Showing posts with label Acrididae. Show all posts
Showing posts with label Acrididae. Show all posts

Tuesday, September 26, 2017

Grasshopper or Locust?

A person on a Facebook insect identification group recently asked a very good question about the difference between a grasshopper and a locust. You would think it is pretty straightforward, but not so fast.

The American Bird Grasshopper, Schistocerca americana, is related to some grasshopper species in Europe and Africa that can become locusts; and it sometimes migrates beyond its usual geographic range in the U.S.

Most of us think of locusts in the context of Biblical plagues in Africa and parts of Europe, in ancient times. Such plagues still happen, and they are almost apocalyptic in their destructiveness. They even occur in North America on occasion, as well as other parts of the world, so there must be more than one species of locust, right? Yes, and no.

Two-striped Grasshopper, Melanoplus bivittatus, has been overwhelmingly abundant in recent years along the Colorado Front Range

Locusts are not a species of grasshopper, they are the result of overcrowding in the nymph stage of many kinds of grasshoppers. Under favorable conditions, there is an extraordinary survival rate of young grasshoppers, which are called nymphs. When they are literally so abundant and concentrated that they are rubbing elbows (well, "knees" is probably a more appropriate term), this friction causes them to detour from their normal route of metamorphosis.

Instead of maturing into the usual grasshopper, the adult stage features longer wings and other body modifications that permit them to fly greater distances, remain airborne for longer periods, and to undertake these migrations from one food source to the next over long distances. They also may be aided by winds ahead of storm fronts.

The Clear-winged Grasshopper, Camnula pellucida, is prone to population outbreaks in the American West

This is something of a simplification of the physiology of locusts versus normal grasshoppers, but a surprising number of species have the potential to morph into locusts when conditions are right. Then they overwhelm the landscape, defoliating every plant in their path.

Locust swarms will devour plants they would not normally eat. I recall a presentation about a locust epidemic in Oregon where the scientist showed slides of juniper trees (yes, juniper trees) that had been reduced to skeletons by grasshopper swarms. The locusts have even been known to eat garments on clotheslines. Grasshoppers are also omnivores, and will not hesitate to eat dead members of their own species, or gnaw on injured or even healthy ones. It is late in grasshopper season here now in Colorado, and I regularly see grasshoppers with wings reduced to stubs thanks to hungry comrades.

A victim of the grasshopper-killing fungus Entomophaga grylli

Fortunately, for us at least, grasshoppers face many mortality factors. While it has been a banner year for grasshoppers this year along the Colorado Front Range, huge numbers have succumbed to the entomopathic fungus Entomophaga grylli. The insidious fungus grows inside the insect, eventually commandeering its brain and forcing it to behave abnormally. The grasshopper, through no will of its own, climbs to the top of a tall weed, assumes a death grip embracing the stem, and dies. The fungal spores then erupt and rain down on healthy grasshoppers below to begin the cycle again. The spores may even decapitate the dead grasshopper as they exit.

Grasshoppers are the chief grazers of the prairie, even more impactful than livestock, deer, pronghorn, elk, and bison. Natural rangeland can usually withstand their feeding, but ranchers obviously see them as competition and exercise chemical controls when necessary. Since grasshoppers are mostly generalist feeders (a few specialize on only certain broadleaved plants), they pose a threat to agricultural crops, too.

A specimen of the extinct Rocky Mountain Locust
© Bugguide.net

Ironically, the Rocky Mountain Locust, Melanoplus spretus, once the most abundant and devastaging insect pests ever to occur in North America, is now extinct. The book Locust, by Jeffrey A. Lockwood, chronicles the rise and dramatic fall of the species, which ultimately vanished from the U.S. landscape by the early 1900s. I will not spoil the solving of the mystery, as Lockwood's account is far more riveting than anything I could craft if I was even prone to writing historical fiction. Let us just say it is a cautionary tale.

Historical range of the Rocky Mountain Locust

We can certainly be grateful that we seldom experience such traumatic explosions of grasshoppers here on American soil, but we should be empathetic to other nations that do. Entire economies can be on the verge of collapse in the wake of such devastation.

Source: Lockwood, Jeffrey A. 2004. Locust. New York: Basic Books (A member of the Perseus Books Group). 294 pp.

Friday, October 7, 2016

The Great Grasshopper Hunt II

I am terribly behind in chronicling field experiences I have participated in this summer, including the second annual(?) "grasshopper hunt" co-sponsored by Mile High Bug Club and the Aiken Audubon Society. Our first one was held last year at Homestead Ranch Regional Park near Peyton, Colorado. This time we opted to head farther south and a little farther east to Chico Basin Ranch; and we were led by grasshopper expert Bill Maynard.

Our intrepid participants © Bell Mead

The ranch is a sprawling 87,000 acres that straddles the El Paso and Pueblo County line. Its wide array of habitats, from sandhills to artificial wetlands, makes for high biodiversity, especially among insects and grasshoppers in particular. In only a few hours our party of roughly ten people observed forty (40) species of grasshoppers, plus many other insects and arachnids.

Pink form of the Broad-banded Grasshopper, Trimerotropis latifasciata

Bill is rather new to the study of grasshoppers, but he quickly masters many aspects of natural history. He is already recognized as a leading authority on birds and dragonflies, with many state and county records to his credit. It is only a matter of time before the same can be said of his expertise in the order Orthoptera to which grasshoppers belong.

Rather than overwhelming you with images here, I will direct you to the Mile High Bug Club Flickr Group where you can peruse the image collection at your leisure.

Snakeweed Grasshopper, Hesperotettix viridis

We would be remiss if we did not also acknowledge the hospitality of the Chico Basin Ranch staff, especially Tess Leach and her family. Her two children were especially curious, and remarkably patient and gentle in their approach to the many grasshoppers we saw.

Three-banded Grasshopper, Hadrotettix triafasciatus (foreground), signaling to a Broad-banded Grasshopper (background) to get out of its territory

The intense heat of that August 6 day sent some members of our party packing by about noon, but who could blame them? The Plains Harvestfly, a type of cicada, made it seem hotter still with its loud, oppressive buzz. All in all, the "expedition" was a resounding success, and no vehicles or people were injured during the odyssey.

Plains Harvestfly, Neotibicen dealbatus

While plains and deserts are prime habitats for grasshoppers, you can find them nearly everywhere. You will be surprised by the number of species you can discover in your own backyard, neighborhood park, vacant lot, or any other patch of wildness. Even now, with the first frosts approaching, grasshoppers are among the few insects left in any abundance. Go take a look for them.

Thursday, October 1, 2015

The Grasshopper Hunt

The Aiken Audubon Society here in Colorado Springs asked me to speak at their September monthly meeting, and to lead a field trip beforehand. I chose the topic of grasshoppers since there is so much diversity here. The field trip was to Homestead Ranch Regional Park near Peyton, Colorado (El Paso County). I was surprised and delighted by the turnout, and the interesting animals we encountered.

Carolina Grasshopper basking

We were fortunate to have two young men, Seth and Zach Vogel, and their father, Tim, along for the trip. The boys helped find many more animals than we would have were we left to my own devices. They have a keen eye, endless stamina, and great enthusiasm. Tim employed a GoPro® camera to record parts of the expedition in this video.

© Tim Vogel

The Mile High Bug Club was represented by Bell Mead and myself; and Aiken Audubon by Jeannie Mitchell, Leslie Holzmann, and Bill Maynard. Alison Kondler even came down from the Denver area. Thankfully, the weather was sunny, but not too hot.

Plains Lubber grasshopper

We had not even made it beyond the playground and picnic shelter before we saw Carolina Grasshoppers basking on the pavement, and the boys had found an enormous Plains Lubber Grasshopper, Brachystola magna. The latter brought out the "'hopper-razzi," cameras clicking away.

Plains Lubber grasshopper draws a crowd

Further along the trail through grassy habitat on a gentle slope, we encountered several species of spur-throated grasshoppers in the genus Melanoplus, plus Pallid-winged Grasshoppers (Trimerotropis pallidipennis), and the Northwestern Red-winged Grasshopper, Arphia pseudonietana.

While I was explaining how to identify a particular species, the boys brought over a really nice find: a male Mormon "Cricket." The Mormon Cricket, Anabrus simplex, is not a true cricket, nor a grasshopper, but a kind of shield-backed katydid.

Mormon "Cricket" male

Seth and Zach located these large insects by homing in on their "song," a kind of buzzing sound produced by the males rapidly rubbing their short wings together.

We entered a narrow zone of pine trees near the summit of the slope we were traversing, and that brought us another species of grasshopper, apparently confined to that wooded habitat. The Kiowa Grasshopper, Trachyrhachys kiowa, is another of the "band-winged grasshoppers" named for the dark band on the colored hind wing. The hind wings are only visible when the insect flies, and most grasshoppers fly only short distances before landing and once again becoming nearly invisible owing to their superb camouflage.

Kiowa Grasshopper with hind wing spread

Band-winged grasshoppers can make noise in flight. This is called "crepitation," and is a rattling or crackling sound, presumably as front and hind wing rub together....but the sound can be produced at will, so it is something of a mystery how it is produced.

The hill terminates in a rolling plateau, and the grassland changes a bit in composition. Here we heard slant-faced grasshoppers, hidden from view. Slant-faced grasshoppers cling to vegetation in the vertical plane rather than crawling on the ground like band-winged grasshoppers usually do. They produce sound not by crepitation but by "stridulation." The male grasshopper rubs the inside surface of his hind femur ("thigh") against veins of the folded front wing. The result is a "zip-zip-zip" kind of song.

We ended our hike at a circular water trough for horses and cattle, fed by a well with a windmill pump. The water looked awful, but was full of life. It took no time at all for Zach to spy a Barred Tiger Salamander (Ambystoma mavortium), one of at least two inhabiting the pool.

Barred Tiger Salamander

There were also water striders (insect family Gerridae), backswimmers (Notonectidae), diving beetles (Dytiscidae), and a Giant Water Scavenger Beetle, Hydrophilus triangularis (family Hydrophilidae). Various dragonflies circled as well.

Giant Water Scavenger Beetle

Everyone appeared delighted by the whole adventure, and I am very happy to see what is apparently a growing demand for field outings geared to organisms other than birds, or at least in addition to birds. I would very much like to do more of this kind of thing, all over the U.S., so keep those invitations coming!

Thursday, November 20, 2014

Lakin Grasshopper

Grasshopper species diversity in the southwest U.S. presents enough of a challenge for the amateur naturalist, but then you have the Lakin Grasshopper, Melanoplus lakinus, that can apparently pass for several hundred species all by itself. That's an exaggeration, of course, but there is such great variability in the color, pattern, and wing length of this species that it is mind-boggling.

Lakin Grasshopper male

Lakin Grasshopper is often overwhelmingly abundant in disturbed habitats such as vacant lots and weedy fields and rangeland filled with its favorite host plants, members of the goosefoot family Chenopodiaceae. This includes Russianthistle ("tumbleweed"), kochia, and native saltbush (Atriplex spp.). It will also feed on various forbs and grasses such as lambsquarters, western wheatgrass, and downy brome. Despite high population densities in some years, it is seldom a crop pest.

Lakin Grasshopper female

This is a grasshopper of the Rockies and Great Plains, ranging from South Dakota and southern Minnesota south through western Iowa, most of Kansas, western Oklahoma, the west half of Texas, plus Nebraska, Colorado, New Mexico, and the eastern two-thirds of Wyoming, Utah, and Arizona. It also occurs deep into central Mexico.

Red form female from New Mexico

Melanoplus lakinus is a pretty "average" grasshopper. Adult males measure about 22 millimeters in body length, females 30 millimeters. Most specimens are short-winged as adults, but some are fully-winged. The overall color varies greatly from brownish or gray to green or even red. The tibia ("shin") segment of the hind leg is usually blue, armed with spines that are black or at least black-tipped. The inner surface of the hind femur ("thigh") is often reddish in part, especially along the bottom edge where the tibia folds into it. The top surface of the femur is most often marked with pronounced dark bands.

Green form female from Colorado

Dark bands on the abdomen, especially near the base, are helpful in recognizing the species in the field, but ultimately one has to examine the external genitalia of the male to confirm identification.

Ok, so how do you even tell apart the different genders? Below is an image that shows the male and female side-by-side, from the rear. The male is on the right. The female is on the left, but her abdomen is twisted to repel his advances, or accept his overtures, I'm honestly not sure which because I did not stick around long enough to see the outcome.

Male on right, female on left, rear view

The male's parts are pretty complicated, but you want to look at the shape of each "cercus," paired tail-like appendages. In the example below, we see that the cercus of M. lakinus is shaped something like a Hershey's candy kiss: broad at the base and tapered toward the tip. Next, take a look at the shape of the subgenital plate. It is best to view it directly from the rear, like in the image above. We can see it has a low, blunt tooth right in the middle. The supra-anal plate also offers species-specific details, but they are more difficult to discern, especially in images.

Anatomy of male M. lakinus

When two grasshoppers do get together, it looks like this:

Mating pair, male on top

Pretty kinky, almost literally! Mated females deposit clusters of eggs ("pods") in the soil by telescoping their abdomen as deep as it can reach. The eggs are held together by a kind of foamy secretion that hardens to protect the mass from environmental extremes. The eggs hatch in late May or early June, on average, the following year. In Arizona, where summer monsoons trigger hatching, emergence is usually in early July. The nymphs pass through five instars (an instar is the interval between molts), reaching adulthood in about a month.

Long-winged female from New Mexico

This year was a good one for the Lakin Grasshopper here in Colorado, and also in New Mexico, as heavy spring rains provided the nymphs with plenty of food after years of draught. The adults have hung around a long time, too. Just yesterday I spotted one basking on the sunny side of a building in our townhouse complex.

Sources: Capinera, John L. , Ralph D. Scott, and Thomas J. Walker. 2004. Field Guide to Grasshoppers, Katydids, and Crickets of the United States. Ithaca, NY: Comstock Publishing Associates (Cornell University Press). 249 pp.
Branson, David H. and Bethany Redlin (eds.). 2004. Grasshoppers: Their Biology, Identification and Management. 2nd Edition. US Department of Agriculture, Agricultural Research Service.
Grasshoppers of Colorado

Thursday, November 6, 2014

Large-headed Grasshopper

I am fortunate to be surrounded by a community of entomologists with a collectively vast knowledge of insects and arachnids, and I meet more of these scholars seemingly every week, at least in the digital world of listservs and social media. I owe it to one such expert, Dr. Charles Bomar, for the identification of the fortieth (40th) species of grasshopper that I have now seen in Colorado Springs alone: the Large-headed Grasshopper, Phoetaliotes nebrascensis.

I encountered the critter on the Rock Island Trail, a concrete bike path through residential and commercial areas in eastern Colorado Springs, on October 26 as my wife and I were walking our dog. I snapped only two images, figuring this was something already familiar, in the genus Melanoplus.

Consulting book and online resources at home I was surprised I couldn't find an immediate match. So, I posted the image shown above to the Orthopterist's Society group page on Facebook. Almost immediately I received an answer from Dr. Bomar. He went on to suggest even more important references that I should have, including a link to one of them.

This is the kind of "above and beyond the call of duty" that is typical of most professional entomologists who consider it an obligation to interact with amateurs and the general public. I, for one, am eternally grateful, and could not produce this blog without their help.

Back to the grasshopper. Phoetaliotes nebrascensis is found in places other than Nebraska, ranging widely from southern Alberta, Saskatchewan, and Manitoba to extreme northern Mexico; and from eastern Washington and Oregon, the northeast corner of California, east to the northern half of Texas, Missouri, and Illinois to southwest Michigan, southern Wisconsin and Minnesota.

Adult specimens are most often found from late July through October, at least here in Colorado.

The mature insect measures 21-25 millimeters (males) or 23-33 millimeters (females), and typically has only very short front wings, missing the hind pair of wings entirely. They are therefore frequently confused with subadult specimens of other species. Occasionally there are fully-winged males of the Large-headed Grasshopper, but it is unusual to find them.

The color pattern of this species is so similar to other species that one cannot readily distinguish them based on those variable characters. Once again it is the shape of the male genitalia at the tip of the abdomen that is useful in identification. An overhead or rear view of the entire insect will, however, reveal the swollen head that gives this species its name. The head is noticeably wider than the thorax.

The Large-headed Grasshopper can be common in a variety of habitats, even being a dominant species, especially in tallgrass prairies. Both grasses and broadleaf herbs are on its menu, but it seems to prefer rangeland grasses. It is considered a low-grade pest at worst, but is usually inconsequential. It prospers with spring rains, populations rising dramatically under such conditions.

I can hardly wait to see what "new" grasshoppers turn up next year here in the Springs. There are some that I know occur here that I just haven't seen yet, so my bugwatching list is sure to grow.

Sources: Capinera, John L., Ralph D. Scott, and Thomas J. Walker. 2004. Field Guide to Grasshoppers, Katydids, and Crickets of the United States. Ithaca, NY: Comstock Publishing Associates (Cornell University Press). 249 pp.
Capinera, J.L. and T.S. Sechrist. 1999. Grasshoppers (Acrididae) of Colorado: Identification, Biology, and Management. Fort Collins: Colorado State University Experiment Station Bulletin 584S.
Johnson, Dan L. 2008. Grasshopper Identification and Control Methods to Protect Crops and the Environment. Ottawa: Agriculture and Agri-Food Canada.

Thursday, October 30, 2014

Cudweed Grasshopper, Hypochlora alba

There is seemingly no end to the diversity of short-horned grasshoppers, family Acrididae, here in Colorado. Hiking the Rock Island Trail, a concrete bicycle path through east Colorado Springs, I added the thirty-ninth species of acridid I've seen here. Initially, I thought it might be a freshly-molted specimen of a familiar species since it was so very pale. On closer examination it proved to be a well-hardened adult of the Cudweed Grasshopper, Hypochlora alba.

Here it was, very late in autumn on October 24, yet there were still large numbers of grasshoppers present in the scrub and grassland habitat along a sandstone ridge that parallels the trail. Vegetation here is a little different than on the plains proper. Sure, there is still yucca, prickly-pear cacti, and rabbitbrush, but also Gambel's Oak, elm trees, cottonwoods, and other plants characteristic of upland habitats. Insect diversity is correspondingly unique.

The Cudweed Grasshopper, also known as the "Mugwort Grasshopper," is not a large insect. Males average 15 millimeters, females like this one only 20 millimeters, maybe slightly larger. This is decidedly a species of the Great Plains, found from southern Saskatchewan and Manitoba south through eastern Wyoming and Colorado to extreme western Minnesota, most of Iowa, Kansas, extreme northwest Missouri, Oklahoma, and north-central Texas. Adult specimens occur late in the season, from August through October.

What makes Hypochlora alba truly unique is that it is *not* a generalist feeder. While most 'hoppers enjoy munching various grasses and/or broadleaved herbs, the Cudweed Grasshopper feeds almost exclusively on Cudweed Sagewort, Artemisia ludoviciana. At least, it certainly doesn't stray far from other Artemisia species.

A. ludoviciana is a silvery-gray plant that also goes by the aliases "Silver Wormwood," "White Sagebrush," "Western Mugwort," and "Gray Sagewort" among others. I had to look it up online and I'm still not sure that it looks familiar. Then again, my "search image" is usually for insects, not plants.

One cannot always choose the best specimens as photographic subjects, and such is the case here. This is a female, missing one hind leg. She *is* an adult, though, despite the short wings. Many spur-throated grasshoppers in the subfamily Melanoplinae are short-winged, or have short-winged individuals or populations, which can make identifying them problematic, especially for novice entomologists. Further, species identification often hinges on the configuration of the male genitalia, cerci, and subgenital plate. Females don't have all of this....hardware.

I have to say I admire the subtle beauty of grasshoppers. They are supremely adapted to their habitat and food plants, so it takes patience and persistence to even notice them most of the time. Go take a look in your own neighborhood and see how many species you can find. You will be surprised, I guarantee it.

Sources: Capinera, John L., Ralph D. Scott, and Thomas J. Walker. 2004. Field Guide to Grasshoppers, Katydids, and Crickets of the United States. Ithaca, NY: Comstock Publishing Associates (Cornell University Press). 249 pp.
Ferguson, David J. 2010. "Species Hypochlora alba - Mugwort Grasshopper," Bugguide.net.
Helfer, Jacques R. 1972. How to Know the Grasshoppers, Cockroaches, and Their Allies (2nd edition). Dubuque, Iowa: Wm. C. Brown Company Publishers. 357 pp.
Pfadt, Robert E. 1996. "Cudweed Grasshopper." Wyoming Agricultural Experiment Station Bulletin 912

Thursday, September 18, 2014

Blue-winged Grasshopper

The band-winged grasshoppers in the subfamily Oedipodinae (family Acrididae) are easy to love. They are colorful and noisy in flight, seldom qualify as pests of agriculture or rangeland, and are endlessly diverse. A case in point is the beautiful Blue-winged Grasshopper, Trimerotropis cyaneipennis.

I first became acquainted with this species during childhood trips to eastern Oregon. They were fairly plentiful around Fort Rock in northern Lake County, but a real challenge to catch, even with a net. Nothing has changed, it took me several tries to net one that Heidi and I encountered in Water Canyon in the Magdalena Mountains of New Mexico last Sunday. I wanted to show Heidi, and my readers here, the blue-green hind wings that give this species its common name.

Like all members of the genus Trimerotrois, T. cyaneipennis is incredibly cryptic when at rest among rocks, or on bare soil. The front wings, called tegmina (singular is "tegmen"), are narrow and in this case speckled with brown, gray, and black, creating vague bands. The hind wings are used in flight, and fold like a Japanese fan, accordion-like, when not in use, concealed beneath the tegmina.

Even if you can follow the flight path of one of these insects, and note where it lands again, good luck spotting it unless it moves. Actually, it might even walk a short distance once it does land, making it even more maddening to locate.

The cloak of (near) invisibility works well, despite the fact that these are not small creatures. Adult males measure 25-35 millimeters, females 28-40 millimeters. Besides the blue hind wings, they can be identified in part by the bright blue tibia ("shin") segment of the hind leg, and the blue tint on the abdomen, visible in the image below.

This grasshopper is most common in rugged, mountainous terrain and canyons at elevations between 3,000 and, 8,500 feet. Look for them along gravel roads, and volcanic soils, especially at the base of steep slopes. They tend to favor oak, pinyon-juniper, or pine forests west of the Rocky Mountains from southeast Washington, Idaho, eastern Oregon, California, Nevada, Utah, southwest Colorado, Arizona, western New Mexico and extreme west Texas. They also range just across the Mexican border.

You might hear this grasshopper when it takes flight, as it generates a loud crackling sound as the veins of the hind wing rubs against the underneath surface of the tegmen. This is called "crepitation," and can be initiated at will by the insect, such that it can also fly silently.

There is continuing debate over the exact status of this species, and in southeast Wyoming, central Colorado, and much of eastern New Mexico, it is replaced by the closely-related "Brother's Band-winged Grasshopper," Trimerotropis fratercula. That species has yellow, or greenish-yellow hind wings, but even T. cyaneipennis does not always have obviously blue or turquoise wings.

Since this is more or less a "wilderness" grasshopper that does not eat crops or rangeland forage, it is not considered a pest. All the more reason to enjoy an encounter with this blue-winged beauty.

Sources: Bentley, Tom and David Ferguson. 2007. "Species Trimerotropis cyaneipennis - Blue-winged Grasshopper," Bugguide.net.
Capinera, John L., Ralph D. Scott, and Thomas J. Walker. 2004. Field Guide to Grasshoppers, Katydids, and Crickets of the United States. Ithaca: Comstock Publishing Associates (Cornell University Press). 249 pp.
Helfer, Jacques R. 1972. How to Know the Grasshoppers, Cockroaches and Their Allies (2nd Ed.). Dubuque, Iowa: Wm. C. Brown Company Publishers. 359 pp.

Friday, September 5, 2014

Great Crested Grasshopper

Yesterday was "OrThoptera Thursday" in the truest sense. I had the car at my disposal, thanks to my wife and a co-worker carpooling, so I drove out into the rural plains of eastern El Paso County in search of grasshoppers. This was the first time since my arrival in Colorado that I simply went out walking in the vast shortgrass prairie east of Colorado Springs. Much to my delight, I managed to find the creature at the top of my list: the Great Crested Grasshopper, Tropidolophus formosus.

This species is also known as the "dinosaur grasshopper" for the resemblance of its pronotal crest to the fin-like structure on the back of Dimetrodon dinosaurs. The grasshopper's crest is studded with fine, prickly teeth on the rear half, barely discernible in the images shown here.

These are large insects, adult males attaining a length of 35-46 millimeters, and female 38-50 millimeters. Males are fully-winged, but the wings of the female are short, barely extending half the length of the abdomen. Despite their size and ungainly appearance, they are wary and surprisingly agile, not to mention cryptic. The only way I managed to find them was by flushing them from the vicinity of dense vegetation and hoping I could follow their flight path. I never did find a female.

The Great Crested Grasshopper is one of the band-winged grasshoppers in the subfamily Oedipodinae, family Acrididae. The hind wings are a lovely vermillion, with a diffuse dark band near the wing margin, as shown here. In flight the species is not easily confused with other red-winged grasshoppers.

The references I have consulted indicate that males have a noisy flight, especially in courtship displays, but all the individuals I encountered flew silently....and far. Invariably, it seemed, they always flew to the other side of the barbwire fence.

The preferred food of this grasshopper is apparently globemallows, (Sphaeralcea spp.), Malvastrum, and other members of the family Malvaceae. It has also been found in association with Buffalo Bur, Solanum rostratum. Because it does not favor crop plants or rangeland forage consumed by cattle, the Great Crested Grasshopper is not considered a pest species. Further, it is not terribly abundant. I found a grand total of about eight or ten specimens yesterday, in hours of looking.

Tropidolophus formosus is not widely distributed, found mostly in the southern Great Plains, but ranging from southeast Wyoming and southwest Nebraska south through eastern Colorado, western Kansas, Oklahoma, and Texas, eastern New Mexico, and southeast Arizona. It is also found in northwestern Mexico. Adult specimens can be found from July through October across that area.

The plains and prairies may seem devoid of life except for the occasional herd of deer, pronghorn, or bison, or soaring hawk, but look closer and you will find an abundance and surprising diversity of life, from reptiles (two lizards and one snake for me yesterday) to insects. I encourage you to explore that biome, and do so often. The animals you find will vary dramatically depending on drought or monsoon conditions.

Sources: Capinera, John L., Ralph D. Scott, and Thomas J. Walker. 2004. Field Guide to Grasshoppers, Katydids, and Crickets of the United States. Ithaca: Comstock Publishing Associates (Cornell University Press). 249 pp.
Helfer, Jacques R. 1972. How to Know the Grasshoppers, Cockroaches, and Their Allies (2nd ed.). Dubuque, Iowa: Wm. C. Brown Company Publishers. 359 pp.

Thursday, August 28, 2014

White-whiskered Grasshopper

One of the most abundant, yet inconspicuous grasshoppers in North America is the little White-whiskered Grasshopper, Ageneotettix deorum. Easily overlooked as just another drab grasshopper, it can be easily recognized by its white antennae and red or orange hind tibia ("shin" segment on the hind leg).

This species is a member of the family Acrididae and the subfamily Gomphocerinae, known as slant-faced grasshoppers. The head of the White-whiskered Grasshopper is not as acutely sloped as its relatives, but it shares other subtle characters in common.

While most slant-faced grasshoppers are found clinging to grasses in the vertical plane, A. deorum is perhaps most often seen on the ground. When flushed from its hiding place it may leap into the middle of a trail where it could either hunker down, hop away again, or crawl rapidly into nearby grass tussocks. Only when it is walking do you easily see those bright red hind legs.

This is not a particularly large grasshopper, males ranging from 11-28 millimeters, female 15-28 millimeters. It is one of the few species in which both genders are nearly identical in size.

The White-whiskered Grasshopper occurs from the Great Lakes (Michigan, south and west to Indiana, Minnesota, and Illinois) through most of Missouri, western Arkansas, and Texas, all the way to the Pacific coast (southeast British Columbia, eastern Washington and Oregon, and much of California). Adult specimens can be found commonly from mid-July through early October.

Ageneotettix deorum frequents dry grasslands with short grasses, so I find it abundantly here in Colorado Springs on the fringe of the Great Plains. I still get confused periodically because of the variability of this species in terms of size and markings. Larger individuals can certainly be mistaken for grasshoppers of other genera. Other grasshoppers can have white antennae, and the White-whiskered Grasshopper can occasionally have darker antennae. The hind tibia is usually hidden under the edge of the hind femur when the insect is at rest, and there are simply few other consistent markings to go by.

The sheer abundance of this species puts it in the category of a rangeland and crop pest. During outbreaks there can be up to 25 adult specimens per square yard; and the species can account for fifty percent or more of the grasshopper fauna. Wheat is particularly vulnerable, but A. deorum also enjoys Kentucky Bluegrass and other kinds of music...I mean....forage. It will even feed on dried, fallen grassblades, seeds, dung, and deceased insects.

Eggs are laid in the soil in the summer and fall, hatching the following spring. Nymphs progress through five instars before reaching adulthood, roughly 40-48 days after emerging from the egg. The adults fly well, but flights are generally short (3-6 feet), and mere inches over the ground.

Sources: Bland, Roger G. 2003. The Orthoptera of Michigan. East Lansing: Michigan State University Extension Bulletin E-2815. 220 pp.
Capinera, John, L., Ralph D. Scott, and Thomas J. Walker. 2004. Field Guide to Grasshoppers, Katydids, and Crickets of the United States. Ithaca, New York: Comstock Publishing Associates (Cornell University Press). 249 pp.
Helfer, Jacques R. 1972. How to Know the Grasshoppers, Cockroaches, and Their Allies. Dubuque, Iowa: Wm. C. Brown Company Publishers. 359 pp.
Pfadt, Robert E. 1996. "Whitewhiskered Grasshopper," Wyoming Agricultural Experiment Station Bulletin 912

Thursday, August 14, 2014

The Homesteader (Plains Lubber grasshopper)

There are not that many insects that you can spot from your car driving at high speed, but the Plains Lubber, Brachystola magna, might be one of them. This heavyweight is a fixture of the Great Plains from the Canadian border to central Mexico. Adult females measure 5-6 centimeters (or more, depending on which resource you consult), while males are a mere 4 centimeters, but they are among the bulkiest of North American insects.

According to one source (Pfadt, 1996), female Plains Lubbers average 4,287 milligrams (0.15 ounces); adult males average 3,935 milligrams (about 0.14 ounces). This might not sound like much, but it is spectacularly weighty compared to your average insect.

The sheer size of Brachystola magna is enough to attract your attention, but they are pretty colorful, too. Most specimens tend toward brown, tan, or beige with black speckling and often a blush of red. Other specimens, especially females, can be bright green. Still others are pink or even blue. These grasshoppers become somewhat duller in color as they age.

The life cycle of the Plains Lubber, also known as the "Homesteader," begins when a female deposits gourd-shaped egg pods in the soil during summer and early fall. Each pod contains 20-35 eggs. The eggs overwinter and are able to remain viable for years during unfavorable conditions such as droughts. Nymphs begin emerging from the eggs in May or June over much of the species' range, though monsoon rains trigger hatching in the southwest U.S.

Nymphs pass through five instars (an instar being the interval between molts) before reaching adulthood. This takes roughly 45 days, during which time the insects are feeding mostly on the foliage of sunflowers and other broadleaf weeds like hoary vervain, annual sowthistle, even dandelion.

Nymph, from Arizona

Adult Plains Lubbers do not confine themselves to a vegetarian diet. Females especially will happily scavenge on their road-killed kin, or devour weak or injured insects, and may even capture and consume smaller grasshoppers. Most members of the order Orthoptera are likewise omnivorous, to one degree or another.

The Plains Lubber can be abundant enough to be a pest, but because it is flightless, the wings reduced to mere pads behind the thorax, its ability to disperse is limited. Just the same, they are powerful leapers, females under distress jumping over one foot, and males up to nine feet when...."encouraged." Normally, a "hop" amounts to 3-5 inches.

Look for these insect giants in marginal habitats such as roadsides, the edges of field crops, and disturbed rangeland. They also occupy shortgrass and tallgrass prairies, desert grasslands, sandhills, and any place with abundant sunflower. Adult specimens can be found as early as mid-June, but they are more abundant in July and August, persisting well into the fall, even November.

Lubbers are often classified in their own family, Romaleidae, or the subfamily Romaleinae under the family Acrididae. There are a total of seven genera and nine species of lubbers in the U.S. All are robust, flightless insects.

Sources: Capinera, John L., Ralph D. Scott, and Thomas J. Walker. 2004. Field Guide to Grasshoppers, Katydids, and Crickets of the United States. Ithaca, NY: Comstock Publishing Associates (Cornell University Press). 249 pp.
Pfadt, Robert E. 1996. "Plains Lubber Grasshopper," Wyoming Agricultural Experiment Station Bulletin 912