Saturday, October 2, 2010

Northern Black Widow


 Black Widows may be one of the most feared spiders in North America. Some would say with good reason, after all they do have venom that is ounce for ounce more toxic than a rattlesnake, and they crawl around on eight legs which completely creeps most people out. This particular species is the Northern Black Widow (Latrodectus variolus) and was photographed at Truman State Park. They are shiny black with a broken red hourglass on their lower abdomen. Northern Widows often have a row of red spots on the back of their abdomen as well (as shown here). While walking the glades, and turning over rocks we found this beautiful female hiding under a rock. She was large with a legspan approximately the size of a quarter. She was very docile and sat perfectly still while I photographed her. I wished I would have had a container to place her in to be able to keep her. It would have been nice to show the public who visit our office exactly what one looks like. While their bite is highly venomous and extremely painful it is rarely deadly except in the very young or the elderly. They deliver very small doses of venom with a bite, which is a good thing. If they delivered as much venom as a rattlesnake we would all be in danger of not recovering from a bite inflicted by one of these awesome spiders.



Black Widows are secretive and elusive spiders. This species generally builds their webs under rocks or logs in open woodlands. If approached they are quick to run for cover. These are not aggressive spiders and will only bite if provoked or caught between your skin and your clothing or if accidentally touched. Males are incapable of biting, it is ONLY the female who bites. The venom contains a powerful neurotoxin and bites can and often do lead to stomach upset, cramps, abdominal pain, sweating, headache, muscle tightness or soreness, delayed pain at the bite sight, and swelling of the hands, feet or eyelids. Swelling at the sight of the bite is rare. Reactions to their bite may last for several days and often require medical treatment for relief. Most human fatalities due to Black Widow bites occur in the Southwestern United States where larger populations of these spiders exist.

These are extremely beautiful spiders, and part of their mystic and beauty may be the fact that they are so highly venomous and potentially dangerous. There is no need to be afraid of these spiders, merely be aware of their possible hazard and avoid contact with them if at all possible. If you have them in your basements, sheds, cellars or anywhere you may frequently encounter them, you might want to consider removing them, especially if you have small children at home. When cleaning in areas where they have been seen always wear gloves. Use caution, but no need to live in fear. They generally never leave the web except when looking for new place to construct their web. Because of their habit of staying close to their web, encounters by humans are rare in Missouri. This particular species is most often found away from human dwellings which makes it even more unlikely we will come in contact with one. I was very excited  to have found one and to get the opportunity to photograph one and it was under the very first rock I flipped. I was flipping stones, with no gloves on, so I was lucky to not have been bitten.

There are two species that live statewide in Missouri; the first and most common in southern counties is L. mactans (Black Widow) and the L. variolus (Northern Black Widow) is found in more central and northern counties. We encountered both species at Truman Lake, I found two L. Mactans within their webs at the bathhouse. Each time I approached I could only catch a short glimpse of them before they darted behind a trim board that their webs were attached to. They were smaller than the Northern Widow that I photographed here.


The good that these spiders provide by eating untold amounts of insects far outweighs any danger that may exist from this spider.

9 comments:

  1. Interesting post. I didn't realize we have two varieties of Black Widow in Missouri. I have a small cabin in the Ozarks, and I'll be more care is the dark corners from now on.

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  2. Wow, interesting. The black widows we have here (in abundance on our property) are (or at least can get) much larger, and the hourglass is only on the ventral side of their abdomen. New visitors to our house sometimes are shocked we have them around (but not in) the house but, as you say, as long as you don't run up and shove a finger at her, you'll be fine. My husband loves the LEGIONS of earwigs they eat. It's awesome to see the carcasses litter the webs.

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  3. Paul most people do not know that there are more than one type of black widow, much less that two of them live in Missouri. In the Ozarks the one you are most likely to encounter is the L. mactans or the one that is just called Black Widow. Where we stayed at Truman State Park in Warsaw Missouri both species exist with great regularity. We saw both varieties the very first night there. They are such beautiful yet fierce spiders.

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  4. Bio the one we found under the rock and that is pictured here in my opinion was huge!!!! Way too big for a venomous spider...LOL I've lived on a farm in NW Missouri for over 20 years and I have never seen one. In fact we have not even seen a brown recluse. I guess I should be supremely happy about that, but somehow it makes me sad. Not that i would want to find one in my house, because I wouldn't. Although I think I would like to find one in a shed or somewhere else safe. They are such gorgeous spiders. Have you ever photographed one in the web with its earwig leavings? If so I would love to see it....maybe I could add it to this post and explain what it going on and give you credit for it.

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  5. Nice shots. In AZ they really sprayed the soil when digging for new homes to prevent these and a few other pests from intruding into the new homes.They were a very agressive species down there, a friend had one and it was amazing food they would conquer.

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  6. Steve I had heard they were a lot more aggressive in the Southwest and that there are more encounters with humans. These seemed very skittish and shy of humans.

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  7. I live in Joplin, Missouri and we have them! My husband and I went out at dark and looked all around the house with a flashlight and killed 9 in one night! We have small children and it scares us to have seen so many! We have been rebuilding our home and it seems so much worse now! Maybe I am just more aware of them! None the less it makes me nervous for my kids! Ugh!!

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  8. I live in Joplin, Missouri also. Last night I found a female Northern Black Widow laying on the threshold to my front door. I am totally arachnaphobic!!! This disturbed me to no end. Well this morning I found another female Northern Black Widow on the door threshold of my screened in front porch. What the heck? I have a TON of brown recluses in my house also. One sticky board has 24 brown recluses stuck to it, ranging in sizes of tiny to the diameter of a quarter. I'm moving!!! Seriously. I have an 8 year little girl. I'm afraid for her safety. I have started packing boxes to move. My father tells me spiders love boxes. I'm afraid I might end up taking them with me. Is there something I can spray or sprinkle my new house with to keep spiders away & kill them?

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  9. i live in Joplin,MO too... I used to live in the KC area and never saw one... the last three summers I have had black widows by the doors and one was in my living room in the fall...

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