Viuda Negra


Ask almost anyone in the United States or Mexico what is the most dangerous spider native to their region and they will more than likely give you the same answer. In Spanish it is called “viuda negra,” which sounds only slightly more ominous than the English translation “black widow,” so named for the female’s habit of consuming the male after mating has taken place, although in reality this is not a chief goal nor is it efficiently accomplished most of the time. Still, the ominous name has struck terror in the hearts of arachnophobes wherever this spider occurs.

fullsizeoutput_c3dAll danger aside, the black widow (Latrodectus mactans) is one of our most beautiful spiders. While the male is a small, thin, spindly-legged, rather dull-colored fellow (a trait atypical in nature, which more commonly favors the male’s gaudy, eye-catching mating display characteristics to the female’s drab one), a female black widow is a gorgeous creature, with an ebony colored body so shiny it reflects light from its almost mirrored surface. The entire animal is black, from the abdomen and cephalothorax to the eight segmented legs. The underside bears some sort of vermillion hourglass shape, its degree of symmetry dependent on species (yes, there are several species of widow). Even the immature stages of this remarkable animal are amazingly patterned, the tear-drop shaped abdomen striped in alternating vertical bands of silver, yellow, and crimson. Occasionally the female retains this early instar coloration, which makes for one very recognizable spider that looks as if it could have crawled from an abstract work of art.

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An adult that retained juvenile coloration

Black widow spiders, for all their eye-catching beauty, possess a nasty reputation that, at least in my opinion, is largely undeserved. This is due largely to their virulent venom, which is a particularly potent cocktail of neurotoxins that hijack the central nervous system, causing little initial pain but later producing a wide range of symptoms, from chills, nausea, and vomiting to intense abdominal cramps, tremors, and – in extremely rare cases – death. Drop for drop, the venom of this potentially dangerous species has been said to be approximately fifteen times more virulent than that of a rattlesnake, although the tiny fangs and equally minuscule venom glands ensure that only a minute fraction of venom is delivered with a single bite. Nevertheless, when one compares liquid volume to human body weight, there is no arguing the fact that these spiders are not to be handled carelessly.

Luckily, the black widow spider is a shy, retiring species that spends the majority of its life on the web and not actively pursuing its prey on the ground, which would bring it into closer accidental contact with people. Although they have been credited as being wildly aggressive spiders, I have not found this to be the case in the field. In 2007 I had the good pleasure of working alongside Mark Neuling, a collector of exotic spiders and other arachnids, as he unloaded several crates of imported stock from Vietnam and Thailand. It was here that I was introduced to the cobalt blue spider (Haplopelma lividum) a stunning, dark tarantula (Mark would argue that it was technically not a tarantula, for reasons I can’t remember) with a dark blue sheen over its body that hails from the humid jungles of the far east. Mark warned me not to get my fingers too close to this species, as they were “super-aggressive.” As we began to unload them from their containers, which were old film vials (don’t ask me how they got them in such a small, tight space) I was taken aback at the ferocity of these big arachnids, which are about the size of our own Texas native tarantula, Aphonopelma hentzi. The spider, after being coaxed from its plastic “burrow,” would immediately dash toward the forceps and attack it, forelegs raised in the classic perturbed spider stance. It would then proceed to throw itself at the instrument, and the immense, dog-toenail fangs made audible grinding noises as they ground at the stainless steel, seeking a point of entry. One careless coworker was bitten after shirking Mark’s warning, and if you have never seen a grown man cry from a spider bite it is not a pretty sight. After the pain and shock wore off, the 270 lb. 6’3” former macho man described the pain as being not unlike having someone bring a ball peen hammer down on your thumb as hard as they could smack it. Indeed, the cobalt blue is a truly aggressive spider, and makes the black widow look like a guest appearance on Sesame Street in comparison.

This in no way means that widows should be treated with indifference. A grain of good sense and caution is never without merit when in the company of any potentially dangerous organism, especially man, but I won’t go there for now. In my own personal experience, the black widow spider is no more or less apt to bite than most of our other native web-building spiders. Two examples of supporting evidence come to mind in regards to their general placidity.

In the summer days immediately following my graduation from high school, I took a job working in an aluminum welding shop. One morning, after putting on my welding helmet and pulling it down over my face, I felt a tickling sensation that traversed from one corner of my forehead to the opposite side of my chin, around the back of my neck, then up in the opposite direction along the same path. I largely ignored this, concentrating on the task at hand and chalking it up to a stray lock of hair (my hair was shoulder-length) blown across my face by the constant expulsion of argon/oxygen gas emanating from the barrel of the welding gun, but the annoyance became so persistent that I eventually took off my helmet and looked inside. There, in the crown, a young female widow had constructed her tell-tale messy web, a non-uniform maze work of irregular diagonal lines criss-crossing each other in all directions. I immediately brushed my hair out onto the table, where the offending spider promptly fell out and was taken and released as a reward for her kindness.

On another occasion, a decade later, my then three-year-old son came running up to me with a small jar, proudly brandishing the “pretty spider” he had caught in the closet. One could imagine my alarm when I took the jar and looked in at a black widow, which had already constructed a web within the confines of her new prison. My concern grew when I inquired as to how he had managed to get the spider into the jar and he replied, “Oh, it was a nice spider. I scooped it up in my hand and it ran right into the jar.” And so goes the trials and errors of parenting, followed by a sit-down lecture on warning colors and toxicology and a concluding explanation as to why we never pick up things we can’t identify. It must have stuck, because to this day my now eight-year-old son has never picked up another black widow, although after the incident it quickly became his “favorite spider.”

While I have never personally been bitten by a widow, I have known people who have. My own uncle was bitten in a very inconvenient place on his body in a port-a-potty, although he played it smart and made a quick trip to the hospital, where he was monitored for a time before being declared none the worse for wear. Unfortunately, the same couldn’t be said for the poor coworker who drew the short straw and was given the inglorious task of extracting the spider from the toilet bowl so the doctor could properly identify it.

On another occasion the man that reads our water meter was bitten on the finger by a widow, which found the consistently dark, damp, insect-rich rectangular burrow with the custom plastic roof much to its liking. I couldn’t have been more than nine or ten at the time, but my reputation for all things “buggy” must have preceded me, because he rang the doorbell and asked if I could come tell him what kind of spider had bitten him. Sure enough, there she sat on her messy silken throne, which she had spun from one end of the meter to the other. Two plump white egg cases, round as marbles, were fixed just above the meter gage. While not aggressive, mother widows have been known to defend their egg sacs, and such was most likely the case here. After confirming the poor guy’s worst fears, I assured him he wasn’t going to die and suggested he call it an early day and head for the E.R.

These experiences and then some have led me to a rather benign opinion of the viuda negra, and I have since become rather complacent to the presence of this often abundant arachnid, although I do treat them with a great deal of respect. It should be noted that only the female widows are capable of envenomating man, and the male’s danger potential is virtually nil.

Black widows are year-round residents of just about every type of habitat one can imagine throughout most of the state. One of the most common places they frequent are the upper eaves of houses, where their presence causes much concern for homeowners. In my pest control days I received many requests to rid otherwise happy homes of these conspicuous spiders, and no amount of scientific explanation as to their timidity, reclusiveness, and beneficial nature could convince them otherwise. I, on the other hand, employ upwards of a dozen black widows each summer around the eave corners and weep-holes of my own dwelling, where they have never bothered me and doubtlessly help to eradicate countless flies, mosquitos, and other pests.

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Even vertebrate animals like this lizard can fall prey to a widow

In the late summer, female black widows become fat with eggs, and lay their marble- sized round white egg sacs in the far back corners of their webs. These usually number two to three, although one is not uncommon and I have seen as many as four in a single web. As was mentioned earlier, the female does become rather protective of her future progeny, although anyone dumb enough to reach into the web of a living black widow spider and attempt to kidnap her babies deserves what they get in my opinion. The young hatch soon after, and are miniature replicas of the adults in shape and form, although they are almost translucent in color except when viewed under the magnification of a hand lens, whereupon the faded stripes that will signify their first few instars become visible. At least one person I have talked to has given credit to hallucinogenic properties of black widow spider venom, which they discovered only after accidentally ingesting several newborn black widows. Exactly how (or why, for that matter) they were ingested is beyond me and (again speaking strictly from personal opinion) if you have to go that far to get a trip you have bigger problems than baby black widows run amok in your house.

In conclusion, the black widow spider is a colorful and beneficial member of our local invertebrate fauna. Studies have shown that juvenile black widows are an important consumer of the red imported fire ant, although the actual depth of their benefit in this regard remains in question. After all, how many spiders does it take to significantly reduce the fire ant population, and does one want that many widows around? In any event, the viuda negra, when left undisturbed, is a fairly harmless denizen of our fields, woods, and even our own back yards. It can be observed in almost any season, although the peak of abundance occurs May through October. I never kill the widows around my own house, as they have yet to give me the slightest reason to. With any luck this frowned-upon species with the notoriously bad reputation will continue to coexist alongside our own for ages to come.

Resources

DesertUSA. Black Widow Spiders. http://www.desertusa.com/insects/black-widow-spider.html

Evans, A.V. 2008. National Wildlife Federation Field Guide to Insects and Spiders & Related Species of North America. Sterling Publishing

Jackman, J.A. 1999. A Field Guide to Spiders & Scorpions of Texas. Gulf Publishing

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