techniques

A non-black background is better… often!

/ Ted C. MacRae / 2 Comments

In my previous post, A black background is better… sometimes, I came to the defense of the oft-maligned pitch black background. Some macrophotographers studiously avoid black backgrounds (BBs), claiming that they look ‘unnatural’. However, as I discussed in my previous post, there are situations—primarily with light-colored or translucent subjects or those that are seen only at night—where BB can be aesthetically pleasing or more consistent with the subject’s natural history (or both, as in the case of the subject of my last post). On  the other hand I do agree that BBs are overused, showing up in many photos where a non-black background would have been a better choice. The reason for this is simple—BBs are easy! All one must do is ensure that the area behind the subject is clear of light-reflecting objects. While this is certainly preferable over cluttered backgrounds with random leaves, branches, grass stems, etc. that distract from the subject, a BB may nevertheless not be the most aesthetically pleasing  choice for the photo (I am guilty of this myself). Non-black backgrounds, on the other hand, require more forethought, not only about what color to use and how to achieve it, but also regarding camera and flash settings which can be a bit trickier due to the fact that both background and subject must be properly exposed.

Argiope argentata (silvery argiope) | Santa Fe Province, Argentina

Choice of background to a large degree reflects the style of the photographer. Some may choose a particular color based purely on aesthetics, but as an in situ macrophotographer I prefer backgrounds that are consistent with the natural history of the subject—diffuse green for subjects typically seen on foliage, gray or brown for those typically found crawling on trunks and branches, and sky blue for those found out in the open (e.g., perched atop flowers). Each of these backgrounds requires different technique, and this large orb weaver, Argiope argentata (silvery argiope), which I encountered in a corn field near Villa Cañas (Santa Fe Province, Argentina) back in April, is an example of the latter. In contrast to the strictly nocturnal orb weaver (Eriophora ravilla) in my previous post, this species and its congeners are commonly seen suspended on their webs in broad daylight. BB worked well with E. ravilla, but it would not be a good choice for A. argentata due to the large amount of dark coloring on the subject. More importantly, it contradicts this spider’s diurnal nature. I could have used natural light, but the sun was shining on the other side of the spider. However, this actually made it easier to achieve the blue sky background while illuminating the subject with flash. The large size of the spider (the body alone measured ~35 mm in length) put a lot of distance between the subject and the lens, which allowed the use of a larger aperture (f/10) with still acceptable depth-of-field. With a bright sky and the sun nearly behind the spider, I was able to keep a low sensitivity setting (ISO 100) to prevent graininess and a fast shutter speed (1/250 sec) to prevent motion blur. The slightly larger aperture was all that was needed to achieve a natural blue sky color in the background. More difficult was actually clearing the background between the spider and the sky, as the web was slung low amongst the tall corn plants. The series of photos below (click to enlarge) shows the results of my earlier attempts to photograph the spider; at first not thinking about the distracting corn plants, and then trying to avoid them by angling myself lower relative to the spider, which ultimately resulted in a bad angle on the spider:

I finally decided to just break over the offending corn plants (above the ears!) to clear the background and give me the angle that I preferred. After that I was able to snap away to my heart’s content. Here is a closer view of the spider:

Lastly, I show the following series of photos to demonstrate the dramatic effect that aperture can have on a blue sky background. If you have a bright sky and don’t need a lot of DOF (e.g., you have a large subject-to-lens distance or a small subject lying within a narrow plane), adjusting the aperture up or down is a great way to achieve the precise color of blue desired. Larger apertures (lower f values) will result in a paler blue color, while smaller apertures (higher f values) create a deeper blue. In the photos below (click to enlarge), flash and camera settings are the same as those mentioned above except aperture: f/10 (left), f/13 (center) and f/16 (right).

Copyright © Ted C. MacRae 2012

A black background is better… sometimes

/ Ted C. MacRae / 6 Comments

Eriophora ravilla (a tropical orb weaver) | Pinellas Co., Florida

If there is one subject that causes more disagreement among macrophotographers, it is the pitch black background. Granted, black backgrounds are common—almost ubiquitous in macrophotography, since they are easily created by using full flash illumination and ensuring that nothing lies behind the subject close enough to reflect the light from the flash. Detractors, however, claim that it gives subjects an ‘unnatural’ look, as they are rarely seen this way in nature. This may be true, but I still believe that for some subjects the black background simply cannot be beat for its aesthetics, even if the subject is not normally seen in this manner. Take, for example, the Great Plains ladies’-tresses orchid—nothing but a pitch black background could better showcase the delicate, white blossom and its almost crystalline lower lip!

That said, however, there are some subjects for which a pitch black background actually can be considered a ‘normal’ background. This tropical orb weaver spider (Eriophora ravilla) is one example. Unlike many other members of the family Araneidae (orb weavers), species in this genus are strictly nocturnal and not seen hanging on a web during daylight hours. Hiding in a curled leaf during the day, they emerge at night and build a large web (up to 1 meter wide), only to consume it by morning and return to their hiding place until the next evening. My nephew Jack and daughter Madison and I first saw this spider during our nighttime foray into the intertidal mangrove marsh behind my sister-in-law’s condominium in Seminole, Florida last month while discovering rare, endemic beetles and their larvae. Knowing that it would likely build its web in the same place on subsequent evenings, I went out a few nights later with my camera and took a few shots.

Some claim that black backgrounds are undesirable for even nocturnal subjects; that there is nothing ‘natural’ about an artificial, narrow beam of light illuminating a single subject at night since no animal other than a person with a flashlight would see something like this. This contention seems a little strained, as one could take such a stance on illumination of any kind. Technically speaking even colors don’t actually exist, so the rendering of subject images on camera film/sensor, whether by natural or artificial illumination,  is itself biased towards human sensibilities. Regardless, the sight of an eerily glowing spider hanging in the blackness strikes a familiar chord with anyone who has wandered the bush by night. A black background not only recreates that human experience, but also emphasizes the subject’s (in this case strictly) nocturnal nature with stark elegance.

At first I took this spider to represent the very common barn spider, Neosona crucifera—widespread across North America. However, after noting the dark femora and yellow “shoulders” of the abdomen I began to rethink that ID. Fortunately, I took one photo of the ventral side (not shown) that shows well the color pattern diagnostic for the circum-Caribbean species E. ravilla.

Copyright © Ted C. MacRae

Working with Cerceris fumipennis—Part 2

/ Ted C. MacRae / 19 Comments

During the 6-week period from late May to early July this year, I collected ~400 jewel beetle specimens representing at least 20 species (see Working with Cerceris fumipennis—Part 1). A final accounting of the species represented won’t be done until this winter, but the genera represented include Acmaeodera, Actenodes, Agrilus, Anthaxia (Haplanthaxia), Buprestis (Knulliobuprestis), Chrysobothris, Dicerca, Poecilonota, and Spectralia. Perhaps two-thirds of the specimens were “ground-picked”¹, while most of the remaining third were “stolen” directly from wasps by netting wasps in flight as they returned to their nest carrying prey.

¹ It’s not clear to me why I found so many abandoned buprestids at nest entrances. The wasps are known to drop prey when threatened and, rather than search for and relocate the prey, fly off to look for a new beetle(Careless et al. 2009). I observed this myself in several cases when I missed netting the wasp but swiped the net close enough to scare it, at which time it dropped the beetle and flew off (and I popped the beetle in a vial). However, the bulk of the beetles I found on the ground were not only at the nest entrance, but even mixed within the diggings surrounding the nest. My first act when checking each field was to check each nest, pick up any adults lying on top of the burrow diggings, and then carefully spread out the diggings with a knife or trowel to collect the beetles hidden within them. One nest contained as many as 13 Agrlus obsoletoguttatus inside the diggings. I wondered at one point if the wasps were leaving the beetles at the burrow entrance and then digging out the burrow before coming back to retrieve them, but I never actually witnessed this. On the other hand, I observed numerous wasps approaching their burrows while carrying prey, and every time the wasp dropped directly into the burrow. In fact, I could even predict what beetle species I was likely to find inside the nest based on the species I found around the entrance (more on that below).

This ball field with contains several dozen Cerceris fumipennis nests.

There is a third method that I used to collect beetles that I haven’t yet discussed, and that is digging them out of nests. In the latter part of the survey period (late June and early July), beetle numbers dropped rapidly, as did apparent wasp activity. As mentioned in the previous post, this drop off in activity came precisely at the time of season when I have observed buprestid beetle activity to decline in Missouri. As the drop off in activity was taking place, I began wondering what I would find if I tried digging up some of the burrows. Of course, digging up a nest takes much more effort than netting wasps or picking beetles up off of the ground, so it becomes important not only to identify whether a nest actually belongs to C. fumipennis and if it is active and likely to contain freshly captured beetles.  In addition, I observed the burrows of a variety of other insects in these fields as well, some of which are shown here and which might be confused with burrow entrances of C. fumipennis.

Cerceris fumipennis nest with Chrysobothris sp. adult left on diggings.

Cerceris fumipennis burrows exhibit perfectly circular, pencil-sized entrances surrounded by a symmetrical mound of diggings with a fine rather than granular texture. There are other Cerceris species that make nearly identical burrows, but they prey on other insects rather than buprestid beetles. At my site I found C. bicornis, a weevil specialist, almost as common as C. fumipennis. Their burrow entrances on the whole seemed slightly larger, but I could not use this as consistent distinguishing character. What I could use, however, was the presence of weevils rather than buprestids lying on the ground near the nest entrance. (I also observed this species returning to its nest and noted a rather faster, more powerful flight that made them even more difficult to capture than C. fumipennis). In contrast, there can be no doubt that the burrow above, with a buprestid beetle lying on the ground near the entrance, belongs to C. fumipennis.²

² The white plastic tag marks the burrow to facilitate locating nests on subsequent visits. It is secured with a golf tee and also can be rotated so that the hole covers the entrance. The hole is large enough to allow the wasp to leave but too small for a returning wasp to enter while carrying a beetle. The idea was to rotate the tags when I first entered a field to cover all the burrow entrances, watch for wasps returning with prey, and then net the wasps as they tried (in vain) to enter the burrow. However, I never actually observed a wasp trying to enter a covered burrow, even after leaving a field and returning 20–30 minutes later.

I presume this nest to be that of Bembix americana (sand wasp).

For the first few weeks, I thought the burrows such as that shown in the above photo also belonged to C. fumipennis. However, I never found beetles lying on the ground near the entrance, nor did I ever observe a wasp to enter or leave the burrow. I eventually noticed several distinct differences in burrow architecture—the burrow entered the ground at an angle rather than straight down, the diggings were distributed asymmetrically to one side of the entrance, and the latter seemed consistently a little larger than those of C. fumipennis. In addition, these burrows always seemed to be in the sandier portions of the fields. While I never associated any insect directly with these burrows, I did observe sand wasps (perhaps Bembix americana) in the vicinity and have seen similar-looking burrows dug by these wasps at Sand Prairie Conservation Area.

Larval burrows of Cicindelidia punctulata and other tiger beetles lack diggings around the entrance.

Tiger beetle larval burrows might also be confused with C. fumipennis burrows, especially after rain or high winds which can wash/blow away the diggings from around the entrance. I found adults of the punctured tiger beetle, Cicindelidia punctulata, fairly commonly at the site and presume the numerous tiger beetle larval burrows that were also present belong to that species. Larval tiger beetles burrows also enter the ground straight down and are, at first appearance, also perfectly round, but they are usually a little too small for C. fumipennis (those of Tetracha spp. being an exception)—the presumed C. punctulata burrow in the above photo measures about 5 mm in diameter. In addition, closer examination reveals a slight “D” shape to the burrow entrance (upper right in the above photo—the tiger beetle larva rests its jaws against the flat side) and, more distinctively, beveling of the ground around the rim of the burrow entrance. Cerceris fumipennis nests lack the slight D-shape and distinctive beveling.

Use a grass stem as a guide while carefully digging away the surrounding soil.

Years of practice digging up tiger beetle burrows prepared me well for my first attempts at digging up C. fumipennis burrows. While it might seem an easy task to follow a hole into the ground while digging soil away from it, in practice the burrow can be quickly lost after even a few inches due to falling soil covering the hole and making it impossible to relocate. I use a thin, flexible but sturdy grass stem to preserve the burrow path, inserting the stem into the burrow and down as far as it will go and then removing the soil carefully from around the hole with a knife or trowel. I try to avoid letting soil fall over the hole by prying the soil away from the hole, but if the hole does get covered the grass stem allows it to be easily relocated.

This nest contained a single Buprestis rufipes…

Cerceris fumipennis burrows are not very deep—only 10–15 cm, and angle to one side a few cm below the surface before leveling out near the bottom. I noticed the nest in the above photo because I saw a wasp fly into it. When I went over to look at it I found a Buprestis rufipes lying on the ground near the entrance and so decided to dig it up. As I expected, I found another B. rufipes at the bottom of the burrow (two above photos courtesy of Madison MacRae).

…while this one contained a cache of seven Agrilus quadriguttatus.

The above photo shows a cache of seven Agrilus quadriguttatus that I found at the bottom of another burrow. In this case, the prey is rather small compared to large prey such as Buprestis and Dicerca. While nests provisioned with species in these latter genera often contained only a single beetle in them, I nearly always found multiple beetles in nests provisioned with the smaller Agrilus species. One nest contained as many as 13 Agrilus obsoletoguttatus, among the smallest of the species I found utilized by C. fumipennis at this site.

Buprestidae taken from five different Cerceris fumipennis nests.

Some of the nests I dug up contained multiple species of beetles, but far more commonly I found only a single species in a given nest. The photo above shows the diversity and number of beetles found on one date after digging up five different nests. From top left the beetles are: 1) 1 Buprestis rufipes; 2) 2 Agrilus quadriguttatus and 1 A. obsoletoguttatus; 3) 2 A. quadriguttatus and 1 A. obsoletoguttatus; 4) 8 A. obsoletoguttatus; and 5) 2 Poecilonota cyanipes, 2 A. quadriguttatus, and 1 A. pseudofallax. It would make sense for wasps to provision nests with greater numbers of smaller beetles to ensure adequate food for their larvae to complete development. How the wasps actually locate their prey, and why this species has specialized almost exclusively on buprestid beetles, is a mystery (at least to me); however (and here comes the speculation du jour), I suspect the wasps may have keyed in on volatiles used by the beetles—either those released by suitable hosts or by each other to facilitate mate location. Use of buprestid pheromones or freshly dead host volatiles would allow wasps to more efficiently locate buprestid prey and, once locating a source (a tree harboring a particular beetle species), could return repeatedly to provision their nest fully. It seems less likely that wasps rely exclusively on visual location of prey, as this would involve a large amount of random searching through trees and passing up numerous, seemingly equally suitable prey.

REFERENCE:

Careless, P. D., S. A. Marshal, B. D. Gill, E. Appleton, R, Favrin & T. Kimoto. 2009. Cerceris fumipennis—a biosurveillance tool for emerald ash borer. Canadian Food Inspection Agency, 16 pp.

Copyright © Ted C. MacRae 2012

Working with Cerceris fumipennis—Part 1

/ Ted C. MacRae / 20 Comments

For nearly 30 years, jewel beetles (family Buprestidae) have been my primary research interest. While some species in this family have long been regarded as forest and landscape pests, my interest in the group has a more biosystematic focus. A faunal survey of Missouri was the result of my initial efforts (MacRae 1991), while later research has focused on distributions and larval host associations of North American species (Nelson & MacRae 1990; Nelson et al. 1996; MacRae & Nelson 2003; MacRae 2004, 2006) and descriptions of new species from both North America (Nelson & MacRae 1994, MacRae 2003b) and South America (MacRae 2003a). Research interest in other groups—especially longhorned beetles and tiger beetles, has come and gone over the past three decades; however, I always return to jewel beetles as  my first and favorite group.

In recent years, one species in particular—the emerald ash borer (EAB, Agrilus planipennis) has garnered a huge amount of research, regulatory, and public interest after reaching North America from Asia and spreading alarmingly through the hardwood forests of Michigan and surrounding states. The attention is justifiable, given the waves of dead native ash trees that have been left in its wake. With huge areas in eastern North America still potentially vulnerable to invasion by this species, the bulk of the attention has focused on preventing its spread from infested areas and monitoring areas outside of its known current distribution to detect invasion as early as possible. One incredibly useful tool that has been adopted by survey entomologists is the crabronid wasp, Cerceris fumipennis. Like other members of the family, these solitary wasps dig nests in the ground, which they then provision with captured insect prey. The wasp uses its sting to paralyzed the prey but not kill it, and once inside the burrow the wasp lays an egg on the prey and seals the cell with a plug of soil. The eggs hatch and larvae develop by consuming the paralyzed prey (unable to scream!). After pupation the adult digs its way out of the burrow (usually the next season), and the cycle begins anew. However, unlike other members of the family (at least in North America), C. fumipennis specializes almost exclusively on jewel beetles for prey. So efficient are these wasps at locating and capturing the beetles that entomologists have begun using them to sample areas around known wasp populations as a means of detecting the presence of EAB. Philip Careless and Stephen Marshall (University of Guelph, Ontario) and colleagues have been leading this charge and have even developed methods for transporting wasp colonies as a mobile survey tool and developed a sizeable network of citizen scientists throughout eastern North America to expand the scope of their survey efforts. Information about this can be found at the excellent website, Working with Cerceris fumipennis (please pardon my shameless lifting of the title for this post).

I first became aware of the potential of working with C. fumipennis a few years ago when Philip sent me a PDF of his recently published brochure on use of this wasp for EAB biosurveillance (Careless et al. 2009). My correspondence with him and other eastern entomologists involved in the work suggested that ball fields with lightly vegetated, sandy soil would be the best places to look for C. fumipennis nests, but my cursory attempts to find the wasp at that time were unsuccessful. I reasoned that the clay-soaked soils of Missouri didn’t offer enough sand for the wasps’ liking and didn’t think much more about it until last winter when I agreed to receive for ID a batch of 500+ buprestid specimens taken from C. fumipennis wasps in Louisiana. What a batch of material! In addition to nice series of several species that I had rarely or never seen (e.g. Poecilonota thureura), three new state records were represented amongst the material. A paper is now in progress based on these collections, and that experience catalyzed a more concerted effort on my part to locate a population of the wasp in Missouri. Museum specimens were no help—the only records from Missouri were from old specimens bearing generic locality labels such as “St. Louis” and “Columbia.” Throughout the month of May, I visited as many ball fields as I could, but the results were always the same—regularly groomed, heavy clay, barren soil with no evidence of wasp burrows (or any burrows for that matter).

Near the end of May, however, I had a stroke of luck. I had switched to a flatter route through the Missouri River Valley to ride my bike to work because of knee pain (now thankfully gone) when I saw this:

Practice fields at Chesterfield Valley Athletic Complex | St. Louis Co., Missouri

Those are “practice” fields in front of regular fields in the background, and unlike the latter, this row of nine fields (lined up against the levee adjacent to the Big Muddy National Wildlife Refuge) showed no evidence of regular grooming or heavy human use. Only ten miles from my home, I made immediate plans to inspect the site at the first opportunity that weekend. Within minutes after walking onto the lightly vegetated, sandy-clay soil of the first field, I found numerous burrows such as this:

Cerceris fumipennis with circular, pencil-wide burrow entrance and symmetrical mound of diggings.

Only a few more minutes passed before I found an occupied nest, the wasp sitting just about an inch below the entrance to its pencil-wide burrow. The three yellow markings on the face indicated it was a female (males have only two facial markings), and in short order I found numerous other burrows also occupied by female wasps. Some were just sitting below the burrow entrance, while others were actively digging and pushing soil out of the burrow with their abdomen. I flicked a little bit of soil into one of the burrows with a female sitting below the surface, which prompted an immediate “cleaning out” of the burrow—this explains the dirty face of the female in the following photo, but the three yellow facial markings are clearly visible:

Cerceris fumipennis female removing soil from burrow entrance.

After finding the burrows and their occupants, I began to notice a fair number of wasps in flight—leaving nests, returning to nests, and flying about as if searching for a ‘misplaced’ nest. A few of these were males, but most were females, and I also caught a couple pairs flying in copula (or at least hitched, if not actually copulating). Despite the number of wasps observed during this first visit, I didn’t see a single wasp carrying a buprestid beetle. This puzzled me, because all of the Louisiana beetles I had determined last winter were taken by standing in the midst of nests and netting those observed carrying beetles. Finally, I had confirmation that I was truly dealing with this species when I found a couple of beetles lying on the ground near the entrance to a burrow. These would be the only beetles that I would find on this visit, but subsequent visits during the following few weeks would show “ground picking” to be the most productive method of collecting beetles. Across the nine fields, I found a total of nearly 300 nests, and the wasps showed a clear preference for some fields over others—one field (P-6) had about 150 nests, while a few others had less than a dozen. The photo shown in ID Challenge #19 shows a sampling of ground-picked buprestids from P-6 in a single day, and occasionally I would find a real prize like Buprestis rufipes:

Buprestis rufipes laying near Cerceris fumipennis nest entrance.

Coincident with the appearance of large numbers of beetles laying on the ground near nest entrances, I also began to see wasps carrying their prey. Wasps carrying large beetles are easily recognized by their profile, but even those carrying small beetles look a little more “thick-thoraxed” (they hold their prey upside down and head forward under their thorax) and exhibit a slower, more straight-line flight path compared to the faster, more erratic and repetitively dipping flight of wasps not carrying prey. Learning how to discern wasps carrying prey in flight from the more numerous empty-handed wasps prevents a lot of wasted time and effort netting the latter. Nevertheless, there does appear to be some bias towards larger beetles when netting prey-carrying wasps in flight, as evidenced in the photo below of beetles taken by this method, also in field P-6, on the same date as the ground-picked beetles shown in ID Challenge #19. This could be a result of visual bias towards wasps carrying larger beetles, as in later visits (and presumably with a more refined search image) I did succeed in catching larger numbers wasps carrying smaller beetles (primarily in the genus Agrilus).

Buprestid prey of Cerceris fumipennis: L–R and top to bottom 2 Dicerca obscura, 2 D. lurida, 3 Poecilonota cyanipes, 2 Acetenodes acornis, 1 Chrysobothris sexsignata, 1 Agrilus quadriguttatus, and 1 A. obsoletoguttatus

All told, I collected several hundred beetles during my twice weekly visits to the site from late May to the end of June. Beetle abundance and wasp activity began to drop off precipitously in late June, which coincides precisely with the end of the adult activity period for a majority of buprestid beetles in Missouri, based on my observations over the years. This did not, however, spell the end of my activities in using C. fumipennis to collect buprestid beetles, which will be the subject of Part 2 in this series.

Congratulations to Joshua Basham, whose efforts in ID Challenge #19 earned him 12 points and the win. Morgan Jackson and Paul Kaufman were the only others to correctly identify the Cerceris fumipennis connection and take 2nd and 3rd, respectively. In an unexpected turn of events, BitB Challenge Session #6 overall leader Sam Heads did not participate and was leapfrogged by Brady Richards, whose becomes the new overall leader with 59 points. Sam now trails Brady by 5 points, while Mr. Phidippus lies another 3 points back. With margins this tight, the overall standing can still change in a single challenge, and there will be at least one more in this current session before an overall winner is named.

REFERENCES:

Careless, P. D., S. A. Marshal, B. D. Gill, E. Appleton, R, Favrin & T. Kimoto. 2009. Cerceris fumipennis—a biosurveillance tool for emerald ash borer. Canadian Food Inspection Agency, 16 pp.

MacRae, T. C. 1991. The Buprestidae (Coleoptera) of Missouri. Insecta Mundi 5(2):101–126.

MacRae, T. C. 2003a. Mastogenius guayllabambensis MacRae, a new species from Ecuador (Coleoptera: Buprestidae: Haplostethini). The Coleopterists Bulletin 57(2):149–153.

MacRae, T. C. 2003b. Agrilus (s. str.) betulanigrae MacRae (Coleoptera: Buprestidae: Agrilini), a new species from North America, with comments on subgeneric placement and a key to the otiosus species-group in North America. Zootaxa 380:1–9.

MacRae, T. C. 2004. Notes on host associations of Taphrocerus gracilis (Say) (Coleoptera: Buprestidae) and its life history in Missouri. The Coleopterists Bulletin 58(3):388–390.

MacRae, T. C. 2006. Distributional and biological notes on North American Buprestidae (Coleoptera), with comments on variation in Anthaxia (Haplanthaxia) viridicornis (Say) and A. (H.) viridfrons Gory. The Pan-Pacific Entomologist 82(2):166–199.

MacRae, T. C., & G. H. Nelson. 2003. Distributional and biological notes on Buprestidae (Coleoptera) in North and Central America and the West Indies, with validation of one species. The Coleopterists Bulletin 57(1):57–70.

Nelson, G. H., & T. C. MacRae. 1990. Additional notes on the biology and distribution of Buprestidae (Coleoptera) in North America, III. The Coleopterists Bulletin 44(3):349–354.

Nelson, G. H., & T. C. MacRae. 1994. Oaxacanthaxia nigroaenea Nelson and MacRae, a new species from Mexico (Coleoptera: Buprestidae). The Coleopterists Bulletin 48(2):149–152.

Nelson, G. H., R. L. Westcott & T. C. MacRae. 1996. Miscellaneous notes on Buprestidae and Schizopodidae occurring in the United States and Canada, including descriptions of previously unknown sexes of six Agrilus Curtis (Coleoptera). The Coleopterists Bulletin 50(2):183–191.

Copyright © Ted C. MacRae 2012

Cicada killer on the fly

/ Ted C. MacRae / 6 Comments

An eastern cicada killer (Sphecius speciosus) searches for her burrow | Jacksonville, Illinois.

I don’t normally spend much time trying to photograph insects in flight. To really do it right requires some rather specialized equipment, including very high-speed flash, and a bucketload of patience and skill. John Abbott exemplifies those whose great talent has produced stunning photographs of insects in mid-flight. That’s not to say that it can’t be done “on the fly,” so to speak, and even a hack like me can get lucky every now and then.

Earlier today I found a rather large number of eastern cicada killers (Sphecius speciosus) in a ball field in Jacksonville, Illinois. These impressive wasps are the largest wasp in eastern North America and have the rather gruesome habit of paralyzing cicadas with their sting, and then dragging them down into their burrows to be eaten alive by their grubs. I’ve recently become interested in solitary wasps (for reasons to be discussed later) and decided to see if I could get some decent photographs. I got a few I like (more on this later), but my favorite is this total luck-out shot of a wasp face-on in mid-flight. As I watched them, I noticed that each wasp spent a fair amount of time trying to identify its burrow amongst the dozen or more that were clustered along one side of the field. Occasionally they would land and search about a bit on foot, then take wing again to continue their search. I decided the best way to get a shot of one on the wing would be to watch for a wasp to arrive and begin its search. When I spotted one I would slowly close distance so I could be ready to get down on my elbows as soon as it landed (closing distance without spooking the wasp was not easy). I had just my center focal point set and autofocus turned on (normally I don’t use autofocus) and had already worked out a good flash exposure compensation setting. As soon as I got on my elbows, I would quickly frame the wasp and repeatedly trigger the autofocus as I got even closer, and when the wasp took flight I took the shot. This was still a crap shoot—I ended up with lots of out-of-focus and out-of-frame photos. Nevertheless, a few turned out fairly decent, one of which was this single, perfectly head-on and well-focused photo (though admittedly somewhat cropped).

Too bad I didn’t collect any of the wasps—at $49 each I could’ve made enough cash to buy that flash bracket I’ve been eyeing!

Copyright © Ted C. MacRae 2012

The importance of background and apparent light size

/ Ted C. MacRae / 8 Comments

I’m still getting submissions for ID Challenge #19 and don’t quite have the followup post ready yet, so I’ll give it a couple more days. In the meantime, I’d like to re-share the photo below, originally shown a few weeks ago in my post  A few people commented that this was their favorite photo in the series—perhaps like me they are suckers for face shots, but I think this photo succeeds in large part because of its soft-green background. This was actually one of several similar face shots that I took, each differing the other almost exclusively in the choice of background. In the end, I chose the green background to include in the post, not only because it was the most aesthetically pleasing, but also because I felt it best represented the environment of the beetle—ensconced within the foliage of its preferred host plant, ninebark (Physocarpus opulifolius).

Green background—achieved by placing a leaf some distance behind the subject.

Such background is easily achieved in full-flash macro photography by placing a green leaf some distance behind the subject, although in practice this can be a little tricky—you want the leaf far enough away from the subject that it is completely out of focus, eliminating distracting details, but close enough so that it actually reflects light from the flash and shows up as green. This becomes trickier still if the photographer is already holding the subject (as I was, or at least the branch on which the subject was sitting), as the distance between the subject and the background must be adjusted by moving the subject (and hence the camera), rather than the leaf.

Black background—the typical background of full-flash macrophotography.

Here is a similar shot of the beetle without placing anything in the background. This is full-flash lighting because I’m using small apertures and high shutter speeds to prevent motion blur and maximize depth-of-field. As a result, only objects in the vicinity of the subject and illuminated by the flash will show up in the exposure. This results in the almost-trademark black background of typical full-flash illuminated macrophotography. Despite what you may read or hear, there is nothing wrong with a black background. Some consider it boring—probably because it is so common in macrophotography. However, there are times when it truly is the best choice of backgrounds—especially with a white or light-colored subject (for example, see this photo of the white-flowered Great Plains ladies’-tresses orchid, Spiranthes magnicamporum). With darker subjects, however, black may not be the most appealing choice of backgrounds, so it’s good to keep this in mind and choose accordingly.

Blue background—bump the ISO up to 320 and point the subject to the brightest part of the sky.

Of course, there is one way to avoid a black background without placing an object behind the subject (or placing the subject in front of an object), and that is to use the open sky to achieve a nice, blue background. This is one of the trickier of the background techniques, as it relies on finding a fine balance between ISO, aperture and shutter speed. For this photo, I bumped the ISO up to 320 (normally I use 160) and slightly opened up the aperture (f/13 rather than f/16). These settings, combined with pointing the subject to the very brightest part of the sky (excluding the sun!) allowed me to keep the shutter speed reasonably fast (1/200 sec). I find that lower shutter speeds nearly always result in some motion blur (all of my photos are hand-held), so I avoid reducing shutter speed if at all possible. I also find that ISO settings above 320 result in unacceptable graininess, so I will back down on the aperture (even down to f/11 or f/10) if I have to in order to avoid going above ISO 320 and below 1/200 sec exposure. On especially bright days, areas of the sky closest to the sun will provide enough light that you can use aperture to fine-tune the background to the desired intensity of blue—the smaller the aperture the more intense and darker the blue will be (along with providing greater depth of field). While a blue background works for this subject, I simply like the green background better. I find that blue background shots are most pleasing with foliage and flower-feeding insects, adding a touch of realism to the photo without the cluttered, distracting look of other natural backgrounds or the “studio” feel of black background shots. This photo of the South American weevil, Megabaris quadriguttatus, is perhaps my favorite example of the use of blue background.

By now, the more technically oriented photographer types among you might have noticed something that all three photos have in common (besides the subject), and that is the difference in specular highlighting exhibited by the left and right eyes of the subject. Reverse engineering suggests that I had two sources of light (which is true, I use Canon’s MT24-EX twin macro flash), and that the light source illuminating the beetle’s right side either had a much larger diffuser or was placed much closer to the subject. In fact, it was the latter, as I simply detached the left flash unit and held it much closer to the subject to confirm for myself what effect this has. Because the flash unit is closer to the subject, it has much larger apparent size, resulting in more even lighting over that side of the subject and, accordingly, softer specular highlights. If I had a third arm I would have done the same with the second light source (and a fourth arm would allow me to also hold a green leaf behind the subject!). Unfortunately, additional appendages are not an option, so I’m going to have to figure out an efficient, light, easy way to get my light sources as close to the subject as possible. Snoot diffusers are one option, but they have limited flexibility to make fine adjustments to the subject-distance as camera distance changes. Going to a single light source and holding it off-camera is another option, but hand-holding a light source leaves one less hand to hold other things (like the subject), and I do prefer the reduction of shadows provided by multiple light sources. I’ve already discussed the , and I do have some other ideas that I’m working on as well. However, your ideas also would be most welcome!

Copyright © Ted C. MacRae 2012

Out with the old (but on a good note)

/ Chris Brown / 10 Comments

This past March was the warmest on record here in Missouri and that made for some nice opportunities to get out and photograph. That said, my enthusiasm for macro photography has been somewhat tempered since my camera body is getting old and showing some signs that it might be on its last leg. The mere fact that I am still using a camera from 2004 may be your first indication that I am something less than a macro photography perfectionist and this is a reflection of the equipment that I first used when I began shooting macro. I started with Canon manual equipment in the mid-1990’s because I thought this would be the best way to learn photography. My stint with a used, and malfunctioning, Canon AE-1 was thankfully short. It was stolen as I returned from a photography trip to the Chiricahua Mountains, but I still lament that the thief made off with the spent rolls of film from the trip! The experience with the AE-1 pushed me towards higher quality, more professional equipment that would stand up to field conditions better. Next up was the Canon F1 and then the wonderfully solid Canon F1N followed later with the game-changing addition of a power winder. The latter was great since insects typically didn’t wait around for me to manually wind the film, refocus, and shoot. The real challenge though was getting the lighting right. At fist I often times had the camera on a tripod which resulted in too many missed shots, restricted what I could shoot, and it didn’t meet what I later realized was my overall goal of macro photography. What I wanted was to have the ability to take satisfactory macro images while not loading myself down with equipment that would detract from also being able to conduct research or simply observe/enjoy nature without trying to capture it on film. I still have a graveyard of old flashes, brackets, and bracket parts that I employed in various combinations to get suitable lighting though it is now clear that I was never able to get the perfect balance. That changed in 2001 when Canon introduced the new MT-24EX macro twin flash and I bought a 1V body. After testing the new system a minimal amount, I realized that macro photography was now made easy relative to what I had wrestled with over the years prior. I had the complete package—no bulky brackets, no hand holding flashes, more certainty of exposure, and quick field set-up. The twin flash allowed me to fire off just the minimal amount of light to obtain my desired depth of field and the flash had sufficient battery power at the lower flash output settings to essentially shoot consecutively without having to wait for the flash to power-up.

Well, at least I thought I had the perfect setup until Ted MacRae took up macro photography and soon demonstrated that options for continuous improvement exist even for this system.

In 2004 I sadly shelved the 1V body and went digital. I briefly used the Canon 10D, which seemed inadequate for various reasons, but then jumped on the newly released Canon 1D Mark II during that same year. It was more than I wanted to spend but there weren’t many options and the benefits were too much to pass up. Most notably, I was sick of buying film, scanning slides, and most of all my hand ached from cataloguing so many slides, i.e., writing a unique code on each slide prior to archiving it in plastic. The time savings alone made the 1D Mark II price palatable and I hoped that investing in a top notch, newly released body would help it remain relevant for a while. I never looked back.

That brings me to that warm day this past March when I settled in to photograph a toad bug, Gelastocoris oculatus (Heteroptera: Gelastocoridae), along the margin of an intermittent creek in Perry Co., Missouri.  As I mentioned above I felt like I was limping along with my dated 1D Mark II but I couldn’t pass up the opportunity to again photograph an individual of G. oculatus that so superbly blended in with its substrate (Figures 1 and 2).

Figure 1. Gelastocoris oculatus, 3.13.2012, Perry Co., MO

Figure 2. Gelastocoris oculatus, 3.13.2012, Perry Co., MO

As I have mentioned before I like to take multiple shots of a subject to help tell a story (yes, including the obligatory head-on close up that Ted always mentions). One important shot in the series can be a photograph from a distance to: 1) better see the subject in its surroundings which can give more insight into its natural history; 2) offer a more artistic view, or, in this case; 3) to show the effectiveness of its cryptic coloration. The actual close-up is great for detail but only gives the viewer an idea that the subject is similarly colored to its background but only a more distant shot really conveys how well the subject melts into the substrate. In this case, Figure 3 was the next progression towards that shot but I was stopped short that day partly due to my middle son falling in the creek and partly due to the apparent malfunctioning of the camera. As you can see, I wasn’t far enough away from the subject to capture what attracted me to the bug in the first place—how well it mimicked its background. In that sense the picture is disappointing because I didn’t finish the story. But on the other hand, the malfunctioning of the camera combined with its age, made it clear that it was now time for a new camera body. So I put on my best frustrated/disappointed face and presented my case to my wife, Jess. It was an easy sell since Jess is… well… at least 95% supportive of my photography. I’ll discuss the new body and the first images soon.

Figure 3. Gelastocoris oculatus, 3.13.2012, Perry Co., MO

Below are more of the variable faces of G. oculatus that I have come across over the years (Figs. 4 – 8). Gelastocoris oculatus is one of two species of Gelastocoris that we have in North America (Arnett 2000). Gelastocoris oculatus can be found continent-wide however G. rotundatus ranges only in the southwest. I love the origin of the family name which the online Merriam-Webster dictionary mentions is from the Greek “gelastos”+ “koris” which translates to “laughable bug”, no doubt due to its odd appearance. Both species are predators that live along the margins of water. Their predaceous nature is made clear by the appearance of their powerful forlegs clearly specialized for catching and securing prey. As you can see, I do not have a picture of their forlegs so I’ve got a great reason to again get down on their level with the new camera.

Figure 4. Gelastocoris oculatus, 5.23.2010, Perry Co., MO

REFERENCE:

Arnett, R.H. 2000. American Insects: A Handbook for the Insects of America North of Mexico. Boca Raton, Florida: CRC Press.

Copyright © Christopher R. Brown 2012

Seeing the unseen

/ Ted C. MacRae / 15 Comments

While trying to nab a cicada from the small trees planted on the grounds at our experiment station here in Fontezuela, Argentina, I happened to notice a bit of movement on one of the branches nearest to me (while the cicada flew off with a screech and a clatter). A closer look revealed what looked like a slight protuberance of the branch to be a nymphal planthopper (family Fulgoridae), and at ~15 mm in length a pretty good-sized one at that. I would have never noticed it had it not moved, so good was its camouflage, but I didn’t have the time to spend trying to photograph it right then and there. Instead, I popped it into a vial (you do always carry a vial with you, don’t you?) and continued my fruitless quest for cicadas.

Undet. fulgorid nymph | northwestern Buenos Aires Province, Argentina

Later that evening I placed it on a palm tree in the hotel courtyard (not really the appropriate host, but it was the only real tree available). I took the standard dorsal view photo, and while not as good a color match as the (still undetermined) tree upon which I found it one still gets a sense for how difficult it might have been to see this nymph flattened against the slightly greenish bark.

A lateral profile view makes the bug much more visible.

One thing I’ve learned from much better photographers than myself is to get down and low relative to the subject—even to the point of looking up at it if possible. This provides views that are far more interesting than the typical looking-down-from-above shots. In the case of this nymph, the above and following low-angle shots really brought it to life and emphasize its unusual form.

Even lower. How did I get the nymph to "prop" itself?

Of course, with the nymph on the side of a fairly large tree, one can only get so low. To get even lower, I placed the nymph on a small stick and used hand-holding and bracing techniques to get even lower. I took quite a few shots experimenting with composition, and the shots I ended up liking the best were frontal-oblique from slightly below bug-level with the stick rather sharply angled down and the bug slightly propped up on its front legs. Easier said than done—this nymph was loathe to stop crawling once I moved it to the stick and tended to be negatively geotactic (crawled upwards). As a result, every time I angled the stick downward it would turn around and start crawling the other way, and in any case when it did stop it tended to flatten itself against the branch. Through trial and error, I learned that if I braced my thumb and forefinger against its head/pronotum to stop its progress and held it in place for awhile it would stay put. I also learned that if I slightly blew on its face when it was flattened against the branch that it would prop itself upwards a bit. Thus, for this shot it was a matter of letting it crawl upwards almost to the end of the stick (to eliminate excess stick that poke into the camera with a frontal-oblique angle), bracing it for a moment, inverting the stick downward and pointing slightly towards the camera, and then blowing on its face a bit—simple, huh? The black transverse band on the lower face adds a lot of character to the shot.

The obligatory face-on shot

The face-on shot is a staple for me, but even with this shot the angle is important—angle the back of the stick down too much and you get the all black background (not in itself bad, just not what I wanted for this shot), angle it too high and too much of the back of the bug shows up as blurred clutter in the background). The foreward projecting “nose” of this nymph prevented me from getting both the tip of the nose and the eyes in focus (without using excessively small aperatures), so I opted for the latter (I’ve never seen a good face shot of an insect in which at least the eyes were not in focus).

Unfortunately, family-level identification is as good as it is going to get for this individual. I sent the photos to fulgorid expert Lois O’Brien, who eliminated several options but couldn’t narrow down further among several remaining possible genera (“Our ignorance of nymphs is abysmal…”). Her recommendation was to go back to the tree and try to find adults, and apparently some species tend to live on the same tree for years and years. I’ll be returning to Fontezuela later in April—hopefully the fall season will not have advanced to far by then.

Copyright © Ted C. MacRae 2012