Shower Spiders

Just when you thought it was safe to take a bath….You throw open the shower curtain and are suddenly confronted with an eight-legged freak. Over the years I have answered many an AllExperts.com question about strange arachnids that people have found in the tub or stall, as well as finding my own specimens now and then.

Recently, I was myself taken aback upon entering the shower and spying a particularly fine specimen of a Philodromus running crab spider on the wall behind my wife. I was startled, which in turn startled her, and we spent the remainder of the time with one eye on the spider. Naturally, Ms. Phyllis Dromus dropped lower and lower, eventually settling by the place where the shower head comes out of the wall.

I know what you are thinking. How can a manly-man like me, equipped with knowledge that allows him to identify most spiders, and who knows this one is not dangerous, still be uneasy? That isn’t what you’re thinking? Why are you laughing? Please, this is a family show. Get your mind out of the gutter.

I think there are simply some places where we don’t expect to find spiders, and where we would prefer not to find them even if we normally appreciate and respect arachnids. No doubt the spiders feel the same way: “Gee, where do I have to go to get away from these monsters?! Uh-oh, it’s getting slippery!”

More recently, while attending the Mothapalooza event in Ohio, I prepared to step into the shower after a hot, sweaty field trip. Apparently, the tub had not seen much activity recently because there guarding the drain was a mature male Barn Funnel Weaver, Tegenaria domestica. I managed to snap one shot before trying to coax him into better viewing. That only drove him down the drain and though I was patient he never re-emerged.

I still wanted to wash off before dinner, so I ran a light stream of water out of the faucet. Sure enough, Mr. Barn Funnel Weaver shot out of the drain with lightning speed. He was at the other end of the tub before I blinked. A few more pictures and then I corralled him in a plastic container to show off to folks later. Now, now, no jokes about which of us is better endowed. What are you, twelve?

It is always a little easier for me to address someone else’s spider-in-the-shower experience than it is to chronicle my own, and I’m sure there will be plenty more such episodes crossing my e-mail or AllExperts.com account. I hope I am successful in calming people’s anxiety, allaying their fears, and otherwise turning fright into fascination. I always offer to accompany my female correspondents into the shower the next time, just in case….Funny, no one has ever taken me up on that.

Spider Sunday: Hololena Funnel-web weavers

Sometimes you go looking for spiders, and sometimes it seems they come looking for you. The second statement isn’t really true of course, but at the least you usually don’t have to go far to find arachnids. Here in the western United States, funnel-web weavers in the genus Hololena are abundant, even in the average yard or garden. Entire hedges can be full of their sheet-like webs.

Meanwhile, juvenile specimens, and mature males, will wander away from their webs, often straying indoors. It can be startling to suddenly have a spider appear on the wall while you are watching television.

Hololena is easily confused with other genera in the family Agelenidae, and to be fair it is only microscopic examination of certain body parts that can confirm the identity of any given specimen. Hololena is, however, readily separated from Agelenopsis based on the length of the spinnerets. Agelenopsis (and Calilena, too) have long spinnerets usually held parallel to each other. Hololena has short spinnerets, often directed somewhat inward toward each other.

These are medium-sized spiders, mature females ranging from 9-12 millimeters in body length, males 8-9 millimeters. Agelenopsis average substantially larger, about 10-20 millimeters. Most funnel-web weavers share a similar color pattern: two parallel or converging dark stripes on a pale carapace; a central reddish or brownish band running the length of the abdomen, often bordered by pale, wavy lines. The legs are often annulated (alternating bands of light and dark).

The genus Hololena appears to be restricted to the western third of the U.S., from Washington and Idaho south to southern California and New Mexico. There are approximately thirty recognized species, but the genus is in dire need of revision according to some arachnologists.

Agelenids in general spin thick, flat, hammock- or bowl-shaped webs with a funnel-like retreat in one corner. The web is not sticky. A tangle of threads above the silken platform intercepts flying insects, knocking them onto the sheet. The spider is extremely sensitive to vibrations and dashes out immediately to subdue its prey. It quickly drags the victim back into its lair to feed.

Male spiders have to approach females cautiously and deliberately. In Hololena, the male more or less bounces his legs and abdomen on the female’s web, creating a bout of one to six vibrations. A receptive female responds by drawing in her legs and lapsing into “cataleptic paralysis.” The male will draw closer and repeat his vibrational overtures until he is accepted or repelled. He then crawls over her back, gently grasping her two hind legs and dragging her deeper into her retreat.

Mating occurs when the male is able to turn the female on her side and insert one of his palps into her genital opening (epigynum). He repeatedly inserts his palp and pumps sperm into her before attempting to maneuver her into a position where he can insert the opposing palp. The female usually offers no resistance during this process. Once finished, the male grooms his palps and walks off the web. Occasionally his mate recovers from her paralysis prematurely and actively chases him off her web.

Mature males can be seen looking for females deep into the fall. The specimen shown above was observed on October 29, 2012 in Colorado Springs.

Researching this post I was startled to learn that there are confirmed cases of Hololena spiders biting people. It should be noted that actual spider bites are a pretty rare phenomenon, and the usual result is mild pain and swelling that doesn’t require medical treatment. Dr. Richard Vetter at the University of California, Riverside, published a note documenting three separate, verifiable instances of adult people who were bitten by Hololena spiders. Two were adult men, bitten by female spiders. The victims experienced headaches and four-hour episodes of vomiting. The third victim was an adult woman, bitten by a male spider, who experienced a very mild reaction. All three were perfectly fine in a matter of days without seeking medical attention (Vetter, 2012).

One need not be fearful of these spiders. I prefer to be enchanted by their delicate yet durable spinning work. I remember vividly a light snowfall we had here in Colorado Springs on October 25, 2012. The only place the flakes persisted was on Hololena spider webs. What an amazing scene! Take a look around your own neighborhood, especially on damp early mornings when dew has condensed. You will be amazed by the number of webs you hadn’t known were there.

Sources: Fraser, Jack B. 1987. “Courtship and copulatory behavior of the funnel-web spider, Hololena adnexa (Araneae, Agelenidae),” J. Arachnol. 15: 257-262.Vetter, R.S. 2012. “Envenomation by Spiders of the Genus Hololena (Araneae: Agelenidae),” Toxicon 60(3): 312-4.

Spider Sunday: Coras

Some spiders are so strange that they defy even experts to properly classify them. Such is the case with the genus Coras, which includes some very common species like C. medicinalis that spin funnel-like webs in and around human structures as well as natural settings.

First described by Nicholas Marcellus Hentz in 1821, C. medicinalis was placed in the genus Tegenaria. Charles Athanase Walckenaer put it in the genus Clubiona in 1837, but this move was not accepted by the bulk of his peers. So, he returned the species to the genus Tegenaria but changed the species to T. nemorensis. Hentz reasserted his intial name on two occasions, in 1847 and 1867. Eugen von Keyserling, in 1887, proposed Coelotes as the proper genus, and urbanus as the species name. Have I lost you yet? No? Good, because it gets more complicated still.

Eugene Simon published a revision of Coelotes in 1898, creating the genus Coras and resurrecting Hentz’s species name: Coras medicinalis thus achieving its currently accepted name. James Henry Emerton still broke ranks with his colleagues in 1902, assigning this species the name Tegenaria (subgenus Coelotes) medicinalis. John Henry Comstock apparently had the final word in 1912, asserting Simon’s revision as the official status for the species.

Even more astonishing, the genus Coras has bounced between families like a taxonomic pinball. Frederick Octavius Pickard-Cambridge originally placed Coras in the subfamily Coelotinae of the family Agelenidae. This genus, as well as the closely-allied genus Wadotes stayed in the Agelenidae until 1986, when Joerg Wunderlich moved them to the family Amaurobiidae. What was wrong with that, you ask? Well, one of the defining characteristics of the Amaurobiidae is the presence of an “extra” plate-like silk-spinning organ called a cribellum, located just in front of the spinnerets. The thing is, Coras and Wadotes don’t have this structure. Just this year the two genera boomeranged back to the Agelenidae, though I cannot presently find the journal article confirming this.

Thankfully, the biology of Coras is more straightforward. There are fifteen species in North America, all of them found principally east of the Mississippi River (southeast Canada south to Florida and west to Wisconsin and Louisiana). The genus can be identified in part by the eyes. The anterior median eyes are larger than the anterior lateral eyes. That means that the row of eyes nearest the jaws has the middle pair larger than the outer pair. I find the pattern of dark lines on the carapace to be fairly diagnostic as well.

Their webs are generally not as large as those of other funnel-web spiders, perhaps because the spiders themselves are not that large. Mature females average between 8 and 13 millimeters in body length, males 8-10 millimeters. Adult spiders are found in summer and fall. Egg sacs are probably produced in autumn since both adult and juvenile specimens have been observed hibernating in silken retreats under rocks during the winter months.

The webs may be well off the ground as evidenced by the one shown above. It was attached to the exterior of a pump house in Mount Sugarloaf State Reserve in South Deerfield, Massachusetts. The multiple retreats, instead of singular, is typical of the genus, too. These are spiders of forested habitats that also build their webs from beneath stones, from crevices in rock walls, and from loose bark on trees and logs. They are not strangers to basements or cellars, though, so look for them there as well.

Coras medicinalis acquired its species name from Hentz’s knowledge that the webs of this spider were used to make a tincture (alcoholic extract) for the relief of fevers back in the 1800s. Good to know we have advanced in our pharmaceuticals since then, leaving us free to simply enjoy these spiders on their own merits.

Sources: Bradley, Richard A. 2004. In Ohio’s Backyard: Spiders. Columbus, Ohio: Ohio Biological Survey Backyard Series No. 4. 185 pp.
Cates, Jerry. 2011. ”Araneae: Agelenidae: Funnel-web Spiders,” Bugs in the News. November 5, 2011.
Gaddy, L. L. 2009. Spiders of the Carolinas. Duluth, Minnesota: Kollath+Stensaas Publishing. 208 pp.
Howell, W. Mike, and Ronald L. Jenkins. 2004. Spiders of the Eastern United States. Boston: Pearson Education, Inc. 362 pp.
Levi, Herbert W. and Lorna R. 1968. Spiders and their Kin. New York: Golden Press. 160 pp.
Moulder, Bennett. 1992. A Guide to the Common Spiders of Illinois. Springfield, Illinois: Illinois State Museum Popular Science Series, Vol. X. 125 pp.
World Spider Catalog.