Archive for Arizona

REFLECTIONS ON ARIZONA’S JEWEL SCARABS-Part 1

Posted in Arizona, Beetles, Insects with tags , , , , on September 27, 2010 by Dr. Art Evans

By Arthur V. Evans

I can still remember the very first Chrysina that I ever saw alive in Arizona. It was August 5, 1973 and Bob Duff and I had just set up our black lights in Bog Springs Campground in Madera Canyon. A soft-spoken man sporting a white t-shirt, khakis, and a crew cut came into our camp and introduced himself as Gayle Nelson. Only later did I discover that Dr. Nelson was one of the world’s leading authorities of jewel beetles (Buprestidae).

As the sun slowly set, the oaks all around us came alive with the buzzings of beetles. As Bob, Gayle, and I conversed, my eyes darted nervously this way and that  to each and every buzz in the bushes. This was my first night of black lighting in Southeastern Arizona’s Sky Islands and I did not want to miss any choice beetles! I did not know then that most of this crepuscular beetle activity was just the mating and feeding frenzy of several species of plain brown or black June beetles (Phyllophaga).

Just as darkness had completely descended upon us, I heard a bigger buzz followed by a thud. There on the sheet in front of me was an apple green beetle on its back with its lavender legs clawing at the air. I picked up the gorgeous beetle with my thumb and forefinger, only to discover that it’s powerful legs were tipped with needle-sharp claws. In spite of this surprisingly painful encounter, I was not about to let go of my very first Beyer’s jewel scarab, C. beyeri.

For several years afterwards the abundance of Chrysina at my lights were used as a barometer of sorts. I used their numbers, rightly or wrongly, as a way of measuring my success during many summer nights of black lighting in the mountains of Southeastern Arizona. Eventually my sensibilities began to change.

During the 1990’s, I collected specimens of C. beyeri and C. gloriosa alive and took them back to California for display in the Ralph M. Parsons Insect Zoo at the Natural History Museum of Los Angeles County, where I worked as the director. Both species thrived for several months on diets of oak leaves and juniper, respectively. Although the captive scarabs produced plenty of grubs, I made no effort to rear them to adulthood. To this day I regret not writing a formal description of the larva of Beyer’s jewel scarab and submitting it for publication; as of this writing, the immature stages of this species remain undescribed.

Now I regard species of Chrysina at my lights simply as old friends and no longer feel the urge to collect them in long series, if at all. I have heard stories of collectors and dealers with considerably less restraint collecting hundreds of specimens from the same mountain canyons, year after year. This annual carnage has led some people to wonder out loud whether or not Arizona’s Chrysina are in real need of some sort of legal protection. Nearly 30 years ago, Arnett and Jacques (1981) declared that both C. beyeri and C. gloriosa, which they mistakenly thought were the only species in the United States, were “…endangered and should not be collected.” However, on a warm and dry night in Madera Canyon this past July, all three species of Arizona’s Chrysina turned up at my light in good numbers. One species, C. gloriosa, was there in incredible abundance. Still, it would be worthwhile for a university or governmental agency to study the overall impact of intensive collecting on Chrysina populations in Madera Canyon and other popular collecting sites in southeastern Arizona.

Commonly known as jewel scarabs, the genus Chrysina is replete with incredibly beautiful, often metallic species. It includes nearly 100 species, most of which occur in Mexico and Central America. The four species in the United States are relics of a rich Neotropical fauna that expanded northward during more favorable (wetter) periods. For the past 10,000 years or so, these species were able to adapt to an increasingly warmer and drier climate by taking refuge in the high elevations of mountains.

 

Weldon Heald

 

The Southwest mountains inhabited by Chrysina are like stepping stones that bridge the gap between the temperate flora and fauna of the Rocky Mountains of the United States and the tropical biota of the Sierra Madre Occidental of Mexico. This archipelago of mountain “islands” in southeastern Arizona, southwestern New Mexico, and northern Mexico are surrounded by hot, dry desert “seas.” As such, they were dubbed “Sky Islands” nearly 60 years ago by the natural history writer Weldon Heald. Arizona’s Sky Islands are home to three species of Chrysina; the fourth American species is found in Texas.

All four of the American jewel scarabs were originally described in the genus Plusiotis. As a result of morphological and DNA evidence, the newer name Plusiotis was deemed redundant in relation to the older monicker Chrysina and it was formally synonymized by Dave Hawks (2001). The first species known in the United States, the glorious jewel scarab (C. gloriosa), was described by the father of American coleopterology, John L. LeConte in 1854. LeConte described this emerald-green and silver-striped species based on specimens collected at a copper mine in Texas that are now in the Museum of Comparative Zoology (MCZ) at Harvard.  These specimens were collected by the Secretary of the United States and Mexican Boundary Commission, Thomas Hopkins Webb. A physician from Rhode Island, Webb was appointed Secretary of the Commission in 1850, a position he held until 1854. In addition to his full-time position as Secretary, Webb enthusiastically collected insects, fishes, and reptiles and sent them to the leading authorities of the day. Later, he would become the secretary and principal executive officer of the Massachusetts Institute of Technology.

According to my friend, colleague, and Arizona scarabaeologist Bill Warner, C. gloriosa occurs in nearly all of the mountain ranges in at least the southern three-quarters of the state where their food plant, Juniperus, grows. Glorious jewel scarabs also occur in New Mexico, and Texas, as well as the Mexican states of Chihuahua and Sonora. With the onset of the summer monsoons, adults often spend their daylight hours feeding and resting on junipers; they are commonly attracted to lights at night, sometimes in large numbers.

In 1882, two years after LeConte’s death, another prominent coleopterist named George Horn described the second American species of Chrysina, LeConte’s jewel scarab (C. lecontei). His description was based on three examples now housed at the MCZ. These included one specimen from Tucson in the cabinet of England-born actor and entomologist Henry Edwards, another from LeConte’s cabinet collected in New Mexico by the curator of the insect collection at the University of Kansas, Professor Francis H. Snow, and a series in his own collection from Prescott, Arizona. Without any fanfare whatsoever, Horn ended his description by quietly dedicating the new species “to a friend.”

Warner notes that LeConte’s jewel scarab has essentially the same range in Arizona as the glorious jewel scarab, but that it is a bit more restricted to the higher altitudes where its food plant, the ponderosa pine, occurs. This species also occurs in New Mexico and the Mexican states of Chihuahua, Durango, Sinaloa, and Sonora.

 

Henry Skinner

 

The third American species of Chrysina was first exhibited by Horn on November 9, 1883 at a meeting of the entomological section of the Academy of Natural Sciences in Philadelphia. He presented two specimens collected in Rio Grande, Texas by his friend and Philadephia physician, Dr. Horatio C. Wood. Wood was a pioneer in American pharmacology who published numerous papers on pharmacology, physiology, and experimental therapeutics and taught neurology and internal medicine at the University of Pennsylvania. Early in his career Wood published papers in botany, entomology, and myriapodology. He traveled to the borderlands to collect specimens for the Smithsonian Institution and was one of the first white men to see the Grand Canyon. Wood recalled to lepidopterist Dr. Henry Skinner (1905) that the beetles he had given to Horn were either collected near El Paso, Texas, or in the valley of Tornellias [Tornillo] Creek at the great bend of the Rio Grande. The beetles were described in the minutes for the meeting as “pale malachite green, narrowly bordered with pale gold, the elytra are not striate, but with rows of fine punctures, the tarsi are beautifully violet.” Horn formally described Wood’s jewel scarab, Chrysina woodii, in 1885. These specimens are also housed in the MCZ. Horn noted that he saw another specimen in the Museum of the Jardin des Plantes in Paris. Wood’s jewel scarabs eat the leaves of walnut trees and are apparently diurnal, although some individuals are attracted to lights at night. It also occurs in Chihuahua, Mexico.

In 1905, Skinner, a gynecologist as well as co-founder and editor (1890-1910) of the Entomological News, described Beyer’s jewel scarab (C. beyeri) from four specimens collected in Carr and Miller Canyons in the Huachuca Mountains in southeastern Arizona. This handsome species first came to his attention the previous year when a specimen was sent to him from Reef in Cochise County. Reef was a mining camp in the southwest corner of Cochise County near the Mexican border. It was located in Carr Canyon in the Huachuca Mountains and was named for a noted landmark Carr Reef, an exposed and thick layer of rock. The site is now a campground in the Coronado National Forest. Skinner examined additional specimens presumably collected from the same locality by Beyer, Schaeffer, and Biederman. The Reef post office was officially relocated to Palmerlee (at the base of Miller Canyon) in December of 1904.

Gustav Beyer was a fur manufacturer from New York and an indefatigable insect collector who frequently travelled with his friend and Curator of Coleoptera at the Brooklyn Museum Institute of Arts and Sciences, Charles F. A. Schaeffer. Schaeffer spent a considerable amount of time collecting beetles at his three favorite haunts: Mt. Mitchell in North Carolina, the Lower Rio Grande Valley in Texas, and the Huachuca Mountains. Charles R. Biederman, a veteran of the Confederate Army and a resident of the Huachuca Mountains, was an ardent insect collector and is buried on his homestead in Carr Canyon. Before the advent of collecting Chrysina and other nocturnal beetles at light, both Biederman (1907) and another collector, Karl Coolidge (1911), noted a decided lack of success in obtaining specimens of C. beyeri, in spite of considerable searching about trees and in leaf litter. After finding a single specimen of C. beyeri in leaf litter, Biederman raked nearly two acres of leaves to find more beetles, but came up empty handed.

Beyer’s jewel scarab has the most restrictive distribution of all Arizona’s Chrysina and is known only from the Santa Rita, Patagonia, and Huachuca Mountains; it also occurs in the Animas Mountains of New Mexico and the states of Chihuahua and Sonora, Mexico. Adults feed on the leaves of Mexican blue oak, Quercus oblongifolia.

In 1915, Colonel Thomas Lincoln Casey, a noted and somewhat controversial coleopterist, described several species of Plusiotis, all of which have long been considered synonyms of the previously mentioned species.

Arizona’s jewel scarabs are not only popular with collectors and macro photographers, they also serve as wonderfully instructive subjects for scientific study, especially for scientists seeking to understand the physical qualities and adaptive significance of their brilliant colors. More on this subject will appear in the second and final installment of “Reflections on Arizona’s Jewel Scarabs.”

Sources:

Arnett, R. H., Jr, and R. L. Jacques. 1981. Simon & Schuster’s Guide to Insects. New York: Simon & Schuster. 511 pp.

Barnes, W. C. 1988. Arizona Place Names. Tucson, AZ: University of Arizona Press.

Biederman, C. R. 1907. Notes on Plusiotis beyeri Skinner. Entomological News 18: 7-9.

Burke, H. R. 2004. Notable Weevil Specialists of the Past. Charles Frederick August Schaeffer (1860-1934). Curculio 49: 5-7. Accessed on 26 September 2010 at: <http://www.texasento.net/Schaeffer.html#Burke>.

Calvert, P. P. 1926. The entomological work of Henry Skinner. Entomological News 37: 225-249.

Coolidge, K. R. 1911. Plusiotis beyeri Skinner. Entomological News 22: 326-327.

Evans, A. V. 2007. National Wildlife Federation Field Guide to Insects and Spiders of North America. New York: Sterling. 497 pp.

Hawks, D. 2001. Taxonomic and nomenclatural changes in Chrysina and a synonymic checklist of species (Scarabaeidae: Rutelinae). Occasional Papers of the Consortium Coleopterorum 4(1):  1-8.

Hawks, D. 2001. Checklist of Chrysina species (Scarabaeidae: Rutelinae: Rutelinae). (URL: http://www.unl.edu/museum/research/entomology/Guide/Scarabaeoidea/Scarabaeidae/Rutelinae/Rutelinae-Tribes/Rutelini/Chrysina/Chrysina-Catalog/ChrysinaC.html). In B.C. Ratcliffe and M.L. Jameson (eds.), Generic Guide to New World Scarab Beetles (URL: http://www-museum.unl.edu/research/entomology/Guide/Guide-introduction/Guideintro.html). Accessed on: 27 September 2010.

Horn, G. H. 1882. Notes on some little known genera and species of Coleoptera. Transactions of the American Entomological Society 10(1): 113-

Horn, G. H. 1885. New North American Scarabaeidae. Transactions of the American Entomological Society. 12: 117-128.

LeConte, J. L. 1854. Descriptions of the Coleoptera collected by Thos. H. Webb, M.D., in the years 1850-51 and 52, while Secretary of the U.S. and Mexican Boundary Commission. Proceedings of the Academy of Natural Sciences of Philadelphia 7: 220-225.

Leng, C. W. 1924. Gustav Beyer. Journal of the New York Entomological Society 32(4): 165-166.

Quincy, J. P. 1882. Memoir of Thomas Hopkins Webb. Proceedings of the Massachusetts Historical Society 19: 336-338.

Roth, G.B. 1939. An early American pharmacologist. Horatio C. Wood. 1841-1920. Isis 30(1): 38-45.

Skinner, H. 1905. Descriptions of new Coleoptera from Arizona with notes on some other species. Entomological News 16: 289-292.

© 2010, A.V. Evans

A MIGHTY MITE!

Posted in Arachnids, Predators/parasites/parasitoids with tags , , , on September 23, 2010 by Dr. Art Evans

By Arthur V. Evans

In the deserts of Africa, Asia, Europe, and North America large velvety red mites appear suddenly after heavy rains. Southwestern United States has at least two species of these amazing mites.

This past July, I came across a lone individual of a giant red velvet mite, Dinothrombium magnificum (LeConte) emerging from its burrow just east of the Patagonia Mountains in southeastern Arizona where it inhabits the Sonoran Desert and adjacent uplands.

Giant red velvet mites are spectacular for several reasons. First, the largest individuals measure in at a whopping one centimeter in length, which makes them the largest mites in the world. They are covered with a thick coat of scarlet hair-like setae. The mite’s bright red color is apparently aposematic in function and serves to warn predators of their bad taste. Entomophagous animals offered giant red velvet mites either rejected the arachnids outright or quickly spit them out.

Although often difficult to find, they are sometimes extremely abundant locally, if only for a few hours at time. For example, after a brief yet intense thunderstorm, a massive emergence of giant red velvet mites was sighted from the air at an altitude of 1500 feet just north of  Tucson. An estimated 3-5 million mites had emerged in an area roughly two acres in size!

The annual emergence of the giant mites is apparently timed to coincide with that of their primary prey, termites. However, their opportunity to gorge themselves on abundant termite reproductives is quite limited. After mating, the termites quickly shed their wings and bury themselves so that they are out of reach of the mite’s predatory embrace. Adult giant red velvet mites spend most of their lives in subterranean burrows in a diapause-like state waiting for a specific set of ecological conditions triggered by summer monsoons.

Resources:

Evans, A.V. 2007. National Wildlife Federation Field Guide to Insects and Spiders of North America. NY: Sterling. 497 pp.

Lighton, J.R.B. and F.D. Duncan. 1995. Standard and exercise metabolism and the dynamics of gas exchange in the giant red velvet mite, Dinothrombium magnificum. Journal of Insect Physiology 41(10): 877-884.

Newell, I.M. and L. Tevis, Jr. 1960. Angelothrombium pandorae n.g., n. sp. (Acari, Trombidiidae), and notes on the biology of the giant red velvet mites. Annals of the Entomological Society of America 53: 293-304.

Tevis, L., Jr. and I.M. Newell. 1962. Studies on the biology and seasonal cycle of the giant red velvet mite, Dinothrombium pandorae (Acari, Trombidiidae). Ecology 43(3): 497-505.

Zhang, Z.-Q. 1998. Biology and ecology of trombidiid mites (Acari, Trombidioidea). Experimental and Applied Acarology 22: 139-155.


© 2010, A.V. Evans

TARANTULA VS. TARANTULA HAWK

Posted in Ants, bees, wasps, Arachnids, Arizona, Insects, Parental care, Predators/parasites/parasitoids with tags , , , on September 15, 2010 by Dr. Art Evans

By Arthur V. Evans

One of nature’s classic battles is that of the lopsided struggle between a tarantula and its arch nemesis, the tarantula hawk (PepsisHemipepsis). I say lopsided because the odds are usually stacked against the tarantula. The arachnid, paralyzed by the wasp’s sting, is destined to be dragged off and stuffed down a previously dug burrow to become an egg-laying site and eventual fodder for a ravenous wasp grub.

In August, I photographed a tarantula hawk as it dragged a paralyzed female desert blonde tarantula, Aphonopelma chalcodes, across a coarsely gravelled driveway at the foot of the Huachuca Mountains in Sierra Vista, Arizona.

I first became aware of this saga in Walt Disney’s Academy Award winning documentary The Living Desert (1953 and later re-released in 1971) that depicted a day in the life of desert flora and fauna and the struggles of the latter to simultaneously find food and avoid being eaten themselves. It was 10 minutes of film footage featuring a tarantula hawk grappling with a tarantula shot by N. Paul Kenworthy, then a doctoral student at UCLA, that inspired Disney to produce his first documentary. Kenworthy later became one of the two macro cinematographers on the project. I met The Living Desert’s other macro cinematographer, entomologist Bob Crandall, while I was in high school. But that is another story for another time.

© 2010, A.V. Evans

GRASSHOPPER LOVE

Posted in Arizona, Defense, Grasshoppers & crickets, Insects with tags , , , , , on September 15, 2010 by Dr. Art Evans

By Arthur V. Evans

Arguably the most spectacular looking and certainly among the most distinctive of all the grasshoppers in North America, painted grasshoppers, Dactylotum bicolor (24-32 mm) are a riot of color. These boldly marked orthopterans are also known as rainbow or barber-pole grasshoppers. Studies have shown that diurnal predators, especially birds, will avoid eating them presumably because of their aposematic coloration. Females tend to be significantly larger than the males.

Painted grasshoppers make their living along the western edge of the Great Plains from southern Saskatchewan south to western Texas and northern Mexico, and west to Arizona. Active from mid- to late summer, painted grasshoppers feed on a wide variety of desert plants, especially grasses and low broadleaf plants.

© 2010, A.V. Evans

SKY ISLANDS, DESERT SEA-Part II, Hornworm Highway

Posted in Arizona, Insects, Moths, Musings, Predators/parasites/parasitoids with tags , , , , on April 26, 2010 by Dr. Art Evans

By Arthur V. Evans

Charged by the onset of the summer monsoons in July or August, the arthropods of Arizona’s Sky Islands and desert seas are stirred into action.  The sudden and intense infusion of life-giving moisture triggers a flush of activity: eggs hatch, hungry larvae gobble up new leaves, adults are released from their earthen or wooden chambers, eager to mate and reproduce.  It is this marvelous intensity of arthropod activity that has drawn me to the mountains, desert scrub and grasslands of southeastern Arizona for nearly 40 years.

My earliest impressions of Arizona’s desert seas were formed by numerous overland trips from California in the 1970’s. Within minutes of crossing the Colorado River, the first saguaros would greet us, stationed like lone sentinels high on the rocky ridges of the Dome Rock Mountains. Although these giant columnar cacti have become symbolic of all arid regions of the southwest, they are strictly indigenous to the Sonoran Desert. These and other nearby desert ranges are capable only of supporting plants and animals adapted to fleeting amounts of rain. The summer monsoons, even at their height, seldom penetrate this far north and west.

Driving east from Gila Bend to the Maricopa Mountains, the stands of saguaros become taller and denser. Compared to the deeply pleated trunks of their western brethren, the almost bulging flesh of these plants is a clear sign of increased precipitation. The saguaros’ spongy inner tissues rapidly expand to absorb and store seasonal supplies of water as a hedge against the inevitable drought ahead.  Even the spiny ocotillo stand taller and greener here, surrounded by dense thickets of palo verde.  Here all living things enjoy the increased benefits of living under the blanket of the summer monsoons.

Another sure sign of increased rainfall is the sporadic population explosion of green and black-striped hornworms, caterpillars of the white-lined sphinx moth, Hyles lineata. Dozens to hundreds of these insects race across the hot, blistering highway in a scramble for tender desert greens. Some years there are so many of the caterpillars that the pavement becomes slick with their crushed bodies. At night marauding three-inch-long shield-backed katydids of the genus Capnobates rip chunks of sun-dried caterpillar from the road and grind them up with their powerful jaws, while scores of ants carve up the leftovers and carry them back to their underground brood.

© 2010, A.V. Evans

SKY ISLANDS, DESERT SEA-Part 1

Posted in Arizona, Environment with tags , , , on April 7, 2010 by Dr. Art Evans

By Arthur V. Evans

“…some of the earth’s most interesting “islands” are nowhere near oceans or lakes. They are strictly land islands but with a climate, vegetation, and animal life as different from their surroundings as if they rose from some remote sea.”

Weldon Heald in Sky Islands

A conservationist and journalist, Weldon Heald coined the term “Sky Islands” nearly 60 years ago to describe the archipelago of mountain ranges spanning the gap between the Rocky Mountains and the Sierra Madre Occidental of central Mexico. Made up of more than 40 isolated mountain ranges, the Sky Islands cover two countries in the states of Arizona, New Mexico, Sonora and Chihuahua. The diversity of flora and fauna inhabiting this region is unmatched in temperate North America. Warmer than the Rocky Mountains and drier than the Sierra Madre Occidentale, these unique and isolated mountain ranges support a wealth of temperate and tropical arthropod species.

The mouth of Cave Creek Canyon, Chiricahua Mountains, Cochise County, Arizona.

The Arizona Sky Islands consist of the Santa Rita, Rincon, Huachuca, Santa Catalina, Whetstone, Bobaquivari, Pinaleño, and Chiricahua Mountains. Climbing thousands of feet into the sky, these lush mountains and their canyons stand in stark contrast to the surrounding lowlands. It is the sheer mass and altitude of these ranges that keeps their peaks and canyons much cooler and wetter than the surrounding desert scrub and grasslands. On average, mountain temperatures drop 4 º Fahrenheit for every 1,000 feet of elevation, while at the same time, annual precipitation increases by four inches. These moisture and temperature gradients create life zones that support populations of arthropods poorly adapted for survival in the relatively harsh, dry environs below. Unable to migrate across this “desert sea,” many of the arthropods inhabiting Arizona’s Sky Islands have been marooned for hundreds of centuries.

© 2010, A.V. Evans

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