A: Very carefully!

This past June I went out to one of my favorite spots in northwestern Oklahoma—Alabaster Caverns State Park in Woodward Co. The park, of course, is best known for its alabaster gypsum cavern—one of the largest such in the world—and the large population of bats that occupies it. Truth be told, in my several visits to the park during the past few years I have never been inside the cavern. The draw for me is—no surprise—it’s beetles. On my first visit in 2009 I found what is now known to be one of the largest extant populations of the rare Cylindera celeripes (swift tiger beetle), previously considered by some to be a potential candidate for listing on the federal endangered species list, and last year I found the northernmost locality of the interesting, fall-active jewel beetle Acmaeodera macra. This most recent visit was the earliest in the season yet, and as I walked the trails atop the mesa overlying the cavern I noticed numerous clumps of prickly pear cactus (Opuntia macrorhiza) dotting the landscape.

Whenever I see prickly pear cactus anywhere west of Missouri I immediately think of cactus beetles—longhorned beetles in the genus Moneilema. A half-dozen species of these relatively large, bulky, clumsy, flightless, jet-black beetles live in the U.S., with another dozen or so extending the genus down into Mexico and Baja California, and all are associated exclusively with cactus, primarily species of the genus Opuntia. It wasn’t long before I found one, and deliberate searching among the cactus clumps produced a nice series of beetles representing what I later determined as M. armatum. The resemblance between Moneilema spp. and darkling beetles of the genus Eleodes is remarkable, not only in their appearance but also in their shared defensive habit of raising the abdomen when disturbed. The genus has been related taxonomically to the Old World genus Dorcadion, but Linsley & Chemsak (1984) regard the loss of wings and other morphological modifications to represent convergence resulting from the environmental constraints imposed by root-feeding, subterranean habits in arid environments and other situations where flightlessness is advantageous.

I have encountered Moneilema beetles a number of times out west, including this species in Texas where it is most common, but since I have only been photographing insects for the past few years this was my first  chance to capture cactus beetle images as well as specimens. The above shot, taken with my iPhone, was straightforward enough, but I wanted some real photographs of the beetle—i.e., true close-up photos taken with a dedicated macro lens. I quickly learned that this would be highly problematic—those cactus spines are long and stiff and vicious, and these beetles are no dummies! Clearly their ability to adapt to such a terrifyingly well-defended plant has had a lot to do with the evolution of their slow, clumsy, flightless, you-don’t-scare-me demeanor. Normally when I photograph insects I do a little pruning or rearranging of nearby vegetation to get a clear, unobstructed view of the subject, and sometimes this also involves “pushing” my way into the vegetation to get the most desirable angle on the subject for the sake of composition. Not so here! In my first attempt, all I could think to do was locate a beetle sitting in repose and try to position myself in some way so that the beetle was within the viewfinder and the cactus’ spines were not impaled within my arms! The photo below shows the only shot out of several that I even considered halfway acceptable, but clearly the spines obstructing the view of the beetle were not going to be to my liking.

What to do? The beetle was behaving fairly well (i.e., it was not bolting for cover upon my approach), so I pulled out a pair of long forceps (that I carry with me for just such cases) and used them to gently prod the beetle into a more exposed position. The beetle crawled up onto one of the unopened cactus flower buds and perched momentarily, and I thought I had my winner photograph. I crouched down again, was able to get a little bit closer to the beetle than before, and fired a few shots. Looking at them in the preview window, however, left me still dissatisfied—the beetle was no longer obstructed, but the background was still jumbled, messy and dark, making it difficult for the dark-colored beetle to stand out. I would need to think of something else.

I actually take a lot of my photos with the insects sitting on plant parts that have been detached from the plant. This allows me to hold the plant in front of whatever background I choose and micro-adjust the position of the insect in the viewfinder for the best composition. This is “easier” (a relative term) with a shorter lens (think MP-E 65-mm) because the lens-to-subject distance matches almost perfectly the distance between my wrist and my fingers, allowing me to rest the camera lens on my wrist while holding the plant part with my fingers to “fix” the lens-to-subject distance. These beetles, however, are much too big for the MP-E 65-mm, so I had to use my longer 100-mm macro lens. The longer lens-to-subject distance does not allow resting the lens on my wrist, so I must come up with other ways of bracing myself and the subject to minimize movement. Detaching the pad on which the beetle was resting (and if you’ve never tried to detach an Opuntia cactus pad from its parent plant while trying not to disturb a beetle sitting on it, I can tell you it is not an easy thing), I also discovered that the pad was quite heavy and that holding it with the same forceps that I had used to prod the beetle (because of its vicious spines) was yet another unanticipated difficulty. I decided the best way to deal with it would be to get down on one knee in front of the plant, rest my arm on my other knee with the cactus pad extending out in front of me, and photograph the beetle with the plant as close in the background as possible to achieve a lighted and colored background that would help the beetle stand out. Following are examples of those attempts.

Better for sure, especially the latter, closer one. Still, I wasn’t satisfied—the backgrounds still just had too much clutter that detracted from the beetle and complicated the lighting. I decided to go for broke—why not go for the blue sky background, the cleanest, most natural and aesthetically pleasing background possible! This actually was my first thought when I saw the beetles, but I could never find one on a high enough plant that was growing in a situation where I was able to crouch low enough to get the angle with the sky in the background. By this time my arm was quite weak from holding the heavy cactus pad and squeezing the forceps firmly, and as I contemplated how I could possibly hold the pad up towards the sky and take the shots without being able to rest the camera on my arm I had an idea. Why not rest my arm on the camera? Specifically on top of the flash master unit atop the camera. I adjusted the camera settings for blue sky background, positioned the cactus pad in the forceps so that the pad (and beetle) were hanging down from the forceps but still in an upright position, pointed the camera to the brightest part of the sky (a few degrees from the sun), and then held the cactus pad out in front of the camera with my arm resting on the flash master unit. It worked! My arm still got tired quickly and needed frequent breaks, and I had to do a number of takes to get the exposure settings and composition I was looking for, but the photo below represents my closest approach to what I envisioned when I first knelt down to photograph these beetles. A clear view of the beetle, on its host plant, with lots of nice value contrast between beetle, plant and background.

Once I had the technique figured out, I was able to get some really close-ups shots as well, still, however, with enough blue sky in the background to make it clean and pretty…

…as well as playing with some unusual compositions that one can afford to try only after they are confident they have gotten the required shots. I am particularly fond of the following photo, in which the beetle appears to be “peeking” from behind its well-defended hiding place on its host plant.

If you have any experiences photographing these or other such “well-defended” insects (without resorting to the white box!) I would love to hear about them.

REFERENCE:

Linsley, E. G. and J. A. Chemsak. 1984. The Cerambycidae of North America, Part VII, No. 1: Taxonomy and classification of the subfamily Lamiinae, tribes Parmenini through Acanthoderini. University of California Publications in Entomology 102:1–258 [preview].

Copyright © Ted C. MacRae 2013