves to would-be predators (and beetle collectors) during daylight hours while actively searching dead trees for mates and oviposition sites.  One thing I can’t figure out, however, is the role of the intensely blue feet in this and other cryptically colored Chrysobothris species (see also C. caddo).  Any ideas?

Photo Details (insect): Canon 50D (ISO 100, 1/250 sec, f/16), Canon 100mm macro lens w/ Kenco extension tubes (68mm), Canon MT-24EX flash (1/4 ratio) w/ Sto-Fen diffusers.  Post-processing: levels, unsharp mask, minimal cropping.

REFERENCES:

Wellso, S. G. and G. V. Manley. 2007. A revision of the Chrysobothris femorata (Olivier, 1790) species group from North America, north of Mexico (Coleoptera: Buprestidae). Zootaxa 1652:1–26 (first page only).

Copyright © Ted C. MacRae 2010

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When is a locust borer not a locust borer?

/ Ted C. MacRae / 26 Comments

…when it is a hickory borer!

Hickory borer (Megacyllene caryae) mating pair on trunk of fallen mockernut hickory (Carya alba).

The hickory borer, Megacyllene caryae, is perhaps the most frequently misidentified beetle in eastern North America due to its almost perfect resemblance to the closely related locust borer, M. robiniae.  Unlike the latter species, however, which is encountered abundantly during the fall on flowers of goldenrod (Solidago spp.) and attacks living black locust (Robinia pseudoacacia), the hickory borer is active only during the spring and breeds in the dead wood of hickories (Carya spp.).  Adults emerge from the wood as soon as temperatures begin to warm in early spring, a fact which causes it to be most frequently encountered during winter when it emerges indoors from firewood brought in from outdoors.  Many times this causes the alarmed homeowner to post a photo of the insect on BugGuide and ask if it will cause damage to their home.  So close is its resemblance to the locust borer that novice insect enthusiasts often identify it as such based on comparison to photos and refuse to believe it is not that species, even when told otherwise.

Of course, there are distinguishing characters that, with a little practice, become quite obvious – the legs of the hickory borer are often distinctly reddish (as seen in the above photo), and the bands of the elytra will many times show an alternating pattern of yellow and white (not quite so apparent in the above photo).  The elytral bands are also slightly narrower and often broken and incomplete in this species, while in the locust borer they are wider and nearly always extend completely across the elytra.  Lastly, the pronotum of the locust borer is narrowly margined with yellow on the anterior edge, while in the hickory borer the anterior margin is black.  That’s a tough character to see without magnification, and all of these characters really are only necessary when examining specimens in a collection (and even then only if there is no date on the collection label).  Season is the easiest distinguishing character – if it occurs during spring it is the hickory borer, and if it occurs during fall it is the locust borer.  There are several other species in the genus that can be confused with these two, but they do not occur in eastern parts of North America.

This mating pair was encountered on the trunk of a recently wind-thrown mockernut hickory (Carya alba) during our early April hike of the lower Wappapello Section of the Ozark Trail.

Photo Details: Canon 50D (ISO 100, 1/250 sec, f/14), Canon 100mm macro lens, Canon MT-24EX flash (1/4 ratio) w/ Sto-Fen diffusers. Typical post-processing (levels, unsharp mask).

Copyright © Ted C. MacRae 2010

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“Trying” to photograph whirligig beetles

/ Ted C. MacRae / 12 Comments

Nobody figured out exactly what I was doing in the photograph shown in the previous post (does anybody now see the whirligig beetles in the lower left corner of the photo?), but I sure enjoyed the guesses.  Several people alluded to dropping the camera or falling into the water, while others mentioned my heretofore unrevealed contortionist abilities.  However, Morgan Jackson‘s tale of trying to photograph Platypsyllus castoris has it all – rarely photographed species and the inordinate lengths we go through to get the shot.

Of course, whirligig beetles (family Gyrinidae) are much more commonly encountered than Platypsyllus castoris, but they can’t be any easier to photograph.  I spotted them as Rich and I balanced our way across a massive sycamore tree trunk while crossing the Black River during our early April hike of the lower Wappapello Section of the Ozark Trail.  I don’t know much more about whirligig beetles (or aquatic insects in general) than your average land-lubbin’ entomologist (in fact, I don’t think I’ve collected any since college systematics – yes, that long ago!), but for some reason I felt the need to try to photograph them.  Sure, the fallen tree provided a rare opportunity to get reasonably close to these very skittish insects without having to wade, but I think it was actually just the challenge of trying to photograph something in constant zigzagging motion that appealed to me.  Rich’s warnings that I would drop my camera were not enough to dissuade me, and after reaching the other side I ditched the backpack and tiptoed out with just my camera.

It seems like I’ve said this often in recent months, but these are my new hardest insect to photograph.  Not only are there the usual difficulties of framing and focusing a subject that is always in motion, but that motion is fast, erratic, and unpredictable, making tracking through the lens an extraordinary challenge.  Moreover, balancing precariously on a debris pile in the middle of the river strains the body and adds an element of danger (yes, I would be in deep doodoo if I dropped that camera).  I kept my eye on one particular individual that was swimming nearest to me, and after watching for a bit I saw that it was making a relatively predictable circuit that passed fairly close to me each time around.  I started trying to follow it through the lens and snap shots as it passed by – most of them turned out like this (actually, most of them turned out worse than this):

However, with each pass I got better, and I started getting shots with at least part of the beetle in focus.  So intent I was on what I was doing that I didn’t even know Rich had taken the photograph of me in the previous post until he showed it to me afterwards (he said he wanted to document the camera drop!).  Eventually I got this shot:

It’s far from a perfect photo – I had to adjust the levels because I hadn’t figured out the best lighting to use for something on the water’s surface, and the specular highlights from the flash on the forward elytron are rather extreme.  But the entire beetle is in focus, and we can make a reasonable guess as to its identity.  There are only two genera of whirligig beetles in Missouri – Dineutus and Gyrinus – and the large size (~12 mm in length) and hidden scutellum clearly identify this individual as something in the former genus.  Moreover, the rounded elytral apices (seen on other individuals as well) narrow it down even further to just a few possible species.  Unfortunately, they are distinguished primarily by ventral coloration; however, the bad first photo clearly does show dark legs, suggesting this may be D. ciliatus and not the orange-legged D. emarginatus.  I don’t even really care what species it is (did you ever think you’d hear me say that?), I’m just happy to have gotten a reasonably good photograph of an insect that surely few people have photographed well.

Copyright © Ted C. MacRae 2010

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Long Weekend Bug Collecting Trip!

/ Ted C. MacRae / 13 Comments

On Saturday, I’ll be joining a number of other Missouri biologists as a Group Leader for a BioBlitz at Penn-Sylvania Prairie (“C” on the map above).  Penn-Sylvania Prairie is a 160-acre tract of native tallgrass prairie in southwestern Missouri owned by the Missouri Prairie Foundation. I’ll be leading the “Beetles” group (of course), and as far as I can tell there has been little to no work done to survey beetles in this prairie.  Late May is an awesome time to look for beetles in southwestern Missouri, and with the forecast calling for sunny skies with highs in the mid-80’s, what better opportunity to add an extra day to an already long holiday weekend and do a…

Long Weekend Bug Collecting Trip!

The BioBlitz is not until Saturday afternoon, so I’ve padded the itinerary with a few nearby southwestern Missouri spots that I’ve wanted to visit for some time now.  The first stop will be Ha Ha Tonka State Park (“B”) and its mosaic of dolomite glades and post oak savanna.  My interest in this area stems from two jewel beetle specimens collected there by a student at the University of Missouri, who gave them to me for identification.  These two specimens caused a stir when I first saw them, as I could not definitely ID them – they resembled Agrilus impexus, a common inhabitant of the desert southwest and Mexico, but they were much larger and, of course, were found in Missouri.  These specimens played a key role in clearing up a case of taxonomic confusion on the identity of Agrilus impexus when I sent them to U.S. Agrilus-guru Henry Hespenheide.  Through comparison with type specimens, he determined that these were among a smattering of specimens collected across the Great Plains that represent the true A. impexus, while the common southwestern U.S. species to which the name had long been applied was actually an undescribed species.  He described the latter as Agrilus paraimpexus (Hespenheide 2007), and the true A. impexus remains rare and little known.  Obviously, my two specimens are the only ones known from Missouri, and indeed only one other specimen of this species has been collected in the past 60 years!  I know that makes finding it a long shot, but the student who collected them told me he swept them from woody vegetation along the edge of a glade at Ha Ha Tonka Savanna Natural Area.  I suspect they may be associated with honey locust (Gleditsia triacanthos), thus, I will have my beating sheet and will be beating lots of honey locust on Friday – wish me luck!

On Sunday, I’ll work my way slightly northeast to some of the sandstone glades that are found in St. Clair Co. where the Osage Plains to the west transition into the Ozark Highlands to the east.  The two most interesting of these are Lichen Glade Natural Area (“D”) and Dave Rock Natural Area (“E”).  Here, sandstone glades and bluffs are surrounded by dry and dry mesic sandstone woodlands dominated by post oak (Quercus stellata) and blackjack oak (Quercus marilandica).  Many years ago, I beat a single specimen of Agrilus frosti off of post oak at Lichen Glade.  I have not collected the species since, and I know of only one other Missouri specimen collected by state agriculture personnel in a malaise trap in central Missouri.  I also hope to photograph the lichen grasshopper (Trimerotropis saxatilis), which I have seen commonly at both of these sites.  This Great Plains species is at its eastern limit of distribution in Missouri, occurring exclusively on sandstone and igneous glades where its cryptic coloration makes it nearly invisible against the acidic, lichen-covered rocks that dominate these habitats.

Otherwise, I have no specific goals for the trip, but as late May is prime time in this area for jewel beetles, I’ll be doing lots of general beating on the oaks and hickories that many species in this family favor as hosts for larval development.

REFERENCE:

Hespenheide, H. A.  2007. The identity of Agrilus impexus Horn, a new species, and taxonomic notes and records for other Agrilus Curtis species (Coleoptera: Buprestidae).  Zootaxa 1617:57–66.

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Cylindera celeripes Larva Revealed

/ Ted C. MacRae / 22 Comments

In a recent post, I provided the first ever glimpse of the previously unknown larva of Cylindera celeripes, or swift tiger beetle.  This little-known flightless species is among the tiniest in North America (adults measure only 8 or 9 mm in length), and so far nobody has succeeded in rearing the species in the lab, or even finding its larva.  As the photographs in that post showed, I am reasonably close to accomplishing that first goal, having successfully obtained a number of eggs from field-collected adults placed in a terrarium of native soil. I fed the subsequent larvae a diet of small rootworm larvae and Lygus nymphs before putting them to sleep for the winter in a cold incubator, and the larvae resumed activity when I pulled them out of the incubator 2 months ago. Since then, they have feasted heavily on small noctuid larvae that we rear in our lab, and now most of the dozen or so larvae have sealed their burrows – I presume for pupation before (hopefully) emerging as adults in the next few weeks.

Cylindera celeripes 3rd instar larva - USA: Oklahoma, Woodward Co.

There is more to the story, however.  I had brought the adults back home in June 2009 from a population I found at Alabaster Caverns State Park in northwestern Oklahoma.  This was a reasonably robust population – news enough for a species that has not been seen in good numbers for many years now, and my discovery of equally healthy populations at several other locations in the general area gives new hope for the long-term prospects of a species that some regard as a potential candidate for listing as an endangered species. It also gave me hope that I might be able to find the larva were I to return to the area in the fall.  I also had a hunch that Cicindela pulchra (beautiful tiger beetle) could be found in the area, based on some very large larvae I found during that June trip, so in early October I made a quick return to northwestern Oklahoma to search for these two species.  While it was too cold and wet to have any hope of finding Cicindela pulchra adults (I still think the species is there), it did not prevent me from realizing my other goal.  May I present one of the first ever field-collected larvae of Cylindera celeripes!

Cylindera celeripes 3rd instar larva - closeup of hump on 5th abdominal segment with hooks to aid in securing the larva in its burrow

I found the larvae at Alabaster Caverns where I had found the adults earlier in June, and although the larval burrows were very small (only 2 to 3 mm in diameter), I knew what they were immediately when I saw them.  As I had observed for the adults, burrows tended to be near the edges of barren patches of soil in proximity to vegetation and not out in the middle of the barren areas.  This makes sense, considering where it would be more likely for prey to be encountered.  Because the weather was cold and gray, I didn’t see (or expect to see) larvae actively sitting at the tops of their burrows, so I began “fishing” to see if I could yank a few from their burrows.  I fished quite a few burrows for the first half hour or so, but none of my attempts were successful.  I began wondering if the larvae were even active at all or if they had already entered hibernation for the upcoming winter.  While I was fishing, I noticed that the burrows all seemed rather shallow – only about 6” or so (most tiger beetles, having larger larvae, dig burrows that are much deeper). This gave me an idea.  I went back to the truck and retrieved a small spade that I carry in case… well, I’d never actually used it before.  Anyway, I inserted a grass stem into a burrow and sunk the spade into the ground right next to it, making sure I got the spade at least as deep as the grass blade.  I then removed the spade and sunk it into the ground on the other side of the burrow, then pried until the entire chunk of soil came up intact.  With the bottom of the soil chunk exposed, I used my knife to carefully remove slivers of soil until I found the end of the grass stem that I had inserted into the burrow.  Carefully removing the soil in this area revealed the larva in a side chamber at the bottom of the burrow.  Success!  I took many photos of that larva right then and there, and over the next hour or so collected several more larvae, all but one of which I presumed were 3rd instars.  I packed each larva in its own small vial of native soil for the trip home, and although I have been attempting to rear them out for confirmation of their identity, there is little doubt that they do indeed represent this species.

Cylindera celeripes 3rd instar larva - that grotesquely beautiful head!

The photographs I’m showing here are not those first field photographs that I took when I first discovered the larvae.  Looking at those photographs after I returned home, I was dissatisfied with the amount of soil and debris that covered the larvae – especially their grotesquely unique head and pronotum.  Instead, I removed one of the larvae from its rearing tube and gave it a “bath” – brushing it with a fine camel-hair brush in a shallow dish of water – to clean it up for the photographs shown here.  After the photo shoot, I sacrificed this larva for the collection – it will be the basis for a formal description of the larva of this species (along with examples of the 1st and 2nd instars that I had sacrificed from my rearing, not yet confident that I would succeed in getting any of the others to 3rd instar).  The only thing I am waiting on before preparing that description is to see whether I actually succeed in rearing this species from egg to adult – stay tuned!

Photo Details: Canon 50D (ISO 100, 1/250 sec, f/13-16). Canon MP-E 65mm 1-5X macro lens, MT-24EX flash (1/8 power) w/ Sto-Fen diffusers. Typical post-processing (levels, unsharp mask).

Copyright © Ted C. MacRae 2010

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Introducing Chrysobothris caddo

/ Ted C. MacRae / 9 Comments

This set of photographs comes from my June 2009 trip to northwestern Oklahoma, which I found at Boiling Springs State Park in Woodward County. They represent only the second buprestid species that I attempted to photograph with my (then) new camera and macro lens setup, the first being Chrysobothris ignicollis which I found at nearby Four Canyon Preserve. The latter species is commonly associated with Juniperus throughout much of western North America – indeed, the individuals I photographed were found on freshly cut J. virginiana (eastern redcedar), and I have reared the beetle from dead branches of this and other Juniperus species. The individual in these photographs represents another species in the same genus – Chrysobothris caddo. It was also found on cut redcedar; however, it is not normally associated with that plant. In fact, it is not very well-known at all, as it was only just described in 2007 (and these may well be the first ever identified photographs of the species).

Chrysobothris caddo is one of a number of new species that were described by Wellso and Manley (2007) in their revision of the Chrysobothris femorata species-group from North America. I’ve previously mentioned the taxonomic difficulties associated with this group, last revised by Fisher (1942), and it had been known for some time that several species – including some unnamed – were masquerading under the “catch-all” taxon of Chrysobothris femorata. Normally, the only people who care about such situations are taxonomists and those who enjoy placing ID labels on specimens (me on both counts – I just hated those “Chrysobothris femorata species-group” labels).  However, there was farther reaching impact in this case since C. femorata is a widespread and important economic pest of shade and fruit trees (eggs are laid on the trunks of the trees, which are then damaged by the boring actions of the larvae that hatch from them). The Wellso/Manley revision has brought some degree of clarity to species limits within the group (doubling its number of described species), but they remain difficult to identify since their recognition relies upon “suites” of characters rather than single “key” characters. For example, we know this individual (a female, based on the form of the pygidium, or upper surface of the tip of the abdomen) represents C. caddo because (see if you can find the characters in the photos as we go here):

  • the antennae are narrowed to the apex (eliminating C. rugosiceps, which has the last antennal segment strongly quadrate)
  • the post-median (back of middle) foveae (circular impressions) of the elytra (wing covers) are joined (eliminating C. viridiceps, which has the foveae distinctly separated)
  • the pygidium is deeply impressed on each side of the middle (eliminating C. quadriimpressa, which has the pygidium shallowly impressed)
  • the pygidium lacks a hyaline (membranous) lateral margin (eliminating C. adelpha, which is unique in possessing this character)
  • the elytra have the posteriolateral margins arcuate and the tips bronze (eliminating C. femorata, in which the margins are straight and the tips reddish)
  • the elytral costae (longitudinal ridges) are connected by cross-veins and interrupted by the foveae (eliminating C. comanche, which lacks cross veins and has indistinct foveae)
  • the frons (face) has the callosities (elevated patches) transverse and bronze (eliminating C. shawnee, which has larger, bronze-black callosities)

Are you cross-eyed yet?! If not, there are four additional species in the group that are distinguished by similarly subtle character suites but whose geographical occurrence outside of Oklahoma (see checklist below) automatically eliminates them from consideration.

Chrysobothris caddo is primarily associated with Celtis (hackberry), and my finding it on redcedar is simply an incidental association. There was a large tree dump in the back area of the park with freshly cut wood from a variety of plant species – such tree dumps are famous collecting grounds for woodboring beetles in the families Buprestidae and Cerambycidae. However, little importance can be given to beetle-plant associations observed in such situations, with multiple potential host plant species in such close proximity to each other. The third photograph shows another female probing cracks in the bark of cut Ulmus rubra (slippery elm) with her ovipositor – perhaps she will have laid an egg or perhaps not, and if she did it is unknown whether the larva that hatched would be able to feed and develop successfully to adulthood on this non-preferred host.

For those with an interest in this group, following is a checklist of the species with their geographical distribution and preferred hosts:

  1. Chrysobothris adelpha Harold – eastern US and southern Canada west to Texas.  Primarily associated with Carya, also reared from Amelanchier and Prosopis.
  2. Chrysobothris caddo Wellso and Manley – Florida west to Arizona and north to Missouri, abundant in Texas.  Primarily associated with Celtis, reared also from Cercis and Ebanopsis [= Pithecellobium].
  3. Chrysobothris comanche Wellso and Manley – New Mexico, Texas, and Utah.  Associated exclusively with Juglans.
  4. Chrysobothris femorata (Olivier) – all continental states and Canada.  Associated with a wide variety of woody plant species, especially those in landscape and orchard settings.
  5. Chrysobothris mescalero Wellso and Manley – New Mexico and Texas.  Associated exclusively with Quercus.
  6. Chrysobothris quadriimpressa Gory and Laporte – eastern US west to Continental Divide.  Primarily associated with Quercus, reared also from Juglans, Liquidamber, and Sapindus.
  7. Chrysobothris rugosiceps Melsheimer – eastern US and southern Canada west to Texas.  Primarily associated with Quercus, reared also from Castanea.
  8. Chrysobothris seminole Wellso and Manley – Georgia and Florida.  Associated exclusively with root crowns of Chrysoma, making it the only species associated with a non-woody host.
  9. Chrysobothris shawnee Wellso and Manley – eastern US west to Colorado.  Primarily associated with Quercus, reared also from Salix and Prunus.
  10. Chrysobothris sloicola Manley and Wellso – Known only from Michigan in association with Prunus.
  11. Chrysobothris viridiceps Melsheimer – eastern US and southern Canada west to Continental Divide.  Associated primarily with Quercus, reared also from Carya, Prosopis, and Ulmus.
  12. Chrysobothris wintu Wellso and Manley – Arizona and California.  Primarily associated with Quercus, reared also from Salix and Prunus.

I have, over the years, collected numerous specimens of most of the species in this group (lacking only mescalero, seminole, and sloicola in my collection), with specimens now assignable to caddo, comanche, shawnee, and wintu included in the original type series as paratypes.

Photo Details: Canon 50D (ISO 100, 1/250 sec, f/14-16), Canon 100mm macro lens, Canon MT-24EX flash (1/4 ratio) w/ Sto-Fen diffusers. Typical post-processing (levels, unsharp mask, minimal cropping).

REFERENCES:

Fisher, W. S.  1942. A revision of North American species of buprestid beetles belonging to the tribe Chrysobothrini.  U. S. Department of Agriculture, Miscellaneous Publication 470, 275 pp.

Wellso, S. G. and G. V. Manley. 2007. A revision of the Chrysobothris femorata (Olivier, 1790) species group from North America, north of Mexico (Coleoptera: Buprestidae). Zootaxa 1652:1–26 (first page only).

Copyright © Ted C. MacRae 2010

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The Marvelously Cryptic Dicerca lurida

/ Ted C. MacRae / 7 Comments

Dicerca lurida on trunk of wind-thrown mockernut hickory (Carya alba).

This is Dicerca lurida (family Buprestidae), another of several woodboring beetle species that I found on the trunk of a large, wind-thrown mockernut hikcory (Carya alba) tree during my early April hike of the lower Wappapello Section of the Ozark Trail.  Actually, I had already spent some amount of time at the tree photographing a checkered beetle (Enoclerus ichneumoneus) and a longhorned beetle (Stenosphenus notatus) giving a ride to a phoretic pseudoscorpion before I even noticed not one, but several of these cryptically colored jewel beetles on the trunk of the tree.

Like other species in the genus, the brilliant metallic gaudiness of Dicerca lurida as a pinned insect specimen in a cabinet belies its near invisibility when sitting on the bark of its host trees.  Several different trees have been reported as hosts (Nelson 1975), but hickories of the genus Carya seem to be the most preferred.  The beetles rapidly colonize wind-thrown or cut trees and branches while the wood is still hard and strong, and I have collected it from a number of hickories and reared it from dead pignut hickory (Cary glabra) and shellbark hickory (Carya laciniosa), as well as sandbar willow (Salix exigua).  Most jewel beetles are active as adults only during a limited time during the season – typically late spring and early summer in eastern North America, but species of Dicerca occur as adults throughout the year – even during winter hibernating under loose bark.  This individual probably represents one of those hibernating adults that resumed activity in the first warm days of spring, searching for freshly killed host trees on which to mate and lay their eggs.  Widespread across eastern North America, it is perhaps the commonest species of the genus and one of the commonest jewel beetles in North America.  Yet, despite its abundance, year-round occurrence, relatively large size, and attractive coloration, its cryptic habits keep it seldom seen by those who don’t look for it.

Photo Details: Canon 50D (ISO 100, 1/250 sec, f/18), Canon 100mm macro lens, Canon MT-24EX flash (1/4 ratio) w/ Sto-Fen diffusers. Typical post-processing (levels, unsharp mask, minimal cropping).

REFERENCE:

Nelson, G. H. 1975. A revision of the genus Dicerca in North America (Coleoptera: Buprestidae). Entomologische Arbeiten aus dem Museum G. Frey 26:87–180.

Copyright © Ted C. MacRae 2010

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