Northern Black Widow

Black Widows may be one of the most feared spiders in North America. The fear of spiders is one of the top ten phobias in the World and when it comes to spiders that humans view as dangerous, like the widow, that fear seems to be magnified. Their bite is highly venomous and can be extremely painful however it is rarely deadly except in the incredibly young, the elderly or in immune compromised individuals. With their glossy black body and legs, bulbous abdomen, and red hourglass, it is a spider we learn early in life to recognize. Their venom is roughly fifteen times stronger than a rattlesnake! Thankfully, they are also 1,000 times smaller and can only deliver minute amounts of venom with each bite. There is an old saying “the dose makes the venom” and this is especially true of black widow venom, she can control how much venom she delivers, and since most bites are defensive in nature, she is unlikely to use substantial amounts of venom when she does bite. It would be counterproductive to her survival. It takes energy to make venom, and food to make energy and venom to kill and consume her food in order to acquire energy to continue hunting, so you can see that wasting venom to warn us away would not benefit her at all.

Consider the black widow spider. It is a timid little beastie, useful and, for my taste, the prettiest of the arachnids, with its shiny patent-leather finish and its red hourglass trademark. But the poor thing has the fatal misfortune of possessing enormously too much power for its size. So, everybody kills it on sight. --- Robert A. Heinlein

Black Widows are secretive and elusive spiders. The species pictured here (Northern widow) generally builds their webs under rocks or logs in open woodlands or rocky glades. 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 capable of biting; however, it is ONLY the female who delivers the venom. The venom contains a powerful neurotoxin and bites can 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 can last for several days and may 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. While the risk of death exists, it is extremely low. There are over three hundred million people living in the United States, and approximately 2,500 black widow bites reported annually and only about four are fatal. While any death is unfortunate and a loss to be sure, the reality is their bite is rarely fatal, in fact you are more likely to die from an allergic reaction to a bee sting, which claims over fifty lives annually.

These are beautiful spiders, and part of their mystic may come from 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 medically significant bite 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. They generally only leave their web when looking for a new place to construct another web. Because of their habit of staying close to their web, encounters by humans are rare in Missouri. Encounters generally happen when we put our hands in places where this shy, secretive spider lives. This particular species is most often found away from human dwellings, which makes it even more unlikely we will come in contact with one.

There are two species that live statewide in Missouri; the first being the common black widow which is found in more southern counties and the Northern black widow is found in more central and northern counties. We encountered both species at Truman Lake where we were camping, I found two common widows within their webs at the bathhouse. Each time I approached I was only able catch a brief glimpse of them before they darted behind the trim board their webs were attached to. They were smaller than the Northern Widow that I photographed here, which was found on a rocky glade we had been hiking.

Juvenile female

Mating takes place in late summer or early fall when males cautiously approach the web where the female is residing. He will tap out a dance on the web to get her attention. If she deems him a worthy mate a new generation will arrive within a couple of months. If not, she may decide he would make a nutritional meal. The reality is cannibalism is rare in natural settings. The males generally have ample opportunity to escape the rath or appetite of the female. In lab settings where spiders are kept in confined cages, and in close contact with each other cannibalism is far more likely and probably where the notion came from that black widows always consume their mate. The female will produce multiple egg sacs each containing more than two hundred eggs. Spiderlings are notorious for dining on their siblings, no brotherly love there! To help thwart this behavior black widows lay eggs that are all identical in size, hatching at the same time into identically sized offspring. This gives each spiderling a fighting chance to escape and live out their spidery lives. If larger spiderlings hatched first, they would consume all their smaller, newly hatched siblings, thus drastically reducing the prodigy the female leaves as her legacy. Spiderlings already have the odds stacked against them, as many predators feed on small spiders, including other spiders, insects, birds, and frogs to name a few. Mother nature gave the black widow an edge in the survival department.

 While many people feel the natural habitat of any spider is under the covers of our beds or some other unwanted location in our homes, as this is often where we are startled by an unwanted encounter with one. This can certainly make us jump and give us the shivers, especially if that visitor is the dreaded widow of exaggerated folklore. In truth they generally live in their own microhabitat created of strong silk, hidden away from our prying eyes and any possible confrontation with us. 

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