Best of BitB 2014

Welcome to the 7th Annual “Best of BitB”, where I pick my favorite photographs from the past year. Before I do this, however, let me briefly recap the year 2014. The trend of increasing travel each year continued, with more days spent on the road than in any prior year. Travel for work over the past few years has settled into a familiar routine—touring soybean fields in Argentina in late February and early March, working in my own field trials at (previously three, now four) sites in Illinois and Tennessee from late May through late September, touring more soybean fields at sites across the southeastern U.S. during mid-September, returning to Argentina in October to finalize plans for field trials in the upcoming season, and—finally—attending/presenting at the Entomological Society of America (ESA) Meetings (this year in Portland, Oregon). This heavy travel load makes scheduling my own insect collecting trips a bit tricky, but I’m a persistent sort! In late May I traveled to Tennessee and Georgia with fellow buprestophile Joshua Basham and lab mate Nadeer Youseff to collect several rare jewel beetles, then in late June I collected prionids and jewel beetles in Colorado, New Mexico, and Oklahoma with Jeff Huether. In addition to these longer trips, I also managed to take advantage of my work travel to check out interesting natural habitats along the way to and from my field sites. I continue to give the occasional entomology seminar as well, speaking in March at “Day of Insects” in Ames, Iowa and here in St. Louis to the Entomology Natural History Group of the Webster Groves Nature Study Society in April and the Missouri Master Naturalists Confluence Chapter in December. On top of all this, I still managed to vacation with my family in Lake Tahoe during March and in Cabo San Lucas, Mexico during late July.

I say all this to highlight the fact that after all these years I still consider myself an entomologist with a camera rather than a bona fide insect photographer. The reason for this is that the science of entomology itself remains my primary focus—photography is simply one of the tools that I have come to use in my pursuit of the discipline. I don’t mean to imply that I don’t continue to work on my photography style and technique—because I do. But my style and technique are not goals in of themselves; rather, they are means to an end—that end being my entomological studies. With that said, I present my favorite BitB photographs from 2014. As in previous years, my photos are largely hand-held, in situ field shots that are intended to tell a natural history story in a (hopefully) aesthetic manner. Links to original posts are provided for each photo selection, and I welcome any comments you may have regarding which (if any) is your favorite and why—such feedback will be helpful for me as I continue to hone my craft. If you’re interested, here are my previous years’ picks for 2008, 2009, 2010, 2011, 2012 and 2013. Once again, thank you for your readership, and I hope to see you in 2015!


Paraselenis tersa? female guarding her eggs | Cordoba Prov., Argentina

Paraselenis tersa (Boheman, 1854) | Cordoba Prov., Argentina

From Tortoise beetles on the job (posted April 20). This photograph of a tortoise beetle female over her egg mass illustrates maternal guarding behavior—rare in insects. The perfect lateral profile shot and clean, blue sky background also give the photo a pleasing aesthetic quality.


Who likes mole crickets?

Scapteriscus borellii Giglio-Tos, 1894 | Emanuel Co., Georgia

From Who likes mole crickets? (posted June 6). This has to be the most comical expression ever on the face of an insect!


Chrysobothris orono Frost, 1920 | South Cumberland State Park, Tennessee

Chrysobothris orono Frost, 1920 | South Cumberland State Park, Grundy Co., Tennessee

From Chrysobothris orono in Tennessee (posted July 29). I found this rare jewel beetle for the first time this year with the help of Josh Basham and Nadeer Youseff. The beetle itself is beautiful enough, but photographing it on a pine root with a presumed adult emergence hole adds considerable natural history interest to the photo. Rock substrate behind the root adds a pleasingly blurred background.


Buprestis (Stereosa) salisburyensis Herbst, 1801 | South Cumberland State Park, Tennessee.

Buprestis (Stereosa) salisburyensis Herbst, 1801 | South Cumberland State Park, Tennessee.

From The Buprestis tree (posted August 10). This was another of several jewel beetles that I found for the first time after more than three decades of collecting this group. I like the value contrast in this photo from the striking, metallic colors of the beetle against the nicely blurred cinnamon-colored pine bark of the tree on which it is sitting.


A "super moon" watches over a parasitized hornworm caterpillar.

A “super moon” watches over a parasitized hornworm caterpillar.

From A time of reckoning (posted August 13). I fully admit this is a composite photograph. Nevertheless, it is a faithful recreation of a true sight, and I don’t consider the use of composite techniques to overcome equipment shortcomings to be unethical. There is a haunting symmetry between the blood red moon—considered by some as a sign of the second coming—and the sad, parasitized caterpillar waiting for its inevitable demise.


The greatly expanded palps are thought to mimic beetle mandibles or spider pedipalps.

Phyllopalpus pulchellus Uhler, 1864 | Hickman Co., Kentucky

From My, what busy palps you have! (posted September 2). I’ve become quite fond of insect photos with the subject “peering” at me, the photographer”, from some unusual vantage point. The “pupils” in the eyes of this red-headed bush cricket give the insect an almost quizzical look.


Acmaeodera immaculata Horn, 1881 | vic. Vogel Canyon, Otero Co., Colorado.

Acmaeodera immaculata Horn, 1878 | vic. Vogel Canyon, Otero Co., Colorado.

From Sunset beetles (posted September 30). Taking photos of insects at sunset is a challenging and ephemeral experience—one has only a few minutes to take advantage of the unusual and serene colors it offers, while at the same time trying to determine the best camera and flash settings to use in the rapidly fading light. Of the several that I’ve tried, this one is my favorite because of the softly complimentary colors of the beetle, the flower upon which it is sitting, and the dying orange sky behind it. If I had to choose, I would probably pick this one as my favorite of the year because of the unusual and serene colors.


Megacyllene decora (Olivier, 1795) | Stoddard Co., Missouri

Megacyllene decora (Olivier, 1795) | Stoddard Co., Missouri

From Amorpha borer on goldenrod (posted October 5). I featured this very same species in Best of BitB 2012 but can’t resist choosing this second attempt at photographing the spectacularly beautiful adult—this time on goldenrod. As with the previous version this is a true in situ field photograph, hand held and using the left-hand technique to achieve precise composition against a clear blue sky—difficult to do with an insect of this size and using a 100-mm lens, but well worth the effort.


Buprestis (Knulliobuprestis) confluenta Say, 1823 | Woods Co., Oklahoma

Buprestis (Knulliobuprestis) confluenta Say, 1823 | Woods Co., Oklahoma

From A Buprestis hat-trick! (posted October 14). I didn’t take near as many of the classic “frontal portraits” this year, but this one of a jewel beetle that had eluded me for more than 30 years until this past June is perhaps my favorite of them all.


Agrilus concinnus  Horn, 1891 | Stoddard Co., Missouri

Agrilus concinnus Horn, 1891 | Stoddard Co., Missouri

From North America’s Most Beautiful Agrilus Jewel Beetle (posted October 19). There was a time when this beetle was considered one of North America’s rarest species of jewel beetle. Several years worth of hunting by me and others revealed this beetle’s association with mallow and its unusually late adult activity period—the two combining to make this beetle “seem” rare. This year I succeeded in photographing the spectacular adult beetle.


Cacama valvata female ovipositing

Cacama valvata (Uhler, 1888) | Vogel Canyon, Otero Co., Colorado

From Scorching plains, screaming cactus (posted December 5). Insect photos are always better when they also show some aspect of the subject’s natural history. I was lucky to find this female cactus dodger cicada in the act of ovipositing into the dry stem of cholla cactus—in a position where I could get a perfect lateral profile with a clean, blue sky background.


Moneilema armatum LeConte, 1853 | Vogel Canyon, Otero Co., Colorado

Moneilema armatum LeConte, 1853 | Vogel Canyon, Otero Co., Colorado

From Cactus beetle redux (posted December 20). Cactus beetles can be difficult to photograph, but sometimes they cooperate by nicely posing on a pleasing pink flower bud with a blue sky in the background and the cactus spines forming a nice, fuzzy “halo” around the jet black beetle. There were surprisingly few cactus spines impaled in the control unit of my flash after this photo session.


I hope you’ve enjoyed this 2014 version of “Best of BitB” and look forward to seeing everyone in 2015.

Copyright © Ted C. MacRae 2015

Cactus beetle redux!

Moneilema armatum LeConte, 1853 | Vogel Canyon, Otero Co., Colorado

Moneilema armatum LeConte, 1853 | Vogel Canyon, Otero Co., Colorado

On my most recent Great Plains collecting tripcactus dodger cicadas weren’t the only residents of the cholla cactus (Cylindropuntia imbricata) that studded the open grasslands in southeastern Colorado—cactus beetles (Moneilema spp.) also were found, though in lesser numbers than their frenetic, screeching neighbors (perhaps the reason for their scarcity?!). I’ve covered cactus beetles before, posing the question, “How do you photograph cactus beetles?” The answer was, of course, “Very carefully!” That is certainly true in most cases, but not all.

Moneilema armatum LeConte, 1853 | Vogel Canyon, Otero Co., Colorado

The clumsy, flightless adults rely on their host’s vicious spines for protection.

Cactus beetles are found almost exclusively on opuntioids (chollas and prickly pear cacti), and while most opuntioids are rather viciously spined the plants themselves vary tremendously in structure. Prickly pears (Opuntia spp.), on which I previously photographed these beetles, generally grow in low, dense clumps, their flattened pads often forming a tangle of well-armed hiding places for the beetles. Such is not the case with chollas, which are generally taller, more erect, and have a much more open structure of well spaced, cylindrical stems. The beetles on these plants still enjoy a great amount of protection by the long, barbed spines that cover the stems, but to entomologists/photographers like me they are still much more easily collected and photographed. In this particular case, no special techniques were needed to get nice close-up photos against a clear blue sky other than crouching down a bit and being careful not to lean too close to the plant. That is not to say, of course, that photographing insects on cholla is completely without risk, as this photo showing the spines impaled in my flash unit afterwards will attest (but better the flash unit than poking the lens!).

The hazards of photographing cactus beetles.

The hazards of photographing cactus beetles.

The cactus beetle in these photographs appears to be an armed cactus beetle, Moneilema armatum, by virtue of the small but distinct lateral spines on its pronotum, lack of pubescence on the elytra, and relatively smooth pronotum lacking large punctures except along the apical and basal margins. These shiny black beetles occur in the western Great Plains from Colorado and Kansas south through New Mexico, Oklahoma, and Texas into northern Mexico. Adults and larvae seem to prefer chollas over prickly pears—adults feeding on the surface and larvae tunneling within the stems. I suspect the adult feeding helps provide nutrition for egg maturation in addition to creating an oviposition site, and plants infested with larvae often appear unthrifty and exhibit black masses of hardened exudate along their stems (Woodruff 1966).

Hardened black masses of plant exudate indicate larval feeding within the stems.

Hardened black masses of plant exudate indicate larval feeding within the stems.

REFERENCES:

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].

Woodruff, R. E. 1966. A cactus beetle new to the eastern United States (Coleoptera: Cerambycidae). Florida Department of Agriculture, Division of Plant Industry, Entomology Circular No. 53, 2 pp. [pdf].

© Ted C. MacRae 2014

A striking mallow caterpillar

Tarache delecta ("mallow caterpillar") on Hibiscus lasiocarpus | Hickman Co., Kentucky

Tarache delecta (“mallow caterpillar”) on Hibiscus lasiocarpus | Hickman Co., Kentucky

Last month while searching stands of Hibiscus lasiocarpus (hairy rose mallow) in western Kentucky, I encountered this rather large caterpillar feeding on the foliage. I presumed that something as large and striking in appearance as this should be a cinch to identify by scanning through photos on BugGuide, and not surprisingly I found photographs (here, here and here) of two very similar looking caterpillars from Oklahoma posted by Charles Schurch Lewallen. None of the photos, however, had an identification associated with them other than subfamily Acontiinae (family Noctuidae). The contributor mentioned in one of the photos that he had found nothing similar in the Wagner (2005) “bible” (a book that I do not yet own but hope to soon). Armed with this scant information (but definitive knowledge of its host plant), I searched Noctuidae of North America and settled on Tarache delecta as a good possibility. According to that site, T. delecta is the only member of the Acontiinae that feeds on plants in the genus Hibiscus. The site references Crumb (1956) for a larval description, but more useful was a plate of black & white photos that I found in Weiss (1919) and that seemed to be a good match for the species I had photographed. Weiss (1919) refers to the larva as the “mallow caterpillar” and notes that full grown larvae are 34–36 mm in length and dark purple with black spots edged with orange—consistent with the caterpillar shown here.

Apparently this species has been considered a pest of ornamental mallows. Weiss (1919) notes that the larvae feed on the upper and lower leaf surfaces usually near the margins, making large holes in the leaves and sometime devouring parts of the bracts around the buds. I will also note that, in recommending control of the caterpillars, he states that “there does not seem to be any reason why spraying with arsenate of lead should not be successful.” My, how times have changed!

REFERENCE:

Crumb, S. E. 1956. The larvae of the Phalaenidae. U. S. Department of Agriculture, Technical Bulletin 1135, 356 pp. + 10 plates [Google Books].

Wagner, D. L. 2005. Caterpillars of Eastern North America: A Guide to Identification and Natural History. Princeton University Press, Princeton, New Jersey, 512 pp. [Amazon].

Weiss, H. B. 1919. The more important insect enemies of the rose-mallow in New Jersey. New Jersey Department of Agriculture, Bureau of Statistics and Inspection Circular 25, 9 pp. + 4 plates [Google Books].

© Ted C. MacRae 2014

A time of reckoning

The sun shall be turned to darkness and the moon to blood, before the day of the Lord comes, the great and magnificent day.

A "super moon" watches over a parasitized hornworm caterpillar.

A “super moon” watches over a parasitized hornworm caterpillar.

I’m not normally one to quote Bible passages, but this line from Acts 2:20 seems appropriately ominous for the predicament of this poor hornworm caterpillar. The white objects on its back are the cocoons of tiny parasitic wasps in the family Braconidae who spent their entire lives inside the body of the growing caterpillar slowly eating away the inner tissues of the caterpillar, eventually consuming all but the most essential of its internal organs before exiting the skin and spinning their tiny, silken cocoons. Inside the cocoons the tiny grubs transformed into adult wasps, chewed their way out through the tip of the cocoon, and flew off to mate and find more hornworm caterpillars to parasitize. Its unwelcome guests now gone, this poor caterpillar has nothing to do but to sit and await its inevitable demise (which I suspect the caterpillar will not regard as such a “great and magnificent day”).

I found this caterpillar resting on a vine climbing a tree along the Mississippi River in southeast Missouri after setting up an ultraviolet light nearby and noticing the softly glowing cocoons. I was going to photograph it in situ, but I’ve learned that choice of background can have a dramatic effect on insect photographs, and the jumble of weeds and tree bark that would have comprised the background had I photographed the caterpillar where it sat seemed decidedly boring. I looked up and saw the blood red moon (a so called “super moon”) rising above the river in the eastern sky and decided to give it a try. The above photograph is actually a composite of two photographs—one of the caterpillar taken with flash and fairly normal camera settings, and another of the moon itself with aperture, shutter speed, and ISO all adjusted for very low light conditions (at least to the extent possible without a tripod). While this may not qualify in some people’s minds as a “real” photograph, it is nevertheless a true representation of what I actually saw, as I also made a number of attempts to capture both the insect and the moon in a single exposure. Since it is impossible to have both the insect (very close) and the moon (very far) in focus at the same time, the resulting photograph has a different, though still striking, effect, as shown in the photograph below:

IMG_6919_enh_1080x720

A more surrealistic version of the above photograph, with both caterpillar and moon captured in a single exposure.

This second photograph is actually much harder to take, as the moon does not appear in the viewfinder as the small, discrete, fuzzy-edged object resulting in the image, but rather as a large, blinding light that is difficult to place within the composition and know exactly where it will end up (at least, without a lot of trial and error). Add to that the fact that my camera image and histogram display panel is, at the moment, not functional, forcing me to “guess” if I had the right settings (in a situation where I’m well outside of my ‘normal’ settings for flash macrophotography). I’m a little surprised that I ended up with any usable photographs at all!

I’ve tried this type of photography with the sun as well—those interested to see how those photographs turned can find them at Sunset for another great collecting trip and Under Blood Red Skies.

© Ted C. MacRae 2014

“Picudo negro” (black weevil) on soybean in Argentina

During my recent tour of soybean fields in Argentina, I traveled north to Tucumán Province and met with entomologists at the Estación Experimental Agroindustrial Obispo Columbre (“Obispo Columbre Agricultural Experiment Station”). This provincial station, established more than 100 years ago (1909), conducts research on agricultural and production technology for the Tucumán agricultural region. Focus crops include sugarcane, citrus, and grain—primarily soybean, corn, wheat, and dry beans, with research activities ranging from basic biological studies on emerging pests (such as Rhyssomatus subtilis, featured here) and Helicoverpa armigera (recently discovered in Brazil and now in northern Argentina) to resistance monitoring for transgenic crop target pests such as Spodoptera frugiperda, Helicoverpa zea, and Diatraea saccharalis.

Rhysommatus subtilis is a significant regional pest of soybean in Tucumán Province.

Figure 1. Rhysommatus subtilis is a significant regional pest of soybean in Tucumán Province.

In recent years the laboratory has had a dedicated effort to characterize the biology and economic impact of R. subtilis on soybean (Fig. 1). Although practically limited to soybean growing regions in Tucumán Province, this insect has increased greatly in importance within that area in recent years along with two other weevils: Sternechus subsignatus (picudo grande, or “big weevil”) and Promecops carinicollis (picudo chico, or “little weevil”) (Casmús et al. 2010). Of the three species, S. subsignatus is perhaps the most serious because of its stem boring habit that can result in stand loss, while P. carinicollis is the least because its feeding is largely limited to leaves. Rhyssomatus subtilis is intermediate in importance, primarily due to larval feeding within developing pods.

Adults feed by clipping leaf petioles. The impact is minor, but it is a characteristic sign of adult presence.

Figure 2. Adults feed by clipping leaf petioles. The impact is minor but signals adult presence.

I have not yet seen S. subsignatus in soybean fields in the area, but I saw P. carinicollis during last year’s tour (see this post) and encountered R. subtilis at several locations during this year’s tour. Rhyssomatus subtilis presence in soybean can be detected even before the adults are noticed by the occurrence of clipped leaflets (Fig. 2), which is caused by adults feeding on leaf petioles.

Adult females chew a small hole into the wall of the developing pod, not to feed but for oviposition

Figure 3. Adult females chew small holes into developing pods, not to feed but for oviposition.

Leaf feeding has little if any impact on the crop; however, as the crop enters pod development stages of growth adult females begin chewing small holes in the pod walls (Fig. 3), not for feeding but for oviposition. Eggs are laid singly in the pod (Fig. 4), with larvae (Fig. 5) feeding on the developing seeds within.

Eggs are laid singly inside the pod.

Figure 4. Eggs are laid singly inside the pod.

This manner of feeding by the larva not only directly impacts yield but also hampers efforts to control active infestations by preventing contact with foliar-applied insecticides. Eventually the larvae mature, exit the pod, and drop to the soil where they burrow, pupate, and emerge as adults during the next cropping season while plants are still in early to mid-vegetative stages of growth.

This neonate larva has just hatched and will feed within the pod on developing seeds.

Figure 5. This neonate larva has just hatched and will feed within the pod on developing seeds.

Management techniques include rotation with grass crops to reduce populations (the weevil is oligophagous on soybean and dry beans), use of insecticide seed treatments to control adults during early vegetative stages of growth, and subsequent use of foliar insecticide applications if adults remain after the effect of seed treatments begins to diminish.

REFERENCE:

Casmús, A., M. G. Socías, L. Cazado, G. Gastaminza, C. Prado, E. Escobar, A. Rovati, E. Willink, M. Devani & R. Avila. 2010. El picudo negro de la vaina de soja en el NOA. Estación Experimental Agroindustrial Obispo Columbre, Tucumán, Argentina, 8 pp.

Copyright © Ted C. MacRae 2014

Not all soybean caterpillars are ‘ugly’!

Although photographs of beetles dominate this site (they are my true love, after all), I am nevertheless an agricultural entomologist by day and, as such, find occasion to post photos of the insects I encounter in my area of expertise—soybean. I think by and large those soybean insects—especially the caterpillars—don’t generate as much interest as the beetles that I feature. I guess this is understandable—caterpillars of the agricultural pest variety seem generally unable to compete with the visual and behavioral charisma exhibited by jewel beetles, tiger beetles, tortoise beetles, etc. Here, however, is an example of a soybean caterpillar that is as beautiful as any beetle you will find—the larva of the silver-spotted skipper, Epargyreus clarus (Lepidoptera: Hesperiidae). Not only are the colors to die for, but that comically big head makes for a truly laughable frontal portrait!

Epargyreus clarus (silver-spotted skipper) late-instar larva on soybean | Baton Rouge, Louisiana

Epargyreus clarus (silver-spotted skipper) late-instar larva on soybean | Baton Rouge, Louisiana

This particular individual was found last September in a soybean field near Baton Rouge, Louisiana (amazingly, this is the first insect I have featured from Louisiana). Silver-spotted skippers feed on a wide variety of plants in the family Fabaceae (of which soybean is a member), but their occurrence on soybean rarely reaches levels that cause any economic impact. Normally the caterpillars hide during the day in a silken nest constructed by folding over a leaflet or tying adjacent leaflets together, emerging only at night to feed.

What a pretty face!

What a pretty face!

I suppose the orange spots on the head are intended to serve as false eye spots—for some reason the larger the eyes the more a potential predator seems to take pause before deciding to eat something. The actual eyes can be seen along the outer edge of the orange spot as a row of simple ocelli—incapable of forming sharp images and serving as little more than light and motion detectors. I can’t even begin to speculate on the function of the curious asperate/rugose texture of the head!

Copyright © Ted C. MacRae 2014

Tortoise beetles on the job

Back in late February and early March I did my annual tour through the soybean growing regions of central and northern Argentina to look at insect efficacy trials (pretty amazing to me still when I think about it—I actually get paid to spend time in Argentina looking for insects!). Normally on such trips there is no shortage of soybean insects to occupy my attentions—of all the large-acre row crops, soybean probably has the greatest diversity of insect associates, and in South America it is rare for any soybean field to not experience pressure from at least one of them. Soybeans, however, are not the only plants that occur in soybean fields—there are also weeds, many of which also have their own suite of insect associates. Sometimes these weed-associated insects can be even more interesting than the soybean insects I’m look for.

Botanochara angulata?

Botanochara angulata? mating pair | Córdoba Prov., Argentina

On this particular day, as I walked through a soybean field in central Córdoba Province I noticed distinctive red and black tortoise beetles (family Chrysomelidae, subfamily Cassidinae) on some of the plants. I thought it odd that tortoise beetles would be on soybean, as I’m not aware of any soybean associates in the group. A closer look, however, quickly revealed that the beetles were not on the soybean plants themselves, but rather on vines that were weaving their way through the plants. The plant was akin to bindweed and obviously a member of the same plant family (Convolvulaceae), but none of my field mates knew which of the many weedy species of the family that occur in Argentina that this particular plant represented. Species of Convolvulaceae are, of course, fed upon by a great diversity of tortoise beetles—always a treat for this coleopterist to see, and it was all I could do to concentrate on the task at hand and finish doing what I needed to do so I could turn my attention to finding and photographing some of these beetles. Once I began photographing them I found them surprisingly uncooperative (not my normal experience with tortoise beetles), but I soon found a mating pair that was a little more cooperative (probably because they were mating), with the above photo being my favorite of the bunch.

Paraselenis tersa?

Paraselenis tersa? female guarding her eggs | Córdoba Prov., Argentina

As I was searching for beetles to photograph, I encountered some yellow tortoise beetles associated with the same plant but that I had not noticed earlier. Unlike the conspicuously red and black colored species (which seems to best match Botanochara angulata according to Cassidinae of the World), the yellow species (which I presume represents Paraselenis tersa, also ID’d using the same site) seemed almost cryptically colored. When I finished taking photographs of B. angulata, I began searching for a P. tersa to photograph and encountered the female in the above photograph guarding her eggs—score!

Undetermined cassidine larvae.

A single tortoise beetle larva was encountered.

Tortoise beetle larvae are always a delight to see as well—their dinosaurian armature and fecal adornments, both obviously designed to dissuade potential predators, form one of the most ironic defensive combinations one can find. If additional tactics become necessary, they are among the few insects that are known to actually “circle the wagons” (the technical term for this being “cycloalexy“). While I only found a single larvae (of which species I don’t know), its presence seems to further suggest that at least one of the species represented an actively developing population and that the adults I found were not just hangers-on putzing around until winter (such as it is in central Argentina) forced them to shut down for the season.

Undetermined cassidine larva.

Spiky spines and a pile of poop make formidable defenses.

My impression is that tortoise beetles are by-and-large noxious to predators, thus explaining why so many species in the group exhibit aposematic coloration. However, the apparent cryptic coloration of Paraselenis makes me wonder if this is not universally true. It seems especially odd for two species to feed on the exact same species of plant but only one of the species to be noxious, which leads me to even more questions about how two species feeding on the same plant at the same time avoid direct competition with each other. I wondered if perhaps one species was on the wax while the other was on the wane (late February is well along into the latter part of the season in central Argentina), but the fact that both species were involved in reproductive activities (mating in Botanochara and egg guarding in Paraselenis) suggests this was not the case.

Ted MacRae photographing tortoise beetles.

A candid photo of me photographing tortoise beetles (and revealing my technique for getting “blue sky” background photographs).

© Ted C. MacRae 2014

Beetle Collecting 101: How to rear wood-boring beetles

I’ve been collecting wood-boring beetles for more than three decades now, and if I had to make a list of “essential” methods for collecting them I would include “beating,” “blacklighting,” and “rearing.” Beating is relatively straightforward—take a beating sheet (a square piece of cloth measuring 3–5 ft across and suspended beneath wooden, metal, or plastic cross members), position it beneath a branch of a suspected host plant, and tap the branch with a stick or net handle. Many wood-boring beetles tend to hang out on branches of their host plants, especially recently dead ones, and will fall onto the sheet when the branch is tapped. Be quick—some species (especially jewel beetles in the genus Chrysobothris) can zip away in a flash before you have a chance to grab them (especially in the heat of the day). Others (e.g., some Cerambycidae) may remain motionless and are cryptically colored enough to avoid detection among the pieces of bark and debris that also fall onto the sheet with them. Nevertheless, persistence is the key, and with a little practice one can become quite expert at efficiently collecting wood-boring beetles using this method. Blacklighting is even easier—find the right habitat (preferably on a warm, humid, moonless night), set up a blacklight in front of a white sheet, crack open a brew, and wait for the beetles to come!

Rearing, on the other hand, takes true dedication. One must not only learn potential host plants, but also how to recognize wood with the greatest potential for harboring larvae, retrieve it from the field, cut it up, place it in rearing containers, and monitor the containers for up to several months or even years before hitting pay dirt (maybe!). Despite the considerable amount of effort this can take, the results are well worth it in terms of obtaining a diversity of species (usually in good series), some of which may be difficult to encounter in the field, and identifying unequivocal larval host associations. I have even discovered two new species through rearing (Bellamy 2002, MacRae 2003)! Moreover, checking rearing containers can be a lot of fun—in one afternoon you can collect dozens or even hundreds of specimens from places far and wide, depending on how far you are willing to travel to collect the wood. Because of the effort involved, however, the more you can do to ensure that effort isn’t wasted on uninfested wood and that suitable conditions are provided to encourage continued larval development and adult emergence from infested wood the better. It is with this in mind that I offer these tips for those who might be interested in using rearing as a technique for collecting these beetles.

I should first clarify what I mean by “wood-boring” beetles. In the broadest sense this can include beetles from any number of families in which the larvae are “xylophagous,” i.e., they feed within dead wood. However, I am most interested in jewel beetles (family Buprestidae) and longhorned beetles (family Cerambycidae), and as a result most of the advice that I offer below is tailored to species in these two families. That is not to say that I’ll turn down any checkered beetles (Cleridae), powderpost beetles (Bostrichidae), bark beetles (family Scolytidae), or even flat bark beetles sensu lato (Cucujoidea) that I also happen to encounter in my rearing containers, with the first two groups in particular having appeared in quite good numbers and diversity in my containers over the years. Nevertheless, I can’t claim that my methods have been optimized specifically for collecting species in these other families.

First, you have to find the wood. In my experience, the best time to collect wood for rearing is late winter through early spring. A majority of species across much of North America tend to emerge as adults during mid- to late spring, and collecting wood just before anticipated adult emergence allows the beetles to experience natural thermoperiods and moisture regimes for nearly the duration of their larval and pupal development periods. Evidence of larval infestation is also easier to spot once they’ve had time to develop. That said, there is no “bad” time to collect wood, and almost every time I go into the field I am on the lookout for infested wood regardless of the time of year. The tricky part is knowing where to put your efforts—not all species of trees are equally likely to host wood-boring beetles. In general, oaks (Quercus), hickories (Carya), and hackberries (Celtis) in the eastern U.S. host a good diversity of species, while trees such as maples (Acer), elms (Ulmus), locust (Gleditsia and Robinia), and others host a more limited but still interesting fauna. In the southwestern U.S. mesquite (Prosopis) and acacia (Acacia) are highly favored host plants, while in the mountains oaks are again favored. Everywhere, conifers (PinusAbies, JuniperusTsuga, etc.) harbor a tremendous diversity of wood-boring beetles. To become good at rearing wood-boring beetles, you have to become a good botanist and learn not only how to identify trees, but dead wood from them based on characters other than their leaves! Study one of the many good references available (e.g., Lingafelter 2007, Nelson et al. 2008) to see what the range of preferred host plants are and then start looking.

I wish it were as simple as finding the desired types of trees and picking up whatever dead wood you can findm but it’s not. You still need to determine whether the wood is actually infested. Any habitat supporting populations of wood-boring beetles is likely to have a lot of dead wood. However, most of the wood you find will not have any beetles in it because it is already “too old.” This is especially true in the desert southwest, where dead wood can persist for very long periods of time due to low moisture availability. Wood-boring beetles begin their lives as eggs laid on the bark of freshly killed or declining wood and spend much of their lives as small larvae that are difficult to detect and leave no obvious outward signs of their presence within or under the bark. By the time external signs of infestation (e.g., exit holes, sloughed bark exposing larval galleries, etc.) become obvious it is often too late—everything has already emerged. Instead, look for branches that are freshly dead that show few or no outward signs of infestation. You can slice into the bark with a knife to look for evidence of larval tunnels—in general those of longhorned beetles will be clean, while those of jewel beetles will be filled with fine sawdust-like frass that the larva packs behind it as it tunnels through the wood. Oftentimes the tunnels and larvae will be just under the bark, but in other cases they may be deeper in the wood. Broken branches hanging from live trees or old, declining trees exhibiting branch dieback seem to be especially attractive to wood-boring beetles, while dead branches laying on the ground underneath a tree are not always productive (unless they have been recently cut).

One way to target specific beetles species is to selectively cut targeted plant species during late winter, allow the cut branches to remain in situ for a full season, and then retrieve them the following winter or early spring. These almost always produce well. Doing this will also give you a chance to learn how to recognize young, infested wood at a time that is perfect for retrieval, which you can then use in searching for wood from other tree species in the area that you may not have had a chance to cut. I have cut and collected branches ranging from small twigs only ¼” diameter to tree trunks 16″ in diameter. Different species prefer different sizes and parts of the plant, but in general I’ve had the best luck with branches measuring 1–3″ diameter.

Once you retrieve the wood, you will need to cut it into lengths that fit into the container of your choice (a small chain saw makes this much easier and quicker). In the field I bundle the wood with twine and use pink flagging tape to record the locality/date identification code using a permanent marker. I then stack the bundles in my vehicle for transport back home. Choice of container is important, because moisture management is the biggest obstacle to rearing from dead wood—too much moisture results in mold, while too little can lead to desiccation. Both conditions can result in mortality of the larvae or unemerged adults. In my rearing setup, I use fiber drums ranging from 10-G to 50-G in size (I accumulated them from the dumpster where I work—mostly fiber drums used as shipping containers for bulk powders). Fiber drums are ideal because they not only breath moisture but are sturdy and may be conveniently stacked. Cardboard boxes also work as long as they are sturdy enough and care is taken to seal over cracks with duct tape. Avoid using plastic containers such as 5-G pickle buckets unless you are willing to cut ventilation holes and hot-glue fine mesh over them. While breathable containers usually mitigate problems with too much moisture, desiccation can still be a problem. To manage this, remove wood from containers sometime later in the summer (after most emergence has subsided), lay it out on a flat surface such as a driveway, and hose it down real good. Once the wood has dried sufficiently it can be placed back in the container; however, make sure the wood is completely dry or this will result in a flush of mold. I generally also wet down wood again in late winter or early spring, since I tend to hold wood batches through two full seasons.

I like to check containers every 7–15 days during spring and summer. Some people cut a hole in the side of the container that leads into a clear jar or vial—the idea being that daylight will attract newly emerged adults and facilitate their collection. I’ve tried this and was disappointed in the results—some of the beetles ended up in the vial, but many also never found their way to the vial and ended up dying in the container, only to be found later when I eventually opened it up. This is especially true for cerambycids, many of which are nocturnal and thus probably not attracted to daylight to begin with. My preference is to open up the container each time so that I can check the condition of the wood and look for evidence of larval activity (freshly ejected frass on the branches and floor of the container). I like to give the container a ‘rap’ on the floor to dislodge adults from the branches on which they are sitting, then dump the container contents onto an elevated surface where I can search over the branches and through the debris carefully so as not to miss any small or dead specimens. I use racks of 4-dram vials with tissue packed inside each and a paper label stuck on top of its polypropylene-lined cap as miniature killing jars. Specimens from a single container are placed in a vial with a few drops of ethyl acetate, and I write the container number and emergence date range on the cap label. Specimens will keep in this manner until they are ready to be mounted weeks or months (or even years) later. If the vial dries out, a few drops of ethyl acetate and a few drops of water followed by sitting overnight is usually enough to relax the specimens fully (the water relaxes the specimens, and the ethyl acetate prevents mold if they need to sit for a while longer).

I store my containers in an unheated garage that is exposed to average outdoor temperatures but probably does not experience the extreme high and low temperatures that are experienced outdoors. In the past I wondered if I needed more heat for wood collected in the desert southwest, but I never came up with a method of exposing the containers to the sun without also having to protect them from the rain. Metal or plastic containers might have eliminated this problem, but then breathability would again become an issue. I would also be concerned about having direct sun shining on the containers and causing excessive heat buildup inside the bucket that could kill the beetles within them. Now, however, considering the success that I’ve had in rearing beetles from wood collected across the desert southwest—from Brownsville, Texas to Jacumba, California, this seems not to be a big issue.

If anybody else has tips for rearing wood-boring beetles that they can offer, I would love to hear from you.

REFERENCES:

Bellamy, C. L. 2002. The Mastogenius Solier, 1849 of North America (Coleoptera: Buprestidae: Polycestinae: Haplostethini). Zootaxa 110:1–12 [abstract].

Lingafelter, S. W. 2007. Illustrated Key to the Longhorned Woodboring Beetles of the Eastern United States. Special Publication No. 3. The Coleopterists Society, North Potomac, Maryland, 206 pp. [description].

MacRae, T. C. 2003. 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 [pdf].

Nelson, G. H., G. C. Walters, Jr., R. D. Haines, & C. L. Bellamy.  2008.  A Catalogue and Bibliography of the Buprestoidea of American North of Mexico.  Special Publication No. 4. The Coleopterists Society, North Potomac, Maryland, 274 pp. [description].

Copyright © Ted C. MacRae 2014