How to tell if a spider is a black widow

How to tell if a spider is a Black Widow

Black Widow spiders are widespread across the globe and you can find them in almost every country, as far north as Canada. Identifying a Black Widow spider is the first step to avoiding its venomous bite. Suppose you see a spider around your home, you may want to know if you are handling a Black Widow. In this case, the best way to go is physical features.

The most obvious way to identify a Black Widow spider is by the red hourglass line on its abdomen underside. The brightness of this line sends signals to attackers and predators. In addition, the spider flaunts a shiny black color that is hard to miss. Again, most Black Widows are about three to ten millimeters in body size.

Identifying black widow spiders is easy when you know the characteristics. For more information about black widow spiders, this post has everything that you need to know.

Where are Black Widow Spiders Found?

Black Widows love dark, hidden spots like crevices, under rocks, and woodpiles on the outdoor habitats. However, sometimes they can inhabit indoor spaces in dim and hidden spots in the house. They thrive best in temperate regions, which is one reason they dominate in the Southern American states.

These creatures can also survive in a wide range of habitats, including dry hot deserts and temperate grasslands. You can find them in the Chihuahuan, Sonoran, and Majave deserts.

Moreover, there are several Black Widow spider species in Texas and Florida. Nevertheless, these spiders prefer to build their webs near the ground to trap crawling insects.

Spiders that Look like Black Widows

There are several spider species that you may mistake for Black Widows. Most of them have resembling features or behaviors but display slight differences.

However, the most outstanding difference is that none is as deadly as the original Black Widow.

Below are some spiders that resemble the Black Widow:

  • Brown Widow (Latrodectus geometricus.)
  • Triangulate Cobweb Spider (Steatoda triangulosa.)
  • Noble False Widow (Steatoda nobilis.)
  • False Black Widow (Steatoda grossa.)
  • Red Widow (Latrodectus bishopi.)
  • Boreal Combfoot (Steatoda borealis.)
  • Rabbit Hutch Spider (Steatoda bipunctata.)
  • White-spotted False Widow (Steatoda albomaculata.)
  • Redback Spider (Latrodectus hasselti.)
  • Katipō (Latrodectus katipo.)
  • European Black Widow (Latrodectus tredecimguttatus.)
  • South American Black Widow (Latrodectus curacaviensis.)
  • Domestic House Spider (Tegenaria domestica.)
  • Black House Spider (Badumna insignis.)
how to tell if a spider is a black widow
Note the tell-tale red hourglass symbol on the underside of this female Black Widow

Spider that Looks like Black Widow without Red   

One of the spiders that look like black widow without red is the False black widow spider (Steatoda spp.) It is easy to confuse it with the Black Widow. The False Widow’s close resemblance to the notorious species can raise alarm whenever you see it near home. However, they are not as harmful as the venomous Black Widows.

With that, it is crucial to differentiate the almost harmless spider from its deadly counterpart. First, every False Widow species has a distinctive set of marking on its abdomen.

You can identify a light or white band across the abdomen towards the head. Nonetheless, sometimes these markings can be lacking, especially on adult females.

You may also distinguish the two by their web shapes. While Black Widows make a mesh-like web, the False Widows create crisscrossing threads that make the web dense in the middle.

Black Widow Spider Markings on Back

Some Black Widow spiders have a red mark on the back similar to that on the underside. For example, there are two Black Widow species in Missouri; southern Black Widow (Latrodectus mactans)and northern Black Widow (L. variolus.)

In the first species, the females have the triangular hourglass pieces connected. On the contrary, the hourglass pieces of the latter are broken. Moreover, the northern species has a series of red marks on its back. The marks can be bright red or faint. Also, sometimes they may have diagonal marks on the sides.

Spider with White Hourglass on Back

The Redback spider, another member of the family Theridiidae, is native to Australia and closely resembles the Black Widow spider. The females in this species are highly venomous and you can identify them by the reddish-orange hourglass on their back while the males have white marks on the backside of the abdomen.

The male and female have a similar mark on the underside of the abdomen. Another key identifying characteristic is the color; dark brown or black. Furthermore, the males and females differ in sizes measuring 0.4 inches and 0.16 inches respectively.

In addition, the females have a longer lifespan of about two years compared to the males that live only a few months.

How big is a black widow spider?

What to do When You Find a Black Widow Spider

Finding one Black Widow spider in your home indicates the presence of more. These creatures move at a high speed, especially when under threat, meaning you may not be able to catch it immediately.

However, if it appears inside your house, you may kill it with insecticide or vacuum. On the other side, it is advisable to call a professional to avoid provoking it to biting you or someone else around.

Sometimes you may find spider eggs on your property, avoid removing them as they may hatch. The best way is to allow a professional handle them safely so they do not hatch in your compound.

Should I kill a Black Widow Spider?

You may decide to kill a Black Widow spider if it invades your house, but you must know that it can bite if threatened. Also, its bite releases a deadly venom that can result in severe symptoms.

Nonetheless, only the female is dangerous as the male has short fangs that cannot dig into human skin. Nevertheless, caution is better than cure, therefore, it would be best to shake your clothes and shoes before putting them on since spiders crawl into hideouts at night.

How to tell if a spider is a Black Widow: Conclusion

Identifying a Black Widow spider will help you avoid trouble with the deadly creature. There are many spiders resembling the typical Black Widow, though harmless. Keep in mind that trying to remove it can trigger it to bite you. Therefore, it is best to involve a professional exterminator to eliminate the spiders plus its eggs.

how to tell if a spider is a black widow

FAQ Related to Black Widow Identification:

What Spiders are Mistaken for Black Widows?

Many people mistake the False Widow for a Black Widow. The two resemble each other in shape and color, but the False Widow is less venomous.

Is There a Black Spider that Looks Like Black Widow?

There are several black spiders that resemble the Black Widow. They include the European Black Widow, black house spider, and South American Black Widow among others.

How to Tell the Difference Between A Black Widow and A False Black Widow?

The most notable difference between the Black Widow and the False Widow is the markings on their bodies. While the Black Widow has red marks, the latter has cream ones.

Do Black Widows Always Have A Red Dot?

All Black Widows, especially females may not necessarily exhibit the red spots. Some have hourglass marks while others exhibit no marks.

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