Most spiders are harmless pests that eat other more annoying pests, like ants, roaches, mosquitoes, flies, and more. However, black widow spiders are among the few venomous spiders in North America. Their bites can cause serious side effects, such as cramping, nausea, tremors, sweating, redness, pain, and swelling. Black widow venom is even 15 times more deadly than a rattlesnake’s venom. Fortunately, black widow bites transfer far less venom at a time than a rattlesnake bite.
However, their bites still have a substantial effect on the human nervous system, so it’s recommended that you see a doctor if a black widow spider bites you. If you’re experiencing severe side effects or have problems breathing or swallowing after the bite — which may indicate an allergic reaction to the spider bite — see a doctor immediately.
Needless to say, black widow spiders are not spiders that you want lurking around your home. So, how do you identify a black widow spider, and what can you do if you find them in your home?
In this article, we’ll cover the following black widow pest management topics:
- How to Identify Black Widows
- Black Widow Behavior & Habits
- What Are Black Widows Attracted To?
- How Do You Get Rid of Black Widows?
Ed has been working in the pest control industry for years helping 1,000's of homeowners navigate the world of insect and rodent management. He manages Pest Strategies now helping homeowners around the world!
Table Of Contents
How to Identify Black Widows
Black widow spiders are relatively easy to identify due to their all-black color, other than the iconic red or orange marking found on their abdomen. When we think of what a black widow spider looks like, we typically think of a female black widow spider with a jet black, shiny body with a prominent red or orange hourglass shape on the abdomen. Keep in mind that many black widow spiders have hourglass-shaped markings on their body, but many will also have red spots on their abdomen, rather than a neat hourglass marking.
Comparatively, male black widow spiders are much smaller than female black widow spiders and have longer legs that make their bodies look smaller proportionally. Female black widow spiders have more proportional bodies and are far more aggressive than male black widows because they are frequently protecting their egg sacs.
Black widow egg sacs are shaped like spheres and usually range from white to gray in color. Each egg sac will contain around 100 to 200 eggs, which will eventually hatch into spiderlings. If you spot one egg sac in your home, there are likely at least several more nearby because female black widow spiders lay more than one egg sac at a time. If you find egg sacs, contact a pest control professional immediately because you are on the brink of a severe spider infestation. Once hatched, black widow spiderlings are white to orange but will develop a jet black appearance as they grow older. Like adults, black widow spiderlings will also have reddish or orangish markings on their bodies.
If you’re looking to identify black widow spiders by their habits, look for these typical signs:
- Irregular webs
- Cobwebs or spider webs in doorways, closets, and basements that are low to the ground
- Getting spider bites
- White or cream spider egg sacs, especially in doorways
Black Widow Behavior & Habits
Black widow spiders are web-building spiders that create irregular webs to catch prey, such as cockroaches, flies, mosquitoes, and grasshoppers. Like other web-building spiders, they have poor vision and rely on their webs to entrap their next meal. Look for black widow spider webs in doorways, tall grass, firewood piles, and low to the ground. If any prey is caught in a spider web, the black widow spider will wrap it in silk and drag it inside her hiding place to eat it.
As a whole, black widow spiders are not an aggressive spider species and do not like to go after humans. Black widow spiders usually only bite if they feel threatened or are guarding their egg sacs against harm. During the day, adult female black widow spiders will hang upside down in their webs, showcasing their red hourglass markings to predators as a warning sign. Once the eggs are hatched, the female black widow spider moves on, and no more care is provided to the newborn spiderlings.
The black widow spider species is mainly solitary and will only come together to reproduce. Typically, a male black widow spider will leave its home, searching for a female black widow spider. Once he’s found one, he will begin to court her by vibrating the threads of her spider web. If she’s interested, they will mate, and the female black widow spider will produce egg sacs. Black widow spiders were initially given this name because the female black widow spiders ate the male black widow shortly after mating. However, this is mainly unfounded and rarely happens in nature.
Unless you have a large black widow spider infestation, you’re unlikely to see vast numbers of black widow spiders together because they’re solitary and more interested in finding their own hiding places, such as the basement or garage. If you spot several black widow spiders, don’t hesitate to contact your local exterminator because black widow spiders can reproduce quickly and spread the infestation throughout your home.
Unless you have a large black widow spider infestation, you’re unlikely to see vast numbers of black widow spiders together because they’re solitary and more interested in finding their own hiding places, such as the basement or garage.
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What Are Black Widows Attracted to?
Black widow spiders could be in your home for a variety of reasons. Like many spiders, they may wander into your house looking for shelter from harsh weather conditions.
Here are a couple of other reasons that you may be experiencing a black widow infestation:
- Easy access (cracks and crevices in your home’s exterior, open windows or doors, etc.)
- Insect infestations, which provide these spiders with plenty of food
- An overgrown yard, which provides them with areas to build webs
- Drought (they may look for water inside)
- Dropping temperatures (they may look for warmth and shelter in your home)
- Debris and firewood piles, which are favorite web-building areas
Ultimately, if your home provides black widow spiders with plenty of food choices and water, they are likely to come in and stick around. Fall and winter are especially popular times of year for increased spider numbers in our homes because of our homes’ protection.
How Do You Get Rid of Black Widows?
So, if you spot black widow spiders in your home, what should you do next?
Here are some of the best steps you can take to address a black widow spider infestation:
- Address existing insect infestation problems. Black widow spiders will only stick around if they have access to a food source, typically insects such as ants, cockroaches, or moths. Before treating spiders, take a moment to look for signs of other pest infestations that may attract spiders to your home. If you find pests, immediately begin treating them to decrease their numbers.
- Seal off entry points into your home. Examine your home for cracks and crevices where pests may be crawling into your home. Then, use a sealing or caulking product to close these holes off so that pests can’t get through. You can also install a door sweep to prevent spiders from crawling underneath your door.
- Keep up with your landscaping. Black widow spiders love creating spider webs in tall grass or unkempt backyards. Ensure that you regularly trim your plants and lawn and clear debris to keep this from happening. Also, make sure that you keep all woodpiles away from your home’s exterior to prevent black widows from creating webs near your home.
- Apply spider pesticides to kill black widows in your home. There are many products on the market that you can use to kill spiders in your home, including pesticides, spider baits, traps, and more.
- Contact a pest control professional. Black widow spiders are dangerous to you and your family’s health, and their bites can require medical attention. Some people can have dangerous allergic reactions to black widow spider bites, while others may suffer from swelling, cramping, and tremors. Widow species spiders are no joke and need to be dealt with immediately, so reach out to an exterminator for help.
Black widow spiders are venomous spiders whose bites can pack a punch and cause serious health problems in humans, especially children, the elderly, and immunocompromised individuals. Don’t hesitate to act if you find black widow spiders on your property because they can quickly reproduce and create a significant problem within your home. Reach out to your local pest control professional for immediate help.