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

Crossidius hirtipes rhodopus in Adobe Valley, California

Crossidius hirtipes rhodopus | Adobe Valley, Mono Co., California

Crossidius hirtipes rhodopus Linsley, 1955 | Adobe Valley, Mono Co., California

On Day 7 of last August’s Great Basin Collecting Trip, we left Bishop and headed back north to the Mono Basin to look for Crossidius hirtipes rhodopus, a distinctive reddish subspecies known only from the Mono Basin. I’d seen this beetle before—almost 20 years ago during one of several trips to the type locality of Nanularia monoensis (described by my late friend Chuck Bellamy in his 1987 revision of the genus), so we drove south of Mono Lake on Hwy 120 through Adobe Valley on our way to the Benton Range where I last saw them. Of course, C. h. rhodopus occurs more broadly in the Mono Basin than just the Benton Range, and as we drove through the valley we saw robust stands of the beetle’s host plant, yellow rabbitbrush (Chrysothamnus viscidiflorus), in full bloom stretching across the floor of the valley to the towering White Mountains in the distance. Impatience can sometimes be a virtue, and in this case our decision to stop and check the plants rather than waiting until we got to the Benton Range paid off—not only were the beetles out in force, allowing us to photograph and collect to our heart’s content, but we saw only a few beetles on but a single flowering plant during our subsequent visit to the Benton Range. Apparently the rains that had caused such a profusion of bloom in the Adobe Valley had not graced the Benton Range, resulting in the driest conditions I have seen during my several visits there.

This subspecies is one of the more darkly colored subspecies

This subspecies is one of the more darkly colored subspecies

Crossidius h. rhodopus is among the most distinctive of all the C. hirtipes subspecies due to its dark reddish-brown coloration. It closely resembles C. h. nubilus, which we had seen the day before at its only known locality further south at Westgaard Pass between the White and Inyo Mountains, but it is not as dark as that subspecies and lacks the extensive clouding of black on the apical portions of the elytra. The red-brown legs and brown antennae becoming darker at the tip further characterize C. h. rhodopus, originally described as a full species (Linsley 1955) but later regarded as a subspecies of the widely distributed and highly polytopic C. hirtipes LeConte, 1854 (Linsley & Chemsak 1961).

Yellow rabbitbrush (Chrysothamnus viscidiflorus) abounds in the valley, as the White Mountains loom in the background.

Yellow rabbitbrush (Chrysothamnus viscidiflorus) abounds below the magnificent White Mountains.

Those who are unfamiliar with the Mono Basin are missing one of California’s greatest natural treasures. A closed, internal-drainage basin bordered to the west by the massive Sierra Nevada Mountains (with Yosemite National Park lying just over the peaks), to the east by the Cowtrack Mountain, to the north by the Bodie Hills, and to the South by the north ridge of the Long Valley, the eerily beautiful Mono Lake is its most prominent feature. Do not, however, neglect other areas of the basin, which offer their own uniquely dramatic beauty. Adobe Valley, stretching south of the lake towards the White Mountains and famous for the wild mustang that live there, is one such area.

A handsome male rests on yellow rabbitbrush flowers (studio shot).

A robustly handsome female perches a terminal flower cluster of yellow rabbitbrush (studio shot).

REFERENCES:

Linsley, E. G. 1955. Notes and descriptions of some species of Crossidius. The Pan-Pacific Entomologist 31(2):63–66.

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

The sublimely beautiful Crossidius coralinus caeruleipennis

Crossidius coralinus caeruleipennis | Inyo Co. nr. Bishop, California

Crossidius coralinus caeruleipennis | Owens Valley nr. Bishop, California

Before driving up into the White Mountains to look for Crossidius hirtipes nubilus and see the grotesquely beautiful trees at Ancient Bristlecone Pine Forest, we made a short two-mile drive north of our hotel in Bishop, California to try our hand with a C. coralinus subspecies that I referred tangentially in my previous postC. c. caeruleipennis. This has to be among the most beautiful subspecies that I’ve seen yet of what must be considered one of North America’s most attractive species of longhorned beetle. In contrast to the other “orange” subspecies, C. c. monoensis, which we had collected the previous day but that I did not even recognize as C. coralinus because of its color and very small size, I knew exactly what I was looking for on this day as we began to scan the gray rabbitbrush (Ericameria nauseosa) plants that stretched out across the Owens Valley sage grassland as far as the eye could see. At first we were worried that we might be a little late, as most of the plants appeared to be somewhat past peak bloom, but it wasn’t long before we found the first individual sitting atop a flower cluster, and then another, and another...

Males are completely orange.

Males are solid, sublimely orange with strikingly contrasting black legs and antennae.

Crossidius c. caeruleipennis is immediately distinguishable from C. c. temprans (and most of the other C. coralinus ssp. that we collected on the trip further north in Nevada and east in Utah and Colorado) by its bright orange rather than dark red coloration. The subspecies is restricted to the Owens Valley of eastern California and greatly resembles another of the orange subspecies that we collected on the trip, C. c. monoensis. That subspecies is found just a short distance north in the Mono Basin, though at much higher elevations, and is easily distinguished from C. c. caeruleipennis by its smaller average size, by having the black markings of the elytra more expanded apically in females and at least present in males, and by the presence of black bands along the apical and basal margins of the pronotum (Linsley & Chemsak 1961).

Females have a distinct apical blue-black marking on the elytra

Females are distinguished by the apical blue-black marking on the elytra and their shorter antennae.

As it turned out, the beetle was as abundant as any we had seen on the trip to that point. Not that it didn’t require some effort to collect them—they were still rather sparsely distributed among the plants and definitely showed preference for plants that were not as far past peak bloom. However, the habitat was extensive—we could have wandered freely for hours on end without looking at the same plant twice (although that did not stop me from re-checking a few plants that were in peak bloom and seemed to be especially favored). The males were simply gorgeous—a bright, creamy orange that sadly takes on a dull quality in preserved specimens and with long black legs and antennae. The females are no dogs either, less strikingly orange due to the blue-black apical markings on the elytra, but certainly more robust than the males in a subspecies that is already one of the larger of the species. Temperatures climbed rapidly at this relatively southern and lower elevation locality compared to most of the others that we visited during the trip, so the beetles became quite active very quickly after we began to see them. I had only a short window of time in which to attempt field photographs, and while I’m not completely satisfied with the ones that I show here, they were the best that I could manage and still get the blue sky background that I desire for “beetles on flowers” photographs.

Sage grassland and gray rabbitbrush dominate the Owens Valley where C. coralinus caeruleipennis is found.

Gray rabbitbrush dominates the Owens Valley sage grassland where C. coralinus caeruleipennis occurs.

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 2014

Clouded beetles amidst spectacular scenery

“Westerly from Westgard Pass is a view equaled in few parts of America. In the middle distance, a dozen miles away and nearly a mile below, lies the fertile Owens Valley, extending at right angles north and south over a hundred miles, and on the farther side, distant a score of miles, tower the snow-clad Sierras, with serrated crests and symmetric domes and peaks outlined against the sky at an approximate height of two and one-half miles vertical above the level of the ocean, and extending north and south far as the eye can see. The vision is rich reward for a journey of a thousand leagues.”—A. L. Westgard, March 1915

View of Westgard Pass from higher up in the White Mountains near Ancient Bristlecone Pine Forest.

View to Westgard Pass from higher up in the White Mountains near Ancient Bristlecone Pine Forest.

After a morning spent searching for Crossidius coralinus caeruleipennis (perhaps the most sublimely beautiful of the subspecies) in the high desert sage of the wide open Owens Valley floor near Bishop, California, we made the short drive south to Big Pine, turned sharply left, and began the slow, twisting ascent through a narrow gap between the White Mountains to the north and the Inyo Mountains to the south. Eventually reaching an elevation of 7,313 ft,  Westgard Pass serves as access to Earth’s oldest living things! and, in doing so, provides some of the most striking scenery in the entire Basin and Range Province of eastern California.

Westgard Pass, Inyo Co., California.

Chrysothamnus viscidiflorus (small plants with yellow flowers) host Crossidius hirtipes nubilus adults.

Field mate Jeff Huether and I no doubt wanted to see the grotesquely beautiful trees growing in Ancient Bristlecone Pine Forest and were happy to enjoy the magnificent scenery along the way, but our trek to Westgard Pass had also a strictly entomological purpose—to search for Crossidius hirtipes nubilus, among the most uniquely colored and geographically restricted of the C. hirtipes subspecies. Approaching the summit, the narrow, rocky gorge opened up to a broad expanse of pinyon/juniper woodland, and nestled among the ubiquitous sage we found the plant we were looking for—yellow rabbitbrush (Chrysothamnus viscidiflorus) in full bloom.

Crossidius hirtipes nubilus (male) on flowers of Chrysothamnus viscidiflorus.

Crossidius hirtipes nubilus (male) on flowers of Chrysothamnus viscidiflorus (field photo).

It took a while, however, before we found the beetles that we were looking for. Robust gray rabbitbrush (Ericameria nauseosa) plants in full bloom conspicuously dominated the roadsides and demanded our initial attentions, but our only reward was the widespread Crossidius ater. Not even a single Crossidius coralinus specimen could be claimed as consolation. Still, we knew the real quarry was further back from the roadsides, on the much smaller and less conspicuous yellow rabbitbrush that serves as an adult host for Crossidius hirtipes and most of its subspecies. Once we turned our attentions to these smaller plants we found the first adult fairly quickly, but precious few were seen considering the many plants that we examined until we finally zeroed in on one area just south of the summit where the beetles seemed to occur with slightly greater frequency. While not numerous, we eventually found enough beetles for us to declare, “Let’s go see the bristlecone pines!”

In addition to their longer antennae, males are distinguished by xxx.

In addition to longer antennae, males are distinguished by less extensive clouding (studio photo).

This subspecies is among the most distinctive of all the C. hirtipes subspecies due to the combination of dark reddish-brown coloration and extreme, dark clouded area of the elytra (Linsley & Chemsak 1961). It most closely resembles C. h. rhodopus, which occurs further north in the Mono Basin, but that subspecies is not as dark and lacks the extensive clouding of black on the apical portions of the elytra.

Females have the elytral markings xxx.

Females have the markings greatly expanded to almost completely cover the elytra (studio photo).

The dark clouding actually represents an expansion of the dark stripe found along the suture of the elytra of many C. hirtipes subspecies, most of which exhibit sexual dimorphism in the degree to which this stripe is developed. In some subspecies the stripe is present in the females but absent in the males, while in others the stripe is present in both but more fully developed in the female. In C. h. nubilus the sutural stripe reaches an extreme state of development, covering much of the apical two-thirds of the elytra in the male and being so greatly expanded in females that almost the entire elytra are covered except for two small subbasal patches revealing the ground color of the elytra.

REFERENCES:

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

The wondrously and eerily beautiful Mono Lake

During my recent Great Basin collecting trip, we stopped briefly at one of my favorite places in the world—Mono Lake in eastern California. My last visit was almost 20 years ago, so it was a thrill for me to see the strange tufa moonscape once again after so many years.

Mono Lake

Mono Lake has no eventual outlet to the ocean. As a result dissolved salts in runoff from the surrounding landscape have accumulated in the lake, resulting in water with high pH levels.

Mono Lake

The late day shadows created a black/white tufa landscape.

Mono Lake

Conservation actions have raised lake levels from their historical lows resulting from diversion of water to Los Angeles, but they have still not recovered to their former levels.

Mono Lake

I held the camera barely above the water’s surface to get this shot. It took several tries to get just a thin sliver of perfectly horizontal water. Yes, it would have been easier to hold the camera higher, look through the viewfinder and then crop, but I wanted the widest view possible (besides, doing that would seem like “cheating”).

Mono Lake

Tufa forms when calcium from underwater springs comes into contact with carbonates in the lake water, causing a chemical reaction that produces calcium carbonate (limestone). The calcium carbonate settles around the underwater spring and over time builds a tufa tower. This happens only underwater, and the tufa towers seen here are visible only because of the lowered lake level resulting from water diversion. Unless the lake level is restored completely, these towers are “dead” and will eventually erode away.

Mono Lake

Smoke and haze from the Rim Fire burning near Yosemite boils over the eastern slope of the Sierra Nevada.

Mono Lake

Mono Lake supports the second largest nesting population of California gulls after Utah’s Great Salt Lake.

Mono Lake

The water level at Mono Lake has dropped not only in recent years because of humans, but over several thousand years. At the end of the last ice age the water level was hundreds of feet higher than today and the lake 5 times its present size.

Mono Lake

Late day shadows, wildfire haze, and perfectly still waters create a surreal scene.

Copyright © Ted C. MacRae 2013

Pedantic Sunday: Blister beetles don’t suck

Nemognatha cribraria cribraria on flower head Chrysothamnus viscidiflorus | Millard Co., Utah

Nemognatha cribraria cribraria on flowers of Chrysothamnus viscidiflorus | Millard Co., Utah

The beetle featured in today’s photo is the blister beetle (family Meloidae), Nemognatha cribraria cribraria. The genus Nemognatha and its relatives in the subfamily Nemognathinae are distinctive due to the greatly elongated adult mouthparts that are modified for feeding on flowers. Specifically, parts of the maxillae, or second pair of mouthparts (behind the mandibles) are elongated to allow access to nectar in flowers with deep corollas, while the fairly standard-issue chewing mandibles are used for feeding on pollen. As pointed out by Enns (1956) in his revision of the North American members of the genus, the length of the maxillae seems to be related to the particular kind of flower preferred for feeding by the various nemognathine species, with species exhibiting longer maxillae adapted to feeding on flowers with deeper corollas. In the photo above, the elongated maxillae can be seen tucked underneath the adult and appear to be nearly half the length of the body—other species in the genus have the maxillae as long as the body, or in the case of a Mexican species (N. chrysomeloides) even longer than the body (Enns 1956).

The proboscis-like mouthparts of nemognathine blister beetles are often depicted in entomological texts as an amazing example of sucking mouthparts in Coleoptera, the vast majority of which possess strictly chewing mouthparts. Borrer et al. 1976, White 1983, Downie & Arnett 1996, and Pinto & Bologna 2002 all mention that the mouthparts are modified into an elongated proboscis for “sucking” nectar, and it has been suggested that nectar uptake occurs through a median food canal, formed by concavities on the inner surfaces when the two structures are locked together into a functional unit. However, Wilhemi & Krenn (2012) used scanning electron microscopy and micro computerized tomography to study the elongated mouthparts of three meloid genera: Nemognatha and Gnathium and Leptopalpus. They demonstrated that neither the elongated galeae of Nemognatha and Gnathium nor the elongated maxillary palpi of Leptopalpus formed a median food canal through which nectar is sucked. Furthermore, the filiform galeae of Nemognatha and Gnathium are densely covered with long bristles, suggesting that nectar uptake in these two genera is accomplished by capillary action along the bristles of the proboscis. In all three genera nectar transport is likely aided by musculature around the mouth.

REFERENCES:

Borrer, D. J., D. M. DeLong & C. A. Triplehorn. 1976. An Introduction to the Study of Insects, Fourth Edition. Holt, Rinehart and Winston, xii + 852 pp.

Downie, N. M. & R. H. Arnett, Jr. (Eds.). 1996. The Beetles of Northeastern North America. Volume II: Polyphaga: Series Bostrichiformia through Curculionoidea. The Sandhill Crane Press, Gainesville, Florida, x + 891–1721.

Enns, W. R. 1956. A revision of the genera Nemognatha, Zonitis, and Pseudozonitis (Coleoptera, Meloidae) in America north of Mexico, with a proposed new genus. The University of Kansas Science Bulletin 37, part 2(17):685–909 [Biodiversity Heritage Library].

Pinto, J. D. & M. A. Bologna. 2002. Chapter 111. Meloidae Gyllenhal 1810, pp. 522–529. In: R. H. Arnett, Jr., et al. (Eds.). American Beetles, Volume 2. CRC Press, Gainesville, xiv + 861 pp.

White, R. E. 1983. A Field Guide to the Beetles of North America. The Peterson Field Guide Series, Houghton Mifflin Co., Boston, xii + 368 pp.

Wilhelmi, A. P. & H. W. Krenn. 2012. Elongated mouthparts of nectar-feeding Meloidae (Coleoptera). Zoomorphology [abstract].

Copyright © Ted C. MacRae 2013