insects

The gloriously dichromatic Dasymutilla gloriosa

/ Ted C. MacRae / 3 Comments

I have a small collection of velvet ants (family Mutillidae) that I’ve accumulated over the years—not through active collection but more as bycatch from my beetle hunting operations. Velvet ants are, of course, not ants at all, but wasps, and as such the females are—like their winged relatives—quite capable of delivering a painful sting if mishandled. They also tend to be seen running rather frenetically across the ground, making them difficult to guide into a collection vial or grab with forceps. You’ve gotta really want ’em if you want to collect them. Still, even though I don’t study them I find them interesting enough to pick up on occasion, and with most groups outside of my area of focus the hope is that eventually they will end up in the hands of somebody who actively studies the group. Such is now the case with my mutillid collection, which will be shipped this week to another collector specializing in the group. In return I will be filling some holes in European representation of my collection of Cerambycidae.

Dasymutilla gloriosa, female | Brewster Co., Texas

Dasymutilla gloriosa, female | Brewster Co., Texas

Without question, the most interesting mutillid species that I’ve encountered is Dasymutilla gloriosa. All mutillids are sexually dimorphic, as only the males are winged, but most also tend to be sexually dichromatic to a greater or lesser degree. No species I am aware of takes this to the same level as D. gloriosa! The males (photo below) are rather typically colored compared to other species in the genus, but the females (photo above) are densely covered with long, strikingly white hairs. While this would seem to make them quite conspicuous, the true effect is the exact opposite as they easily confused with fuzzy plant seed. For this reason they are commonly called thistledown velvet ants. I encountered the female in west Texas in 2003 while walking a mountain trail and at first thought it was the fuzzy seed of a creosote bush (Larrea tridentata) being blown by the wind—except there was no wind! It took me a little while looking closely at it before I could figure out what it actually was. This is the only female of this species that I’ve seen in the wild, and I’ll be a little sad to see it sent to another location.

Dasymutilla gloriosa, male | Riverside Co., California

Dasymutilla gloriosa, male | Riverside Co., California

The male also is the only one I’ve encountered—or at least taken the trouble to collect. I would have never suspected this male, which I collected in southern California in 1991, was the same species as the female that I collected many years later. My thanks to Kevin Williams, who provided the identifications for both of these specimens.

Also called the ''thistledown velvet ant''

Also called the ”thistledown velvet ant”

Copyright © Ted C. MacRae 2012

Spider, insect or something else?

/ Ted C. MacRae / 21 Comments

I recently received a batch of fossil insects from a local fossil collector, who is hoping that I and other local entomologists will be able to provide some level of identification beyond just “insect.” All are from the Green River Formation, a lake bed shale deposit dating back to the early to mid-Eocene epoch (45–50 mya). Most major insect orders and families were established and undergoing rapid diversification by this time, and as a result most of the fossils are clearly identifiable at least to order or even family. There is one fossil, however, that has got me stumped. The label that came with the fossil indicates “Spider (?)”, and while at first glance this is the first thing that comes to mind, the more I look at it the more I become convinced that it represents something else. What, however, I do not know.

The fossil is a cast and mold from a split rock, so two views of the fossil are available. I’ve photographed them to try to get a better look at the details and still can’t come to a decision (I’ve even considered a small crustacean or even a plant part). Perhaps somebody who reads this might have an idea?

Colorado: Garfield, Hwy 139, Douglas Pass. Maximum diameter = 22.5 mm.

Colorado: Garfield, Hwy 139, Douglas Pass. Maximum diameter = 22.5 mm.

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Mirror half of same fossil.

Copyright © Ted C. MacRae 2012

Dainty, delicate, little fairies

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Adela caeruleella | Wayne Co., Missouri

Ever since I saw Chris Grinter’s beautiful photographs, I have wanted to see (and possibly photograph) the tiny little moths known as fairy moths (family Adelidae, formerly considered a subfamily of Incurvariidae). These dainty, delicate, little moths are characterized by their unusually long antennae—especially the males, which can have their antennae up to three times the length of the forewings. This past April I got my wish as my father and I hiked the Shut-ins Trail at Sam A. Baker State Park in Missouri’s southeastern Ozark Highlands.

Females have the antennae ”only” twice as long as the forewings…

Chris was fortunate to see a number of individuals representing at least two species, presumably all males (based on the extraordinary length of their antennae) that were engaged in some rather interesting territorial behaviors. I, on the other hand, saw only this single individual (presumably a female) who seemed content enough to calmly nectar the golden Alexander, Zizia aurea (Apiaceae), flowers on which I found it. This was fine by me, as the dense woodland setting where I saw it wasn’t very conducive to photographing the moth. I wanted a clean, bright background to highlight the moths dark metallic luster, so I snipped the flower (carefully!) on which the moth was nectaring and held it up to the small patch of bright blue sky visible from the trail to take these photos.

…and the basal half distinctly thickened.

I presume this individual represents the species Adela caerueleella based on comparison with online photos. According to Powell (1969) this species is widespread across the eastern U.S. and has been recorded on flowers of American bittersweet, Celastrus scandens (Celastraceae). Microleps.org notes the species is most frequently found along deciduous forest trails and shows a preference for flowers of black snakeroot, Sanicula marilandica (Apiaceae). My late April observation is consistent with the April and May activity period noted by Powell (1969) and late May period for central Illinois noted by Microleps.org.

REFERENCE:

Powell, J. A. 1969. A synopsis of Nearctic adelid moths, with descriptions of new species (Incurvariidae). Journal of the Lepidopterists’ Society 23:211–240.

Copyright © Ted C. MacRae 2012

Life at 8X: MPMI Cover

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The January 2013 issue of Molecular Plant-Microbe Interactions (volume 26, number 1) is now online. Why do I mention this? You may recall the cover photos of the soybean aphid, Aphis glycines, from my post —one of a series of posts I’ve done featuring insects photographed at 8X life-size.

MPMI is a publication of The American Phytopathological Society, and I have Dr. Gustavo MacIntosh at Iowa State University to thank for the appearance of these photos on the cover of this Special Focus Issue. Dr. MacIntosh is Associate Professor of Biochemistry, Biophysics and Molecular Biology and studies hormone-based defense mechanisms in soybeans. In a paper appearing in this special issue, Dr. MacIntosh and co-author Matthew Studham published the results of a study that suggests soybean aphids are able to “short-circuit” soybean defense mechanisms, making it easier for other pests (e.g., soybean cyst nematode) to colonize infested plants as well. Their study revealed large differences in transcription profiles of soybean varieties with and without an endogenous resistance gene (Rag1) in response to aphid infestation and suggested that the aphids are able to circumvent the defense response in susceptible plants by triggering activation of abscissic acid (normally associated with abiotic stress responses) as a “decoy” strategy (Studham & MacIntosh 2013). Plants infested with aphids have been shown to also become more susceptible to soybean cyst nematode—even varieties with genetic resistance to nematodes (McCarville et al. 2012). Dr. MacIntosh saw my photos when I posted them here and asked permission to submit them as candidates for the cover of the MPMI issue in which his paper was to appear.

Dr. Macintosh hopes that his research will enable the development of soybean varieties that will be more resistant to aphids and other pests.

REFERENCE:

McCarville, M. T., M. O’Neal, G. L. Tylka, C. Kanobe & G. C. MacIntosh. 2012. A nematode, fungus, and aphid interact via a shared host plant: implications for soybean management. Entomologia Experimentalis et Applicata 143(1):55–66 [DOI: 10.1111/j.1570-7458.2012.01227.x].

Studham, M. E. & G. C. MacIntosh. 2013. Multiple Phytohormone Signals Control the Transcriptional Response to Soybean Aphid Infestation in Susceptible and Resistant Soybean Plants. Molecular Plant-Microbe Interactions 26(1):116–129 [DOI: 10.1094/MPMI-05-12-0124-FI].

Copyright © Ted C. MacRae 2012

One Bad Beetle

/ Ted C. MacRae / 9 Comments

Almost every tiger beetle trip that I take has a mix of gimmes and stretch goals. That’s alright—it’s impossible to find everything every time out, and if I eschewed the common and was happy only when I found something truly rare, then I would probably find myself rather unsatisfied most of the time. For the stretch goals, however, “success” can mean many things—obviously the best case scenario is to find it in good enough numbers to allow responsible collection of an adequate series and photograph enough individuals in situ to ensure that at least a few shots will have the focus, lighting, and composition that I want. Success can also be something less than that—maybe I find only a few and don’t get a very good series, or I have trouble getting field shots and am not happy with the shots I got…or worse I don’t even get field shots! The least successful version of “success” is when I end up with just one single beetle, and the only photographs I get are very ordinary-looking shots of that one beetle in confinement. Like what happened with Cicindela decemnotata (Badlands Tiger Beetle).

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Soda Lake, Wyoming—we searched theses areas of alkaline exposures but never found beetles…

Chris Brown and I knew this species would be a stretch goal when we added “Soda Lake, Wyoming” to the itinerary of our 7th Annual Fall Tiger Beetle Trip™ (location “H” on this map). Cicindela decemnotata is the westernmost representative (Rocky Mountains from the northwestern Great Plains and northern Great Basin north to Yukon) of a group of species that seem to be closely related and resemble each other in their green coloration varying degrees of red on the head, pronotum and elytra and their variably developed white elytral markings (Pearson et al. 2006). Cicindela limbalis, C. splendida and C. denverensis occur as a partially allopatric species complex further east in the Great Plains, while C. sexguttata, C. patruela and C. denikei occupy more forested regions even further to the east. On this trip we were focusing on Great Plains tiger beetles and the dune specialists of the Yampa River Valley of northwestern Colorado. Our drive from northwestern Nebraska to the Yampa Valley would skirt the eastern edge of C. decemnotata‘s distribution, so we decided to stop by Soda Lake where Matt Brust had seen the species in previous years.

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…until we started searching these small ridges of exposed sandy soil.

It took most of the morning to reach the spot, so by the time we arrived we were anxious to get out and start searching the sage brush habitat. For me it was an unfamiliar landscape—at that time my northwesternmost push for tiger beetles yet, and like many western habitats it seemed vast and unending. We were optimistic, however, because it just “looked” like good tiger beetle habitat, with ribbons of alkaline flats weaving through open brush. Of course, as time passes and one starts to recognize that they are again searching ground already covered with no sign of beetles, optimism begins to wane and searches become more deliberate. We were there for almost an hour before I heard Chris call out. He had abandoned the alkaline flats—obvious habitat it would seem—and started looking upon some slightly sandier low ridges a little further to the south. I hustled to where he was standing, and we both looked at the beetle, calmly sitting on the sand, as we deliberated our next move. Should we try to photograph it? It seemed not at all skittish—but what if we failed, it got away, and then we never saw another one? We played it safe, netted it (easily), and placed it in a vial for transfer to a container of native soil should further efforts at finding and photographing the species fail. It was perhaps another 45 minutes before we saw another beetle—I don’t know if it was just a less cooperative individual or the heat of the day had kicked in, but as soon as I started my approach it was gone. We saw another not long after, but same story. Finally we saw one last beetle that seemed to tolerate my approach to the point that I even began looking for it in the view finder—at which point it promptly zipped away. This small prospect of success only served to prolong our vain searching before we eventually we accepted defeat and tried to be happy with the single individual that we had caught and the photographs that we would take of it in its artificial home.

Cicindela decemnotata

Cicindela decemnotata (Badlands Tiger Beetle) | Soda Lake, Wyoming

Part of me really doesn’t like showing photographs of confined tiger beetles—not for any philosophical reasons, but because I just don’t like the way they look. Rarely do they exhibit the elegant stilting and other thermoregulatory behaviors that place them in much more pleasing postures when photographed in situ. Rather, they often have a “hunkered down” look that says “I’m not happy and I don’t want to be here, so I’m not going to smile for the camera!” Since these photos were taken, I have learned a few tricks to deal with confined beetles and achieve more aesthetically pleasing photographs—these include the use of much larger arenas, allowing the beetles more time to accommodate to their environs, and elevating the substrate relative to the camera (maybe a subject for a future post). In the end, however, they are still confined and can’t be passed off as anything but that.

The bold white markings, media band sharply angled and not reaching the edge of the elytra, and ''greasy'' appearance distinguish this species.

The bold white markings, media band sharply angled and not reaching the edge of the elytra, and ”greasy” appearance distinguish this species.

As an aside, tiger beetle pros Barry Knisley, Ryan Woodcock and Mike Kippenhan have recently published the results of an impressive study of this species in which a combination of morphological and molecular evidence support the recognition of four subspecific entities—three described as new (Knisley et al. 2012). The molecular analyses not only support the subspecific distinctions postulated from morphology but also suggest that populations have undergone rapid phylogenetic radiation in the recent geological past. Much of the area occupied by C. decemnotata was covered by an ice shield during the most recent glaciations and, thus, has opened up for colonization only during the past 10,000 years (Pearson and Vogler 2001). The molecular analyses showed a relatively low amount of genetic divergence within C. decemnotata populations, which combined with marked morphological differences suggests recent and rapid radiation—most likely in the wake of glacial recession. A similar situation has been observed with members of the Cicindela maritima species-group, which occupy much the same range as C. decemnotata and, presumably, have experienced similar selection pressures in the recent geological past.

REFERENCES:

Knisley, C. B., M. R. Woodcock & M. G. Kippenhan. 2012. A morphological and mtDNA analysis of the badlands tiger beetle, Cicindela (s. str.) decemnotata Say, 1817 (Coleoptera: Carabidae: Cicindelinae) with the description of three new subspecies. Insecta Mundi 0214:1–49.

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

Pearson, D. L. and A. P. Vogler.  2001. Tiger Beetles: The Evolution, Ecology, and Diversity of the Cicindelids.  Cornell University Press, Ithaca, New York, 333 pp.

Copyright © Ted C. MacRae  2012

Another autumn oedipodine

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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

Where siblings mingle: Ellipsoptera marginata vs. E. hamata

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When Erwin & Pearson (2008) formally broke up the great genus Cicindela by elevating most of its former subgenera to full genus rank, it caused a bit of consternation amongst some North American cicindelophiles. The argument went something like, “Now we have all these new genus names to learn, and we’ll have to relabel and reorganize everything in our collections, and how do we know the names won’t change again, and we can’t even tell them apart in the field anyway, and blah blah…” Pardon me, but since when did taxonomy become more about slotting species into fixed, easy-to-learn categories and less about best reflecting dynamic knowledge of complex evolutionary relationships? In the case of Cicindela and its former subgenera, however, even these arguments don’t hold up to close scrutiny—tiger beetle enthusiasts in North America should have already been quite familiar with the former subgenera due to their inclusion in the widely accepted Pearson et al. (2006) field guide, many of which actually do present a unique suite of morphological/ecological characters that facilitate their recognition in the field, and I personally find that nomenclatural recognition of individual lineages helps my attempts to learn and understand them much more than dumping them into a large, all-encompassing genus based on superficial resemblance. As for insisting that names don’t change, well that has never been a tenet of taxonomy. Stable, yes, but fixed and immutable, no.

Ellipsoptera marginata male | Pinellas Co., Florida

Enough waxing philosophic. One of the more distinctive of the former subgenera is Ellipsoptera. Morphologically the genus is defined by details of male genitalia, but the 11 North American species are generally recognizable in the field by their relatively “bug-eyed” look and long legs (Pearson et al. 2006) and, as a group, seem ecologically tied to extreme habitats with sandy and/or saline substrates that are nearly or completely devoid of vegetation. Coastal marshes and mudflats, saline flats, sandy river banks, and deep sand ridges representing ancient coastlines are some of the habitats where species in this genus are most commonly encountered. Most of the species exhibit a fairly uniform facies but differ in the details of maculation and dorsal coloration, but two species that stand apart from the rest are E. marginata (Margined Tiger Beetle) and E. hamata (Coastal Tiger Beetle) due to the highly diffuse middle band of their elytra. These are both eastern coastal species and presumably represent sibling species that have diverged based on geographical range partitioning—E. marginata along the Atlantic Coast and E. hamata along the Gulf Coast. In the field, the two species are almost identical in appearance but nonetheless easily identifiable based on geographical occurrence. There is, however, a small stretch of coastline—the lower Gulf Coast of Florida—where the ranges of the two species overlap and geography alone isn’t sufficient for species determination.

Ellipsoptera hamata lacerata male | Dixie Co., Florida

Fortunately, despite their strong resemblance to each other, field identifications in areas where these species co-occur are still possible due to the presence of small but distinct sexual characters present in one species but absent in the other. Close examination is necessary to see the characters (or their absence), so it is best to net a few individuals and examine them in the hand or, as I have done here, look at them through the viewfinder of a camera. The photos in this post include the male and the female of both species, each showing the presence or absence of the distinguishing character.

Ellipsoptera marginata female | Dixie Co., Florida

In most tiger beetles, male individuals are distinguished by a number of secondary sex characters, but easiest to see in the field are the brush-like pads on the underside of the front tarsi (“feet”). Males of E. marginata and E. hamata are further distinguished from each other by the presence (E. marginata) or absence (E. hamata) of a distinct tooth on the underside of the right mandible. Photo 1 above shows a male E. marginata from Pinellas Co., Florida, and the tooth is easily seen in that relatively distant view. Photo 2 above shows a male E. hamata lacerata (Gulf Coast Tiger Beetle)—the Floridian subspecies, and while a small bump can be seen on the underside of the right mandible, it is not nearly as well developed into a distinct tooth as in E. marginata.

Ellipsoptera hamata lacerata female | Dixie Co., Florida

Female tiger beetles, on the other hand, lack the brush-like tarsal pads present in the males and are further distinguished by the “mesopleural coupling sulcus”—an area just behind the side of the pronotum that receives the male mandible during mating and is thus devoid of setae (compare the females in Photos 3 and 4 with the males in Photos 1 and 2). Neither E. marginata nor E. hamata females possess the mandibular tooth found in E. marginata males, but they can be distinguished from each other by their elytral apices. In E. marginata females (Photo 3), the elytra are curiously “bent” at the tips, forming a distinct indentation at the apex of the elytra where they meet, while female E. hamata (Photo 4) lack this indentation.

Are there other tiger beetle sibling species groups for which you would like to see comparative posts such as this one?

p.s. I completely neglected to mark yesterday’s 5th anniversary of Beetles in the Bush! I don’t know how I missed a milestone as big as five years—hopefully my ability to provide interesting content is faring better than my middle-aged memory!

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

It’s a Mayfly…It’s a Moth…It’s Thyridopteryx

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Mississippi River @ Hwy 62 bridge

One of the nice things about the study of insects is the endless opportunity for discovery. It could be a new species, or it might just be something already known but not yet seen personally. I’ve been collecting insects most of my life, and although much of it has been done in far away places the bulk has occurred in my home state of Missouri. Despite my long experience in this state, this past summer I had the opportunity to experience collecting within the state in a way that I’ve not yet done before—blacklighting up and down the length of the Mississippi River regularly during the months of July through September. Each time, I would arrive at the selected spot in the early evening while there was still daylight and search the (hopefully sandy) beaches for evidence of several tiger beetle species that might occur in such habitat. Then, as the sky turned aglow from the setting sun, I would setup the blacklights and wait for the appearance of those particular tiger beetles that are attracted to such.

Thyridopteryx ephemeraeformis | Mississippi Co., Missouri

Expectedly, beetles were seen at only some sites, and numbers and diversity generally decreased as summer approached its end. By early September beetles were no longer showing up even though the habitat seemed good (I guess that’s why they call them “summer” species). Still, on this particular night, the lights setup at the Hwy 62 bridge in far southeastern Missouri were attracting a variety of other insects, so I kept them on to see what might come in. I had nothing else to do. At some point, I noticed a strange insect that seemed like a cross between a mayfly and a moth, and then another…and another. Although I had never seen one of these in person before, I knew exactly what they were—male bagworms! Bagworms (order Lepidoptera, family Psychidae), of course, are extraordinarily common in Missouri, and the sight of dozens or even hundreds of their silken/twig bags attached to ornamental evergreen shrubs in the neighborhood where I lived as a kid remains vivid. I can remember “popping” the larvae inside to see their innards ooze out from the tip of the bag (I know—I’m not proud of it) and even cut open a few of the bags to see the larvae inside (that is, once the less sadistic and more scientifically curious side of me took over). Despite all of this, I had never seen an adult bagworm—male or female—until this night.

Dorsal view

Obviously, these are males because they have wings—females remain wingless into adulthood and, in fact, never even leave the bag in which they’ve spent their entire lives. Bagworm males are distinctive in that their wings are virtually devoid of any scales, and I surmise that the generic name of the most common species in eastern North America—Thyridopteryx ephemeraeformis—is derived from the Greek thyris (window) and the Latin ptera (wing) in reference to this. I was fascinated by the strange appearance of these moths and even more fascinated by the curious manner in which the males held out the tip of their abdomen when at rest; reminiscent of a female releasing sex pheromone. This can’t be true, because it is the females that call from their bags to attract the males, and since the females remain within their bag, the male must insert his abdomen through the tip of the bag and all the way to the top where he can reach the female genital opening. Thus, the male abdomen is highly extensible and prehensile—I guess the males can’t keep an abdomen with that much stretching capacity still for very long.

Two males

Based on gestalt, I presumed these represented T. ephemeraeformis since it is such a common and widespread species, but it’s not always wise to presume, especially in a relatively more southern location. The Moth Photographers Group lists five species in this genus in North America, two of which (T. alcora and T. meadii) seem to be southwestern in distribution. Of the remaining three, T. ephaemeraeformis is the only one I could find any photos or information beyond simple listings (the Moth Photographers Group lists no distribution records for T. rileyi or T. davidsoni), so I asked my lepidopterist friend Phil Koenig for his opinion. Phil informed me that T. ephemeraeformis has been recorded in Missouri 285 times in 49 counties, while T. rileyi is known from the state based only very old literature records and T. davidsoni not at all. Thus, the odds are definitely favor these males representing T. ephemeraeformis. Late summer is apparently the prime period of adult bagworm activity. I’ve not done much blacklighting late in the season because most of the beetles on which I’ve focused over the years and that are attracted to blacklights are active more during spring and early summer. This could explain why I’ve not until now seen male bagworms despite their commonness in Missouri.

Copyright © Ted C. MacRae 2012