Tuesday, April 17, 2012

Life-changing Events

Ladies and gentlemen, I am delighted to announce that on Sunday, April 29, I will be marrying my fianceé, Heidi Genter, here in Colorado Springs. It promises to be a momentous event, and I am looking forward to it. It also means my priorities will change drastically.

I will not be able to guarantee regular posts to either of my two blogs (Sense of Misplaced is the other) from this day forward. Last minute errands will take up most of the next two weeks. I am also working on a couple of projects that have guaranteed income potential.

After the wedding, our priorities will be merging our two households, and finding a more regular income-generating job for me. As the weather continues to warm, we will be taking advantage and going afield as often as we can.

In short, "real life" will be largely replacing the virtual one I have been leading the last several months. This does not mean I plan to give up putting new content on my blogs, but it will be on a as-I-can-do-it basis. I appreciate your understanding. Thank you.

Sunday, April 15, 2012

Spider Sunday: Triangulate Cobweb Weaver

One of the spiders most frequently encountered in basements, garages, and cellars over much of North America is the Triangulate Cobweb Spider, Steatoda triangulosa. It is a member of the cobweb weaver family Theridiidae, and therefore related to black widows. Not surprisingly, it is sometimes mistaken for a widow.

This species is widely distributed in the U.S., from Massachusetts to Nebraska, Colorado, Utah, Oregon, and California, and all points south (though nearly absent in the southwest and in Florida). It is also recorded from southern Ontario, Canada. It is also known from central and southern Europe, the Mediterranean region, and what was formerly southern Russia. Indeed, it is suspected that S. triangulosa was introduced to North America from overseas.

Adult females are only 3.6-5.9 millimeters in body length, males even smaller at 3.5-4.7 millimeters. Both genders usually sport the same distinctive pattern on the abdomen: a background color of dirty white or beige with a pair of bold, wavy, rusty or purplish brown lines down the back. The cephalothorax is normally dark reddish brown, and the legs pale brown or yellowish with dark bands at the joints. Males have a more slender, leggy appearance than females.

The Triangulate Cobweb Weaver spins an irregular, tangled web with a more-or-less sheet-like central platform. It seems to prefer dark recesses where it can dash into a crevice if disturbed. Look for them in your basement, cellar, garage, water meter box, or under bridges and in culverts, where the entire web may be protected from the elements. The spider hangs upside down in its web.

Mating occurs from late spring through early autumn. Females deposit about thirty eggs at a time, wrapping them in an opaque, white, spherical sac. The eggs may be seen through the sheer fabric enclosing them. A female may produce six or more egg sacs in her lifetime.

This species preys on a variety of insects, including the Red Imported Fire Ant (“RIFA”) in the southern U.S. Unfortunately, it is an unlikely candidate as a biological control agent of that pest (MacKay and Vinson, 1989). This is apparently a spider that “plays well with others,” as it may build its web in relatively close proximity to the webs of other cobweb weavers, cellar spiders, and even brown recluse spiders.

Don’t be alarmed by the presence of this species. It is not recognized as being dangerously venomous to people or pets. Indeed, it is such a small spider that its bite is unlikely to puncture human skin anyway

Sources: Howell, W. Mike and Ronald L. Jenkins. Spiders of the Eastern United States: A Photographic Guide. Boston: Pearson Education, Inc. 361 pp.
Jackman, John A. 1997. A Field Guide to Spiders & Scorpions of Texas. Houston: Gulf Publishing Company. 201 pp.
Jones, Dick. 1983. The Larousse Guide to Spiders. New York: Larousse & Company, Inc. 320 pp.
Levi, Herbert W. 1957. “The Spider Genera Crustulina and Steatoda in North America, Central America, and the West Indies (Araneae: Theridiidae),” Bull Mus Comp Zool 117(3): 367-424.
MacKay, W.P. and S.B. Vinson. 1989. “Evaluation of the spider Steatoda triangulosa (Araneae: Theridiidae) as a predator of the red imported fire ant (Hymenoptera: Formicidae),” J NY Entomol Soc 97: 232-233.
Moulder, Bennett. 1992. A Guide to the Common Spiders of Illinois. Springfield: Illinois State Museum Popular Science Series, vol. X. 125 pp.

Wednesday, April 11, 2012

Wasp Wednesday: Anoplius

Spider wasps are already active over much of North America. Here on the Front Range in Colorado Springs, Colorado, the genus that is out now is Anoplius. A visit to the Starsmore Discovery Center at the entrance to North Cheyenne CaƱon Park produced three specimens in a small area. I patiently followed one as she dug her burrow.

Unfortunately, most spider wasps in the family Pompilidae are wholly blue-black in color, with few features one can distinguish in the field, or even from images of live specimens. Only years of experience has me the least bit confident in concluding a genus for these Colorado specimens. I did note that the outer edge of the hind tibiae (“shins”) on these wasps are smooth, which pretty much rules out any spider wasp in the subfamily Pepsinae. Since she was digging her own burrow and not invading that of another wasp, I can rule out the subfamily Ceropalinae (cuckoo spider wasps are also vividly marked).

There are five subgenera within the genus Anoplius. Roughly 26 species occur in Colorado. The majority of them are black, and 10-20 millimeters in body length. The one depicted here was about 12 millimeters.

Interestingly, this particular female wasp appeared to be digging three or four burrows simultaneously. Whether she would ultimately choose one to finish, or complete all of them, remains a mystery to me. The soil was full of pebbles, so perhaps she was seeking the path of least resistance. Even so, she unearthed several pebbles that to her must have been like boulders. The persistence, strength, and agility of these insects is amazing. They appear tireless, pausing only periodically to groom soil particles from their eyes and antennae.

It is difficult to generalize about Anoplius because of their diversity in habits. Most species prey on wolf spiders (family Lycosidae), either exclusively or in part. A few are generalists, catching mostly other kinds of wandering spiders. Prey records include crab spiders (Thomisidae), jumping spiders (Salticidae), ground spiders (Clubionidae, Corinnidae, and Gnaphosidae), and grass spiders (Agelenidae).

The female wasp stings its prey into paralysis, then excavates a burrow or transports the spider to a burrow she dug previously (or a pre-existing cavity). An egg is laid on the victim and then the burrow is closed. This process is repeated as often as the wasp is able.

We are still learning the biology of most Anoplius species, so observations you document could represent something new to science. Collecting specimens is helpful in this case, where the wasps cannot be reliably identified without voucher specimens. It is also perfectly permissible to simply enjoy watching these wasps without taking notes or images.

Sources: Evans, Howard E. and Carl M. Yoshimoto. 1962. “The Ecology and Nesting Behavior of the Pompilidae (Hymenoptera) of the Northeastern United States,” Miscellaneous Publications of the Entomological Society of America 3(3): 67-119.
Krombein, Karl V. and B. D. Burke. 1979. Catalog of Hymenoptera in America North of Mexico Volume 2 Apocrita (Aculeata). Washington, DC: Smithsonian Institution Press. Pp 139-2209.
Kurczewski, Frank E. and Edmund J. 1968. “Host Records for Some North American Pompilidae (Hymenoptera) With a Discussion of Factors in Prey Selection,” Journal of the Kansas Entomological Society 41: 1-33.
Wasbauer, M. S. and L. S. Kimsey. 1985. “California Spider Wasps of the Subfamily Pompilinae (Hymenoptera: Pompilidae),” Bulletin of the California Insect Survey, vol. 26: 1-130.

Sunday, April 8, 2012

Spider Sunday: Phidippus asotus

Jumping spiders (family Salticidae) are just about as “cute” as spiders can get. They are usually fuzzy, often flamboyantly colorful, and have one pair of their eight eyes greatly enlarged and forward-facing. They are alert to your approach and turn to face you. Adorable. Just the same, I have found them exceedingly difficult to photograph. Recently, I finally got a cooperative subject in the form of a lovely female Phidippus asotus.

My partner in spider sleuthing, Mandy Howe of Spiders.us, helped me identify the spider’s species and gender. P. asotus is known to occur from California east through northern Utah and Colorado, and south to extreme west Texas and northern Mexico. The male is the more colorful of the sexes, most specimens being a pale orange in color. Both genders average around seven millimeters in body length.

This species typically favors fairly high elevations, between 5,000 and 7,000 feet. Indeed, Colorado Springs sits at a little over 6,000 feet. I spotted this specimen off the Rock Island Trail, sitting on a leaf of Oregon Grape. I initially thought she was just basking in the warm sun, but it turns out she had another agenda….

I had been taking a few images of a Yellow Dung Fly, Scathophaga stercoraria (below), that was enjoying the nectar of the Oregon Grape flowers. I suddenly noticed the spider sitting on the leaf of another plant adjacent to the one with the fly. Well, the fly had not escaped the spider’s notice, and she was actively stalking it.

To say that jumping spiders are stealthy hunters is an understatement. The spider was beneath the fly, so she hopped over to the flower stalk but stayed beneath and out of sight of her quarry. The fly must have eventually seen or sensed the predator, for it suddenly flew off (much to the spider’s disappointment, I presume). I could almost hear the spider sigh in regret.

My information on this species says that P. asotus matures in the fall, but this was an adult female. She probably overwintered somewhere snug and cozy. They prowl for prey on oak, juniper, and various shrubs.

There are a total of ten species of Phidippus that likely range in the Pikes Peak region, so I look forward to finding the other nine. Keep an eye out for this genus in your own backyard. Despite their relatively large size and engaging personalities, these spiders are not that well known.

Sources: Edwards, G.B. 2004. “Revision of the Jumping Spiders of the Genus Phidippus (Araneae: Salticidae). Occasional Papers of the Florida State Collection of Arthropods Vol. 11. 156 pp.
Proszynski, Jerzy. 2004. Salticidae: Diagnostic Drawings Library.

Wednesday, April 4, 2012

Wasp Wednesday: Eupelmidae

Eupelmus sp. by Marie L. Schmidt via Bugguide.net

The overwhelming majority of wasps are stingless insects that are very small, and usually parasitic on other insects at some point in their life cycle. Chalcidoidea is a “superfamily” that includes a great many families of tiny parasitic wasps. Among these are wasps in the family Eupelmidae. There are roughly 935 species known globally, 119 of those occurring in North America north of Mexico (Grissell, 2010).

Metapelma sp. from Tucson, Arizona (Eric R. Eaton)

The different subfamilies and genera have disparate life histories as internal or external parasites of arthropods as diverse as scale insects, cockroaches, lacewings, gall midges, moth and butterfly caterpillars, and other wasps. Some are egg parasites of various insects, or spiders. Some are parasitic on gall-forming insects or stem- and twig-borers. Others are hyperparasites: parasites of other parasitic insects already present in a host insect. Most species overwinter as mature larvae, or pupae.

Licrooides umbilicatus by Jon Hart via Bugguide.net

An interesting aspect of the subfamily Eupelminae is their ability to jump….with their middle legs. The segments and musculature of the mesothorax (middle thoracic segment) are designed to give great power to the middle pair of legs, propelling the insect quickly away from a potential predator. The build-up of tension is so great that it deforms the thorax prior to the insect launching itself. Note that the middle leg also has a well-developed spur on the terminal tip of the tibia, the better to anchor a jump (Pitkin, 2004). The wasps die in a contorted posture as a result of the shrinkage of those mesothoracic muscles (image below).

Eupelmid from Massachusetts (Eric R. Eaton)

At about six millimeters in body length, members of the genus Metapelma are enormous by the standards of chalcidoid wasps, and you might actually encounter them in the field. They are parasitic on wood-boring insects, probably the beetle families Buprestidae and Cerambycidae. Look for them on tree trunks with exposed dead wood.

Metapelma sp. from Cincinnati, Ohio (Eric R. Eaton)

Most other eupelmids can only be observed by rearing parasitized host insects. Harvesting galls may yield them, along with a variety of other parasitic wasps. There is great potential for learning more about the relationship of eupelmids to their hosts; and there is also the possibility that more species could be employed as biological controls of agricultural and forest pests.

Sources: ”Family Eupelmidae,” Chalcidoidea Site. 2003. USDA Systematic Entomology Laboratory
Grissell, Eric. 2010. Bees, Wasps, and Ants: The Indispensable Role of Hymenoptera in Gardens. Portland, Oregon: Timber Press. 335 pp.
Pitkin, B. R. 2004. ”Notes on Families: Eupelmidae,” Universal Chalicoidea Database. The Natural History Museum (UK).

Sunday, April 1, 2012

Spider Sunday: Itsy Bitsy Spider

The Itsy Bitsy Spider, Teeny tineus, is one of the world’s most common and popular spider species. Its life history includes some unique behaviors; and the history of its discovery and scientific description is both mysterious and creative. The spider is amazingly elusive, hence there is not one single image of the species known to exist.

The Itsy Bitsy Spider is also known as the “Incy Wincy Spider,” “Eency Weency Spider,” “Ipsy Whispy Spider,” and “Ipsy Dipsy Spider.” The species was first described in the nursery rhyme “Itsy Bitsy Spider,” but the words cannot be traced to one individual. Still, the anonymous description was published in the prestigious journal Mother Goose.

The paper has been reprinted hundreds of times, and even set to music. Among the recording artists who have performed the manuscript are Carly Simon (1987, from the album Coming Around Again), Little Richard (1991, from his children’s album Shake It All About), and EliZe (from her 2006 debut album In Control).

Part of the reason for this spider’s apparent scarcity is its preferred habitat: The downspouts of roofline rain gutters. Only one spider occupies each vertical pipe, and it is not an easy life. Down comes the rain and washes the spider out. Luckily, out comes the sun and dries up all the rain. Then the Itsy Bitsy Spider climbs up the spout again. The persistence of the spider is legendary, as it repeats this behavior over and over. The spiders invariably have no flood insurance, yet insist on retaining their residences.

The other reason the spider is seldom seen is that it is very small….Itsy Bitsy in fact. No one knows how long each Itsy Bitsy Spider lives, how it reproduces, the nature of its egg sac (one assumes it is waterproof), or what kind of prey the spiders feed on. Clearly, there is much yet to be learned about the species, and subsequently put into rhyming verses.

What?! You don’t know what day this is? Happy April first, friends.