Ceti Eel offspring?

Nicrophila americana (American carrion beetle) larva | Sam A. Baker State Park, Wayne Co., Missouri.

If this creature was a tad bit slimier, you might think it had just been plucked from underneath the armor of an adult Ceti Eel and was looking to slip inside the ear of Chekov or some other human to wrap itself around the unsuspecting victim’s cerebral cortex. In reality, this creature lives not on Ceti Alpha V., but right here on earth, and while it’s natural history may not include making human hosts ”extremely susceptible to suggestion“, it does include an appetite for dead flesh and the maggots that try to compete for it. Say hello to the larva of Nicrophila americana (American carrion beetle), a member of the family Silphidae (carrion and burying beetles) (not to be confused with the endangered Nicrophorus americanus, or American burying beetle). Like most beetles, the larvae can be difficult to recognize as such due to its very different form compared to the adult. However, the one-segmented tarsi, distinct head, presence of chewing mouthparts, and presence of spiracles along the sides of the body give the clues to its identity.

While not the offspring of a Ceti Eel, its habits are almost as… er, disgusting!

The genus name (literally meaning “attracted to corpses“) is a perfect descriptor of this beetle’s natural history. Adults are attracted to animal carcasses, where they lay their eggs and prey on maggots (fly larvae) as they hatch to give a competitive advantage to their own larvae once they hatch. The larvae also will eat maggots and other larvae within the carcass, along with the carcass itself. This larva had completed its development and was searching the ground for a suitable spot to dig a burrow for pupation and eventual emergence as an adult.

Copyright © Ted C. MacRae

Raining spit

Cephisus siccifolia 3rd instar nymph | Buenos Aires, Argentina

Even though it was November (and thus spring in Argentina), conditions were already unusually dry—a portent of the worst drought that would hit Argentina in 70 years. Because of this, I found the occasional wet spot on the pavement as I walked the trails in La Reserva Ecológica Costanera Sur rather odd. At first I thought they were spit—the trails were popular on this day for runners and bike riders, but I quickly realized that those would have to be some truly ginormous spit wads based on the size of the splatter. It wasn’t long before I thought to look up, and this is what I saw on the branch directly above me:

Cephisus siccifolia spittle mass on unknown species of tree.

I knew right away this was the work of a froghopper, or “spittlebug,” a true bug (order Hemiptera) in the family Cercopidae. Spittlebugs are common in the eastern U.S. where I live and are famous for the spit-like wads of froth (“cuckoo spit” to some) within which the nymphs conceal themselves until they reach adulthood. Our eastern U.S. species, however, are most commonly seen on herbaceous plants rather than in trees, and the frothy masses they produce are fairly small—about the size of a real wad of spit (at least, according to my direct comparison when I was 12 years old). The spittle masses I was seeing today were enormous, frothy, liquid masses that literally dripped from the trees by their own weight—raining spit!

Nymphs produce bubbles by siphoning air into a channel under the abdomen.

I was about to move on when I noticed some movement in the spittle mass. A closer look through the macro lens revealed the tip of the abdomen of a nymph slowly circling around near the surface of the spittle and creating new bubbles as it did this. As one can imagine, living inside a mass of bubbly liquid presents a challenge to breathing, and the nymphs get around this problem by protruding the tip of the abdomen outside the spittle mass and taking in air through a tubelike canal below the abdomen (Hamilton & Morales 1992). Strong contractions of the abdomen inside the spittle mass eject air from the canal, resulting in bubble formation.

Nymphs partially exposed by removal of spittle mass.

I sent these photos to Andy Hamilton (Canadian National Collection of Insects, Arachnids and Nematodes), specialist in world Cercopidae, to see if there was any chance he might recognize the genus or species based on these photos. I noted that these were the biggest spittlebug nymphs I had ever seen (the individual in the first photo measuring ~10mm in length). Not only did he recognize them as belonging to the genus Cephisus, but he was actually in the process of finishing up a revision of the New World members of the tribe Ptyelini—Cephisus being the sole New World genus to represent the tribe. Based on its white coloration and occurrence as far south as Buenos Aires, Argentina, he suggested this must be C. siccifolia—a species that can sometimes achieve economic pest status (Ribeiro et al. 2005) but which still apparently needs to be properly recorded from Argentina (Hamilton 2012). Based on degree of wing pad development, Andy surmises the individual in Photo #1 represents a 3rd instar (if the 3rd instar measures 10 mm, can you imagine the size of the 5th instars?!). Andy asked me if I would grant him use of the photos in his soon-to-be-published revision (of course I agreed), and here is the plate with the photos (as well as an adult photographed by someone else) as it appears in his paper:

As Andy notes in his paper, it seems rather unusual that Cephisus is the only tribal representative in the New World despite having successfully colonized all of its tropical and subtropical mainland areas. There are several other genera in the tribe in Africa, which would suggest that the Ptyelini arose prior to the late Cretaceous rifting that separated South America and Africa into two continents. It is thus puzzling why the tribe went on to further diversify in Africa but not in the New World.

A tight crop of Photo #3 above was featured in Super Crop Challenge #15, for which Ben Coulter was the hands-down winner. Honestly I thought this might end up being a slam dunk challenge—people have gotten very good at designing Google search strings to come up with answers that in pre-internet days might have been impossible to find. Nobody stumbled upon the magic search string for this challenge—”MacRae Cercopidae” which pulls up the Hamilton paper and above plate as the very first result. Still, Ben used good old fashioned intuition based on the locality tag to correctly surmise the species and take the early lead in BitB Challenge Session #7. Congratulations, Ben!

REFERENCES:

Hamilton, K. G. A. 2012. Revision of Neotropical aphrophorine spittlebugs, part 1: Ptyelini (Hemiptera, Cercopoidea). Zootaxa 3497:41–59.

Hamilton, K. G. A. & C. F. Morales. 1992. Cercopidae (Insecta: Homoptera). Fauna of New Zealand 25, 40 pages.

Ribeiro, G. T., M. da Costa Mendonça, J. Basílio de Mesquita, J. C. Zanuncio G. S. & Carvalho. 2005. Spittlebug Cephisus siccifolius damaging eucalypt plants in the State of Bahia, Brazil. Pesquisa Agropecuária Brasileira 40(7):unpaginated.

Copyright © Ted C. MacRae 2013

How to collect larvae of Amblycheila cylindriformis

Amblycheila cylindriformis larval burrow | Major Co., Oklahoma

Step 1. Go to your favorite grassland habitat in the western half of the Great Plains anywhere from Texas north to South Dakota and look for barren soil amongst the vegetation. Clay banks near streams or in ravines and even vertical clay bluff faces are also good (although I have not myself observed the latter). “My” spot is in the Glass Mountains of northwestern Oklahoma, where talus slopes in mixed-grass prairie beneath flat-topped mesas and the ravines that cut through them provide just enough slope for this species’ liking.

Burrow diameter of ~8mm identifies this as a 3rd instar larva.

Step 2. Look for large, almost perfectly round burrow entrances that go straight down from the surface. By large, I mean approximately 6–8 mm in diameter—as large a burrow as any tiger beetle in North America will make. Many other insects create burrows, but tiger beetle burrows are generally recognizable by their almost perfectly circular shape and clean, beveled edge. Look closely, and the burrow will be seen to actually be slightly D-shaped to match the shape of the tiger beetle larva’s head—the large, sickle-shaped, upward-facing jaws resting against the flat part of the D. In the case of this species, they tend to be found in clusters of several burrows in close proximity to each other. The burrow in these photos was found at the upper edge of a drainage ravine on the upper part of the talus slopes (see diagram in this post).

Dig around the burrow, carefully excavating along the grass stem, until the larva is reached.

Step 3. Try this first—chew the end of a long, narrow grass stem (frayed and sticky will be easier for the larva to grab hold of) and stick it down the burrow until it hits bottom, tap lightly a few times to entice a bite, then yank (and I mean yank!) the stem out. With luck, the larva will come flying out of the burrow and land somewhere on the ground in front of you. (By the way, if you have never done this, you are missing one of the greatest treats that insect collecting has to offer. If you have done it, you owe it to yourself to show this to somebody else who has not ever seen it—their shocked reaction at the sight of the flying larva is beyond priceless!) Larvae are not always in the mood to bite, however, so if the so-called “fishing” technique does not work then you will have to dig. Stick the grass stem back down the burrow and begin excavating around the burrow, carefully prying away the soil adjacent to the burrow to prevent it from falling into and obscuring the burrow. Keep excavating as you follow the grass stem down until, at least, you reach the larva. In the photo above you can see in the lower right-center area the burrow with the grass stem protruding from it and the larva placed on a clump of soil in front of the shovel (for sense of scale). It seems I had an easy time of it with this larva, as literature sources report larval burrows extending down to depths of a meter or more.

Amblycheila cylindriformis 3rd instar larva.

Step 4. Behold the beast! There is nothing more that can be said—these larvae are ginormous! This particular larva measured a full 62 mm from the tips of its mandibles to the tip of its abdomen—that’s 2½ inches! No other tiger beetle larva in North America reaches this size, except perhaps the related A. hoversoni (South Texas Giant Tiger Beetle).

The distinctly smaller 2nd pair of eyes confirm this is not Tetracha or Cicindela (sensu lato)…

Step 5. If size alone isn’t enough, you can confirm that the larvae does indeed belong to the genus Amblycheila by looking at its eyes—their are two pairs, and the 1st pair (closest to the mandibles) are distinctly larger than the 2nd pair. This isn’t clearly visible in the photo above because I doused the larva with water to remove the mud and dirt that encrusted it upon removal from its burrow.

…and the distinctly separated hooks on the 5th abdominal segment confirm it is Amblycheila.

Step 6. Another way to distinguish larvae of the genus Amblycheila is by looking at the hooks on the hump of the 5th abdominal segment, best done with a hand lens (or, even better, with an MP-E65 lens!). All tiger beetle larvae have several pairs of large hooks that the larva uses to brace itself against the wall of its burrow when capturing prey to prevent the struggling prey from pulling the tiger beetle larva out of its burrow. Larvae in the genus Omus, restricted to the Pacific region of North America, have three pairs of hooks (referred to as the outer, middle, and inner hooks), while all other North American tiger beetle genera have two (having lost the outer pair). In Amblycheila and Tetracha the hooks are simple and thornlike, while larvae of all other North American genera have much longer middle hooks that are curved and sickle-shaped (e.g., Cylindera celeripes in this post). Amblycheila larvae can be distinguished from Tetracha larvae by the middle and inner hooks on each side being distinctly separated rather than touching at the base (e.g., Tetracha floridana in this post). There is also a cluster of short, stout hairs around the base of each hook in Amblycheila that is missing in Tetracha (e.g., Tetracha virginica in this post).

The numerous stout setae are also characteristic of the genus.

Step 7. Lastly, don’t forget to look at the hump in lateral profile—it is as alien a structure as any in the insect world. In the case of Amblycheila larvae, the bed of hairs posterior to the hooks is comprised of much shorter, stouter, and more densely placed hairs than larvae of Tetracha.

Copyright © Ted C. MacRae 2013

Best of BitB 2012

Welcome to the 5th Annual “Best of BitB”, where I pick my favorite photographs from the past year. 2012 was one of the most intensive travel years I’ve ever had—I spent 8 weeks in Argentina from February through April, made separate trips to Puerto Rico and Arkansas in May (bracketing a personal week in California), traveled almost weekly to Illinois and Tennessee from June to September (interrupted by a personal week in Florida in July), toured the southeastern U.S. (Arkansas, Louisiana, Mississippi and Georgia—great food!) in early September, chased tiger beetles in Oklahoma, Texas and Arkansas in late September, went back to Argentina for a week in October, and capped off the travel year by attending the Entomological Society of America Annual Meetings in Knoxville, Tennessee (for the first time in more than 10 years!)—whew! While many would cringe at such a travel load, I am among the lucky few who actually get paid for doing something that is also my hobby—entomology! This gives me ample opportunity to further hone my photography skills (nine of the 13 photos I’ve selected below were actually taken while I was on business travel), resulting in two key accomplishments this year—my first ever photography talk at the ESA’s insect photography symposium and my first commercial sales (look for the BitB commercial site to go online in 2013).

Enough blather! Here are my favorite BitB photographs from 2012. Click the link in the text below the photo to see the original post. I would greatly appreciate knowing if you have a favorite (and why)—your feedback will be enormously helpful to me as I continue to learn and develop as a photographer.  For those interested, here are my previous year picks for 2008, 2009, 2010 and 2011. And, as always, thank you for your readership!

---

Spintherophyta (?) sp. in flower of Abutilon pauciflorum | Buenos Aires, Argentina

From Pollen Bath (posted 2 Feb). One of my 2012 learnings was that sometimes a photograph that is not so close is more effective than one that is as close as possible. In one of my earlier attempts at “not-so-close” macrophotgraphy, the soft colors of the flower compliment the brash shininess of the tiny leaf beetle that has been feeding on its pollen. Pink lines lead the eye directly to the subject and create a pleasing composition, and pollen grains stuck to the beetle—a distraction in some situations—add to the miniature natural history story of the photo.

---

Apiomerus flavipennis with stink bug prey and kleptoparasitic flies | Chaco Province, Argentina

From Lord of the flies! (posted 11 Mar). I selected this photo solely for the complex natural history story drama it shows—stink bug (Piezodorus guildenii) feeding on soybean becomes prey of an assassin bug (Apiomerus flavipennis), with volatiles from the chemicals it emitted in a vain attempt to defend itself serving as cues to kleptoparasitic flies (families Milichiidae and Chloropidae) that benefit from the assassin bug’s labors.

---

Planthopper nymph | Buenos Aires Province, Argentina

From Seeing the unseen (posted 26 Mar). Another learning that I began putting into practice in 2012 was the use of low perspective for compositional impact. The cryptic coloration of this planthopper nymph (family Fulgoridae) made it almost invisible on the branch on which it was sitting when viewed from a normal “top-down” human perspective. Getting “down under” it, however, brought the nymph to life and emphasized its unusual form.

---

Megabaris quadriguttatus | Corrientes Province, Argentina

From I fear no weevil (posted 12 Apr). I spent much of 2012 working on the “blue sky background” technique, with these weevils from northern Argentina representing one of my better attempts. Macrophotography of insects with a blue sky background involves setting exposure, ISO, and aperture to achieve two separate exposures—full flash illumination of the subject for maximum depth-of-field, and ambient light from the sky to create a clean, uncluttered, natural-looking background. In this shot I managed to achieve an almost ideal shade of blue to compliment the wild black, white and red colors of the beetles. (My one criticism of the photo is having clipped one of the beetle’s feet.)

---

Bombylius sp. cf. mexicanus | Scott Co., Missouri

From One-shot Wednesday: Upside-down bee fly (posted 16 May). This photo is unusual if nothing else. Focus, lighting, depth-of-field, and composition are all better than can be hoped for in a single shot, but the subject—perfectly alive—is in a most unusual position. Read the original post to find out how this happened.

---

Perisphaerus sp. (a pill roach) | Vietnam (captive individual)

From Holy conglobulation, Batman! (posted 27 May). White-box photography is an excellent technique for clean, uncluttered photographs of insects, but it also isolates them from their natural surroundings and limits their natural history appeal. The best white-box photos are those that highlight a key feature or behavior of the subject—in this case a pill roach’s comically conglobulating defensive posture.

---

Micronaspis floridana (Florida intertidal firefly) larva | Pinellas Co., Florida

From Even a 12-year old can discover the larva of a rare, endemic species! (posted 31 July). Here is another photo whose back story played a big part in its selection. This firefly larva not only represents a rare Florida-endemic species but was also first seen by my then 12-year old nephew, who willingly accompanied me through a dark, spooky salt marsh in the middle of a humid Florida night to see what he could learn. The lesson here for budding natural historians (and old-timers like me) cannot be overstated!

---

Arctosa littoralis (beach wolf spider) | Lewis Co., Missouri

From ID Challenge #20 (posted 23 Aug—prelude to Ghosts in the night posted 28 Aug). Those who follow this blog know of my obsession with close-up portraits, and while tiger beetles are the subjects I most commonly photograph in this manner, I am always on the lookout for good subjects in other taxa. This wolf spider “face” almost looks human, with “two” eyes, two “nostrils” and a shiny upper lip above huge (albeit hairy) buck teeth! It’s enough fill-the-frame spidery goodness to melt (or explode) the heart of even the most ardent arachnophobe!

---

Anticarsia gemmatalis (velvetbean caterpillar) egg on soybean leaf

From Life at 8X—Guide to lepidopteran eggs on soybean (posted 3 Sep). “Life at 8X” was a new series I introduced this year, featuring insects photographed at magnifications testing the upper limit of my equipment and photographic skills. Diffraction is the chief difficulty with magnifications as high as this and is the primary flaw in the above photograph. Nevertheless, such view of a moth egg on the underside of a soybean leaf provides a spectacular view of the otherwise unseen micro-world that lives right beneath our noses.

---

Megacyllene decora (amorpha borer) on snakeroot flowers | Mississippi Co., Missouri

From A classic fall ‘bycid (posted 12 Sep). This second example of “blue sky background” was taken later in the year and was considerably more difficult to capture than the first because of the larger size of the subject and resulting need for a longer focal length macro lens. Getting a well-lit, focused, and composed image with a desirable shade of blue in the background depended not only on finding the proper camera settings, but also secure body and camera bracing techniques for this completely hand-held shot.

---

Cicindelidia politula politula (Limestone Tiger Beetle) | Montague Co., Texas

From Photographing the Limestone Tiger Beetle (posted 28 Sep). I will go ahead and say it—this is my favorite photograph of 2012. As discussed under the first entry, panning back from the subject can allow for some very interesting compositions. This photo combines charismatic pose by a wary subject with panning back and low perspective to create an image that scores high in both natural history and aesthetic appeal.

---

Calosoma sayi (black caterpillar hunter) | New Madrid Co., Missouri

From Black is beautiful! (posted 7 Nov). Of course, close-as-possible can also be used to create striking photos, especially if the subject exhibits features that are best seen up close. Anything with jaws fits the bill in my book, and highlighting the mandibular sculpturing of this caterpillar hunter (a type of ground beetle) required precise angling of the flash heads for maximum effect.

---

Cicindela repanda (Bronze Tiger Beetle) | St. Louis Co., Missouri

From Persistence Pays (12 Nov). This final selection is not a rare species, but it is as close as I have come to what I consider the “perfect” tiger beetle macrophotograph—a close, low angle, lateral profile of an adult in full-stilt posture (a thermoregulatory behavior), well lit, perfectly focused, and with a dynamic but pleasingly blurred background. It’s a perfect storm of a photo that took the better part of two hours to achieve—rarely do all of these elements come together in a hand-held photograph of an unconfined tiger beetle in its native habitat.

---

Well, there you have it. I hope you’ve enjoyed my selections, and again please do let me know if you have a personal favorite. See you in 2013!

Copyright © Ted C. MacRae 2012

Eye to eye to eye to eye with a tiger beetle larva

After the past few years of hunting tiger beetles, I’ve learned not only how to find the larval burrows but—at least for most of the species occurring in Missouri—how to identify the larvae in the field. While conclusive identifications rely upon morphological characters, a preliminary field ID is often possible based on a combination of burrow size, placement, soil type and knowledge of which species are likely to occur in a given habitat. Tiger beetle larvae don’t have the same aesthetic appeal to many people that the adults have, and for this reason many species remain undescribed in the larval stage—even the well-studied North American fauna has only about 60% of its species with the larval stages described (Pearson et al. 2006). Nevertheless, the ability to find, collect and rear tiger beetle larva remains an important part of my studies because it not only expands my survey power (most tiger beetles have more restricted temporal occurrence as adults than as larvae) but can also lead to novel findings such as previously undescribed larvae and unknown parasitoid associations.

Tetracha virginica 3rd instar larva | Mississippi Co., Missouri

This larva was dug from its burrow in bottomland forest habitat in the southeastern lowlands of Missouri. However, before I even saw the larva I knew it belonged to the genus Tetracha and probably represented the species T. virginica (Virginia Metallic Tiger Beetle, according to Erwin & Pearson 2008). How did I know this? First, the size of the burrow (~8 mm in diameter) excluded all but one other non-Tetracha species known to occur in Missouri—Cicindelidia obsoleta vulturina (Prairie Tiger Beetle), a species known to occur only in the dry, rocky, dolomite glades in the White River Hills region of extreme southwestern Missouri. Secondly, while T. carolina (Carolina Metallic Tiger Beetle) is also found in southeastern Missouri, that species has been associated almost exclusively with treeless habitats—at least in southeastern Missouri (K. Fothergill, personal communication). Since the burrow from which this individual was dug was found in wet, bottomland forest, chances were high that it instead represented T. virginica.

Simple, thorn-like outer hooks with much smaller inner hooks distinguish larvae of Tetracha.

Notwithstanding the circumstantial evidence, there are morphological characters that also distinguish both the genus and the species of this larva. Of primary importance are the hooks and setae on the prominent “hump” of the fifth abdominal segment. This hump is braced against the vertical wall of the larval burrow as it sits at the entrance waiting for passing prey. Once the prey is seized, the hump armature provides traction against the burrow wall, preventing the struggling prey from pulling the tiger beetle larva out of its burrow (where it would not only be ineffectual as a predator but also highly vulnerable to predation itself). Tiger beetle larvae can often be distinguished at the generic level by the shape and size of the main hooks. Tetracha larvae have four hooks—two outer and two inner—that are simple and thorn-like, with the inner hooks much smaller than and placed much closer to the outer hooks than to each other (other genera either have six hooks, or they have the outer pair 1) highly curved or 2) the inner pair larger and nearly as close to each other as to the outer hooks). There are also fine details of the pattern of the setae (smaller hairs) on the hump that identify this larva as T. virginica, but the presence of numerous hairs over the surface of the abdominal segments is a much easier character to see in the field (see first photo).

Note also the white-margined pronotum and nearly equal sized simple eyes.

Finally, there is that head—two pairs of large, simple eyes sitting behind gaping, cocked jaws that give them an oh so alien aspect! An often metallic, shield-like pronotum sitting behind the head, both used in concert to seal the burrow entrance as the larva lies in wait, serve to complete the alien ensemble but also offer clues to the larva’s identity. All larvae of Tetracha and closely related genera bear a distinctive rim of white around the pronotal margin, making them instantly recognizable even while still sitting in their burrow. Also useful is the relative size of the eyes, which in the case of Tetracha the second pair of eyes are nearly as large as the first pair (Amblycheila and Omus have the second pair distinctly smaller than the first, while Cicindela and related genera also have the eyes more nearly equal-sized).

P.S. This is what I was photographing when my friend Kent Fothergill surreptitiously took this photograph of me!

REFERENCES:

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

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

Copyright © Ted C. MacRae 2012

Another autumn oedipodine

Shortgrass/sage brushland habitat in Medicine Bow Natl. Forest, Wyoming

In September 2010, Chris Brown and I explored shortgrass/sage brushland habitat atop the Laramie Mountains in southeastern Wyoming’s Medicine Bow National Forest (location “J” on this map). We were entering the final days of our 7th Annual Fall Tiger Beetle Trip™ and, to that point, had found every tiger beetle species we had set out to look for. This day, however, was the official “skunk” day of the trip, for although we did see one Cicindela limbalis (Common Claybank Tiger Beetle)—collected live to become the subject of one of the crappiest tiger beetle photos I’ve ever taken—we did not see the tiger beetle that we were there to see; Cicindela longilabris (Boreal Long-lipped Tiger Beetle). Of course, I rarely have trouble finding consolation on a skunk day, and during fall this is even easier—the deep blue sky, crisp fall air, and vivid colors of a morphing landscape are enough to make even a bad day of insect collecting better than a good day of just about anything else. And then there are the band-winged grasshoppers (family Acrididae, subfamily Oedipodinae)!  When there are no tiger beetles to be had, there are almost always members of this group around, and other than tiger beetles I don’t think there is another group of insects that I enjoy photographing more.

Arphia pseudonietana (red-winged grasshopper) | Medicine Bow Natl. Forest, Wyoming

As we walked the trails not finding tiger beetles, I noticed these very dark grasshoppers every once in a while. They flew with a particularly noisy crackling sound that exposed bright red hind wings before dropping to the ground and instantaneously becoming almost completely invisible. Once I accepted that tiger beetle photography just wasn’t gonna happen that day, I began paying attention to these grasshoppers and, after working a few individuals, finally found one who was willing to let me get close enough for some photos. I’m not terribly fond of this first photo—the perspective is still too high as I had not yet learned by that time to get down flat on my belly for photographing anything on the ground (remember, this was two years ago). Nevertheless, it is the only one that I have that shows the entire body of the grasshopper. Since this location isn’t too far west of the Nebraska border, I figured an identification should be possible using the Nebraska grasshopper guide (Brust et al. 2008)—based on that work and subsequent examination of photos at BugGuide, I surmise this individual represents Arphia pseudonietana (red-winged grasshopper). There are other species of Arphia in Nebraska, some of which are easily confused with A. pseudonietana; however, most of these are more common further east. The only other species in the genus that occurs west into Wyoming is A. conspersa (speckle-winged grasshopper), and although it is similar in appearance and may have red hind wings (though more commonly orange to yellowish), adults are most common during spring and early summer. Arphia pseudonietana adults, on the other hand, are most active during mid-summer through fall.

The pronotum bears a single notch just in front of the middle.

Grasshoppers, particularly in the western states, tend to be loathed by ranchers who see them as competitors with cattle for meager forage resources, especially in dry years. This species does feed preferentially on a variety of grasses such as western wheatgrass (Pascopyrum smithii), buffalograss (Buchloe dactyloides) and blue grama (Bouteloua gracilis); however, it doesn’t seem to occur at economically important levels except in association with other, more numerous grasshopper species. I’m glad to know this, because for some reason I just don’t want anybody regarding band-winged grasshoppers of any kind as a pest. Other grasshoppers, fine—just not my beloved bandwings!

I presume this 5th instar nymph also represents A. pseudonietana

Later in the day I came across this presumed 5th-instar grasshopper nymph, and although it was quite skittish I eventually managed to get this single photograph before it resumed its frenetic hopping and I gave up in frustration. This is one of the better “one-shots” that I’ve managed to take—my only criticism being that the focus was just a tad too deep to catch the front metafemoral face. I really didn’t have much time to setup for this shot—once I got the critter reasonably in-frame I fired! Anyway, I’m inclined to think this also represents A. pseudonietana, although I’m less confident in that ID than I am for the adult as I wasn’t able to find a real good comparative photograph. Nymphs of A. pseudonietana are apparently most common from mid-spring to mid summer, so the seasonality is a bit off. I would be grateful to any acridophile who stumbles across this post and can provide an ID confirmation or correction (for either the nymph or the adult). Until then, I leave you with a shot that shows why I love fall regardless of whether I’m finding insects!

Quaking aspen glows under the late September sun.

REFERENCE:

Brust, M. L., W. W. Hoback and R. J. Wright.  2008. The Grasshoppers (Orthoptera: Acrididae and Romaleidae) of Nebraska.  University of Nebraksa-Lincoln Extension, 138 pp.

Copyright © Ted C. MacRae 2012

Inchworm, Inchworm, Oh So Small

Soybean looper (Chrysodeixis includens) | 3rd-instar larva

Okay, I know this is not a real ”inchworm” (generally restricted to caterpillars in the family Geometridae), but this young larva of a soybean looper (Chrysodeixis includens, family Noctuidae) is just too cute to not have an equally cute name. I believe it is an early 3rd instar, based on its small size (~7mm in length), lightly colored head capsule, and distinct bristles around the head and on the body—1st instars have a black head capsule, while 2nd instars have a light brown head capsule, and in both the bristles on the body are smaller and not as distinct.

This larva hatched from an egg laid on soybean by a laboratory-reared adult.

Copyright © Ted C. MacRae 2012

Life at 8X—Guide to lepidopteran eggs on soybean

Most of you are aware of my passion for beetles, but in reality that is just my evenings-and-weekends gig. By day, I am an agricultural entomologist conducting research on insect pests of soybean. I’m not sure how many latent soybean entomologists there may be among readers of this blog, but for this installment of “Life at 8X” I thought it would be interesting to feature eggs of several of the more important lepidopteran species that infest soybean in the U.S. Soybean is primarily a New World crop, and of the many lepidopteran species that attack soybean on these two continents, most belong to the great family Noctuidae (owlet moths). The species shown here include the most important species in North America, and in some cases South America as well.

See this post for details on photographic technique; however, note that most of the photos in this post that were shot at 8X have been cropped slightly (~10–15%) for composition (should I call this post “Life at 9X”?).

---

Anticarsia gemmatalis. Velvetbean caterpillar (“oruga de las leguminosas” in Argentina; “lagarta-da-soja” in Brazil) has long been the most important lepidopteran soybean pest throughout the New World. In North America its attacks are confined to the lower Mississippi River delta and southeastern Coastal Plain, but in South America nearly 100% of the soybean growing area is subject to attack. Eggs of this species are laid almost exclusively on leaf undersides throughout the canopy and are intermediate in size compared to the other species shown below (~7,000 eggs per gram). They are distinctive in their slightly flattened spherical shape and turn pinkish as they age and the developing larva takes form inside the egg.

Anticarsia gemmatalis—velvetbean caterpillar

---

Chrysodeixis includens (=Pseudoplusia includens). Soybean looper (“oruga medidora falsa” in Argentina; “lagarta falsa-medideira” in Brazil) was until recently primarily a North American pest with the same southern occurrence as velvetbean caterpillar. In recent years, however, it has gained importance in Brazil and northern Argentina as well, with its impact magnified by the capacity to develop resistance against most of the insecticides that have been used to control it. The egg of this species is quite small (~10,000 eggs per gram) and are are irregularly spherical with a somewhat translucent, crystalline appearance. Like velvetbean caterpillar, eggs of this species are laid almost exclusively on the leaf undersides, but the moths exhibit a clear preference for the middle or upper canopy depending upon plant growth stage.

Chrysodeixis includens (= Pseudoplusia includens)—soybean looper

---

Helicoverpa zea. Soybean podworm is better known in other crops as corn earworm, cotton bollworm, or tomato fruitworm (a testament to its polyphagous nature), and in South America the common names are even more diverse depending on both crop and country (“gusano bellotero,” “gusano cogollero del algodón,” “gusano elotero,” “isoca de la espiga en maíz,” or simply “bolillero” in Argentina; “lagarta-da-espiga-do-milho” or ”broca-grande-do-fruto in Brazil). While it has long been considered a secondary pest of soybean in North America, recent years have seen a marked increase in its incidence across the mid-south growing areas. Unlike the above two insects, larvae of this species feed not only on foliage but also directly on pods, typically breaching the pod wall and consuming the developing seeds inside. This method of feeding not only causes direct yield impacts but also affords some protection to larvae from insecticide applications.

Also unlike the first two insects, eggs of this species can be laid anywhere on the plant—leaves (upper or lower surface), petioles, stems, pods, and even flowers. The eggs are rather large compared to the other species shown here (~3,500 eggs per gram) and assume a distinctive barrel shape when laid on the leaf. The creamy-white coloration, often with a light brown ring below the apex, is also distinctive compared to the previous two species. Eggs laid on pods tend to be attached to trichomes (hairs) rather than the pod surface, in which case they take on an almost perfectly spherical shape.

Helicoverpa zea—soybean podworm

Helicoverpa zea eggs on soybean pod

---

Heliothis virescens. Like the previous species, tobacco budworm has only recently gained attention as a pest of soybean. This importance, however, seems to be confined to Brazil (where it is known as “lagarta-das-maçãs”), while in North America it is usually found in combination with H. zea at minor levels. This is bad news for South American farmers; like soybean looper, tobacco budworm has developed resistance to all the insecticides that have been used against it in significant quantities. The oviposition and feeding behaviors of this species are very similar to those of H. zea, with eggs again laid on all parts of the plant and being very similar in appearance to those of H. zea except their slightly smaller (approx. 5,000 eggs per gram). In practical terms, eggs and young larvae of H. virescens and H. zea can be reliably distinguished only through species-specific immunoassay (Greenstone 1995) or feeding disruption bioassay using a diagnostic concentration of Bacillus thuringiensis ( Bailey et al. 2001).

Heliothis virescens—tobacco budworm

Heliothis virescens eggs on soybean pod.

As with H. zea, H. virescens eggs laid on pods tend to be stuck to hairs and assume a spherical shape.

This H. virescens egg has apparently died—note the shriveling and uniform black coloration.

---

Spodoptera frugiperda. Fall armyworm is a minor pest of soybean that rarely reaches economically damaging levels. However, its incidence in South America (where it is called ”oruga militar tarde in Argentina and “lagarta-militar” in Brazil) has increased somewhat with the adoption of no-till cultivation of soybean. The species prefers grass hosts, but when these are knocked down by applications of post-emergence herbicides the larvae then move onto the soybean plants and continue feeding. Unlike any of the above species, eggs are laid in distinctive masses that are covered by abdominal setae and wing scales for protection. These eggs are also small (~8,500 eggs per gram), exhibit much finer and more numerous ridges than the above species, and are often colored orange, pink, or light green.

Spodoptera frugiperda—fall armyworm

Individual eggs inside the mass are covered by abdominal setae and wing scales.

---

REFERENCES:

Bailey, W. D., C. Brownie, J. S. Bacheler, F. Gould, G. G. Kennedy, C. E. Sorenson & R. M. Roe. 2001. Species diagnosis and Bacillus thuringiensis resistance monitoring of Heliothis virescens and Helicoverpa zea (Lepidoptera: Noctuidae) field strains from the southern United States using feeding disruption bioassays. Journal of Economic Entomology 94 (1):76–85.

Greenstone, M. H. 1995. Bollworm or budworm? Squashblot immunoassay distinguishes eggs of Helicoverpa zea and Heliothis virescens (Lepidoptera: Noctuidae). Journal of Economic Entomology 88(2):213–218.

Copyright © Ted C. MacRae 2012