Tag Archives: southern black widow (Latrodectus mactans)

Hands off!

Some arthropods are dangerous simply because their defenses are automatic, like venomous caterpillars.  Some arthropods are dangerous because they will defend themselves if pushed, like assassin bugs.  And some arthropods are dangerous because they have stings or bites that can deliver venom, like spiders.

One such spider, the southern black widow (Latrodectus mactans), lives ubiquitously around our family farm in East Texas.

A female southern black widow (Latrodectus mactans) hanging inside her web (IMG_1297)

The southern black widow is the most common of the three North American species of widow spiders, with its telltale black carapace and red hourglass mark on the underside of the abdomen.  Well, perhaps I should say with her telltale markings, since males look altogether different, not just in size but in color and markings.

The first black widow I found, seen above, hunkered in an old tree trunk, her web a messy menagerie of this way and that way, up and down, a jumbled mess covering her little hole in the world.  That was back in April 2012 (yes, here in the South they get started early, going all year if winter is mild enough or if they have someplace to protect them from the elements).  The only photo I took was while I approached her, shot using a telephoto lens, because she quickly vanished into her lair when I leaned in close for a macro image.

A male southern black widow (Latrodectus mactans) meandering across a patio chair (IMG_2953)

And when I say males look altogether different, I mean it.  This one I found in May 2012 as he wandered across an outside chair.  From the looks of his pedipalps (the boxing gloves he holds out in front of him), he’s ready to mate.  You see, male spiders deliver sperm via their pedipalps.

Though when seen dorsally he doesn’t look at all like a widow…

Underside of a male southern black widow (Latrodectus mactans) (IMG_2955)

…from below he most certainly bears the mark of the beast—the red hourglass design on his abdomen.

(Yes, I flipped him over, which seems to go against my general rule for nature photography: in situ only and don’t interfere.  Ah, but I had to get him off the chair since someone wanted to sit in it, so I most definitely was going to interfere with his life.  Therefore, giving him a quick flip didn’t seem too problematic for me as I was about to give him the boot—metaphorically, I mean, as in booted off the chair and on his way.)

I’ve read in a few places that people think the males are harmless.  That’s untrue as they can inject the same venom the female uses, although, being smaller with smaller teeth, males inject less venom.

In addition, juveniles of either sex can look just like adult males.  So messing with a spider that looks like him could well lead to a young female giving you a good dose of venom.  Hence, don’t mess with either gender.

A female southern black widow (Latrodectus mactans) tucked in a corner with a dessicated green June beetle (Cotinis nitida) nearby (IMG_1883)

When they bite with their 1mm/0.04in teeth (chelicera), the female black widow delivers no more than 0.03 milligrams of venom.  That’s 3/100ths of a milligram, I should point out, which equates to a miniscule fraction of a single raindrop.  Yet widows have some of the most potent venom in the spider world, and female black widows have unusually large venom glands.  So you do the math.

The above female, with her dessicated green June beetle (Cotinis nitida) meal nearby, hid beneath the loading ramp we use with the feed barn.  Tucked in a corner where she disappeared into the shadows after the first picture, she remained on the ramp for many months.  Trust me—I checked regularly.

A female southern black widow (Latrodectus mactans) finishing hew new egg sac (20120627_00674)

Found in June 2012 as she put the finishing touches on her first egg sac, this female showed no interest in me as I moved around her snapping shots from a respectable distance.  But when I leaned over her and moved in for some closer pictures?

A female southern black widow (Latrodectus mactans) protecting her new egg sac (20120627_00707)

She responded.  She moved quickly to intercept me—to protect her offspring—and she made it clear that closer was not acceptable.

Mom has also encountered an aggressive female black widow who would challenge her if she came too close.  Usually reclusive and reluctant to engage, black widows—especially females, and most especially females protecting egg sacs—can be quite aggressive when in the mood.  Most often they run, but sometimes they challenge instead.  You won’t know which to expect until they act.

Close-up of a female southern black widow (Latrodectus mactans) hanging on her web (20120627_00734)

Needless to say I respected her personal space, capturing images with good distance between us, all the while with her following my every move, keeping herself between me and the egg sac—and keeping her business side (biting side) aimed toward me.  Oh yes, I heard her loud and clear.

And don’t let her missing leg fool you.  With only seven legs to move on, she moved just fine, with rapidity and precision I might add.

A female southern black widow (Latrodectus mactans) perched on a steel grate (20121012_04632)

Then in October 2012 I decided to invade the personal space of a female who had spent the whole year beneath a porch mat.  I knew she was there—I even warned my family she was there so they’d be careful.

Because being careful in black widow territory is important.  Something Mom learned with a near-miss of a bite.

A female southern black widow (Latrodectus mactans) perched on a steel grate (20121012_04638)

Near the back porch is an overturned flower pot.  It hasn’t been used in quite some time, so it’s been resting there waiting for someone to use it.  For some reason, my mother decided to flip it over and look in it—without thinking, because she pushed her finger through the drainage hole in the bottom, flipped it over and glanced inside.

Only to be greeted by a female black widow with a few eggs sacs who had obviously lived under the pot for some time.  Um…  Oops!

Around here, the general rule is to look under and around things outside before lifting, moving or otherwise manipulating them.  That’s because black widows like secluded spots, making them easy to find under things, like vehicles, floor mats, buckets and barrels, and anything else that gives them shade and cover and protection from the world at large.

Time of year is irrelevant, I’ll add, for as I noted earlier they can be found for most of the year given southern mild temperatures.  More importantly, if they have cover that keeps them from dying, they can live right through harsh conditions.

Dad found this out just a few weeks ago when he flipped over a storage barrel, making it ready for use, only to find two female black widows alive and well and protecting seven egg sacs (though the eggs had hatched long ago and the sacs had discolored).  Regardless of that, two adult females hiding out in late January under protective cover shows just how careful you have to be in this neck of the woods.

Otherwise you might just get an extremely potent neurotoxin bite with effects lasting sometimes for months afterward (though the first week will be so bad that residual issues later will seem glorious by comparison).

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This is the second entry in my intermittent series of posts focused on arthropods that can be dangerous if mishandled.  The first entry—about wheel bugs—is here.