Month: October 2012

The “Other” Marvelously Monstrous Microstylum

/ Ted C. MacRae / 7 Comments

Microstylum galactodes | Brewster Co., Texas

A couple of years ago during the initial testing of my DIY diffuser, I pulled a selection of rather impressive insects from my collection and photographed them on a white background to see how effectively the diffuser worked with different types and sizes of insects. I posted some of those photos for the larger insects in the following weeks, including the tank-like eastern Hercules beetle, the frightful-looking stag beetle, and the downright evil-looking red-eyed devil. There were, however, a number of smaller insects that I had also photographed but whose photos never made it onto these pages as a flush of new photography began the following spring. This is one of them: the robber fly, Microstylum galactodes (order Diptera, family Asilidae). I collected this specimen nearly 20 years ago in western Texas, and until the last few years it was the largest robber fly I had ever seen. That honor now goes to the closely related M. morosum (North America’s largest robber fly), which I have seen in northwest Oklahoma and as a previously unreported occurrence in southwestern Missouri. Still, M. galactodes is an impressive beast, and these photographs of the preserved specimen do little justice to its appearance in life.

The ”beard” (mystax) of Microstylum is confined to the oral margin and composed of stout bristles.

Both species of Microstylum are distinguished by the mystax (dense moustache of bristles on the face) confined to the oral margin and composed chiefly of stout bristles, but M. galactodes may be separated from its larger cousin by the light-colored wings and even, whitish bloom (powdery covering) covering the head and thoracic dorsum (Back 1909). Despite being the relatively commoner species, M. galactodes seems to be a little more specific in habitat preference, most often found in short grass prairies and scrub lands (Beckemeyer & Carlton 2000). Also, even though both species occur broadly in the southcentral to southwestern U.S., M. galactodes seems to have a slight western shift in its distribution compared to M. morosum, extending north only into the western parts of Oklahoma and Kansas (Beckemeyer & Carlton 2000); while M. morosum occurs across these states and eastward into northwestern Arkansas (Warriner 2004) and southwestern Missouri (MacRae unpublished—gotta get that note submitted!

REFERENCES:

Back, E. A. 1909. The robberflies of America, north of Mexico, belonging to the subfamilies Leptograstrinae and Dasypogoninae. Transactions of the American Entomological Society 35:137–400.

Beckemeyer, R. J. & R. E. Carlton.  2000.  Distribution of Microstylum morosum and M. galactodes (Diptera: Asilidae): significant extensions to previously reported ranges.  Entomological News 111(2):84–96.

Warriner, M. D.  2004.  First Arkansas record of the robber fly Microstylum morosum (Diptera: Asilidae).  The Southwestern Naturalist 49(1):83–84.

Copyright © Ted C. MacRae 2012

The Third of Florida’s Three Metallic Tiger Beetles

/ Ted C. MacRae / 7 Comments

Tetracha virginica (Virginia Metallic Tiger Beetle) | Levy Co., Florida

After three straight posts not about tiger beetles, I’m hoping readers will forgive my return to this fascinating group. The photos in this post represent Tetracha virginica (Virginia Metallic Tiger Beetle), the most widely distributed (at least in the U.S.) of the four species occurring in North America north of Mexico. Even though this species occurs in my home state of Missouri, I’d not found an opportunity to photograph it until August last year at Florida’s “Road to Nowhere“—famous among U.S. cicindelophiles as one of the country’s true tiger beetle “hot spots.” In fact, it was on the very same night at this same place that I photographed the related Tetracha carolina (Carolina Metallic Tiger Beetle) (featured in Not all Florida tiger beetles are rare) and just one day after I photographed the endemic Tetracha floridana (Florida Metallic Tiger Beetle) (featured in Why I Roamed the Marsh at Night). That’s all three species of Tetracha occurring in Florida in just two days (and if I want to photograph the fourth and only remaining U.S. species, Tetracha impressus (Upland Metallic Tiger Beetle), I’ll have to go to Brownsville, Texas and get very lucky!).

The solid green elytra without apical markings distinguish this species from all other Tetracha spp. in the U.S.

Truthfully, I had no plans to post these photos after I took them. Like the other species they were photographed at night, and when I got a better look at the photos on the computer I was disappointed to see the subject was badly covered with large particles of sand. I don’t mind a little bit of debris on insects—it is, after all, a normal part of their appearance. However, too much debris is, for me, an aesthetics killer! “Wait a minute… these don’t look too bad”, you say? Well, thanks to the Clone Stamp Tool in Photoshop Elements, and as a followup to my recent post on this subject, I now have enough confidence to tackle not only small pieces of debris, but also more difficult “debris cases” such as this one with relatively large particles. Here is the same photo as shown above and processed in exactly the same manner, except that no cloning was used to remove the debris:

Aren’t I a dirty boy?!

Obviously, there are limits to what the Clone Stamp Tool can do, and I didn’t try to deal with the sand particles clinging to more difficult to clone body parts such as legs and antennae (although I’m sure that in the right hands even these could be cloned out). Nevertheless, even just cleaning the dorsal surface of the beetle does much to improve its appearance with a relatively minor amount of effort.

And, of course, what would a tiger beetle post be if it did not end with my signature face portrait (notwithstanding a few large sand grains that I wasn’t sure I could clone out effectively)?

Copyright © Ted C. MacRae 2012

A visit to the Dallas Arboretum

/ Ted C. MacRae / 10 Comments

This post is a little different from my normal fare, so feel free to glance and move on (or if you like it, let me know that too). Earlier this week I traveled to Argentina, but along the way I found myself unexpectedly spending a day in Dallas due to a missed connection. Such travel snags are never fun, especially when the result is an entire day lost from a tight itinerary. I do, however, have to give American Airlines props for comping me a night’s stay at the Downtown Crowne Plaza Hotel (very, very nice!). The following day, my flight to Buenos Aires would not leave until early evening, so I had to find some way to occupy myself after my noon checkout. Whenever I find myself in a large city looking for something to do, my first thought is always the local botanical garden. Dallas, of course, has a world class example of such—the Dallas Arboretum, situated in the heart of the city on the east side of White Rock Lake. Any time of year is a good time to visit a botanical garden, but fall is without question my favorite time. Turning leaves and late-season blooms would have been enticement enough, but this particular day found the garden in the midst of its annual fall festival, featuring a Pumpkin Village and a charming little “Small Houses of Great Artists” exhibit, and artfully placed throughout the garden were glass sculptures by world-famous Dale Chihuly. There was a lot to see, and I’m thankful that I had the luxury of exploring the garden’s many meandering paths at a leisurely pace without feeling rushed for time.

Frustratingly, I had decided not to bring my good camera with me on this trip since I didn’t anticipate any opportunities for photography. Even though I’m not normally inclined to photograph gardens and especially sculptures (preferring instead native and naturalized landscapes), I found the expert fusion of art and nature in the displays irresistible and did what I could with my smart phone (which, it turns out, takes surprisingly good photos for its size, especially for certain applications such as wide-angle landscapes). Obviously, armed with such, it’s hard to take “unique” photos of subjects that thousands of others (also armed mostly with smart phones) are passing by daily. Hopefully, however, I managed one or two that provide a different perspective. With that, I’ve picked out my 24 favorites and present them here in a brief slide show (the slides cycle continuously, beginning with “Mexican Hat Tower” and ending with “Blue Icicles”). Below that is a gallery of the photos in case the slideshow does not function in your browser or if you would like to see a larger version of a particular photo.

I know which are my favorites—are there any that you would call out (compositionally at least)?

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Copyright © Ted C. MacRae 2012

Post processing—then and now

/ Ted C. MacRae / 10 Comments

I recently happened upon one of my first attempts at post processing a photograph of a pinned insect specimen. The subject was Anomalipus elephas (large armoured darkling beetle), a tank of an insect (this example measuring 32 mm in length) belonging to the family Tenebrionidae. At the time, I was quite pleased with the results of my crude post processing efforts and proudly posted the “enhanced” photo in full-sized glory for all to behold. Since then, I’ve gained some experience with post processing of photos, and when I saw the processed photo this time I knew that there was considerable room for improvement. I thought it might be interesting to give the photo another PP whack and compare the two efforts from then and now.

Here is the original photo—keep in mind that the photo was taken with a small (though fairly decent) point-and-shoot camera (Panasonic DMC-FX3) a few months before I made the move to my current dSLR setup. I pinned the specimen to a styrofoam board, illuminated it with two 23w compact fluorescent light bulbs, and took the photo with the camera set on its “macro” setting. For the original post processed version (using Adobe Photoshop Elements version 6.0), I rotated and cropped the photo, then increased brightness and contrast (I don’t remember the values for each), used the clone tool to remove the pinhead (I’d just figured out how to do this), and increased sharpness using unsharp mask. This is all well and good (although I think the added contrast was a little excessive); however, I did make two big mistakes. The first was using the eraser tool to create a white background—a tedious process, especially around the perimeter of the subject to avoid “clipping” any of the subject’s body. The second was leaving the numerous small pieces of debris clinging to the subject. Debris on pinned (and even live) specimens is now a pet peeve of mine—I find it detracts greatly from the appearance of the photo, yet it is remarkably easy to remove in all but the most extreme of cases. At any rate, here is the result of that original attempt:

For the latest attempt, I rotated and cropped the original photo as before. Next, I created a white background, not with the “Eraser Tool” but rather by opening “Levels”, clicking on “Set White Point”, and touching the darkest part of the background. Voilá—a beautiful white background with no clipped subject edges! The subject still needed to be brightened up (two 23w fluorescent bulbs don’t put out that much light); however, instead of directly adjusting brightness I set “Lighten Shadows” to a value of +30% (a rather heavy handed setting) to also reduce shadows around the subject’s legs. Then I used the “Clone Stamp Tool” to clone out the pinhead, but this time I didn’t stop there—I continued using the tool to clone out all of the tiny little pieces of debris on the subject surface. Using the clone stamp tool effectively requires some practice, but eventually one learns to adjust the size and define the source set point to achieve almost perfect results. Lastly, I increased sharpness with “Unsharp Mask” (118%, 1.0 pixels, 8 levels). That’s it—took me all of about 3 or 4 minutes to post process the original photo to achieve the following result:

To compare the two post-processed images directly click here. Of course, my current camera setup is capable of much higher quality photographs than the point-and-shoot used for the subject of this post; however, the sequence of post processing  steps that I use is essentially the same (if less heavy handed). One final note—I am not a Photoshop expert, and perhaps some of the processes I have described can be done even more effectively or easily than in the manner I have described. I would welcome any comments or tips that you think might offer a better way to post process photos of pinned specimens.

Copyright © Ted C. MacRae 2012

Life at 8X—Bandedwinged Whitefly

/ Ted C. MacRae / 10 Comments

Trialeurodes abutiloneus (bandedwinged whitefly) | Obion Co., Tennessee

The world of minute insects can seem strange and even bizarre when compared to our relatively giant perspective. To the unaided human eye, this bandedwinged whitefly (Trialeurodes abutiloneus), measuring only 1 mm in length, looks like nothing more than a fleck of dandruff. Through a Canon MP-E 65mm 1–5X macro lens with 68 mm of extension tube (resulting in 8X magnification), however, we see an almost moth-like insect with a decidedly adorable “face” negotiating the “trichome forest” of a soybean leaf under-side.

A more conventional 2X view of a whitefly infestation on the underside of a leaf

Whiteflies (order Hemiptera, family Aleyrodidae) are tiny insects (more related to aphids than true flies) that colonize a variety of host plants, often building to extraordinary numbers and densities while sucking juices from the leaves. The bandwinged whiteflies in these photos were seen in a soybean field in northwestern Tennessee this summer and can be easily identified as this species due to the transverse, zig-zag bands on the forewings (Malumphy et al. 2010). In the photo above numerous eggs can also be seen distributed over the leaf surface—a sign that this population is about to explode given the numbers of eggs present.

Zooming in to 8X allows the zig-zag wing pattern to be seen easily.

Whiteflies are an occasional pest of soybean in the U.S., but yield reduction has been documented only in the southeastern U.S. by another species, Bemisia tabaci (sweet potato whitefly). Whiteflies are also occasionally seen on soybeans in the Midwest by B. tabaci or yet another species, Trialeurodes vaporarium (greenhouse whitefly); however, yield impacts in this area are rare. Trialeurodes abutiloneus is occasionally reported from soybean, but this species is actually more commonly encountered on sweet potato and malvaceous crops such as cotton and hibiscus (Clower et al. 1973). There was a lot of cotton growing in the area of this soybean field, so perhaps this infestation was a result of spillover from that crop.

Piercing/sucking mouthparts are inserted into the leaf for feeding.

“Adorable” and “cute” are not words that I’ve ever associated with whiteflies, but these ultra-closeup photographs give them a personality that I’ve not seen before. For an even more astounding view of the face of a greenhouse whitefly, see this incredible 16X photograph by Huub de Waard. Taken with the same lens as these—though I suspect with a 2X converter rather than extension tubes, it shows an amazing level of sharpness compared to the admittedly soft photos in this post. The larger aperture used (f/6.3) may also be a better choice than the small f/13 aperture I used in an attempt to preserve as much depth of field as possible but with which diffraction is likely significantly greater. Stay tuned as I do some more testing…

A cute couple!

REFERENCE:

Clower, D. F. & C. M. Watve. 1973. The bandedwinged whitefly as a pest of cotton, pp. 90–91. Proceedings of Beltwide Cotton Production and Research Conference, 11–12 January, Phoenix, Arizona. Cotton Council of America, Memphis, TN.

Malumphy, C., A. MacLeod & D. Eyre. 2010. Banded-winged whitefly Trialeurodes abutiloneus. Plant Pest Factsheet, The Food and Environment Research Agency (Fera), 4 pp.

Copyright © Ted C. MacRae 2012

Tiger lovin’

/ Ted C. MacRae / 4 Comments

It seems I’m not the only one that finds tiger beetles irresistible. Gorgeous colors, long legs, and big eyes, they captivate me endlessly with their big, toothy jaws and charismatic behaviors. I blather incessantly about them, but today I’m going to do something that I rarely do here—shut up and let somebody else do the talking!

First up is Troy Bartlett (author of Nature Close-ups), who has just posted some stunning photographs of the super rare Cicindelidia highlandensis (Highlands Tiger Beetle) taken during his recent trip to Florida. I’ve photographed this species before, but not as well as Troy—the face shot he got has me green with envy!

Scarcely three minutes after Troy posted his photos, Delbert La Rue (author of Crooked Beak Workshop), a coleopterist who has studied scarabs for most of his life, shows that he too has fallen prey to the tigers’ charms. It’s a sad thing when collectors pin tiger beetles and put them in a collection drawer without doing anything to protect those stunning colors and amazingly intricate white markings. Delbert describes in detail just how he accomplishes this task, a beautifully prepared unit tray of the Willcox Playa classic Habroscelimorpha fulgoris erronea (Willcox Tiger Beetle) serving as proof of his technique. What mojo!

Please visit both of these blogs and let the authors know you’re down with their tiger lovin’!

Sexual Profiles

/ Ted C. MacRae / 3 Comments

I recently happened upon these photographs of Habroscelimorpha severa (Saltmarsh Tiger Beetle), taken in early August last year at the terminus of Florida’s famous “Road to Nowhere“. I hadn’t thought to post them afterwards because I’d already shown a photograph of this species taken at the same spot during the previous year’s visit. I should have, as they are much better photographs than that initial attempt. Blame part of the first attempt on the fact that I was only in my third month of insect macrophotography, but the biggest reason for the improvement was because I’d gotten a little smarter and learned to use a blacklight to bring these extremely wary beetles to me at night rather than try to chase after them during the day. Still, I don’t get much enjoyment out of posting photos for no other reason than to post photos, so they’ve sat on my hard drive for the past year and a half. In looking at them again, however, I realized that the first and second, profiles of a female and a male, respectively, make for a nice comparison of the secondary sexual characters exhibited by adults of this species.

Habroscelimorpha severa (female) | Levy Co., Florida

Females exhibit fewer sexual characters than males, the main one being the presence of grooves on each side at the back of the pronotum (neck). These grooves function during mating, at which time the male grasps the female by the pronotum with his mandibles. This helps to provide a more secure grip for the male to prevent him from being dislodged during mating and subsequent mate guarding. The grooves themselves are not obvious in the photo, but the lack of setae (hairs) within them is, giving the female a less “hairy” look than the male. As with most insects, females also are more robust—their abdomens larger to make room for egg-making machinery, although in this and other tiger beetle species the difference is not that obvious.

Image

Habroscelimorpha severa (male) | Levy Co., Florida

Males are immediately recognizable by several respects. In addition to the smaller abdomen and “hairier” pronotum lacking lateral grooves, male tiger beetles in most of the “higher” genera exhibit brush-like pads on the undersides of the front tarsi (feet). The function of these pads is not completely clear, but prevailing opinion is that they somehow aid in gripping the female during mating. I’m not sure I buy into this—males do sometimes hold onto females with their front legs during mating, but how these pads improve grip escapes me. Further, it is my experience that males actually spend more time during mating and mate guarding with their front legs outstretched to each side. I’ve also noticed that males are reluctant to release females even when danger approaches (even in the form of a giant insect macrophotographer). I’ve seen males tenaciously clinging to the female as she violently tries to shake him off and flee from my approach. It makes me think that perhaps the tarsal pads serve some tactile function as a final warning of impending danger to a grasping male, allowing him to not give up his female until absolutely necessary (hey, it’s an idea—if you have an alternative idea I’d love to hear it). There is more, however—look at that big head!

Habroscelimorpha severa (male) | Levy Co., Florida

Actually,  the male’s head is no larger than the female’s, but the proportionately longer mandibles give the male a distinctly “big-headed” look.  In contrast, the labrum (upper lip) is shorter than the female’s (making the mandibles look longer still). Both of these characters are, again, related to the habit of grasping the female pronotum, with the longer mandibles allowing a more secure grip of the female pronotum and the shorter labrum adding even more functional length to the mandibles (I can also imagine that this might have some effect on choice of prey by males versus females). The male mandibles also have a greater amount of white coloration at their bases—this might simply be a function of the relatively larger size of the mandibles, but given that males of many species exhibit more white overall on both the mandibles and the labrum (the latter of which is usually smaller), it seems more logical to me that the white coloration serves as a visual cue for potential mate recognition.

“Hey baby, I like your grooves!”

“Yeah, well your white lips aren’t so bad either.”

Copyright © Ted C. MacRae 2012

Just repanda… er, wait a minute…

/ Ted C. MacRae / 7 Comments

Update 10/7/12, 10:41 a.m.—Thanks to Ben Coulter, who pointed out my rather silly misidentification of these beetles that actually represent Cicindelidia ocellata rectilatera (Reticulated Tiger Beetle). I have only my failure to even consider the possibility of a southwestern species to blame for the error, as the evidence was staring me right in the face (the lack of any trace of lateral connecting band and, most obviously, the reddish parts on the underside). No wonder the habitat didn’t seem quite right! I was not aware of the occurrence of this species east of Texas, so I’ll have to dig a little bit to see if this is an unusual record. Pearson et al. (2006) show the northeastern limit of distribution coming very close to but not actually reaching the southwestern corner of Arkansas, and the closest records given by Graves & Pearson (1973) are in western Louisiana and adjoining Texas. It would be immensely rewarding should this turn out to be a new state record (though there are many sources still to check to confirm this)—not to mention the irony of it in view of the post title (call it a double “er, wait a minute”!). At any rate, I should have been a lot more excited when I saw it than I was.

After a fun-filled day of photographing the Limestone Tiger Beetle in northern Texas, it was time to start working my way back to Missouri. I had one last goal that I wanted to accomplish before spending my last day in our state’s White River Hills, and that was to find and photograph the unbelievably gorgeous Cicindela formosa pigmentosignata. Dubbed the “Reddish-green Sand Tiger Beetle” by Erwin & Pearson (2008), this brilliant violaceous and nearly immaculate subspecies of the Big Sand Tiger Beetle is restricted to sandy areas of open pine forests in eastern Texas, southwestern Arkansas, and northwestern Louisiana (Pearson et al. 2006). I had a few specific localities that I’d gleaned from colleagues and the literature and targeted the two “best” (specificity of location, recent occurrence, and reasonably “on the way” back to Missouri) for Day 7 of the trip. The first site in Texas looked perfect—deep, dry sandy 2-tracks leading through open pine/oak forest, and I was actually surprised when I’d searched a mile or so of track and hadn’t yet seen one (the habitat just looked that good). Still, I spent quite a bit more time searching, thinking that numbers could be low and it might take such an effort. Sadly this was all in vain, and the time came to give up and try again at the second locality in Arkansas. The story was largely the same at this second locality also, and by late afternoon I had come to accept that this was one challenge that I was going to lose (for now at least).

Cicindela duodecimguttata Cicindelidia ocellata rectilatera | Nevada Co., Arkansas

As I searched one bit of potential habitat at the Arkansas location, I noted the presence of Cicindela repanda (Bronzed Tiger Beetle). This species is dreadfully common throughout much of the eastern U.S. in just about any near-water habitat, which told me I was probably too close to water to find the higher, drier-ground preferring Big Sand Tigers. I’ve seen millions of C. repanda through the years (this may not be an exaggeration), and since they show so little polytopism (geographically-based variation), at least in the parts of its distribution that I have visited, I hardly pay them mind anymore. As I was walking, however, something caused me to take a closer look—some of them didn’t seem quite “right.” Of course, you can’t just walk up to a tiger beetle and stoop down for a good look at it. Stalking is required, usually of several individuals before finding one that you can approach closely enough to see the necessary characters, and when I did this I realized most of the C. “repanda” I was seeing were actually a different species—Cicindela duodecimguttata (12-spotted Tiger Beetle)!

Even tiger beetles get bored during sex—this female preening her antennae seems oblivious to the male engaging her.

I get the impression from literature sources that 12-spotted Tiger Beetles are quite common further east, especially in the northeastern U.S. and southeastern Canada. However, here in the central U.S. they are not commonly encountered. In fact, these are the first of the species that I have seen since I began photographing tiger beetles more than 3 years ago. In Missouri the few instances that I have seen them were along creeks and small rivers with banks composed of sand and a fair bit of dark clay. This makes sense, given their generally darker coloration compared to Bronzed Tiger Beetles, and it is this character that first stands out amongst the hoardes of C. repanda with which it usually co-occurs.  Once the darker coloration draws the eye, the markings of the elytra—reduced and broken into six spots (usually) on each one—confirm its identity. Despite the similarity of appearance to C. repanda, this species is actually more closely related to Cicindela oregona (Western Tiger Beetle), an exceedingly common species found from the Rocky Mountains to the Pacific Coast and north deep into Alaska. In fact, the two species are so closely that they have formed a hybrid zone where they come into contact along the front range of the Rockies—one could almost argue that they are only subspecifically distinct because of this. 

A male pauses briefly while hunting for prey (or mates).

That I found them in this particular habitat was a bit of a surprise to me. I mentioned that in Missouri I’ve seen them on darker creek and river banks, but the creek bank at this location was quite lightly colored and seemed to consist almost entirely of sand. There were a few C. repanda mixed in with this small population. In all, it was a welcome consolation prize that made up for not finding C. formosa pigmentosignata—sort of!

Habitat for Cicindela duodecimguttata Cicindelidia ocellata rectilatera along Mill Creek, Nevada Co., Arkansas.

REFERENCES:

Erwin, T. L. and D. L. Pearson. 2008. A Treatise on the Western Hemisphere Caraboidea (Coleoptera). Their classification, distributions, and ways of life. Volume II (Carabidae-Nebriiformes 2-Cicindelitae). Pensoft Series Faunistica 84. Pensoft Publishers, Sofia, 400 pp.

Pearson, D. L., C. B. Knisley and C. J. Kazilek. 2006. A Field Guide to the Tiger Beetles of the United States and Canada. Oxford University Press, New York, 227 pp.

Added: Graves, R. L. & D. L. Pearson. 1973. The tiger beetles of Arkansas, Louisiana, and Mississippi (Coleoptera: Cicindelidae). Transactions of the American Entomological Society 99(2):157–203.

Added: Pensoft

Copyright © Ted C. MacRae 2012