Wasp Wednesday—Not!

In early September, the agricultural landscape in the central U.S. awakens from its monotonous cloak of summer green and turns ablaze with a hundred shades of yellow, gold, and tawny. The “fall composites” as they are commonly called, a dazzling diversity of mostly yellow-flowered herbaceous plants in the family Asteraceae, are one of the chief contributors to this explosion of color, and among them none contribute more than goldenrod (Solidago sp.). Occupying nearly every fence row, drainage ditch, and fallow field, the bright yellow fronds of tiny flowers are not only pleasing to the eyes of humans, but a smorgasbord of pollen for all manner of flower-feeding insects. Bees, flies, wasps, beetles, and moths all flock to the bounty in numbers rarely seen during the dog days of summer. Spiders, ambush bugs, mantids, and other predators take up residence amongst the flowers as well—not to feed on the flowers, but rather the abundance of flower-feeding insects upon which they will prey. It is rare to find a goldenrod plant without at least a few insects upon it.

Synanthedon decipiens (oak gall borer) on Solidago sp. | Mississippi Co., Missouri

My favorite goldenrod insects are, of course, the longhorned beetles of the genus Megacyllene, and at least here in Missouri there are none finer than Megacyllene decora (see A classic fall ‘bycid). However, I keep an eye out for other insects as well, and when I first saw this “wasp” sitting on a flower head I had to do a bit of a double take—”something” just didn’t seem quite right about it. A little lean forward was all that was needed to confirm that this was indeed no wasp, but rather a clearwing moth (order Lepidoptera, family Sesiidae)¹. To my mind, of the many insects that try to mimic wasps, none do so more effectively than members of this family. From the elongate body to the yellow abdominal banding and narrow transparent wings, everything about this moth says “wasp”—well, almost everything or I wouldn’t have done a double take to begin with.

¹ I hope Eric Eaton, author of Bug Eric and its Wasp Wednesday series, will forgive my use of his title for this post.

Apparently a male, these moths use pheromones to locate females for mating.

I actually did a fair bit of work with this group in my early years with the Department of Agriculture. Females of most (all?) species emit species-specific pheromone blends that males can detect at incredibly low volumes (only a few molecules are needed to elicit a response by the male antenna). Components of these pheromones have been synthesized, and since a number of species have economic importance in landscape and nursery settings (larvae of most species are borers of woody or perennial plants), these synthetic pheromone blends are commonly employed in traps for survey and detection (e.g., Snow et al. 1985). I conducted surveys for several years during the mid 1980’s in east-central Missouri using these traps and, thus, developed a good eye for distinguishing these moths in flight from the wasps that they so effectively mimic. In fact, I used to keep a pheromone tag on my waist bag, which resulted in male moths frequently flying up to me and “searching” for the female. I never tired of seeing the faces of nursery growers—first showing concern as they were convinced I was under attack by a wasp, and then shock as I calmly reached out and grabbed the “wasp” in mid-flight with my bare hand! (And to be perfectly honest, it took me a while before I could bring myself to start grabbing them out of the air!) I even had one nursery grower continue insisting it was a wasp and could sting even after I had caught it (“Naw, them things sting—I seen ’em!)

The moth in these photos seems to best match Synanthdedon decipiens, widely distributed east of the Rockies and inhabiting the woody galls of cynipid wasps on oaks. In Georgia adults of this species exhibit a bimodal pattern of seasonal occurrence suggestive of two generations per year (Snow et al. 1985), so this September-occurring male might represent a second Missouri generation as well.

REFERENCES:

Snow, J. W., T. D. Eichlin & J. H. Tumlinson. 1985. Seasonal captures of clearwing moths (Sesiidae) in traps baited with various formulations of 3,13-0ctadecadienyl acetate and alcohol. Journal of Agricultural Research 2(1):73–84.

Copyright © Ted C. MacRae 2012

BitB Top 10 of 2010

Welcome to the 3rd Annual BitB Top 10, where I pick my 10 (more or less) favorite photographs of the year.  My goal for 2010 was to continue the progress that I began the previous year in my quest to become a bona fide insect macrophotographer.  I’m not in the big leagues yet, but I have gotten more comfortable with using my equipment for in situ field photographs and am gaining a better understanding of lighting and the use of flash.  I also began experimenting with different lighting techniques (e.g. white box) and diffusers and am putting more effort into post-processing techniques to enhance the final appearance of my photographs.  I invite you to judge for yourself how successful I’ve been toward those goals by comparing the following selections with those from 2009 and 2008 – constructive feedback is always welcome:


Best Tiger Beetle

Cicindela denverensis - green claybank tiger beetle

From ID Challenge #1 (posted December 23).  With numerous species photographed during the year and several of these dramatic “face on” shots, this was a hard choice.  I chose this one because of the metallic colors, good focus throughout the face, and evenly blurred “halo” of hair in a relatively uncluttered background.


Best Jewel Beetle

Buprestis rufipes - red-legged buprestis

From Special Delivery (posted July 13).  I didn’t have that many jewel beetles photos to choose from, but this one would have risen to the top no matter how many others I had.  The use of a white box shows off the brilliant (and difficult-to-photograph) metallic colors well, and I like the animated look of the slightly cocked head.


Best Longhorned Beetle

Desmocerus palliatus - elderberry borer

From Desmocerus palliatus – elderberry borer (posted November 18).  I like the mix of colors in this photograph, and even though it’s a straight dorsal view from the top, the partial dark background adds depth to the photo to prevent it from looking “flat.”


Best “Other” Beetle

Enoclerus ichneumoneus - orange-banded checkered beetle

From Orange-banded checkered beetle (posted April 22).  The even gray background compliments the colors of the beetle and highlights its fuzziness.  It was achieved entirely by accident – the trunk of the large, downed hickory tree on which I found this beetle happened to be a couple of feet behind the twig on which it was resting.


Best Non-Beetle Insect

Euhagenia nebraskae - a clearwing moth

From Euhagena nebraskae… again (posted October 21).  I photographed this species once before, but those photos failed to capture the boldness of color and detail of the scales that can be seen in this photo.


Best “Posed” Insect

Lucanus elaphus - giant stag beetle

From North America’s largest stag beetle (posted December 30).  I’ve just started experimenting with photographing posed, preserved specimens, and in fact this male giant stag beetle represents only my second attempt.  It’s hard to imagine, however, a more perfect subject than this impressively stunning species.


Best Non-Insect Arthropod

Scolopendra heros - giant desert centipede

From North America’s largest centipede (posted September 7).  Centipedes are notoriously difficult to photograph due to their elongate, narrow form and highly active manner.  The use of a glass bowl and white box allowed me to capture this nicely composed image of North America’s most spectacular centipede species.


Best Wildflower

Hamamelis vernalis - Ozark witch hazel

From Friday Flower – Ozark Witch Hazel (posted March 26).  The bizarre form and striking contrast of colors with the dark background make this my favorite wildflower photograph for the year.


Best Non-Arthropod

Terrapene carolina triunguis - three-toed box turtle

From Eye of the Turtle (posted December 10).  I had a hard time deciding on this category, but the striking red eye in an otherwise elegantly simple photograph won me over.  It was also one of two BitB posts featured this past year on Freshly Pressed.


Best “Super Macro”

Phidippus apacheanus - a jumping spider

From Jeepers Creepers, where’d ya get those multilayered retinae? (posted October 5).  I’m not anywhere close to Thomas Shahan (yet!), but this super close-up of the diminutive and delightfully colored Phidippus apacheanus is my best jumping spider attempt to date.  A new diffuser system and increasing comfort with using the MP-E lens in the field at higher magnification levels should allow even better photos this coming season.


Copyright © Ted C. MacRae 2011

Euhagena nebraskae… again

Euhagena nebraskae - male

Earlier this year I showed a photograph of a mating pair of the clearwing moth (family Sesiidae) species, Euhagena nebraskae – seen last year in the Gypsum Hills of south-central Kansas on a cold, early-October day.  It was an okay photograph, made interesting primarily by nicely showing the high degree of sexual dimorphism seen in these moths.  Still, I wasn’t completely happy with the photo, wishing I had gotten a closer photograph of just the male with his highly bipectinate antennae and wispy, white thoracic tufts.  I got my wish on the first day of my recent fall tiger beetle collecting trip, seeing just this single male in the Pine Ridge area of northwestern Nebraska.  Despite the relatively warmer temperatures, he perched cooperatively atop a dried flower head and allowed me to photograph him to my heart’s content.

p.s. this one you really should click on to see the larger version, because the hair-like thoracic scales and flattened marginal scales on the wings are quite remarkable.

Photo Details: Canon 50D w/ 100mm macro lens (ISO 100, 1/250 sec, f/16), Canon MT-24EX flash w/ Sto-Fen + GFPuffer diffusers. Typical post-processing (levels, minor cropping, unsharp mask).

Copyright © Ted C. MacRae 2010

Euhagena nebraskae in Kansas

Gypsum Hills region of south-central Kansas (Barber Co.)

One of my favorite destinations for insect collecting is the Gypsum Hills region in Barber County of south-central Kansas.  I first went there in May 1986 after seeing a diverse selection of more typically Texan Buprestidae that J. Richard Heitzman, an iconic lepidopterist in the Kansas City area and author of Butterflies & Moths of Missouri, had collected there on soapberry (Sapindus saponaria).  I had my own success with Buprestidae as well during that trip, but in recent years I have returned to Barber County several times during the fall to look for one of North America’s most beautiful tiger beetles, Cicindela pulchra (Beautiful Tiger Beetle).  This species had been recorded in the area by the well-known cicindelophiles Ron Huber and Dave Brzoska, who suggested that I look in the red clay hills just west of Medicine Lodge.  My first trip to look for this beetle in 2004 was unsuccessful, and I suspect the early September timing of my trip may have been a tad too early.  I returned again in 2005, this time in early October and also enlisting the help of local entomologist “Beetle Bill” Smith, who knew of a population on private land near his home in Hardtner (south of Medicine Lodge).  Although at first it looked like success might again elude me, in the end I saw a robust population of these spectacular beetles and published an account of that marvelous experience (MacRae 2006).

As with so many of the things that I have seen over the years, they came before my interest in photography, and I now find myself wanting to re-find some of the more spectacular insects that I’ve previously found so that I can properly photograph them.  Such is the case with C. pulchra, so in October of last year I returned to Barber County in hopes of seeing this species armed not only with an aerial net, but also a Canon 50D.  Sadly, this would not come to pass – the same sudden cold snap that dashed my hopes of finding this species in nearby Woodward/Major Counties, Oklahoma would keep any tiger beetle activity to a bare minimum the following day in Barber County as well.  Despite bright sunny skies, I would see only two tiger beetles the entire day, both representing the dreadfully ubiquitous Cicindela punctulata (Punctured Tiger Beetle).  Not all insect activity, however, was squelched, and after scanning the red soils for an hour or so without seeing the object of my desire I began to notice some of these other not-so-temperature-finicky species.  One of the more magnificent of these is shown in the photo below — Euhagena nebraskae in the family Sesiidae (cess-EYE-id-ee) (formerly Aegeriidae).

Euhagena nebraskae

Euhagena nebraskae (Lepidoptera: Sesiidae)

Although I wasn’t sure of the species at first, I recognized it immediately as a clearwing moth.  I had an interest in this family of moths for a time in my early days as a field entomologist with the Missouri Department of Agriculture.  Many species are important pests of woody plants in orchard and ornamental landscapes, and it was during that time that synthetic pheromones became widely used for monitoring purposes.  I often walked around with a pheromone tag pinned to my bag to attract the male moths — it was fun watching people seeing these moths “buzzing” me and thinking I was under attack by the wasps that they so effectively mimic (despite my calmness in these situations, I still found it hard to actually grab one from the air with my hand – so convincing is their mimicry).

Euhagena nebraskae is one of two species in the genus in North America, both of which develop as larvae in the roots of plants in the evening primrose family (Onagraceae) (Eichlin and Duckworth 1988).  In fact, I had seen its congener — E. emphytiformis — many times in the 1980s in pheromone traps that I used to place in the glades of Jefferson County just south of St. Louis, where it presumably breeds in one or both of two Oenetherea species growing there (O. gaura and O. macrocarpa).  Euhagena nebraskae is a more western species that does not occur in Missouri, occurring instead across the Great Plains west to California and from southern Alberta and Saskatchewan south to Mexico.  It is likely that many entomologists never see this species, as adults are active only during late fall.  Thus, its perception as an uncommon species may be an artifact of its late seasonality. 

I thought it odd that nearly every individual that I saw was sitting on the ground rather than perched higher on a plant.  At first I wondered if the cold temperatures were a reason for this, perhaps causing the moths to seek out the ground as a source of radiant heat.  This seems doubtful, however, since females always seemed to be “calling” – their tufted abdominal tips raised in the air with the scales spread apart, apparently releasing pheromone.  I was fortunate to find this mating pair, which shows nicely the rather high degree of sexual dimorphism seen in these moths.  Note the much more highly bipectinate antennae of the male (pectinate = resembling a comb, bipectinate = ‘teeth’ on both sides of the main stem) versus the simple antennae of the female — males use their antennae for detecting female pheromones, and the bipectinate form presumably provides greater surface area for placement of sensory pores. Note also the male’s smaller size, “hairier” head and thorax, and greater amount of white coloration on the abdomen and wings.  Engelhardt (1946) supposed that the excessive hairiness of adult Euhagena species was an adaptation to their late-season emergence (principally during October and sometimes as late as November), a time when frosty nights prevail in their high-elevation haunts.    

REFERENCES:    

Eichlin, T. D. and W. D. Duckworth. 1988. The Moths of America North of Mexico, Fascicle 5.1, Sesiodea: Sesiidae. Wedge Entomological Research Foundation, Washington, 176 pp.

Engelhardt, G. P. 1946.  The North American clear-wing moths of the family Aegeriidae. Bulletin of the United States National Museum 190:1-222.

MacRae, T. C. 2006. Beetle bits: The “beautiful tiger beetle”. Nature Notes, Journal of the Webster Groves Nature Study Society 78(4):9–12.

Copyright © Ted C. MacRae 2010

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