One-shot Wednesday: Mallodon dasystomus

Mallodon dasystomus | southeast Missouri (Mississippi Co.)

Mallodon dasystomus | southeast Missouri (Mississippi Co.)

Today’s (slightly belated) edition of “One-shot Wednesday” features a beetle that I saw just about this time last year while blacklighting along the Mississippi River in the southeastern lowlands of Missouri. Mallodon dasystomus¹ is a prionid longhorned beetle (family Cerambycidae, subfamily Prioninae) that is sometimes called the “hardwood stump borer”. It is perhaps one of the most widely distributed members of its group, occurring across the southern tier of the U.S. down through Mexico and Central America as far as northern South America.

¹ Until recently the specific epithet was consistently misspelled in most of the literature as “dasytomus“. A closer look at the Greek root words dasus (δασύς), meaning “hairy”, and stoma (στόμα), meaning “mouth”, shows the misspelling to be nonsensical. I, myself, am guilty of using the wrong spelling in my checklist of Missouri longhorned beetles (MacRae 1994), although I can claim to have been “going with the flow”.

Despite the beetle’s wide geographical range, I searched for it both eagerly and unsuccessfully during the 1980s as I was gathering data for my checklist of Missouri longhorned beetles (MacRae 1994). I eventually published that checklist and included the species on the basis of a few specimens seen in other collections, but I never encountered it for myself until some years later during a visit to Cave Creek Canyon in southeast Arizona. As noted by Linsley et al. (1961), this species is common there and is associated with large, partially dead Arizona sycamores (Platanus wrightii). Although nearly 20 years ago, I still recall seeing the large beetles crawling high up on the trunks and sitting in their emergence holes with only their massively-mandibled heads protruding as they tantalizingly waved their antennae about.

That experience would directly lead to my eventually finding this species for myself in Missouri. Shortly after returning to the state in the mid-90s, I was driving along a road in the state’s southeastern lowlands when I passed a very large, half-dead American sycamore (Platanus occidentalis). Even at a speed of 40 mph I could see the large emergence holes that immediately reminded me of what I had seen in Arizona, so I hit the brakes, made a quick U-turn, and came back to look at the tree a little more closely. I was convinced the holes were made by this species, and my hunch was proven when I eventually found several beetle carcasses on the ground around the base of the tree. I returned the following weekend with a chainsaw, cut several one-cubic-foot sections of wood from the dead portion of the massive tree’s trunk (with landowner permission), and eventually reared a nice series of adults from the wood. Having uncovered the association of this species with sycamore in the state, I was able to find the species also in several other locations in southeastern Missouri, but I have not managed to find the species in any areas north of the southeastern lowlands in Missouri despite the common occurrence of the host tree.

The beetle in the above photograph landed on the foliage of a large silver maple (Acer saccharinum) next to the ultraviolet light I had setup in wet bottomland forest along the Mississippi River, and wanting to ensure that I got at least one in situ photo of the beetle that is where I shot it. I did try to move it to the trunk of a large, dead sycamore nearby for a more realistically representative photo of how these beetles are usually encountered, but the beetle became quite agitated when I moved it and my considerable patience was never rewarded. I popped it into a vial in hopes of photographs the next morning, but conditions were not to the beetle’s liking and it expired before I had another chance to photograph it. Just the other night I setup a blacklight in a spot not too far from where I saw this beetle in hopes of getting another chance to photograph it. That effort was not successful, but I did find a longhorned beetle species that I had not seen in nearly 30 years! I was successful in photographing that species but (please excuse the teaser) will save those photos for a future post.

REFERENCES:

Linsley, E. G., J. N. Knull & M. Statham. 1961. A List of Cerambycidae from the Chiricahua Mountain Area, Cochise County, Arizona (Coleoptera). American Museum Novitates 2050:1–34 [full text, pdf].

MacRae, T. C. 1994. Annotated checklist of the longhorned beetles (Coleoptera: Cerambycidae and Disteniidae) known to occur in Missouri. Insecta Mundi 7(4) (1993):223–252 [pdf].

© Ted C. MacRae 2014

Mrs. Monday Jumper

Phidippus princeps female | Howell Co., Missouri

Phidippus princeps female | Howell Co., Missouri

In my previous post, Monday Jumper, I featured a photo of a strikingly colored jumping spider (family Salticidae) that apparently represents an adult male Phidippus princeps. Far too skittish to attempt photographing in the field, I placed him in a vial and photographed him later in the hotel room but still only got one photo that was good enough to post. Shortly after gathering him up, I came across another jumping spider that proved far more cooperative for field shots. This was no doubt due in large part to the fact that she had just captured a fat, juicy caterpillar. I find predaceous insects to be far less skittish when they are involved in the act of consuming prey. This not only makes them easier to approach and photograph, but also adds a desirable natural history element to photos that is sometimes missing in “portrait-only” photographs.

Somber coloration, large abdomen, and small carapace contrast distinctly with the male

Somber coloration, large abdomen, and small carapace contrast distinctly with the male

I say “she” because of the classic female characters exhibited—relatively large and rounded abdomen (males tend to have a smaller and more tapered abdomen), smaller carapace, somber coloration, and absence of a “boxing glove” aspect to the pedipalps. Like the male I had just collected, she was on the foliage of an oak sapling, and as I began taking photographs I noticed in the preview screen the brilliant, metallic blue chelicerae that are a hallmark of the large salticid genus Phidippus. I had also presumed the male I had just collected belonged to this same genus based on gestalt, but I could have never imagined that the two individuals actually represented male and female of the very same species. Such appears to be the case, however, as a thorough perusal of the salticid galleries at BugGuide leads me to believe that the individual featured here is the adult female of Phidippus princeps.

Check out those metallic blue chelicerae!

Check out those metallic blue chelicerae!

These photos still may not approach the technical and aesthetic perfection exhibited by master salticid portraitist Thomas Shahan, but I think they do represent an improvement over my first attempt at photographing a feeding female. The first two photos are fine, but the third suffers from the focus being a little too “deep”, which seems to be my most frequent macrophotography mistake on higher mag shots. If you have any tips on how to overcome this particular problem I am all ears!

© Ted C. MacRae 2014

Monday Jumper

Phidippus pinceps, adult male | Howell Co., Missouri (studio shot).

Phidippus princeps, adult male | Howell Co., Missouri (studio shot).

A couple of weeks ago, shortly after my friend Rich and I began hiking a 9-mile stretch of the North Fork Section of the Ozark Trail in the far southern reaches of Missouri, we encountered this colorful jumping spider (family Salticidae) on the foliage of an oak sapling. He was not at all in the mood to be photographed—dashing persistently from one side of the leaf to the other and finally dropping to the ground as I tried to close in for some shots. So active was the little guy, that even had I managed to get him within the camera’s field of view it would have been nearly impossible to get him properly focused, much less achieve a nice composition. Hoping he would be a little easier to work with in the confines of a hotel “studio”, we coaxed him into a vial with a sprig of foliage and then got him out and placed him on a branch of dogwood flowers (Cornus florida) that evening once we were in our room. Yes—he was easier to work with, but only by the fact that being in a hotel room made it more difficult for him to escape! He was just as active as in the field, darting from flower to flower in his persistent efforts to elude the large glass eye that kept trying to look at him. For many subjects, I would have given up rather than spend an inordinate amount of time trying to get photographs that likely would not turn out to be what I wanted. But this spider was just so attractive—red and black and white with flashy blue chelicerae! I persisted in my efforts, got about two dozen shots off before he finally did escape, then promptly deleted all but five immediately after seeing them on the computer. The photo shown here is the only “keeper” that I can actually bring myself to post—the focus is a bit too deep, but not so much that it detracts greatly from what is otherwise a fairly decent composition. The more I shoot jumping spiders, the more I am amazed at the portraits that Thomas Shahan achieves with these delightful little arachnids.

After browsing through the salticid galleries at BugGuide, I am inclined to believe this is the species Phidippus princeps, with the coloration and white-stripes on the pedipalps suggesting it is an adult male. ID correction welcome.

© Ted C. MacRae 2014

One-shot Wednesday: pale green assassin bug

Zelus luridus (pale green assassin bug) | Howell Co., Missouri.

Zelus luridus (pale green assassin bug) | Howell Co., Missouri.

As my friend Rich and I set out a week ago Sunday on the final stretch in our quest to hike the 350-mile Ozark Trail in its entirety, I saw this slender, green assassin bug (family Reduviidae) sitting on a tender young leaf of an oak sapling. I already had my camera out but had outfitted with the 65-mm, 1–5× macro lens in anticipation of small beetles that I wanted to photograph on dogwood flowers. Nevertheless, it was still a bit on the cool side, making me think I might yet succeed in getting off some super-closeup shots of this delicate predator. I managed to carefully snip the leaf from the sapling and move the bug up close to the camera for a nice, blue-sky background shot, but one shot is all I got—as soon as the shutter clicked the bug took flight and left me with this single photo. As I have observed to usually be the case, the body of this individual is thickly covered with debris, which I take to be pollen from the abundant oaks at the height of their flowering period.

I’ve seen this species regularly over the years during my springtime forays in upland, oak-hickory Ozark forests. I presume the species is Zelus luridus, based on an online synopsis of the genus Zelus in eastern North America. As true bugs go, assassin bugs are undeniably cool—sometimes large, often colorful, and pure predators! Interestingly, these bugs have adopted a rather diverse array of strategies to assist their predaceous habits, mostly involving modifications of the front legs. Some involve a more typical raptorial design (similar to mantids) with chelate surfaces or even spines on the femora and tibiae, while others have developed flexible, cushion-like structures on the tips of the tibiae to aid in prey handling (Weirauch 2006). Gross morphological modifications, however, are not the only strategy employed by assassin bugs—some groups use secretions either to paralyze or immobilize their prey. Species in the genus Zelus employ the latter strategy—essentially using their front legs as “sticky traps”. The sticky substance is derived from glands on the front legs and is used to coat numerous, microscopically branched setae on the legs called “sundew setae” in reference to the similarity of appearance and function with insectivorous sundew plants. Interestingly, sundew setae have also been found on other parts of the body, at least in first-instar Z. luridus nymphs, leading to speculation that they may also serve some other function besides prey capture. Perhaps these setae explain why most individuals I see are so debris-covered, as with the pollen-laden individual above.

REFERENCE:

Weirauch, C. 2006. Observations on the sticky trap predator Zelus luridus Stål (Heteroptera, Reduviidae, Harpactorinae), with the description of a novel gland associated with the female genitalia. Denisia 19, zugleich Kataloge der OÖ. Landesmuseen
Neue Serie 50:1169–1180 [pdf].

© Ted C. MacRae 2014

Baby box turtle on white

Box turtles of the genus Terrapene are extraordinarily common in Missouri, especially in the eastern and southern forested regions of the state where the three-toed box turtle (T. carolina triunguis)—Missouri’s state reptile—is the most commonly encountered form. Despite this abundance and the author’s more than a half-century spent scrabbling through the sticks of Missouri, I have never encountered a youngster as tiny as the one shown in this post (shell length about 2 inches). In fact, I didn’t even find it—my daughter rescued it from our dog, who had found it crossing the gravel driveway at our family’s cabin west of St. Louis. Such overwhelming cuteness demanded a photo session, and rather than deal with the active little hatchling’s persistent efforts to duck into the leaf litter I decided to photograph it on a clean, white background and arrange some of the photos in a “Naskreckian” collage. My daughter wanted to keep the little guy, but eventually she agreed that it would be better off released back into the forest. While it may lead a more perilous life in the forest, the opportunity to dine on fresh earthworms and strawberries should make up for it, and from these photos my daughter can always remember it for the little pup it once was.

Box-turtle-collage_1080x1407

Copyright © Ted C. MacRae 2014

An arboreal fishing spider

Last week was my birthday, and as is my usual custom I took the day off in favor of the season’s first “official” bug collecting trip. Falling in late April as it does, my birthday usually coincides nicely with insect activity beginning in earnest here in Missouri, and for this year’s edition I decided to look for Cicindela scutellaris lecontei (Leconte’s Tiger Beetle) on sand prairies in the extreme northeastern corner of the state. Sadly, this year’s unusually protracted spring had resulted in a mostly still-sleeping landscape, and whatever hopes I had of seeing the earliest emerging adults were dashed as thick, gray clouds hung stubbornly in the sky and temperatures refused to edge much above 60°F. Still, a bad day of collecting is better than a good day of just about anything else, and in such situations there are still wintertime collecting methods—peeling bark, cutting wood, breaking stems, etc.—at my disposal.

The "W"-shaped markings on the abdomen with interrupted white borders distinguish this species from the otherwise similar D. scriptus (xxx fishing spider).

Dolomedes tenebrosus (dark fishing spider) | Frost Island Conservation Area, Clark Co., Missouri.

While exploring a sand prairie at Frost Island Conservation Area (Clark Co.), I found a large, dead willow in one of the draws that had apparently been killed by recent prescribed burning activities, and when I peeled back a section of the trunk bark I found this medium-sized spider (leg spread ~40 mm) sitting underneath. Based on general appearance I first thought it was some type of wolf spider, although it struck me odd that it would be under the bark of a tree rather than on the ground where wolf spiders are normally encountered. However, after consulting BugGuide and not finding it among the wolfies, I decided to widen the net and quickly stumbled onto the fishing spiders (genus Dolomedes, family Pisauridae). I’ve seen fishing spiders before—normally they are found at water’s edge and periodically demonstrate a remarkable ability to dash across the surface of the water to grab an errant insect, using the same surface tension for support that had trapped its hapless prey. As odd as it would have been to find a wolf spider high up in a tree, it seemed even more unlikely that I would find a fishing spider in such a dry, arboreal habitat. Things became clearer, however, after I settled on the species D. tenebrosus (dark fishing spider)—distinguished from other fishing spiders by the interrupted white borders behind the “W”-shaped markings on the abdomen (see BugGuide). According to Jacobs (2002) this species is frequently found far away from water, usually in wooded settings, and hibernates as an immature adult (penultimate instar) under—you guessed it—loose bark (also stones). Barnes (2003) also provides a good discussion of this spider along with diagnostic photos and references for further reading.

Dolomedes tenebrosus (dark fishing spider) | Clark Co., Missouri

The “W”-shaped markings on the abdomen with interrupted white borders distinguish this species.

Based on this information, I’m guessing this individual is a still hibernating subadult, presumably a female based on the small pedipalps (the little “legs” next to the mouth). The spider moved slowly across the exposed wood as I took these photographs, wandering onto sections of different color as she did. I like the two photos for different reasons—the first (light background) seems to better show the shape and silhouette of the spider, while the second (dark background) highlights the spider’s beautifully intricate markings.

REFERENCES:

Barnes, J. K. 2003. Dark fishing spider. University of Arkansas Arthropod Museum Notes 15 [full text].

Jacobs, S. 2002. Fishing spider, Dolomedes tenebrosus. PennState College of Agricultural Sciences Insect Fact Sheet [full text].

Copyright © Ted C. MacRae 2014

The importance of post-processing

One of the most frustrating realizations I had when I began photographing insects was the fact that photographs didn’t come out of the camera “ready-to-go”—i.e., they still needed to be processed to some degree to make them look good. Even worse, this required processing is to large degree subjective based on the taste of the individual photographer, and as such a “quick manual” describing the exact process in a way that beginners can understand doesn’t exist. Essentially, I didn’t know that when I decided to become an insect photographer, that I would also have to become proficient at photo processing. This frustrates me a lot less now because I’ve finally worked out a process for doing this that works for me and that I am comfortable with, and having done so I also realize that every photographer has to go through this process for themselves to make their photographs look the way they want them to look. That said, I wish I’d had access to some easy tutorials when I was trying to figure out the process that could have saved me some stumbling time before arriving at a process I liked. With that in mind, I thought I would share a quick overview of how I deal with post-processing in the hopes that somebody else mind find a useful tip or two here as they try to figure out their own process. This is not meant to be an exhaustive description of all the post-processing tools that I might use, but rather the typical adjustments that are needed for almost all of the photographs that I take. To illustrate the process, I use a rather basic shot of a cricket that I photographed last week in northeastern Missouri. You can click on each photo to access a larger and better see the issues discussed and resulting enhancements.

Straight from the camera (JPG converted from original RAW file).

The photo above is basically how the shot came out of the camera. These days I shoot only in RAW format, as this allows the maximum amount of data to be retained regardless of how many times the file is accessed. The image above is a JPG converted directly from the unaltered RAW file, and you can see that it looks rather flat and could benefit from levels and color adjustments as well as sharpening and some general “cleaning up” of sensor dust artifacts and debris on the subject. Since I use a Canon body, I have the Digital Photo Professional software that came with the camera, and I also have Photoshop Elements. For my purposes, I’ve found it most convenient to do certain enhancements directly to the RAW file in DPP, generate a TIFF format version of the file from the edited RAW file, and then do the final enhancements to the TIFF file. Since TIFF is also a “loss-less” format, I can then use the enhanced TIFF to generate JPGs of whatever size and resolution on an as-needed basis without worrying about data loss in the full-sized, fully enhanced version of the photo. I think this is preferable to shooting JPGs directly or generating them directly from the RAW file because JPGs are not loss-less files, and as a result every time a JPG is accessed or modified there is a loss of data. Sure, you can go back to the original RAW file and generate a new JPG, but any enhancements made after the first conversion will have to be repeated. Another advantage to making adjustments in DPP is that they are reversable—the original, unaltered RAW file can always be recovered without the need to create multiple backups representing different stages of enhancement.

After initial processing (JPG converted from edited RAW file).

So, what enhancements do I do in DPP? First I open the tool palette and adjust the white balance—in this case it was a full flash photo, so I select “Flash” from the drop-down menu. Then I select the RGB tab and adjust the upper and lower levels on the histogram. The general approach is to cut off data-lacking areas at either extreme, but there is also a lot of subjectivity in deciding what “looks right”. I then open the Stamp Tool (I find cloning adjustments easier and more effective in DPP than in PS) and clone out dust marks in the background (I know, I need to clean my sensor) and debris on the subject. On that last point, there are purists who will argue that this is an “unnatural” alteration. I take a much less conservative position on such alterations, since in my opinion the entire photograph itself is the result of interpretation—not just of the photographer, but of the equipment used and settings chosen. If debris on the subject is an important aspect of the subject’s natural history, then it should remain. However, in most cases, dirt flecks on the subject are not an important part of the story and provide an unnecessary detraction from the aesthetic appearance of the photo. If any cropping is necessary I prefer to do this also in DPP since this is reversible should I change my mind at some point in the future. The second photo above shows what the image looks like after this initial round of post-processing in DPP. At this point, the RAW file is ready to be converted to TIFF format for final post-processing in PS.

After additional processing in Photoshop (jpg converted from edited TIFF).

After additional processing in Photoshop (jpg converted from edited TIFF).

Because I’ve done much of the levels adjustment and cloned out any flaws in DPP, the original TIFF needs only minor adjustments. I generally like to start with “Autocorrect” and see what it does, as this function usually does a good job of toning down highlights and shadows and especially giving a more natural color to blue sky backgrounds such as in this photo. If I don’t like the result from Autocorrect, I hit Ctrl+Z and adjust levels and color manually until I like the result. I find that most photos still benefit from a little bit of brightening and increased contrast (usually ~10% each), and this often also serves to add a little color saturation that is generally sufficient but can sometimes be too much. If the latter occurs, it’s an easy matter to adjust the saturation back down a little bit. After the levels and color are fully adjusted the only thing left to do is apply unsharp mask to sharpen up the photo and bring out the detail—remember to zoom the image to 100% to get the best view of how the settings affect the appearance of the photo, as the settings that you will need depend greatly on the size of the image. Once these adjustments are made, I save a new version of the file (I like to append the file name with “_enh”). The third photo above represents the final enhanced version, and it is this file that I will use to generate JPGs of whatever size I need on an as-needed basis. The original TIFF can be retained if desired, but since an identical version can always be generated anew from the enhanced RAW file this is not essential.

The head slightly narrower than the pronotum and early spring occurrence of this large nymph make me think this is the northern woods cricket (Gryllus vernalis).

The head slightly narrower than the pronotum and early spring occurrence of this large nymph in northeastern Missouri make me think this is the northern wood cricket (Gryllus vernalis).

I hope you’ve found one or tips of use in this little tutorial, which I end with the above frontal portrait of the subject shown in the previous photos. Based on its all black color, the head slight narrower than the pronotum, and its early spring occurrence as a late-instar nymph in northern Missouri, I take this to be a northern wood cricket, Gryllus vernalis, but of course I am open to being corrected by somebody more knowledgeable about crickets than I.

Copyright © Ted C. MacRae 2014

I’m a fun guy!

The habit of looking at things microscopically as the lichens on the trees & rocks really prevents my seeing aught else in a walk.—Henry David Thoreau

I should have loved an opportunity to go for a walk in the woods with Thoreau—especially during the winter when my preoccupation with insects no longer restrains my fascination with all things natural. While many entomologists see winter as a break from field work—a time to indulge/suffer (depending on mood) the more mundane curatorial tasks associated with their studies, my time in the field continues uninterrupted with long walks in the woods. Hiking stick replaces insect net. Energy foods replace vials. I still pry bark and flip rocks—I cannot completely ignore the potential to find insects. But I also peer through miniature forests of moss, poke about the mushrooms on a fallen log, and squint at the lichens encrusting a rock. Yes, insect specimens collected during the previous summer still need to be pinned, but there is time for that. There will always be time for that—if not now then in my later years when my ability to scramble through the bush begins to wane. For now, the woods sing their siren song, and I must listen.

Trichaptum biforme (purple tooth) on fallen river birch (Betula nigra) | Reynolds Co., Missouri

Trichaptum biforme on fallen trunk of Betula nigra | Reynolds Co., Missouri

Purple tooth (Trichaptum biforme) on dead red maple (Acer rubrum) | Reynolds Co., Missouri

Trichaptum biforme on fallen branch of Acer rubrum | Reynolds Co., Missouri

Multicolored gilled polypore (Lenzites betulina) on river birch (Betula nigra) stump | Reynolds Co., Missouri

Lensites betulina on dead stump of Betula nigra | Reynolds Co., Missouri

"Gills" distinguish this shelf fungus from turkey tails and other similar types.

“Gills” distinguish this shelf fungus from turkey tails and other similar types.

Cladonia chlorophaea or C. pyxidata on chert-trail | Reynolds Co., Missouri

Cladonia sp. (poss. C. chlorophaea or C. pyxidata) on chert-trail | Reynolds Co., Missouri

(Cladonia pyxidata)

A forest in miniature!

Irpex lacteus? on fallen branch of Acer rubrum | Iron Co., Missouri

Irpex lacteus (?) on fallen branch of Acer rubrum | Iron Co., Missouri

Spores are released from the toothy cap underside

Spores are released from the toothy cap underside

Leucobryum glaucum on forest floor | Reynolds Co., Missouri

Leucobryum glaucum on forest floor | Reynolds Co., Missouri

Postscipt: all photos shown taken on 30 November 2013 while hiking a 7-mile stretch of the Ozark Trail (Karkaghne Section in Reynolds Co. and Middle Fork Section in Iron Co.).

Copyright © Ted C. MacRae 2014