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

Wednesday, October 29, 2014

It's a Corylo-what?

That was my reaction when I learned the identity of a tiny beetle that I found back on October 14. I posted the image you see below to the Facebook group "Friends of Coleoptera at the Natural History Museum [London]" in hopes that someone might recognize it. Michael Geiser, Tommy McElrath, and Jong-Seok Park quickly agreed that it was a corylophid. I had never even heard of the family Corylophidae until then; and the common names "minute hooded beetles" and "minute fungus beetles" didn't ring any bells, either.

That's how it goes in entomology if you are a generalist with limited knowledge of specific orders. You are guaranteed to be baffled half the time by what you find.

My eyesight is so bad now that in the field I barely recognized the critter as an animate object, let alone a beetle. The thing measures about two (2) millimeters, and the only reason I noticed it at all was that it was crawling on the base of a tall, plastic-covered utility box of some kind (for electrical or cable I assume), beneath a large cottonwood tree in our residential Colorado Springs neighborhood. I coaxed the critter into a vial so I could take a few more images indoors.

Consulting several references, I learned a little more about corylophid (Korry-LO-fid) beetles. There are 61 species in ten genera (plural of "genus") found north of Mexico, and my particular specimen probably belongs in the genus Clypastraea. Collectively, minute hooded beetles are generally very small (surprise!), and have the head concealed by a shelf-like projection of the pronotum (top of thorax). They feed as larvae and adults on fungal spores. Different genera and species find such morsels in a variety of habitats from the surfaces of leaves and flowers to crevices in bark, or nests of birds, or in leaf litter. Clypastraea is apparently most often found in fungi and mold in rotting wood and under bark on dead trees.

I have learned not to ignore the small insects, as that is where the real diversity and strangeness occurs. Finding a whole new (to me) family of beetles is a really exciting experience, one I hope that my readers will share in during their own searching.

Sources: Arnett, Ross H., Jr., Michael C. Thomas, Paul E. Skelley, and J. Howard Frank, editors. 2002. American Beetles Vol. 2, Polyphaga: Scarabaeoidea through Curculionoidea. Boca Raton, FL: CRC Press. 861 pp.
Evans, Arthur V. 2014. Beetles of Eastern North America. Princeton, NJ: Princeton University Press. 560 pp.
White, Richard E. 1983. A Field Guide to the Beetles of North America (Peterson Field Guides). Boston: Houghton Mifflin Company. 368 pp.

Saturday, October 25, 2014

Another Odonata Record

Earlier this year I was fortunate enough to report a species of dragonfly never before seen in Colorado. Last Monday, October 20, I got lucky again, with a Fremont County record for the Black-fronted Forktail, Ischnura denticollis. This is a type of damselfly in the family Coenagrionidae.

I can only take credit for spotting the insect in the field, along the edge of a backwater pond in John Griffin Regional Park, CaƱon City, Colorado. It was clearly a male damselfly, perched on a rock by the shore, with nearby cattails. The area is part of the "Riverwalk" along the Arkansas River. I decided to snap a few pictures, if only because insects in general were few and far between that day. Also, the rock was the steadiest object with the gusty winds that were blowing. Anyway, I didn't think much about the whole encounter, except that I was puzzled by a forktail that did not have the usual requisite blue or green spots (or stripes) on the back of the thorax. Oh, well.

Once we returned home, it was my wife, Heidi, that took it upon herself to look up the diminutive (22-26 mm in body length) creature online and in books we have in our library.

"Hey," she said, "I think that damselfly might be something pretty cool." She had already consulted several resources by this time, and concluded that it was an unusual geographic location, and therefore a potential county record.

I uploaded my own images, cropped them, and posted them on Facebook to group pages where I know dragonfly and damselfly experts lurk. Sure enough, it was determined to be a Black-fronted Forktail, a county record, and an exceptionally late date of observation.

Males of this species are pretty easily identified. Besides lacking pale markings on the dorsum (top) of the thorax, the blue on the abdominal segments 8 and 9 is restricted to a spot on the top, instead of a ring around the entire couple of segments. Unfortunately, females are much more difficult to identify, resembling several other forktails.

The late date is perhaps not too much of a surprise because these are oddly long-lived insects as adults, persisting about six weeks in some instances. At least one specimen was shown to have lived 42 days.

The Black-fronted Forktail is a decidedly western species, ranging from southeast Oregon and southwest Idaho through California, Nevada, western Utah, Arizona, and New Mexico. It does not occur in the Cascade, Sierra Nevada, or Rocky Mountains, but creeps north again into eastern Colorado, on out to west Texas, Oklahoma, and Kansas.

Look for adults on the wing at almost any time of the year in the southerly reaches of this forktail's range, but reliably between about April and October just about anywhere else. They hang out around springs, both hot and cold, ponds with lots of emergent vegetation, and even very slow-moving stretches of streams.

Sources: Abbott, J.C. 2006-2014. Odonata Central: an online resource for the distribution and identification of Odonata.
DuBois, Robert. 2010. Dragonflies & Damselflies of the Rocky Mountains. Duluth, MN: Kollath+Stensaas Publishing. 301 pp.
Paulson, Dennis. 2009. Dragonflies and Damselflies of the West. Princeton, NJ: Princeton University Press. 535 pp.

Thursday, October 23, 2014

Camel Crickets

At least once each year I am asked about spider-like creatures that jump, living in someone's basement, cellar, shed, garage, or home. People don't like to get too close to spidery-looking things, so sometimes the inquiring individual includes a picture, but often not. No matter, it is almost always "camel crickets" they are describing, from the family Rhaphidophoridae in the order Orthoptera.

Camel cricket, Crested Butte, Colorado

The common name of "camel cricket" may describe their hump-backed appearance, but these are not true crickets. Adults are wingless, for one thing, and thus unable to "sing." The exceptionally long antennae give these insects a sensory advantage in the perpetually cool, damp, dark habitats they mostly prefer: old wells, cellars, mine shafts, rodent burrows, basements, and caves (to which they owe their other common name, "cave crickets").

Adult camel crickets can be fairly large, with a body length varying from 9-35 millimeters depending on the species. The average legspan is even greater, which makes the whole insect appear larger. This can be intimidating to the average homeowner, no question.

Female Ceuthophilus sp., Colorado Springs, Colorado

Fortunately, camel crickets are not dangerous in the least, and rarely even do damage to property. Female camel crickets do bear a blade-like organ called an ovipositor that protrudes from the rear of the abdomen. This sword-like "tail" is often mistaken for some kind of stinger, but in reality it functions to insert eggs in the soil. Larger camel crickets can probably give you a good nip with their jaws, but good luck catching one. Many camel crickets can jump several feet when disturbed.

Ceuthophilus sp., Chicago area, Illinois

Like most members of the order Orthoptera, camel crickets are ominvorous. They feed on virtually anything organic, but have been known to damage paper products and occasionally fabrics. Some species are pests in mushroom-growing operations. Camel crickets will also capture and eat other insects and invertebrates, especially those that are injured or otherwise weakened.

Since camel crickets are highly moisture-dependent, keeping the below-ground areas of your home dry will discourage them from colonizing. They are not social in the sense of ants or bees, but seem to enjoy each other's company. Large numbers of them are often found hiding together under boards, stones, bricks, logs, leaf litter, and other debris.

Ceuthophilus sp., Madera Canyon, Arizona

There are roughly 150 species, in 21 genera (plural of genus), found in North America north of Mexico. Many of these are specialist species found only in cave systems, sand dunes, and similar geographically-isolated habitats. The "sand-treader" camel crickets, for example, are restricted to dunes, and equipped with long spines or "sand baskets" on their legs that help them dig in the soft, shifting sands. These and other arid-land inhabiting species are more robust and compact than their leggy forest- and cave-dwelling relatives. They are important scavengers of animal droppings and dried vegetable matter.

Greenhouse Stone Cricket, Leavenworth, Kansas

The Greenhouse Stone Cricket, Diestrammena asynamora, is native to China and other parts of Asia, but was established here in North America before 1900. This is fast becoming the most frequently-encountered camel cricket in urban areas east of the Rocky Mountains. As the name implies, it can do occasional damage to vulnerable young plants inside greenhouses.

Greenhouse Stone Cricket, Cape May, New Jersey

Our most common native camel crickets belong to the genus Ceuthophilus, which includes about 90 species. I often find them at night, clinging to the exterior of buildings, or clambering over rock walls, in rural areas. Nighttime is definitely the right time to find camel crickets in general, when the venture from their daytime shelters.

Ceuthophilus sp., southern Ohio

Entomologists attract camel crickets by laying a trail of dry oatmeal and returning at night to look for the insects. Molasses is also used as an attractant, smeared on tree trunks and logs.

Indoors, camel crickets may be grazing on mold, mildew, and fungi, so it might be wise to inspect for potential problems with those agents of decay should camel crickets appear in abundance.

Sources: Bartlett, Troy, et al. 2014. "Family Rhaphidophoridae - Camel Crickets," Bugguide.net.
Bland, Roger G. 2003. The Orthoptera of Michigan - Biology, Keys, and Descriptions of Grashoppers, Katydids, and Crickets. East Lansing: Michigan State University Extension. Extension Bulletin E-2815. 220 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.
Preston-Mafham, Ken. 1990. Grasshoppers & Mantids of the World. London: Blandford (Cassell plc). 192 pp.