Arthropoda

Arthropods – insects, arachnids, crustaceans, myriapods, & relatives

Cleaning Tiger Beetles

/ Ted C. MacRae / 22 Comments

Cicindela scutellaris scutellaris - the festive tiger beetle

This is Cicindela scutellaris (festive tiger beetle), one of the six species of tiger beetles that we found last September at Monroe Canyon in the Pine Ridge area of northwestern Nebraska.  The red elytra and green head and pronotum are characteristic of nominotypical populations of this species that are found in sandy habitats throughout the Great Plains.  This is your classic tiger beetle in a classic tiger beetle pose; however, photographs such as this are not so easy to come by.  The biggest challenge is the beetle itself – rarely are they so accommodating to allow this nice lateral profile perspective with the head slightly cocked towards the camera while standing up on their front legs.  This posture is seen only when the beetles are warm and active, and warm beetles are skittish beetles that yield lots of not-as-interesting back shots (head directed away from the camera) as they persistently run away from the photographer.  Cooler temperatures make them less skittish and easier to approach from the desired angle, but in this case they often lay flat on the ground trying to absorb heat – flay-laying beetles are not very photogenic either.  With practice and patience, one learns how to “work” an active, skittish subject and get them accustomed to the photographer so that the above perspective can be achieved.

Getting the shot, however, is only half the battle.  Tiger beetles are dirty bugs!  They run around over bare ground and dig in it, often leaving them covered with debris.  This is particularly true for species that frequent sandy habitats.  For those of us who like to photograph wild individuals in their native habitats, debris-covered beetles is something we have to live with.  Or do we…?  The beetle in the above image looks squeaky-clean thanks to some simple digital image processing tools that I used to “clean up” the subject (I use Photoshop Elements 6.0).  Now, I’ve never been one to want to spend a lot of time on post-processing of my photographs.  I’d rather be looking for bugs, photographing them, studying them, and writing about them – time spent on post-processing is time not spent on any of these other activities.  However, I have developed a little routine that I follow for most of my tiger beetle photographs now that cleans them up a bit – some more than others – and doesn’t take too much time.  Maybe some of you will find this useful for your own photographs.¹

¹ Disclaimer:  I am not a Photoshop expert.  I’m not even a photographer.  I’m an entomologist with a camera.  As a result, this post is intended to be not so much an authoritative tutorial on the use of Photoshop as a summary of what I’ve learned in dealing with my own photographs.  Constructive dialogue about these and other techniques is welcome. 

Like it or not, no digital image comes out of the camera ready to use (still perhaps the most perplexing aspect of this whole digital photography thing for me personally).  Almost every image needs some levels adjustment and unsharp mask applied to it, and while others are against it I’m not above doing a little cropping to enhance the final composition of the photograph (hey, it’s difficult enough just getting these guys in the frame, much less positioned exactly where you want them).  These are the basic steps that I follow for almost every photograph, as illustrated in the following sequence (reduced versions used for all photos):

Original photograph before processing.

Slight cropping to enhance composition.

Levels adjusted to brighten photo.

Unsharp mask applied (amount = 80%, radius = 2.0 pixels, threshold = 12 levels).

 Normally I would be done at this point, but there are two things that bother me about this photo: 1) the dark shadow on the distal back portion of the elytra (common with this pose), and 2) the debris scattered about on the eye, mandibles, thorax, and elytra.  To fix the shadow, I used the Magic Wand Tool (set on contiguous) to select the shadowed area of the elytra, then used the Dodge Tool set on Highlights (exposure = 25%) to lighten the shadowed area.  For the debris, I enlarged the photo to 100% and used the Spot Healing Brush Tool to remove most of the sand particles, adjusting the size of the brush to just larger than the size of the individual sand particles.  This works fine for particles surrounded by a uniform background, but it doesn’t work so well for particles along edges (particularly the mandibles).  For this, I used the Clone Stamp Tool (again, with the photograph enlarged to 100%) and carefully “cloned” a clean spot along the edge of the mandible next to the sand particle and then replaced the piece of debris with the cloned piece of the image.  As with the Spot Healing Brush Tool, the pixel size is set to the smallest size needed for the size of the debris particles.  Compare the above image with the finished image below to see the difference.

Finished photo with dark shadows on elytra and sand debris on body removed.

 The biggest improvements can be seen with the eyes, always the focal point of a photo such as this, and the mandibles – both now appearing nice and clean.  Is this cheating?  Have I compromised my ideal of getting an image of a wild individual of this species in its native habitat?  I’d be interested to know your opinion about this.

Photo Details: Canon 50D w/ 100mm macro lens (ISO 100, 1/250 sec, f/16), Canon MT-24EX flash w/ Sto-Fen + GFPuffer diffusers.

Copyright © Ted C. MacRae 2010

Monroe Canyon – A Tiger Beetle “Hot Spot”

/ Ted C. MacRae / 16 Comments

Steep, sparsely vegetated, fine sand road cut on the Nebraska Pine Ridge escarpment.

The vast landscape surrounding the Nebraska Pine Ridge boasts two entirely different natural communities – the High Plains shortgrass prairie atop the ridge stretching endlessly to the south, and the eerie, desolate Badlands on the north side of the ridge extending to the Black Hills of South Dakota.  Separating these two distinctive communities is the Pine Ridge escarpment itself – a precipitous 1,400-ft drop whose ponderosa pine forests and sage brushlands are more reminiscent of the Rocky Mountains some distance to the west rather than the Great Plains that surround them.  Instead of hard igneous and metamorphic rocks, however, the Pine Ridge is composed of soft, erodable sand- and siltstones, giving rise to canyons with dramatic white bluffs and escarpments.  One of the more scenic of these is Monroe Canyon, located six miles north of the tiny town of Harrison and part of the Gilbert-Baker State Wildlife Management Area.  I first explored Monroe Canyon two years ago, when Matt Brust took me there after our successful quest to see Cicindela nebraskana (prairie long-lipped tiger beetle) in the prairies above.  The steep, eroded road cuts in Monroe Canyon had become one of Matt’s favorite spots to look for tiger beetles, but on our visit there was not much going on save for single individuals of the ubiquitous sand-loving species Cicindela formosa (big sand tiger beetle) and Cicindela scutellaris (festive tiger beetle).  Still, the fine, deep, sparsely vegetated mixture of sand and silt extending far up the embankment is classic tiger beetle habitat, so when Chris Brown and I returned to the area this past September, we decided to give Monroe Canyon another try.

Of the several sand-associated tiger beetles that I thought we might encounter here, Cicindela lengi (blowout tiger beetle) was the one I was really hoping for.  I had encountered a few scarce individuals of this C. formosa-look alike during my 2008 trip and eventually reared another individual from suspected larvae plucked from their burrows.  My only photographs of this species, however, were taken during my PNS days, and I longed to see them once again through the viewfinder of a proper macro-rig.  The day hadn’t started well, getting skunked at a clay bank site in Crawford on the way to Monroe Canyon (where I resorted to photographing itty bitty little moths), and early indications once we got to Monroe Canyon were that it was going to be slow there as well.  Sporadic sightings of Cicindela purpurea audubonii (Audubon’s tiger beetle) had me yawning, and a lone individual of the remarkably infidel Cicindela ubiquita [= C. punctulata] (punctured tiger beetle) seen close to the roadside did little to boost my enthusiasm.  Still, conditions just seemed “right” and the habitat was extensive enough that it deserved a thorough searching before passing judgement.  I got a little more excited when I encountered a few C. purpurea audubonii black morphs, of which I got my first nice field photographs (you’ll see these in a future post), and then spent some time staking out larval burrows for attempted photographs.  We ended up spending a couple of hours at the site without seeing anything remarkable, but by then it was early afternoon and there was little point in trying to find another locality to search – it was a gorgeous spot on a gorgeous day, and just being out there was almost reward enough.  (I’m guessing by now you see where this is going…)

Cicindela lengi - blowout tiger beetle

As I began my umpteenth pass along the lower stretch of the embankment, I heard Chris call out, “I’ve got it!”  Chris hadn’t previously seen this species, so I fully expected when I walked over to where he was standing that I would find instead the much more common and amazingly similar C. formosa.  However, when I spotted the adult as he pointed to it, there was no doubt – the longer, obliquely straight humeral lunule (shoulder marking), the slightly more cylindrical, parallel-sided body, the more extensive brilliant green marginal highlights on the head and pronotum – it was, indeed, C. lengi!  The close resemblance of C. lengi to C. formosa is not the result of a close relationship, but rather an example of convergent evolution in response to similar habitat.  Cicindela lengi is actually more closely related to C. tranquebarica (oblique-lined tiger beetle) and other species formerly placed in the now defunct subgenus Tribonia.  As the first finder, Chris had first photo honors as well while I stood back, ready with the net should it spook and become uncooperative.  It did make a few short escape flights at first, but as I’ve learned before this species tends to make very short, weak flights before dropping straight down, making it rather easy to follow even on the steep embankment that we found ourselves.  This contrasts with C. formosa, whose long, powerful escape flights and bouncing tumbles upon landing can make them difficult to follow.  Eventually it became accustomed to our presence, and after Chris was satisfied with his photographs it was my turn.  We then we took turns again just to make sure we really got the shots we wanted.

Cicindela lengi - note the obliquely straight humeral lunule and relatively narrow, parallel-sided body.

It’s a good thing we didn’t pull the plug on Monroe Canyon that day, as tiger beetle activity really picked up during the afternoon hours.  Not only did we end up seeing several individuals of C. lengi during the next couple of hours, but also a few individuals of C. formosa and C. scutellaris and a single, seemingly misplaced Cicindela denverensis (green claybank tiger beetle), more fond of clay substrates than sand) – making Monroe Canyon a veritable “hot spot” of tiger beetle diversity.  While Monroe Canyon may not equal Willcox Playa, Laguna del Perro, Salt Plains National Wildlife Refuge, or Florida’s Road to Nowhere, six species is still a respectable amount of diversity by any measure, especially for a dry, upland site (all of the other sites mentioned are lowland saline habitats that owe their tiger beetle diversity at least in part to their broad range of available moisture zones).  After two days in the field, our trip total now stood at ten species, and in retrospect we were lucky to see C. lengi when we did as our subsequent search of the C. lengi spot 4 miles east of Harrison later that day turned up nothing.

Brilliant green highlights contrast spectacularly with the red body and bold white markings.

Copyright © Ted C. MacRae 2010

Answer to Super Crop Challenge #2

/ Ted C. MacRae / 8 Comments

I was hoping that Super Crop Challenge #2 would prove a little more difficult than the first one, but first responder Troy Bartlett quickly sniffed out the correct answer – the top part of the abdomen of the marmorated orb weaver, Araneus marmoreus.  As the first correct responder he earns bonus points.  Dennis also came up with the same answer after temporarily being led astray, and Colton got it right as well (once he realized the challenge was here and not over on FaceBook).  I might be justified if I deducted points for misspellings in the genus and common names (if there is any field unforgiving of spelling errors, it’s taxonomy); however, I’m watching a Christmas movie with my family and am feeling the holiday spirit.  That spirit extends to Dave as well, who earns pity points for refusing to believe that I would offer consecutive spider challenges (actually the first Super Crop Challenge was an opilionid, but the ID challenge before that was another spider, making this the third straight arachnid challenge I’ve posted – it wasn’t by design).

The crop I used for this challenge was taken from the above photo – not the best of the series, but it had the most symmetrical view of the dorsal abdominal pattern that some think looks like a face.  This is just one of many color variations exhibited by this most variable of North American spiders – see this BugGuide page for a pictorial summary of the extraordinary amount of variation found in this species.

My friend Rich and I encountered this individual – a female – in an upland oak/hickory forest while hiking the lower North Fork Section of the Ozark Trail in extreme southern Missouri.  These spiders normally hide in a retreat during the day (usually a curled leaf) and spin a new web at night – I’m not sure why she was out during the day, as it didn’t appear she was recycling the web, tattered and torn and probably still remaining from the previous evening.  When I first approached, I accidentally brushed against one of the support lines, which sent her scampering up into her retreat.  I figured “tapping” on the leaf might cause her to drop back out – Rich was skeptical, but after a few taps, the spider not only dropped out but obligingly went right back down to the center of the web and stayed in place long enough for me to get a few shots of the ventral surface.  (I couldn’t suppress a smug chuckle as Rich muttered in exasperated disbelief!)  Moving around to the other side disturbed the spider again, and she once again took refuge in her retreat.  This time, rather than fight it, I carefully uncurled the leaf that formed her retreat, working gingerly to avoid disturbing her, and took a series of photos of her attractive dorsal surface as she sat in the retreat.

Photo Details: Canon 50D w/ 100mm macro lens (ISO 100, 1/200 sec, f/16), Canon MT-24EX flash w/ Sto-Fen + GFPuffer diffusers. Typical post-processing (levels, minor cropping, unsharp mask, etc.).

Copyright © Ted C. MacRae 2010

Tiny little slivers of life

/ Ted C. MacRae / 13 Comments

Day 1 of the 2010 Fall Tiger Beetle Trip™ had been an unqualified success.  Not only did we achieve our top goal of the trip – seeing good numbers of the recently discovered South Dakota population of Cicindela pulchra (beautiful tiger beetle), but we also saw C. nebraskana (prairie long-lipped tiger beetle) and a variety of other interesting insects in the nearby Nebraska Pine Ridge.  For Day 2, our destination was Monroe Canyon on the north face of the Pine Ridge escarpment, but on the way there we decided to check out some roadside clay banks in the town of Crawford.  Despite their appearance as perfect tiger beetle habitat, all we saw was a single individual of the normally ubiquitous C. purpurea audubonii (Audubon’s tiger beetle).  The area looked quite dry, and in fact there was little insect life of any kind present… or so I thought.  As I stood there looking out onto the embankment while deciding my next move, I glanced down at a nearby composit shrub with small yellow flowers.  These are often attractive to a variety of beetles (Crossidius longhorned beetles would be nice!), but I saw none.  I started to move on, but before I did I noticed some tiny little slivers of life moving about on the flowers.  Kneeling down to take a closer look, I saw that they were moths – in fact, they were some of the smallest moths that I had ever seen, and the shrub was covered with them.  Now, I may pride myself on my broad-based entomology knowledge, but when it comes to microlepidopterans there is a decided gap in that knowledge.  I really had no idea what they might be, but for some reason the combination of their unknown identity and tiny size became for me an irresistible photographic challenge (made truly challenging by the unrelenting prairie wind).  I’m fortunate that Chris also became distracted photographing something – any other collecting partner surely would have grown impatient waiting for me to finally be satisfied I’d gotten some good shots.

As far as I can tell, these moths represent something in the genus Scythris or perhaps Neoscythris.  These are the so-called flower moths, placed either in the family Scythrididae (Microleps.org and Moth Photographers Group) or subfamily Scythridinae of the Xylorictidae (BugGuide.net and Tree of Life).  According to Microleps.org, the life histories of relatively few scythridid species have been determined – the few that have showing a preference for feeding (usually internally, e.g., as leaf miners) on members of the Asteraceae.  There are images of several species of Scythrididae at the aforementioned sites; however, it’s a large group, and the individuals in these photos don’t appear to match any of the illustrated species.  Perhaps Chris Grinter or some other microlepidopterophile will chance upon this post and either confirm or further elucidate the identity of these individuals. 

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

Copyright © Ted C. MacRae 2010

Kirby’s Tiger Beetle

/ Ted C. MacRae / 23 Comments

Dry alkaline creek in the Oglala National Grasslands, Sioux Co., Nebraska

At the northern edge of the Pine Ridge in northwestern Nebraska, the land drops precipitously from verdant High Plains to the eerie Badlands below.  The sterile landscape of eroded slopes and irregularly shaped landforms is at once beautiful and harsh.  Short grasses and silver sagebrush seem to be the only plants capable of living here, providing the meagerest of forage for the mule deer and pronghorn antelopes that dot the gently rolling hills.  Dissecting these arid grasslands are a series of seasonally dry alkaline creeks that support a number of tiger beetle species.  The most interesting of these is Cicindela fulgida fulgida (crimson saltflat tiger beetle), a beautifully colored little species that is restricted to wet, alkaline habitats.  It was this species that I and colleagues Chris Brown and Matt Brust wanted to see when we stopped by one such creek after finishing up at the C. pulchra site in South Dakota (and still recovering from “pulchra-fever”).

Cicindela tranquebarica kirbyi - Kirby's tiger beetle

I had been to this spot two years before and encountered a small number of C. fulgida along with much higher numbers of C. purpurea audubonii (Audubon’s tiger beetle) and C. tranquebarica kirbyi (Kirby’s tiger beetle).  Our luck wasn’t any better this time, and in fact we would encounter only a single C. fulgida that day.  This was Chris’ first opportunity to photograph this species, while I had already gotten some reasonably good field photos of the species during my 2009 visit to Salt Plains National Wildlife Refuge in northwestern Oklahoma.  As he photographed the individual, I continuing scanning the bright, alkaline barrens.  While I was not finding any C. fulgida, I was seeing a fair number of C. tranquebarica kirbyi, and it occurred to me that I still lacked good field photographs of this species.  I began stalking different individuals, but in the heat of the day I found it impossible to get close enough to any of them to attempt any shots.  It wasn’t until I encountered the individual shown above, apparently dragging something from its rear end, that I was able to close in for some shots.  A closer look revealed the individual to be a male who had somehow gotten his genital capsule pulled out of his abdomen.  Just the thought of how this might have happened makes me cringe.  At any rate, the individual exhibits the relatively broader white maculations that distinguish this Great Plains/Rocky Mountain subspecies from the more eastern nominotypical subspecies.

A newly emerged Kirby's tiger beetle sits at the entrance of his burrow.

As I continued scanning the soil, I noticed a number of larval burrows of what I took to be this species located up near the edge of the vegetated zone.  One burrow in particular caught my attention – partly because of its slightly larger size and irregular outline, but also because there appeared to be something sitting within it.  A closer look revealed an adult tiger beetle sitting just below the burrow entrance.  Cicindela tranquebarica is a so-called “spring-fall” species that emerges initially in the fall as a sexually immature adult before digging back in for the winter and re-emerging in spring for mating and oviposition.  I thus took this individual to be a newly emerged male that had not yet decided to leave its burrow and burst forth into a life of adulthood.  The opportunity couldn’t be passed up – I took a few photos of him sitting there, then switched out the 100mm lens for the 65mm 1-5X lens.  I had to get real close for this last shot, which caused him to retreat somewhat in his burrow.  However, a knife thrust into the burrow below him, followed by careful twisting until it touched his rear, caused him to return to the burrow entrance and once again pause before embracing his new world.

A male Kirby's tiger beetle prepares to leave his emergence burrow.

Copyright © Ted C. MacRae 2010

Litaneutria minor – agile ground mantid

/ Ted C. MacRae / 13 Comments

Litaneutria minor - agile ground mantid

Have you ever seen a mantid that lives exclusively on the ground?  Most mantids are ambush predators, hiding amongst the bushes while patiently waiting for unsuspecting prey to happen within striking range.  However, a few small groups of mantids have adopted a different strategy – running down their prey!  One such group is the ground mantids, represented in the U.S. by two genera – Litaneutria and Yersiniops.  These small mantids, cryptically colored brown or gray, occur in desert and grassland habitats across the western U.S.  This particular individual was seen in the expansive shortgrass prairie atop the Pine Ridge in northwestern Nebraska.  The rounded eyes and brown coloration identify it as as a member of the genus Litaneutria (the tops of the eyes are pointed in Yersiniops, giving them a “horned” appearance, and they tend to be more gray).  Two species of Litaneutria are found in the U.S. – this one, L. minor, occurring broadly throughout the Great Plains and western U.S. into southwestern Canada (it is Canada’s only native mantid), while a second species, L. obscura, is restricted to the desert southwest.¹  Several common names have been applied to L. minor, including lesser ground mantid, minor ground mantid, and agile ground mantid.  While the first two represent more precise literal translations of the scientific name, I like the latter which well describes the ability of these mantids to hop over rocks and dart swiftly through sparse prairie vegetation in pursuit of prey or to evade predators (and inexperienced collectors!).  Despite its small size (total length less than 1.5″), the presence of wings – albeit small – indicate this is an adult. All females of this species are brachypterous (short-winged), but most males are as well.  However, males apparently have a small spot at the base of the forewings, which seems lacking in this individual, and a smoother pronotum – also not readily apparent in this individual, so I’m guessing that this is an adult female. 

¹ BugGuide and many other web sources list five additional U.S. species in the genus (including L. borealis, described from northwestern Nebraska).  However, Vickery and Kevan (1983) note that these were all synonymized under L. minor by Hebard in 1935 (sorry – I couldn’t find that reference).

“Mantid” vs. “mantis” vs. “praying mantis.”  It has become common to use the terms “mantid” and “mantis” (or even “praying mantis”) interchangeably.  However, in its strictest sense the term “mantis” is most properly applied to species of the genus Mantis – of which Mantis religiosa – the European mantid or praying mantis, introduced to the U.S. in the late 19th century (either accidentally on a shipment of nursery plants or deliberately for pest control – depending on the source) is the most widely recognized.  The term “mantid” refers to any species in the suborder Mantodea as a whole.

Carnivorous cockroaches!  When I was in college back in the late 1970s, mantids and most other “orthopteroid” insects had long been considered suborders of a single order, the Orthoptera.  Around that time began a great dismantling of the Orthoptera, pared down to only the grasshoppers, crickets, and katydids while the other former suborders (mantids, walkingsticks, cockroaches, etc.) were raised to full order status.  The walkingsticks (Phasmida), grylloblattids (Grylloblattodea), and gladiators (Mantophasmatodea) all continue to enjoy their elevated status (Tree of Life Web Project 2003); however, a close relationship has been established between the mantids, cockroaches, and termites² (Kristensen 1991), resulting in the sinking of all three former orders into a single order, the Dictyoptera (Tree of Life Web Project 2002) (and not to be confused with the lycid beetle genus Dictyoptera).  Mantids, thus, can be considered derived cockroaches with morphological specializations for predation!

² Long accorded an order of their own – the Isoptera, recent molecular phylogenetic studies have placed termites not only with the cockroaches, but within them (Ware et al. 2008).  Just as mantids can be considered cockroaches that evolved as predators, termites can be considered cockroaches that evolved to eat wood (with the help of cellulose-digesting gut symbionts)!

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

REFERENCES:

Kristensen, N. P. 1991. Phylogeny of extant hexapods. Pp. 125–140 in Insects of Australia: A Textbook for Students and Research Workers. Volume I and II. Second Edition. I. D. Naumann, P. B. Carne, J. F. Lawrence, E. S. Nielsen, J. P. Spradberry, R. W. Taylor, M. J. Whitten and M. J. Littlejohn eds. Carlton, Victoria, Melbourne University Press.

Tree of Life Web Project. 2002. Dictyoptera. Version 01 January 2002 (temporary). http://tolweb.org/Dictyoptera/8253/2002.01.01 in The Tree of Life Web Project, http://tolweb.org/

Tree of Life Web Project. 2003. Neoptera. Version 01 January 2003 (under construction). http://tolweb.org/Neoptera/8267/2003.01.01 in The Tree of Life Web Project, http://tolweb.org/

Vickery, V. R. and D. K. M. Kevan. 1983. A monograph of the orthopteroid insects of Canada and adjacent regions. Lyman Entomological Museum and Research Laboratory Memoir 13:216–237.

Ware, J. L., J. Litman, K.-D. Klass, and L. A. Spearman. 2008. Relationships among the major lineages of Dictyoptera: the effect of outgroup selection on dictyopteran tree topology. Systematic Entomology 33(3):429–450.

Copyright © Ted C. MacRae 2010

Answer to Super Crop Challenge #1

/ Ted C. MacRae / 19 Comments

Seemingly correct answers came quickly to yesterday’s inaugural Super Crop Challenge, which featured a curious structure atop a harvestman (class Arachnida, order Opiliones) that I encountered while hiking the lower North Fork Section of the Ozark Trail in extreme southern Missouri. “Seemingly” I say, because even though some points were earned, others remained left on the table – the organism was rightly recognized as a harvestman, and the structure in the photo does indeed contain the ocelli (or eyes).  However, nobody actually named the structure itself (see update below) – the ocularium (ocular or optical tubercle would also have been accepted).  Hey, I’m pedantic and proud!

As near as I can tell, this individual belongs to the genus Leiobunum (family Sclerosomatidae).  Species in this genus are notoriously difficult to identify; however, the super long legs, dark dorsal stripe, pointed abdomen, and very long palps with “knees” that extend dorsally to a level well above the ocularium suggest a male L. vittatum or one of its close relatives (Schulz 2010). Leiobunum vittatum is a common inhabitant of wooded habitats across the eastern U.S.

I took this shot with an MP-E 65mm macro lens at about 2.5X. The short working distance of the lens at this level of magnification makes it difficult to photograph these longer-legged species in lateral profile due to their habit of “waving” their especially elongate 2nd pair of legs in the air as pseudo-antennae – one touch of any part of the camera sends them scampering. I chased this guy back and forth across a downed tree trunk for some time before I finally got lucky when it encountered some prey (note the long structure extending down from the mouth area – I believe it is the antenna of a tiny, nymphal blattodean) and became distracted just long enough for me to close in and fire off a couple of close shots. He was actually closer to the underside of the log, so when I took this photo I was leaning far over the log with the camera almost upside-down!

Okay – Art earns points for being the first to identify it as a harvestman, while Geek snaps rare duplicate ID points for using the order’s scientific name (no complaining – scientific names will always get points on this blog).  Art, Aniruddha, and Geek also get half-points for mentioning (in order of correctness) eye, ocelli (technically more correct, but wrong plurality), and ocellus (yes, only one is visible – did I mention my pedantic tendencies?).  However, I’m going to declare arachnologist and Opiliones specialist Chris as the winner of this round for his impressive display of generic-level identification based on the meagerest of evidence!

Update 11/22, 11:00 a.m. – actually, Chris did name this structure in an email sent to my office address while the comments box was unchecked and, thus, earns a clean sweep of this challenge.

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

REFERENCE:

Schulz, J. W. 2010. The Harvestmen of Maryland (accessed 20 November 2010).

Copyright © Ted C. MacRae 2010

Super Crop Challenge #1

/ Ted C. MacRae / 8 Comments

ID quizzes and challenges seem to have become an increasingly popular subject for natural history blogs. I’ve done a few of my own, but my straight up ID challenges are starting to seem a little unimaginative compared to the DNA sequence, crypsis, mimicry, taxonomy fail, and other challenges being offered up by bug blogdom’s more creative types. To step it up a notch, I offer the first Super Crop Challenge. Small structures that we take for granted within a larger context often take on alien qualities when viewed in isolation. Can you identify this structure and the organism that possesses it?


Copyright © Ted C. MacRae 2010