Are Spiny Orb Weaver Spiders Poisonous? Debunking Myths and Revealing Facts

Spiny orb-weaver spiders are easily identifiable by their colorful and unique appearance.

They are part of the Araneidae family and are commonly found in gardens, where they spin intricate webs to catch their prey.

While these spiders might look intimidating due to their spiny appearance, it’s essential to determine whether they are actually poisonous or not.

These eye-catching spiders serve as a beneficial aspect of the ecosystem, as they help control various insect populations.

They are typically not considered harmful to humans.

Although this topic might raise concerns for those who encounter these spiders, understanding their nature and venomous properties will put one’s mind at ease.

One of the well-known spiny orb-weaver spiders is the Gasteracantha cancriformis, which comes in a variety of colors and boasts a unique shape.

It is not considered to be dangerous to humans, as its venom is mild and not potent enough to cause severe harm.

Nonetheless, it’s essential to practice caution when coming into contact with any spider, as individual reactions may vary.

Spiny Orb Weaver Overview

Species

Spiny orb weaver spiders belong to the family Araneidae and can be commonly found under the genus Gasteracantha.

Their unique physical characteristics make them stand out among other orb-weavers.

Appearance

The spiny orb weaver’s most distinctive feature is its spiny, hard abdomen, which often comes in various colors like white, yellow, or orange.

They also have hairy legs and unique patterns on their abdomen, making them easily identifiable.

Spiny Orb Weavers vs. Banana Spiders

Feature	Spiny Orb Weavers	Banana Spiders
Abdomen	Spiny, hard abdomen with colors ranging from white to yellow or orange	Large, elongated, cylindrical, may display yellow, silver, black, and bright blue
Size	Typically smaller in size	Larger, with longer legs
Legs	Hairy legs	Long, smooth legs
Habitat	Found on exterior light fixtures, in forests, or near forest edges	Found mostly in forests

Habitat

Spiny orb-weaver spiders can be found in a variety of environments, from forests to near exterior light fixtures or forest edges.

They tend to create their webs in areas with varying levels of sunlight.

Size

These spiders usually have a small to medium size. Their legs may vary in length, but the spiny abdomen ensures they maintain a visually striking appearance.

Biology and Behavior

Diet and Prey

Spiny orb weaver spiders primarily feed on small insects. Some examples of their prey include:

• Flies
• Mosquitoes
• Moths

These spiders create circular webs to catch their prey, which they then paralyze before consuming.

Reproduction

Spiny orb weavers exhibit sexual dimorphism, meaning males and females are different in size and color.

For example, females are larger and brightly colored, whereas males are smaller and duller.

During reproduction, the female spider creates one or more egg sacs to protect her eggs.

The egg sacs are usually placed close to the web. After hatching, the spiderlings disperse to find their own habitat.

Diurnal and Nocturnal Activity

Spiny orb weaver spiders are both diurnal and nocturnal, meaning they are active during the day and night.

Their behavior can vary depending on environmental factors and the availability of prey.

Comparison Table:

Males	Females
Smaller in size	Larger and brightly colored
Duller coloration	Vibrant colors
Non-aggressive	Non-aggressive

Overall, spiny orb weaver spiders are non-aggressive creatures that contribute to controlling insect pests in their environment.

Their striking appearance and fascinating biology make them an interesting subject for nature enthusiasts.

Are Spiny Orb Weaver Spiders Poisonous?

Are They Poisonous?

Spiny orb weaver spiders may appear menacing due to their unique appearance, but they are generally not considered dangerous to humans.

These spiders have venom, but it is relatively mild and typically causes minimal symptoms, much like a bee sting.

Comparing Venom with Other Spiders

When comparing spiny orb weaver venom to other spiders, the venom is significantly less toxic than that of the notorious black widow or brown recluse spiders.

Below is a comparison table of venom potency:

Spider	Venom Toxicity
Black Widow	High
Brown Recluse	High
Spiny Orb Weaver	Mild

Do Spiny Orb Weaver Spiders Bite?

Bite Symptoms and Treatment

A spiny orb weaver spider bite is rare and usually occurs when the spider feels threatened. When bitten by a spiny orb weaver, symptoms can include:

• Pain
• Swelling
• Itchy welts

Treatment for a spiny orb weaver bite usually involves simple measures such as cleaning the bite area, applying ice to reduce swelling, and using over-the-counter pain relievers.

Risk to Pets

These spiders pose minimal risk to pets like dogs or cats. Generally, spiny orb weaver bites are not fatal, and symptoms are mild.

Benefits of Spiny Orb Weavers in Gardens

Spiny orb weavers can be beneficial for gardens by:

• Preying on garden pests
• Controlling insect populations
• Providing natural pest control, reducing the need for chemical pesticides

These spiders create orb-shaped webs, capturing various insect species, making them helpful allies against common garden pests like flying insects, wasps, or even small frogs.

They are an essential part of the ecosystem and pose minimal risk to humans.

Pest Control Methods

Spiny orb weaver spiders are not aggressive and are considered beneficial for pest control.

They feed on various insects, playing a crucial role in maintaining a balanced ecosystem.

Let’s take a closer look at their diet and the ways they help in controlling pests.

Diet:

• Flies
• Beetles
• Moths
• Mosquitoes
• Other small insects

Their presence is especially prevalent along the southeast coast of the United States. By eliminating insects such as flies and mosquitoes, spiny orb weavers reduce the threat to humans and crops from these pests.

Spiny orb weaver spiders build their webs off the ground, often using sheltered areas and ground litter.

This behavior enables them to capture a diverse range of prey and maximizes their impact on pest populations.

However, hummingbirds may occasionally get caught in these webs, posing a potential threat to the birds.

But overall, spiny orb weavers do more good than harm in controlling insect populations.

Here’s a comparison table of the pros and cons of having spiny orb weaver spiders for pest control:

Pros	Cons
Effectively control insect pests	May trap hummingbirds
Non-aggressive and not poisonous
Contribute to a balanced ecosystem

In conclusion, spiny orb weaver spiders are beneficial for pest control, as they help maintain the natural balance of ecosystems by feeding on flies, beetles, moths, mosquitoes, and other insects.

Conclusion

Spiny orb-weaver spiders are colorful spiders that have spines or horns on their backs.

They are not poisonous to humans, but they can deliver a painful bite if disturbed or handled.

Spiny orb-weaver spiders are found in warm and tropical regions, where they spin large and intricate webs to catch their prey.

They are harmless and helpful predators that control the population of insects and other pests.

Spiny orb-weaver spiders are unique and amazing creatures that deserve respect and admiration.

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about spiny orb weavers. Scroll down to have a look at some of them.

Letter 1 – Crablike Spiny Orbweaver

Subject: Key West Devil Spider
Location: Key West, Florida
September 9, 2012 10:32 pm
Hi, We see this spider that has red horns and a white body and it looks like a magic marker drawing of a face on his body: eyes mustache and a really bad chin strap beard.

The only reason I know it is a spider is because it has web. I googled spiders in Key West Florida and a picture of it came up immediately. But only pictures no info. I want to know more about this little guy. Do you know another name for it so I can read a little more info on him.
Signature: Jen

Hi Jen,
Now that you know that this is a harmless Crablike Spiny Orbweaver, Gasteracantha cancriformis, you should be able to find plenty of information on our website, on BugGuide, on the University of Florida website and countless other places on the internet.

Letter 2 – Crablike Spiny Orbweaver

Creepy crawler in my roses
Location: Central Florida
September 11, 2011 4:14 pm
Dear Bugman,
My husband and boys were outside today trimming back some severely over-grown trees when this brightly colored horned little creature was looking up at them. She is absolutely gorgeous! We searched Google and believe it is a Tiny Orb Weaver??

My son keeps calling it a crab spider.Either way we wanted to send you the photo because it is one of the most amazing spiders we have ever seen. Do not worry, we never kill or move them out of the garden on purpose. She is currently recreating her web we so maliciously destroyed.
Signature: Your friends in Florida

Dear friends in Florida,
You are correct about this Gasteracantha cancriformis being an Orbweaver, and your son has noticed its resemblance to a crab, hence the common name for this spider, the Crablike Spiny Orbweaver.

Letter 3 – Crablike Spiny Orbweaver

Subject: “Thorny” spotted spider

Location: Houston, TX
September 23, 2014 9:29 pm
We live in the Houston, TX area. I’ve lived all over and never seen a spider like these anywhere. Found about 8 of them and their lovely webs all over our yard — some yellow, some red.

An online search turned up some similar spiders from far-reaches of the globe, but nothing definitively local. I’m curious to know what type and whether they are native.
Thanks in advance for any information.
Signature: Kelly in TX

Dear Kelly in TX,
The Crablike Spiny Orbweaver, Gasteracantha cancriformis, which is quite variable in terms of coloration, is native to Texas and a significant portion of the warmers parts of North America as well as the Central American neotropics and the Caribbean. 

We would love to post images of your red and your yellow individuals shot in the same manner as the white individual we posted.  See BugGuide for additional information on the Crablike Spiny Orbweaver, which is harmless.

Letter 4 – Crablike Spiny Orbweaver

Subject: Spider ID needed
Location: Space Coast, Florida
August 10, 2015 5:31 am
Found this spider on the handle of my pool broom. We just moved to Florida, so there are a lot of new bugs! I’ve never seen anything like this spider, and it really creeps me out! Do you know what it is, and is it poisonous?
Signature: Creeped out in Florida

Dear Creeped out in Florida,
The Crablike Spiny Orbweaver is considered a harmless spider.

Letter 5 – Crablike Spiny Orbweaver

Subject: Strangest Spider
Location: Central Texas Hill Country
November 7, 2016 1:20 pm
This spider had a giant web that was catching mostly monarch butterflies in Central Texas. It appears to be some sort of a crab-like creature with 6 spikes around the top portion.

The markings on the top are off-white with black, and on the bottom… look strangely reminiscent of the side of a monarch, with little dots. When it’s threatened, it hunches down and folds up into a nondescript little ball. What on earth??
Signature: Amaris in Wonderland

Dear Amaris in Wonderland,
This Crablike Spiny Orbweaver, Gasteracantha cancriformis, is a highly variable species.  In addition to the black and white color variation in your image, there are individuals will yellow and red markings as well. 

According to BugGuide, common names include:  “Crab Spider, Spiny Orbweaver Spider, Crab-like Orbweaver Spider, Crab-like Spiny Orbweaver Spider, Jewel Spider, Spiny-bellied Orbweaver, Jewel Box Spider, Smiley Face Spider, Crablike Spiny Orbweaver.”

Thank you! You guys are the best!!
Have a great day.

Letter 6 – Crablike Spiny Orbweaver

Subject:  Identification of strange insect
Geographic location of the bug:  Starkville, MS
Date: 10/22/2017
Time: 01:33 PM EDT
I found this crab-like spider maybe? That’s what it looks like anyway I was too scared to count the legs. The web was thick green and not silky like a spider web
How you want your letter signed:  Alexandra B

Dear Alexandra,
The Crablike Spiny Orbweaver is spider that poses no threat to humans.  The spider has variable coloration in shades of black, white, red and yellow.  According to BugGuide: 

“This species of spider does not live very long. In fact, the lifespan only lasts until reproduction, which usually takes place the spring following the winter when they hatched. Females die after producing an egg mass, and males die six days after a complete cycle of sperm induction to the female” and

“This spider adds little tufts of silk to its web. According to Florida’s Fabulous Spiders ‘these little flags serve a warning function to prevent birds from flying into the web, destroying it.‘”

Letter 7 – Crablike Spiny Orbweaver

Subject:  Spider
Geographic location of the bug:  South Florida
Date: 12/13/2017
Time: 11:51 AM EDT
Eewww. Grandmas house has a lot of these ugly spiders, what is it?
How you want your letter signed:  Dawn

Dear Dawn,
Beauty, hence its antonym ugly, is relative.  We find this Crablike Spiny Orbweaver to be quite beautiful.  Like other Orbweavers, the Crablike Spiny Orbweaver is harmless and it poses no threat to humans. 

We are postdating your submission to go live at the end of the month while we are out of the office for the holidays.

Thank You.  My first encounter wasn’t pleasant when I walked into a web!  Yikes  The more I look at it, the more interesting it becomes.

Letter 8 – Crablike Spiny Orbweaver

Subject:  Hello Spikey Crab Spider
Geographic location of the bug:  Virginia Beach VA
Date: 06/16/2018
Time: 06:10 PM EDT
Your letter to the bugman:  Hello,
I have never seen this spider before. There are lumps of spider web all around it’s web. It looks like it has spikes and a shell.
How you want your letter signed:  Me!

This is a Crablike Spiny Orbweaver, a common species, especially in the South.  Like other members of the Orbweaver family, the Crablike Spiny Orbweaver is perfectly harmless.