Archive for Natural history

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

COW KILLERS LACK THE VELVET TOUCH

Posted in Ants, bees, wasps, Defense, Insects, Parental care, Predators/parasites/parasitoids with tags , , , , on September 22, 2010 by Dr. Art Evans

By Arthur V. Evans

Velvet ants, some of which are also known as cow killers, are actually solitary wasps. The females are wingless and sting, while the stingless males are fully winged. Although incredibly painful, the sting is seldom dangerous. Velvet ants are rarely abundant enough to need any sort of control and are best left alone to go about their business.

Velvet ant diversity is greater in southwestern United States, less so in the Southeast. Although there are more than 40 species of velvet ants found in the Southeast, only one species in the region, Dasymutilla occidentalis, stands out. It is the largest species of velvet ant in North America and occurs from Connecticut to Florida, west to South Dakota and Texas.

In spite of its nickname “cow killer,” the stings of the female D. occidentalis are not fatal to cattle. The bold and contrasting colors of this velvet ant serves to warn predators that they are quite capable of defending themselves. They also make a squeaking sound by rubbing two abdominal plates across one another as an additional warning. The stingless male is automatically defended by its close resemblance to the female.

Lone females are often seen wandering about on the ground in open habitats from spring through late summer. Winged males patrol these same habitats for mates. Both males and females drink nectar for their nourishment. After mating, females begin searching for the ground nests of bumble bees. Upon finding a nest, the female velvet ant lays a single egg at the entrance of a bumble bee nest. The larva develops inside the nest as an external parasitoid on a bee grub; pupation occurs in the bumble bee’s nest.

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

© 2010, A.V. Evans

CAN YOU SAY OSMETERIUM?

Posted in Butterflies, Defense, Education with tags , , , , , , , on September 16, 2010 by Dr. Art Evans

By Arthur V. Evans

This summer a cadre of dedicated parents and volunteers joined forces at a nearby elementary school to create an outdoor classroom. The Holton Learning Project Garden includes a vegetable and butterfly garden that will introduce Holton Elementary School students, their families, and the residents of Belleview and beyond to the pleasures and benefits of urban gardening.

Compared to the dreary, sterile plantings of exotic trees, shrubs, and groundcovers found throughout much of the neighborhood, the vegetable and nascent butterfly garden has rapidly become a local hot spot for insects and spiders. As such, it provides an excellent site for macro photgraphy. Since August, I have endeavored to photograph as many of its multi-legged denizens as possible as part of an ongoing effort to document the arthropod diversity of my neighborhood in Richmond, Virginia.

While walking through the garden yesterday afternoon, I noticed several clumps of green spikes rising sadly from the straw-covered beds. I soon confirmed my initial suspicions as to the identity of the culprits that laid these once fat bunches of parsley to waste. At the very base of one of the clumps were two brightly banded larvae of the black swallowtail, Papilio polyxenes, polishing off the last few leaves.

When I knelt down to photograph the ravenous caterpillars, I accidentally brushed up against their food plant. Both caterpillars reacted immediately by assuming defensive postures. Bent over backwards, they spit up green fluid and produced a pair of long tentacles (osmeterium), that resembled bright orange horns. Soon my nostrils were filled with a strong, disagreeable odor that is best described as “spicy vomit.”

The osmeterium consists of two soft, finger-like tubes that are everted from inside the body through a slit in the prothorax just behind the head as a result of  increased blood pressure. This defensive gland is found in the caterpillars of swallowtail butterflies and is coated with highly noxious chemical compounds (2-methylbutyric acid and isobutyric acid) that deter predators, especially ants.

© 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

A BEVY OF BUCKEYES

Posted in Butterflies, Insects, Virginia with tags , , , , , , on September 15, 2010 by Dr. Art Evans

By Arthur V. Evans

For the past month or so, Virginia has been awash with the Common Buckeye, Junonia coenia. The name Junonia is derived from the diminutive form of the Greek Juno, Zeus’ consort, while the specific epithet, coenia, comes from the Greek kionos meaning common. With six distinct eyespots on their wings, these handsome and energetic insects cannot be confused with any other butterfly species in the Commonwealth.

Their rapid, low, and somewhat erratic flight consists of fluttering strokes occasionally interrupted by meandering glides usually of no more than a foot off the ground. When alarmed, Common Buckeyes are capable of taking to the air in a rapid and sustained flight. They sip nectar from a variety of flowers and frequently rest in open, sunny spots in neighborhoods, parks, wetlands, fields, roadsides, and other open habitats with plenty of low-growing vegetation.

The orange-headed and metallic blue-spined caterpillars are highly variable in color and pattern. They feed on plants in several families and are especially fond of those in the snapdragon (Scrophulariaceae) and acanthus (Acanthaceae) families.

Although they occur throughout the United States, Common Buckeyes only persist in the frost-free southern and eastern halves of the country; individuals observed in the Great Lakes States, New England, and southern Canada are migrants. In eastern United States, these butterflies are in evidence throughout the winter in Florida and the coastal regions of southeastern and Gulf States.

© 2010, A.V. Evans

BEETLES OF EASTERN NORTH AMERICA: EASTERN HERCULES BEETLE

Posted in Beetles with tags , , , on September 15, 2010 by Dr. Art Evans

By Arthur V. Evans

The eastern Hercules beetle, Dynastes tityus (Linnaeus) (40.0 to 60.0 mm) is a large, spectacular olive-green animal mottled with irregular black spots. Well-hydrated individuals, especially those feeding or have just fed, are sometimes almost completely dark.

Males have a single horn on the head that is held in apposition to the largest of three on the pronotum. Together, these horns are used like forceps to dislodge rival males from sapping spots on the branches of ash trees. These sapping spots provide food for both sexes and are created by males specifically to attract hornless females.

Eastern Hercules beetles are found throughout much of eastern United States, from New York south to Florida, west to southern Illinois, western Arkansas, and eastern Texas. Both sexes are often encountered at lights, but seldom in numbers. However, large numbers of individuals are reported aggregating on ash (Fraxinus) or in tree holes used as breeding sites.

Larvae of eastern Hercules beetles.

The larvae develop and feed on rotting wood of various hardwoods, especially oaks, and occasionally pine. Large tree holes are sometimes used continuously as breeding sites year after year where the larvae feed on damaged rotten and crumbling heartwood; no harm is done to living trees. Their dark, rectangular fecal pellets are quite distinctive.

Pupa of a male eastern Hercules beetle.

The entire life cycle of eastern Hercules beetles may take two or three years, depending on conditions. Adults live several months in captivity on a diet of soft fruits cotton balls saturated with a 1:1 solution of water and maple syrup.

© 2015, A.V. Evans

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