Cochise County Spiders: The Black Widow, Latrodectus hesperus

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We’ve seen black widow spiders, the Latrodectus hesperus species, on our Cochise County, Arizona, acreage…more years than not. The property was purchased in early 2009, so that’s not a lot of years, but the distinctive black shape of the spider–not to mention the clincher, the red hourglass on the bottom (ventral) side of the abdomen–has been positively identified in the following places:

    1. Heading for cover under an aging piece of OSB strand board near our Yamaha generator. (We live off grid and used that gennie as our primary power source until the portable solar generator arrived in May of 2012.) One female.

    2. Hanging out in their tangled webs beneath the floor of a small (2′ x 4′ footprint), open faced shed that houses propane tanks. Five females, apparently content to live in close proximity with each other.

    3. Webbed up and hanging out inside an overturned wheelbarrow. One female.

One online source states that the black widow spider is “relatively rare”. I’m not sure whose relatives that author has been hanging out with, but I wouldn’t call the sightings in southern Cochise County anything close to rare.

However, today’s sighting (inside the wheelbarrow when I righted it to go haul a few loads of rocks for a construction project) was the first that offered any real photo opportunity. The one near the Yamaha scooted out of sight pretty quickly, and the colony of five female black widows under the propane shed had to be terminated; they were mere feet from the front door of our house.

We have no basement for them to enjoy, so we weren’t about to invite them inside.

This one, by contrast, was a photographer’s joy to behold. She’d been lying around, right side up on her web, so when the wheelbarrow was lifted up on its side, her red hourglass was staring straight at the camera. She didn’t want to leave the only home she’d likely ever known, so despite her obvious alarm at my presence, she wasn’t going anywhere until I moved her. The sun was still high enough in the sky for decent shooting light. And glory be, she was far enough away from the front door of the Border Fort (our home) that she presented no threat.

I was thus able to promise to do her no harm, and to get about my business of taking pictures. Once the photos were enlarged on the computer, the species identification became possible. Our model is a Lactrodectus hesperus, the western black widow spider.

When this post was first published, she was misidentified as a Lactrodectus mactans, or southern black widow. Sonoran Desert field guides eventually helped me correct that.

The black widow spider was lying on her web until I turned the old, concrete encrusted wheelbarrow on its side, exposing the telltale red hourglass on the underside of her abdomen.

The black widow spider was lying on her web until I turned the old, concrete encrusted wheelbarrow on its side, exposing the telltale red hourglass on the underside of her abdomen.

The leg length of the Lactrodectus hesperus (black widow spider) is impressive; check out that reach.

The leg length of the Lactrodectus hesperus (black widow spider) is impressive; check out that reach. Also, note the lighter colored pattern on the top (dorsal) side of the abdomen. These black widows come with many topside color variations.

We all know black widow spiders are extremely venomous and can in some cases kill, especially if a bite victim does not seek medical treatment. My father knew this firsthand. Serving as a young aircraft mechanic in the U.S. Navy during World War II, he was at one time stationed at Pensacola, Florida, where I was born. Mom, Dad, and I ended up knowing the naval hospital rather well. In addition to my birth, the man who sired me got an extra treat one day; a black widow spider treated him to a bite on the neck.

It nearly killed him.

Or at least, so my parents both stated, and they weren’t in the habit of exaggerating about such things.

I wanted to get some photos of the spider’s top (dorsal) side, but there didn’t seem to be an easy way to get this remarkable photographer’s model right side up…until I began shifting the web with a stick, figuring to carry the black widow with a portion of her web away from the wheelbarrow and onto the ground, or close to it.

My stirrings somehow flipped things over a bit…and suddenly the spider was right side up, just begging to have its picture taken.

On the upper side of the abdomen, there were some markings that caught the eye, sort of ragged looking stripes that could have painted on the Lactrodectus mactans with a fine artist’s brush. I didn’t know then that black widows come with a whole variety of topside patterns from which to choose. They’re really quite colorful little critters.

This black widow spider's "butt pattern" looks like it could have been painted on there with a very fine, delicate brush.

This black widow spider’s “butt pattern” looks like it could have been painted on there with a very fine, delicate brush.

With the silk of the web totally invisible against the light background of the concrete encrusted old wheelbarrow, the black widow spider appears to be floating in midair.

With the silk of the web totally invisible against the light background of the concrete encrusted old wheelbarrow, the black widow spider appears to be floating in midair.

Finally, enough pictures had been taken and it was time to move the black widow on out of the wheelbarrow. This was accomplished by stirring around the web (some distance away from the spider) with a stick until enough of the web could be removed (while attached to the stick) that the spider simply came along with.

The spider-web combo was then deposited as gently as possible in the old dead grass and leaf mold a few feet from our toes. The black widow was still very much alive and unharmed, hanging belly up beneath a portion of the web, looking for all the world like she’d intentionally spun her web out in the open.

Still hanging onto a portion of her relocated web (relocated by me), the black widow spider acts as if this was where she'd meant to spin her web all along.

Still hanging onto a portion of her relocated web (relocated by me), the black widow spider acts as if this was where she’d meant to spin her web all along.

As usual, the extensive photo op ended up being quite educational for me. Prior to this afternoon’s picture taking session, all I knew about black widows was (a) how to recognize them from the red hourglass designs on their abdomens, (b) their highly venomous nature, and (c) their general preference for living under things, such as–in the old days–outhouse seats. On the other hand, new learning these past few hours included the following:

    1. Black widows clearly (and for the most part, wisely) consider any recognition by humans to be a threat to their existence and react accordingly, hiding swiftly or biting according to the particular circumstances and conditions.

    2. Not all black widow spiders are of the same species. As Wikipedia puts it,

    (The) Black widow spider is one of several spiders in the Latrodectus genus. The name of the group is derived from the practice of the female of the species devouring the male after copulation.

    Spiders within the group include:
    +Western black widow or Latrodectus hesperus
    +Southern black widow or Latrodectus mactans
    +Northern black widow or Latrodectus variolus
    +Mediterranean black widow, or European black widow, or Latrodectus tredecimguttatus
    +Redback spider or black widow, Latrodectus hasselti
    +Katipo or black widow, Latrodectus katipo

    3. Although the general shape, dark base coloration, and distinctive red hourglass on the belly exist in every female black widow spider (the males lack the hourglass, tend toward lighter browns, and also lack the highly toxic venom of the females), there are many variations of secondary color patterns on the topsides of both genders. A quick look at Google images, using the keyword “black widow spider color variations” is quite interesting. It’s like Mother Nature went happily crazy with her paintbrush.

    4. Despite their justified fear of large critters like people, these girls do not like to leave their webs for any reason. They will scuttle around, trying to avoid contact when the camera comes too close–but they are not leaving home, thank you very much! Of course, why would they? A black widow spider away from her web is highly vulnerable to predation by many other species, not just Homo sapiens.

This fact, the spider’s reluctance to leave the tangled web, was discovered by moving the camera in quite close to take the photos you see here. In some cases, the lens–which must look like a space alien giant’s eye in the sky to the spider–was within three to four inches from the subject, yet she mostly held position, not moving a muscle until the ordeal was over.

Curiously, much like just about everything else in nature, this most beautiful of spiders illustrates a principle I’ve long believed to be a near absolute truth: The greater the beauty, the greater the danger.

Okay, so maybe that’s not true for butterflies and bunny rabbits, but consider this:

–Black widow spiders possess beauty of form and coloration…and can be deadly.

–There are few things more dangerous than a beautiful woman, as she is (a) often underestimated by men and (b) draws men willing to kill each other to possess her.

–There is absolutely nothing more dangerous than beautiful country. In fact, any stunning landscape can put the deadliness of a black widow spider or a movie star quality human female to absolute shame. If you don’t believe that, ask any Native American: How hard was it to hold on to attractive pieces of land when the white men came?

But I digress. This post is about black widow spiders, specifically. To that end, let’s close with a close up of the upper side of our model’s decoratively painted abdomen.

Blowing the tiny section of the photo up this far leaves us looking at a rather blurry image, but there’s no denying the beauty of the pattern.

Extreme magnification of a black widow spider's abdomen (dorsal side).  This Lactrodectus hesperus shows one of the many artistic patterns produced by nature's paint brush.

Extreme magnification of a black widow spider’s abdomen (dorsal side). This Lactrodectus hesperus shows one of the many artistic patterns produced by nature’s paint brush.

2 thoughts on “Cochise County Spiders: The Black Widow, Latrodectus hesperus

  1. UGH, I hate these spiders. I lived in an apartment with a laundry room at the end of the building. A black widow took up residence in the keyhole. Only way to get it out of there and allow us to use the laundry room was to kill it. Only way we could find to do that was by shooting the keyhole full of WD40. Amazing stuff. She came rushing out of there, in her death throes. I was really careful for awhile there, until I was sure there were no more of them. We lived in the end apartment, just before the laundry room and I had a new baby at the time; as well as a 2 year old.

  2. That would be mighty scary, knowing a black widow encounter was all too possible and having wee ones on hand. Presume that keyhole must have been one of the old school kind, big enough for a black widow to fit comfortably.

    You’re certainly right about WD-40, too. Amazing is the right word for it.

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