- Author: Kathy Keatley Garvey
This just in for Halloween!
Ever seen a false black widow spider?
Commonly known as the cupboard spider, it's a semi-cosmopolitan spider that's often confused with the "real" black widow spider, known for its powerful venom.
Adrienne Shapiro of Davis took this photo (below) of a spider on the Shapiro property (photographed and released). Her husband, Art, distinguished professor of evolution and ecology, identified it as a female false black widow, Steatoda grossa.
"The overall appearance is very similar to the real thing, except it lacks the red spot on the belly and usually--but not always--has some yellow patterning on the dorsal abdomen: a crescent-like line at the anterior end and a row of triangular spots down the midline, visible here," Shapiro commented.
"But a few may be all black, or the yellow is barely visible," he noted. "This is a semi-cosmopolitan species usually found in or around buildings. It's originally from the Mediterranean region and in the United States and is mostly urban-bicoastal, absent from the heartland. Its habits are nearly identical to the black widow. It's not very common and I personally have never seen it in Davis before. The bite of the female IS venomous, but not to the degree a true black widow bite is. The symptoms are usually local pain, redness and blistering, but some people report generalized malaise for up to a couple of days. I am unaware of any deaths or serious sequelae."
Steve Heydon, senior museum scientist at the Bohart Museum of Entomology, UC Davis, says he gets a few calls about the false black widow. "Steatoda mostly lives under things on the ground," he said, "while the black widows live a little bit off the ground."
We've never seen the false black widow, but have seen numerous black widows (genus Latrodectus.) One black widow homesteaded on the rim of our swimming pool several years ago and we managed to photograph Mama straddling her egg cases. The familiar red hourglass was definitely visible!
The black widow's bite, particularly harmful to people, contains neurotoxin latrotoxin, which causes the condition latrodectism, both named for the genus. Only the female bite is harmful. But the bite is rarely fatal to humans.
We watched Mama scurry around, seemingly trying to protect both egg cases simultaneously from the long-lensed camera.
She was like a Mama Grizzly protecting her cubs.
- Author: Kathy Keatley Garvey
You'd never know that if you looked in the backyard of UC Davis entomologists Robert and Lynn Kimsey.
The UC Davis Entomology Club, advised by Robert Kimsey, is building a 40-foot-long black widow spider for the UC Davis Picnic Day Parade on Saturday, April 18.
Latrodectus hesperus has never looked so...well...huge!
And so colorful--right down to the distinctive red hourglass.
What's it like seeing a huge spider coming to life in your backyard?
“Well, it is very weird!” said Robert Kimsey, a forensic entomologist and longtime advisor of the club. “It is huge and currently in pieces as it is getting its skin and pedipalps and other minor body parts and whatnot. It is anatomically correct in every way! The students have been trained well in arachnology!”
“There are legs all over the place,” Kimsey said. Each is slightly less than 20 feet long. "Again, it is huge. I have to admit that there are some brilliant artists and engineers in this group! But looking out the windows into the backyard takes your breath away. Any non-biologist would completely go to pieces.”
Along with anyone suffering from arachnophobia.
The last time the the UC Davis Entomology Club entered a float in the UC Davis Picnic Day Parade was about 20 years ago. And yes, it was a black widow spider (see photo below)
“The spider idea collectively came from all members of the cabinet after hearing about past picnic days from Bob,” said Entomology Club vice president Alex Nguyen. “When we presented it to the club we received very positive feedback so we decided to commit to marching in the parade with a float this year.”
The spider represents a month of planning and two weeks of building, Nguyen said.
During the parade, Entomology Club president Marko Marrero will be inside the spider, hoisting it up, and walking with it, along with two people at each leg.
If you want to see the spider, the opening ceremony of the parade begins at 9:25 a.m. in the grandstands on the North Quad Avenue across from Wickson Hall. The parade begins at 10, snakes downtown, and ends at noon. Announcement locations include the beginning of the parade; second and D Street in downtown Davis; F street in front of PDQ Fingerprinting; and third and C Street in downtown Davis.
You can also see the spider after the parade. It will be showcased in front of Briggs Hall, off Kleiber Hall Drive, where scores of entomological events will take place, including cockroach races, maggot art, honey tasting, and fly-tying. There will be a bee observation hive, ant displays, and displays of mosquitoes, forest insects and aquatic insects.
The UC Davis Entomology Club and the Entomology Graduate Student Association will be working the booths, along with faculty and staff.
Membership in the UC Davis Entomology Club is open to all interested persons (email entomologyclub@gmail.com). Members are faculty, staff, students (college and high school) and community residents.
They have at least one thing in common: they're interested in insects and other arthropods, including arachnids (spiders).
Even at picnics...and parades...
- Author: Kathy Keatley Garvey
A sure-fire way to frighten arachnophobics is the very mention of "spiders"--especially on Halloween.
Spiders aren't insects but arthropods, order Araneae. They have eight legs, which according to some, are seven legs too many. They are also distinguished by their chelicerae with fangs that inject venom.
You've seen them. Black widow spiders. Jumping spiders. Crab spiders. Garden spiders.
If you fear them, there's a name for that fear: Arachnophobia. Wikipedia says that "People with arachnophobia tend to feel uneasy in any area they believe could harbor spiders or that has visible signs of their presence, such as webs. If arachnophobics see a spider, they may not enter the general vicinity until they have overcome the panic attack that is often associated with their phobia. Some people scream, cry, have trouble breathing, have excessive sweating or even heart trouble when they come in contact with an area near spiders or their webs. In some extreme cases, even a picture or a realistic drawing of a spider can also trigger fear."
So many myths about spiders. The Burke Museum of Natural History and Culture, University of Washington, Seattle, has posted some of the myths, misconceptions and superstitions on its website.
The general fallacies, as listed by Rod Crawford, curator of arachnids:
General Fallacies
- Spiders are insects.
- "Arachnid" is just a fancy name for spider.
- You can always tell a spider because it has eight legs.
- All spiders make webs.
- The orb web (round or "geometric" web) is a "normal" spider web.
- A "daddy-longlegs" is a kind of spider.
- Most spiders could not bite humans because their fangs are too small.
- Any spider species can be found anywhere.
- All spiders are male.
- Spiders are most numerous in late summer.
- You are never more than three feet from a spider.
- Spiders "suck the juices" of their prey, and do not literally eat it.
- Spiders don't stick to their own webs because their feet are oily.
Meanwhile, over at the Bohart Museum of Entomology at the University of California, Davis, plans are underway for an open house themed "Insect Myths." They will focus on spider myths, too.
The event, free and open to the public, is set for Sunday, Nov. 23 from 1 to 4 p.m. in Room 1124 of the Academic Surge Building on Crocker Lane, off LaRue Road. Directed by Lynn Kimsey, professor of entomology at UC Davis, the museum houses a global collection of nearly eight million specimens and is the home of the seventh largest insect collection in North America, and the California Insect Survey, a storehouse of the insect biodiversity. The museum is open to the public four days a week, Monday through Thursday (9 a.m. to noon and 1 to 5 p.m.) but it sponsors special weekend open houses as well.
The remaining schedule:
- Sunday, Nov. 23: “Insect Myths,” 1 to 4 p.m.
- Saturday, Dec. 20: “Insects and Art,” 1 to 4 p.m.
- Sunday, Jan. 11: “Parasitoid Palooza,” 1 to 4 p.m.
- Sunday, Feb. 8: “Biodiversity Museum Day,” noon to 4 p.m.
- Saturday, March 14: “Pollination Nation,” 1 to 4 p.m.
- Saturday, April 18: UC Davis Picnic Day, 10 a.m. to 3 p.m.
- Sunday, May 17: “Name That Bug! How About Bob?” 1 to 4 p.m.
- Saturday, July 18: “Moth Night,” 8 to 11 p.m.
When you attend the Bohart Museum open houses, you'll probably have the opportunity to hold and/or photograph "Rosie," a 24-year-old tarantula. It's one of the critters in the live "petting zoo," which also includes Madagascar hissing cockroaches, millipedes and walking sticks.
/h3>/span>- Author: Kathy Keatley Garvey
The female black widow spider stood guard.
She clutched her two teardrop-shaped egg sacs, suspended from the web she'd earlier woven on the lip of the swimming pool. She spent the day crawling up, over and around them. Two sacs, about 300 eggs inside each one.
Her future offspring. Proud Mama. Dangerous Mama.
Below, honey bees buzzed in the catmint (Nepeta), a white cabbage butterfly fluttered about, ladybugs snatched aphids, and a cellar spider (aka "daddy long-legs," Pholcus phalangioides) waited for the spiderlings to emerge to partake of an all-you-can-eat buffet. Sometimes that can be a four-week wait.
The female black widow spider is a force to be reckoned with--her bite is the most venomous of all spiders in North America. The neurotoxic venom can kill humans, but that rarely occurs. Statistics show the human mortality rate is less than 1 percent.
Not so with the insects and other arachnids she traps in her web. They blunder into the sticky web, get stuck, get bitten, and get eaten. While they're struggling in the web, she punctures them and sucks out their body fluid.
Not a pretty picture. But it is when it's a house fly or cockroach!
The female black widow spider (Latrodectus hesperus) is easy to distinguish. About half an inch long and shiny jet black, she's characterized by a red hourglass pattern on the underside of her bulbous abdomen. But don't bet on the pattern or coloring. Some black widows have a fragmented pattern, and some display no hourglass pattern or no red coloration at all.
You'll often find black widows in the garage, in woodpiles, rock piles, backyard clutter, in corners of sheds or playhouses, and sometimes inside your basement or elsewhere in your home. They spin an irregular, sticky silken web, conveniently located near their future prey.
This arachnid is named "black widow" because of the old wives' tale that she always kills her mate and consumes it after mating. Not true, scientists say. The mating ritual is not always violent.
However, it's when the female black widow is guarding her egg sacs that she's considered the most dangerous. When she bites humans, the bite itself can be painless or quite painful, but should always require medical attention.
That's because the venom is a powerful neurotoxin that causes muscles to contract. "This spider's bite is much feared because its venom is reported to be 15 times stronger than a rattlesnake's," according to a National Geographic post. "In humans, bites produce muscle aches, nausea, and a paralysis of the diaphragm that can make breathing difficult; however, contrary to popular belief, most people who are bitten suffer no serious damage—let alone death. But bites can be fatal—usually to small children, the elderly, or the infirm."
Be careful out there!
- Author: Kathy Keatley Garvey
The very presence of a black widow spider, shiny black with a globe-shaped abdomen, strikes fear in most people.
And not just on Halloween.
"Many spiders will bite when trapped but black widow spiders (Theridiidae: Latrodectus) are the most dangerous North American species," write Charley Eiseman and Noah Charney in their newly published book, Tracks and Sign of Insects and Other Invertebrates: A Guide to North American Species.
"Their strong venom can kill," agrees George C. McGavin in the Smithsonian Handbooks' Insects, Spiders and Other Terrestrial Arthropods, "but a fast-acting antivenom can be given by injection."
The black widow is a cobweb spider and "the females produce about 200 to 250 eggs, attached to the web in a sac," McGavin says.
So, where can you find black widow spiders? They're usually in more concealed places than the common house spider, which is "found in any dry structure, including houses, basements an barns, as well as under natural 'roofs' such as overhanging ledges," according to Eiseman and Charney.
And, Eiseman and Charney point out, the black widow spider webs are "composed of extremely strong, coarse threads"--unlike those of common house spiders.
McGavin says black widow spiders are commonly found in leaf litter, under stones and in and around buildings.
We sighted one under leaf litter recently at the Harry H. Laidlaw Jr. Honey Bee Research Facility at UC Davis. Its distinguishing mark: the reddish-orange hourglass on its stomach.
Then last week we spotted a black widow spider guarding her gumdrop-sized sac in a secluded area of a UC Davis parking garage.
She didn't pay attention to the "permit parking only" signs.