Big, black (and red), and beautiful!

While I may have already declared Plinthocoelium suaveolens (bumelia borer) as North America’s most beautiful longhorned beetle, any short list of top candidates for this title must also include the species Crossidius coralinus. Like most other members of this strictly North American genus, these gorgeous beetles emerge as adults during late August and September to feed on the profusion of yellow blooms put forth by their larval host plants, Ericameria nauseosa (gray rabbitbrush). Across the Great Basin and adjacent areas, the relatively large size, spectacularly long antennae, and stunning value contrast between red/black or orange/black beetles, yellow flowers, and blue skies combine to make the sight of C. coralinus a highlight on any fall insect collecting trip. If beauty alone isn’t enough, the species also exhibits an unusual level of polytopism across its range. Red in some areas (e.g., C. c. temprans), orange in others (e.g., C. c. monoensis), bigger or smaller, and varying degrees of development of the black areas that cover the basal edge and apical portion of the elytra, the species segregates into several described subspecies and many more unnamed but locally distinct populations. This post features photos of individuals from several populations that field-mate Jeff Huether and I encountered during last August’s Great Basin collecting trip.

Crossidius coralinus coralinus

Crossidius coralinus ssp. coralinus (male) | Montezuma Co., Colorado

Crossidius coralinus coralinus

Crossidius coralinus ssp. coralinus (female) | Montezuma Co., Colorado

One of the most impressive populations I’ve encountered is illustrated by the male and female individuals shown in the above photos, which were seen near the city of Cortez in southwestern Colorado. Linsley & Chemsak (1961) assigned specimens from this area to the nominate subspecies, characterizing them as “moderate-sized”; however, some of the individuals that we encountered at this site were truly gargantuan (exceeding 20 mm in length). Note how extensive the black areas are in these individuals, especially the female.

Crossidius coralinus jocosus (male) | Costilla Co., Colorado

Crossidius coralinus ssp. jocosus (female?) | Costilla Co., Colorado

Crossidius coralinus jocosus (female) | Costilla Co., Colorado

Crossidius coralinus ssp. jocosus (female) | Costilla Co., Colorado

On the other side of the state near Fort Garland (southeastern Colorado) we encountered a population that Linsley & Chemsak (1961) considered representative of the subspecies C. c. jocosus. In contrast to the larger size and extensive black markings of the nominotypical population we found near Cortez, individuals in this population were considerably smaller in size and exhibited less extensively developed black areas of the elytra. Their small size also made them a little harder to notice—perhaps that is the reason we found so few individuals (~7 total at several sites along Hwy 160). We did note also, however, that the gray rabbitbrush flowers seemed to be well past their prime, so perhaps an earlier appearance of the rains upon which plant flowering and beetle emergence rely had us on the tail end of their activity period.

Crossidius coralinus coralinus

Crossidius coralinus ssp.? (male) | San Juan Co., Utah

Crossidius coralinus coralinus

Crossidius coralinus ssp.? (female) | San Juan Co., Utah

Linsley & Chemsak (1961) noted several populations across middle and southern Utah, but the only one to which they assigned a name was C. c. coccineus in Washington Co. (southwestern Utah). While we didn’t visit Washington Co. on this trip, we did look for these beetles at several sites north of Monticello in San Juan Co. (southeastern part of the state). Geography would place this population close to nominotypical populations, and while the beetles in this population resembled them in size they clearly differed in the greatly reduced black areas of the elytra. Note the male especially, with the black area reduced to little more than a sutural stripe in the apical half of the elytra. Linsley & Chemsak (1961) related specimens collected just a few miles further south from ours to an unnamed population in adjacent Wayne Co. (near Hanksville), both of which seem to be close to C. c. coccineus due to their robust size and the reduced black elytral markings of the male.

Crossidius coralinus ssp. (female) | Nye Co., Nevada

Crossidius coralinus ssp.? (female) | Nye Co., Nevada

Crossidius coralinus is found commonly along the western edge of the Great Basin in the form of C. c. temprans. However, Linsley & Chemsak (1961) presented very few records of the species further east in Nevada. We stopped at several spots in central Nevada while traveling along Hwy 6, but despite an abundance of gray rabbitbrush stands in peak bloom we found but a single male and a single female, the latter shown in the above photograph. Geographically this female should be assignable to C. c. temprans, but the black area of the elytra is not nearly so expanded as is typical for that subspecies. The only record from central Nevada in Linsley & Chemsak (1961) is a single male from White Pine Co. (a little further to the east), but they related that specimen to an unnamed population near Marysvale in Piute Co., Utah of smaller size and with the black area of the elytra distinctly expanded in both sexes.

The author photographing insects on flower head of Ericameria nauseosus.

The author photographs insects on gray rabbitbrush in San Juan Co., Utah.

There are those who say “Subspecies, schmubspecies!” I concede they may be right for a large number of named subspecies, possibly including C. coralinus, and while the basin and range topology of the Great Basin and discontinuous distribution of host plants within that geography provide ideal conditions for the development of distinctive, geographically based populations, I suspect C. coralinus has sufficient mobility to allow gene flow across its range (with the possible exception of populations in California’s Central and Owens Valleys). Moreover, the inability of Linsley & Chemsak (1961) to segregate the central Great Basin populations into discrete taxonomic units suggests that the subspecies concept may not be applicable. Nevertheless, it cannot be denied that distinctive, localized populations of this species do exist. Moreover, I hesitate to dismiss subspecies in problematic taxa such as C. coralinus, because doing so makes it easier to ignore variability and presume (possibly incorrectly) no geographic component. Variability is interesting and should be thoroughly evaluated to determine its basis regardless of its basis. Geographically based variability is especially interesting because it suggests the existence of distinct genetic traits that contribute to the genetic diversity of species. Such traits are valuable to protect, and the use of subspecies provides a convenient shorthand for referring to the populations that contain them in both taxonomic and conservation contexts.

REFERENCE:

Linsley, E. G. & J. A. Chemsak. 1961. A distributional and taxonomic study of the genus Crossidius (Coleoptera, Cerambycidae). Miscellaneous Publications of the Entomological Society of America 3(2):25–64 + 3 color plates.

© Ted C. MacRae 2014

Black is beautiful!

Most species in the genus Crossidius exhibit varying amounts of yellow/red/orange coloration on the body. However, one species—Crossidius ater—dispenses with such adornments and remains all-black throughout its expansive range across the Great Basin and surrounding areas. Despite this, they are no less pretty than their more gaudily colored relatives. The adults in these photos were seen on flowers of yellow rabbitbrush (Chrysothamnus viscidiflorus) at two locations in White Pine County, Nevada on 30 August 2013 (all photos w/ natural sky background).

Crossidius ater | 7.2 mi SW NV318 on US6, White Pine Co., Nevada.

Crossidius ater | 7.2 mi SW NV318 on US6, White Pine Co., Nevada.

Crossidius ater | Ely,  1.2 mi S Jct US6/50/93, White Pine Co., Nevada.

Crossidius ater | Ely, 1.2 mi S Jct US6/50/93, White Pine Co., Nevada.

Crossidius ater | Ely,  1.2 mi S Jct US6/50/93, White Pine Co., Nevada.

Crossidius ater | Ely, 1.2 mi S Jct US6/50/93, White Pine Co., Nevada.

© Ted C. MacRae 2014

A Crossidius hirtipes subspecies blend zone…

…or, “There’s something fishy going on here!”

After a day in the vicinity of Yearington, Nevada  looking for (and eventually finding) a population of Crossidius hirtipes longhorned beetles assignable to subspecies “rubrescens“, field mate Jeff Huether and I dropped a little further south to look for two additional subspecies—C. h. immaculipennis and C. h. macswaini. Like C. h. rubrescens, populations assignable to these two subspecies are also restricted to a small area in west-central Nevada. Chemsak & Linsley (1959) described C. h. immaculipennis from specimens collected 10 miles north of Smith (Lyon Co.) and two years later (Linsley & Chemsak 1961) described C. h. macswaini from 19 miles SE of Wellington (Douglas Co.). We were still under the smoke plum from the now 9-day old Rim Fire in the nearby Sierra Nevada, which came and went during much of the day (top photo) and eventually settled in to create some amazing sunset landscapes (bottom photo).

19 mi S of Wellington, Toiyabe National Forest, Nevada.

Rim Fire smoke moves in and out of the area | 19 mi S of Wellington, Toiyabe National Forest, Nevada.

As had happened the day before with C. h. rubrescens, success did not come quickly or easily. We first searched for the type locality of C. h. immaculipennis, but many parts of the area have been converted to agriculture, and in the precise area 10 miles north of Smith we found only vast fields of dark green, irrigated alfalfa and not the rabbitbrush chaparral habitat required by these beetles. We did a little searching in surrounding areas and eventually found one rather nice-looking patch of ground with healthy stands of Chrysothamnus viscidiflorus in full bloom. Mindful of the previous day’s experience with finding the beetles often ensconced down within the inflorescences—especially as cooler temperatures set in, we took care to carefully inspect the blossoms in case the cool morning temperatures were inhibiting the beetles from coming back up for the day. Alas, we saw no beetles despite spending a considerable amount of time searching.

Crossidius hirtipes immaculipennis (male) | 6.3 mi W of Wellington, Nevada.

Crossidius hirtipes immaculipennis (male) | 6.3 mi W of Wellington, Nevada.

Rather than beat a dead horse, we decided to drive a short distance south and west to the town of Wellington, where a fellow cerambycid collector had found the subspecies a few years earlier. He had provided us with some detailed notes on the specific localities where he found the beetles, and these proved to be of great help as we passed through endless, seemingly acceptable chaparral habitat trying to decide exactly where we should stop and invest more time to look for the beetle. We stopped at one of the sites indicated in the notes and immediately found a beetle on one of the first plants we checked, and eventually after a gap in finding any more we found an area where good numbers of the plants were supporting decent numbers of the beetles. Chemsak & Linsley (1959) distinguished C. h. immaculipennis by its reddish legs, pale color, and complete lack of elytral markings in the male, exemplified by the male shown in the photo above.

Crossidius hirtipes macswainei? (female) | 6.3 mi W of Wellington, Nevada.

Crossidius hirtipes macswainei? (female) | 6.3 mi W of Wellington, Nevada.

As we searched the plants and found more and more individuals, I noticed an occasional adult that seemed to be a little more yellowish than reddish and with distinct sutural maculae. I didn’t think much about it then, chalking it up to individual variability, but after returning home and having a chance to look at the specimens more closely I was surprised to determine that these few beetles actually are a better fit for the second subspecies we planned to search for that day—C. h. macswainei. We had found both subspecies at the same site and didn’t even realize it. Okay, I know what you’re thinking… subspecies must exhibit allopatric geographic distributions (cannot occur together at the same place and time). It is, thus, tempting to declare that the two “subspecies” are actually not distinct, but rather represent distinctive extremes of individual variation in a single interbreeding population. However, one must also consider the possibility that the two subspecies represent reproductively isolated populations and, thus, qualify as distinct species. I’m not qualified to make that judgement, but I will note that most of the individuals encountered were assignable to C. h. immaculipennis  and the rest to C. h. macswainei, but that no “intergrades” were found.

Crossidius hirtipes macswainei (male) | 19 mi S of Wellington, Nevada.

Crossidius hirtipes rhodopus? (male) | 19 mi S of Wellington, Nevada.

After collecting adequate series from W of Wellington, we traveled further south of town to the type locality of C. h. macswainei (not knowing we already had it!). The holotype and most of the paratypes were collected 19 miles S of Wellington (Linsley & Chemsak 1961), but a number of paratypes had also been collected 14 miles south of town, so we stopped there first in an unsuccessful bid to find the subspecies before moving on to the type locality a few miles further south. Within a few minutes of arriving, I found the individual shown in the photo immediately above, presumed that I had found the subspecies we were looking for, and popped it into a vial alive as a photo backup if we did not find any other individuals with which I could attempt field photographs. Ironically, that is exactly what happened—despite Jeff and I scouring every plant we could find in about a 1-mile stretch along each side of the road, we never found another beetle. Later that evening I took the above individual out of its vial for photographs, but it never really “perked up” to look fully natural, resulting in “bum” antennae that give away the staged nature of the photograph. Again, it was not until I got back home and could look at the specimen closely before I realized that it did not at all fit the description of C. h. macswainei, but instead seemed to be a good match for the subspecies C. h. rhodopus, known from only a short distance further south but—until now, at least—apparently restricted to the Mono Basin in east-central California (see this post for more details about this subspecies). Jeff has since reported to me that some of the beetles he collected at the “C. h. rubrescens” locality (see this post) also are a match for C. h. macswainei, adding yet another wrinkle to those that resulted from this day’s collecting. Such inconsistencies with the published literature may tempt some to scrap all of Linsley & Chemsak’s subspecies, but considering that those two authors examined more than 12,000 specimens during the course of their studies such a reaction would be both premature and presumptuous. What is needed is more study—more specimens from more localities, hopefully augmented with DNA sequence analysis. For the latter goal we did our part, dropping a specimen or two from every locality in which we found beetles into ethanol for just such purpose. Until such studies are done, I prefer to withhold judgement about whether C. hirtipes is comprised of one highly polytopic population, several subspecifically distinct populations, or perhaps even multiple distinct species.

14 mi SE of Wellington, Toiyabe National Forest, Nevada.

Evening haze creates a spectacular sunset | 14 mi SE of Wellington, Toiyabe National Forest, Nevada.

Even though we found only a single beetle at the second locality, our persistence in searching until the day ran out was rewarded by a most spectacular sunset caused by thick haze from the nearby Rim Fire in California. It would also be our last day in Nevada before dropping south into California and spending the next several days in successful bids for C. coralinus monoensisC. c. caeruleipennisC. h. nubilus, and C. h. rhodopus.

REFERENCE:

Chemsak, J. A. & E. G. Linsley. 1959. Some new species and subspecies of Crossidius from western North America. Journal of the Kansas Entomological Society 32(4):176–183.

Linsley, E. G. & J. A. Chemsak. 1961. A distributional and taxonomic study of the genus Crossidius (Coleoptera, Cerambycidae). Miscellaneous Publications of the Entomological Society of America 3(2):25–64 + 3 color plates.

Copyright © Ted C. MacRae 2014

GBCT Beetle #4—Crossidius hirtipes rubrescens

Crossidius hirtipes rubrescens (male) | Lyon Co., Nevada

Crossidius hirtipes rubrescens (male) | Lyon Co., Nevada

Linsley & Chemsak (1961) characterize the longhorned beetle species Crossidius hirtipes as “probably the most diverse species within the genus.” Occurring throughout the Great Basin and adjacent areas, the variability it expresses in punctation, color, elytral pattern and pubescence have resulted in the recognition of 16 named subspecies and numerous additional distinct but unnamed populations. During our Great Basin Collecting Trip (GBCT) in late August, we targeted ten of the named subspecies (representing the majority of populations found across the southern half of the species’ distribution) and succeeded in finding eight of them. I’ve already featured C. h. immaculatus, occurring across northern Nevada and northeastern California and the first beetle we found on the trip, and the photo above shows a male of what we consider to represent C. h. rubrescens—one of three C. hirtipes subspecies restricted to a very small area in west-central Nevada. Linsley & Chemsak (1961) described this subspecies from a series taken just north of Yearington on Chrysothamnus greenei (now Ericameria greenei), noting that it differs from other subspecies by its pinkish cast to its coloration and its pale appendages.

We almost did not find this subspecies.  We had stopped at several places along the road as we approached Yearington from the north and finally stopped at a spot 2.6 miles north of town with good stands of E. greenei. Although we found a few C. coralinus temprans on the plants, we did not see C. hirtipes. While we were searching we noticed a much smaller yellow-flowering asteraceous plant that at first we thought might be something in the genus Haplopappus but which I now believe represents a variety of Chrysothamnus viscidiflorus—the normal host plant for most subspecies of C. hirtipes (a plant voucher was collected and has been sent off for identification). We searched these plants as well but didn’t see any beetles on them, and after a while we decided we’d given the locality a good enough look and that we should move on. We began walking back towards the car, and as we approached the car I happened to look down and saw a mating pair of C. hirtipes sitting on a C. viscidiflorus flower. The pair split and bolted right when I saw them, but we managed to capture one of them and decided maybe we should look around a little more. The beetles were scarce, and another hour of searching produced only a handful—mostly in a small area further north of the area we had been searching. We then checked a couple of other nearby spots but found only a few host plants and no beetles, so we decided to go back to the site and search again. While none were seen in the original spot, we found much better stands of the plant in the adjacent area even further to the north and managed to collect a decent though not large series of adults before the setting sun caused the beetles to retreat and end our day. The individual in the photo above (recognizable as a male by its relatively longer antennae and immaculate elytra) was photographed as the setting sun turned the smoke-filled sky to a soft, burnt orange color that nicely compliments the color of the beetle.

REFERENCE:

Linsley, E. G. & J. A. Chemsak. 1961. A distributional and taxonomic study of the genus Crossidius (Coleoptera, Cerambycidae). Miscellaneous Publications of the Entomological Society of America 3(2):25–64 + 3 color plates.

Copyright © Ted C. MacRae 2013

Under Blood Red Skies

At the start of my recent Great Basin collecting trip, I found myself presented with a rather unique and unanticipated photographic opportunity. As I landed in Reno, Nevada, the then 6-day old Rim Fire was already well on it’s way to becoming the largest wildfire on record in the California Sierra Nevada. As acre after acre of the Sierra’s dramatic coniferous forest succumbed to the blaze, an enormous plum of smoke drifted northward for several hundred miles over eastern California and western Nevada, blanketing the area in a thick haze that turned the sun’s hot glare to a soft glow and limited visibility to under a mile. It was like a thick overcast foggy day, only without the cool, damp humidity. This was of little consequence to our business at hand—collecting beetles (although it did make pointless most attempts to photograph the area’s stunning landscape). At day’s end, however, a dramatic transformation took place in the sky as the sun sank lower and lower, turning to an increasingly red globe as it strained to shine through the ever thicker layer of smoke and haze. Then, for a few brief moments, the sun floated—a dark red globe under blood red skies—before the thick bottom layers of haze finally extinguished its fading light.

I’ve just begun trying to incorporate setting suns into my photography, having made to this point only a few attempts over Midwestern landscapes. I’m not really sure what gave me the idea, but I thought it might be fun to try incorporating the spectacular sun and unusual sky I was seeing as backgrounds in full-flash insect macrophotographs. Perhaps it seemed a logical progression from the natural sky background macrophotographs that I’ve put a lot of effort into perfecting this year. It was certainly a learning experience, but the basic principle is the same as it is for blue sky background—finding the right combination of camera and flash settings to balance flash illumination of the subject with ambient illumination of the background. The most difficult thing was, surprisingly, getting the sun in the desired position within the composition, as it does not appear through the viewfinder as the discrete ball that is seen in the photos. Rather, it appears as a large, amorphous, blinding flash that comes and goes as one pans across it, leading to a lot of guesswork regarding its actual position within the composition.

I gave a sneak preview of one of these photos in Sunset for another great collecting trip, and several of the photos I’ve shared since then have featured the remarkably colored sky in the background. Here are some other attempts that I was happy with:

Agrilus walsinghami (female) | Washoe Co., Nevada

Agrilus walsinghami (female) | Washoe Co., Nevada

Agrilus walsinghami (male) | Washoe Co., Nevada

Agrilus walsinghami (male) | Washoe Co., Nevada

Crossidius coralinus temprans (male) | Pershing Co., Nevada

Crossidius coralinus temprans (male) | Pershing Co., Nevada

Initially hot yellow (previous photo), the sun turns to soft yellow...

Initially hot yellow (previous photo), the sun turns to soft yellow…

...then yellow-red...

…then yellow-red…

...and finally blood-red!

…and finally blood-red!

Crossidius hirtipes macswainei (female) | Lyon Co., Nevada

Crossidius hirtipes macswainei (female) | Lyon Co., Nevada

Sunset over Toiyabe National Forest | Lyon Co., Nevada

Sunset over Toiyabe National Forest | Lyon Co., Nevada

Gray rabbitbrush (Ericameria nauseosa) | Lyon Co., Nevada

Gray rabbitbrush (Ericameria nauseosa) | Lyon Co., Nevada

Copyright © Ted C. MacRae 2013

GBCT Beetle #3—Crossidius coralinus temprans

On Day 2 of our late August Great Basin Collecting Trip (GBCT), we headed east from Reno towards Fallon (Churchill Co.) and surrounding areas of western Nevada. Our quarry on this day was one of the spectacular Crossidius coralinus subspecies—in this case C. c. temprans. This subspecies was described by Linsley & Chemsak (1961) from large series of specimens collected in Lassen Co., California, but also mentioned were specimens from several locations in west-central Nevada. This material was not included in the type series because of the disjunct distribution but was otherwise not distinguished from the temprans populations, and for us the drive to Churchill Co. was much more feasible logistically than Lassen Co.

Crossidius coralinus temprans (female) | Churchill Co., Nevada

Crossidius coralinus temprans (female) | Churchill Co., Nevada

The female in the photo above is the first individual I encountered at the first stop we made to look for them—a swale about 12 miles west of Fallon in which we noted thick stands of gray rabbitbrush (Chrysothamnus nauseosus) in the early stages of flowering. It was still fairly early in the day, and though we scoured the area thoroughly only a few individuals were seen. The female exhibits some of the main characteristics that set this subspecies apart from the other red/black coralinus subspecies, including the faint bluish overtones, the deep red color, the relatively fine but dense elytral punctation, and its smaller average size. Females in particular exhibit a uniform, broadly expanded black pattern on the elytra that extends along the suture to at least the basal third of the elytra and also possess broadly black humeri connected by a black basal band.

A male from Churchill Co. shows reduction of elytral markings relative to females.

A male, also from Churchill Co., shows reduced elytral markings compared to females.

We had better luck finding individuals in the area 10–15 miles south of Fallon. I’m not sure whether this was due to actual greater abundance or the fact that it was now late morning and temperatures had warmed since our first stop. Nevertheless, we found a mating pair on one of the plants that I had hoped to photograph, but the female got skittish and took flight. Normally when one partner flees the other one does as well, but for some reason the male stayed put—nicely perched on top of the plant—and allowed me to take some photographs. Because I had already disturbed the female, I was pretty sure any attempted handling of the plant to position it with the sky in the background would cause the male to flee as well, so I photographed it as it sat—messy background and all. Still, the male shows the typical characters for males of the subspecies, in particular the faintly bluish dark pattern that is slightly expanded laterally and tapers anteriorly along the suture to the basal one-third of the elytra.

Lateral profile of the male shows a hint of black at the elytral base.

Lateral profile of the male (same individual as above) shows a narrow black band at the base of the elytra.

This lateral shot of the same male was taken, in part, to get an angle that allowed for a cleaner background, but it also more clearly shows the very narrow black band at the base of the elytra that connects the humeri, though the black markings are not as broad as in the female. After photographing this male, we found a spot near Carson Lake where the rabbitbrush was common not just along the road, but in the adjacent rangelands and along dikes adjacent to the wetlands surrounding the lake. There we found pretty good numbers of adults and worked the area for a couple of hours until we had adequate series.

This male from Pershing Co., Nevada has the elytral marking reduced to a narrow sutural stripe.

This male from Pershing Co., Nevada has the elytral markings reduced to a narrow sutural stripe.

Another reason for going east on this day was to take a shot at C. hirtipes bechteli, a subspecies known from only a few localities along the I-80 corridor in north-central Nevada. The westernmost locations were close to Lovelock—a 90-minute drive from where we were, so when we finished up in the area around Fallon we headed towards Lovelock. We knew finding this subspecies was a long shot, since all of the records in Linsley & Chemsak (1961) were from mid- to late September, but since making the effort didn’t impact our ability to arrive at the first planned stop the next day at a decent hour we had nothing to loose by looking for it. We found one of the localities, but the plants at this relatively higher altitude site were still in the earliest stages of bloom, and we didn’t see any adults within about a half-mile stretch of roadside. The effort, however, was not for naught (I love saying that!), as the lateness of the hour and a heavy blanket of smoke from the nearby Rim Fire created a most beautiful blood red sky. Before the day slipped away completely, we stopped at a spot closer to Lovelock to see if we could find a C. coralinus temprans adult to photograph against this unusual backdrop and were immediately rewarded with the fine male shown in the photograph above. Sitting against this marvelous background, the male shows a much reduced black elytral marking that is sometimes the case with males of this subspecies. I hurriedly took as many shots as I could (getting that one photo that I really like is, for me, still a numbers game), but the conditions were fleeting and within a short time it became too dark to take any more.

REFERENCE:

Linsley, E. G. & J. A. Chemsak. 1961. A distributional and taxonomic study of the genus Crossidius (Coleoptera, Cerambycidae). Miscellaneous Publications of the Entomological Society of America 3(2):25–64 + 3 color plates.

Copyright © Ted C. MacRae

Red Rock Canyon National Conservation Area

Calico Hills.

Calico Hills at Red Rock Canyon National Conservation Area | Las Vegas, Nevada.

In mid-August I traveled to Las Vegas with several hundred of my colleagues for week-long, organization-wide meetings. As would be expected, the itinerary was full with little time for diversions, but management was kind enough to call time out on Wednesday afternoon and offer up a choice of activities for us to choose from. Golf, a tour of Hoover Dam, and a massage at the spa were popular choices, but for me and a few other more adventurous sorts the natural choice was a jeep tour of Red Rock Canyon National Conservation Area. I’ll be honest—I hadn’t heard of RRCNCA before then (but then I’d never been nor even had the desire to visit Las Vegas, either), and I’m also not really a guided-tour-sort-of-guy. All I knew was that I was going to have a chance to get outside, at least for short stints, in rugged, natural terrain (something I need a regular dose of in normal circumstances, much less when I’m in the midst of week-long meetings). What I found, however, was an incredible landscape of rock, sky, color and texture that ranks among the most interesting landscapes I’ve ever seen. While I questioned it at the time, I’m really glad I brought my big camera. Not only did the landscape shots turn out so much better than they would have had I decided to settle for iPhone shots, but my long lens (100mm macro) proved to be essential for shots of some petroglyphs that visitors are kept a good distance from. I’ll not go too much into the geology of RRCNCA, as such information can easily be gleaned from Wikipedia (or for more detailed information see this excellent PDF by Tom Battista).

Some of my favorite photos from the afternoon are shown in the following slide show. The photos here are notably free of people (with two very slight exceptions)—more people-based photos featuring the colleagues I was with can be found in my “Red Rock Canyon – Aug 2013” album at my Facebook page.

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Copyright © Ted C. MacRae 2013

GBCT Beetle #2: Agrilus walsinghami

Late summer and early fall is not normally a very good time to go looking for woodboring beetles, which for the most part are found in their greatest diversity and abundance during spring and early summer. This is especially true in the drier western U.S., although notable exceptions occur in the so called “Sky Islands” of southeast Arizona (where most species have shifted their adult activity periods to coincide with late summer “monsoons”) and the lower Rio Grande Valley of south Texas (where spring and fall rains have resulted in bimodal patterns of adult activity for many species). Across the rest of the U.S. a rather limited assemblage of late-season species is found, mostly longhorned beetles associated with fall-blooming composites such as Megacyllene (e.g., M. decora) on goldenrod (Solidago) and Crossidius (e.g. C. hirtipes immaculatus) on rabbitbrush (Chrysothamnus and Ericameria) and snakeweed (Gutierrezia). Late-season jewel beetles are even less common, but one of the few species that does prefer the latter part of the season is also among North America’s most striking species—Agrilus walsinghami.

Agrilus walsinghami (male) | Davis Creek Park, Washoe Co., Nevada

Agrilus walsinghami (male) | Davis Creek Park, Washoe Co., Nevada

This sexually dimorphic species occurs broadly across the western U.S., from British Columbia (Davies 1991) south to Baja California (Hespenheide et al. 2011) and east to Colorado (Nelson & MacRae 1990). Adults are encountered almost exclusively on gray rabbitbrush, Ericameria nauseosa (formerly Chrysothamnus nauseosus, Asteraceae), which despite the lack of any rearing records is nevertheless presumed to serve as the larval host (Hespenheide et al. 2011).  I was hoping I would encounter this species on my recent Great Basin Collecting Trip (GBCT), as I’ve only seen it once previously (in southeast Arizona). The timing seemed right, as most published dates of collection range from mid-July to mid-September, and in fact I encountered and was able to photograph both male and female on the very first day of the trip (23 August) at the very first locality we visited (Davis Creek Park, Washoe Co., Nevada). As it turned out, I would see this species at perhaps a dozen localities or more during the course of the trip, although never in great numbers at any one locality nor with the sky conditions that allowed for the unusual background colors in these photographs (more on that in a future post).

Agrilus walsinghami (female) | Davis Creek Park, Washoe Co., Nevada

Agrilus walsinghami (female) | Davis Creek Park, Washoe Co., Nevada

The notable feature of this species is, of course, its sexual dimorphism, and it is remarkable that no author even mentioned such until Fisher (1928) discussed it in his revision of the genus in North America. Males have the head and pronotum bronzy brown with faint coppery reflections and the elytra brassy with slight purplish tints, while females are larger and more robust and are uniformly blue to greenish blue above. Both sexes have the underside strongly bronzy green with prominent white densely pubescent patches along the lateral portions of the thorax and abdomen and more or less coppery legs, making them truly one of the more spectacular species of Agrilus.

Pubescence

Males (above) and females both exhibit dense lateral pubescent patches.

All told I probably collected between two and three dozen specimens across the localities we visited in western Nevada and southeastern California. Too bad I don’t have more of a commercial mind, as I later discovered that somebody actually purchased one of these beetles on ebay for $16.38! All I would have needed was ~100 specimens of this “very uncommon!” (not!) species and I could have paid for the entire trip!

REFERENCES:

Davies, A. 1991. Family Buprestidae (metallic wood-boring beetles), pp. 160–168. In: Y. Bousquet [ed.], Checklist of the Beetles of Canada and Alaska. Agriculture Canada Publication 1861/E, Ottawa.

Fisher, W. S. 1928. A revision of the North American species of buprestid beetles belonging to the genus Agrilus. Bulletin of the United States National Museum 145:1–347.

Hespenheide, H. A., R. L. Westcott & C. L. Bellamy. 2011. Agrilus Curtis (Coleoptera: Buprestidae) of the Baja California peninsula, México. Zootaxa 2805:36–56.

Nelson, G. H. & T. C. MacRae.  1990.  Additional notes on the biology and distribution of Buprestidae (Coleoptera) in North America, part III.  The Coleopterists Bulletin, 44(3):349–354.

Copyright © Ted C. MacRae 2013