Spiny Orb Weaver Spider Bite: Is it Poisonous? Find Out Now!

Spiny orb-weaver spiders are fascinating creatures that often capture our attention because of their vibrant colors and unique shapes. As you encounter these tiny architects in your garden or near your home, it’s natural to wonder if their bites are poisonous.

While bites from spiny orb-weaver spiders may cause some discomfort, they are generally not considered dangerous to humans. The symptoms from a bite can include itching, rash, or localized pain, but these effects are typically mild and short-lived. So, while their appearance may be intimidating, there’s no need to fear these beneficial arachnids as they help keep other insect populations in check.

Overview of Spiny Orb-Weaver Spiders

Spiny orb-weaver spiders are a fascinating group of arachnids belonging to the family Araneidae. They come in various shapes, patterns, and colors. One of the most well-known species is Gasteracantha cancriformis or the spiny-backed orb-weaver. You might also have heard of it as the jewel spider.

These spiders are known for their unique appearances and intricate webs. They have a habit of incorporating their own body shape and patterns into their web designs. For example:

• Some species have spines protruding from their abdomens
• Others may have a crab-like shape or jewel-like patterns on their bodies

When it comes to the bite of a spiny orb-weaver spider, you might be concerned about its potential toxicity. In general, orb-weaver spiders are not considered dangerous to humans. Their venom is usually harmless, and their bites may only cause mild irritation or discomfort.

Here are some key features of spiny orb-weaver spiders to remember:

• Belong to the family Araneidae
• Known for their unique body shapes and patterns
• Not considered dangerous to humans

As you encounter different species of spiny orb-weaver spiders, it’s important to remember that their appearance can vary widely. Comparing the features of a few common species can be helpful in identifying the spiders you may come across. Here’s a comparison table to guide you:

In conclusion, spiny orb-weaver spiders are a diverse group with unique appearances, but their bites are generally not a cause for concern.

Appearance and Identification

Color and Pattern

The spiny orb-weaver spider is known for its distinctive appearance. It can typically be identified by its vibrant colors and unique patterns. For example, their abdomen is usually black with contrasting spots of yellow or white, giving it a striking look. In addition, their body is covered in spines or humps that can vary in size and location, providing them with their “spiny” moniker.

Usually, you might find these spiders in various environments such as gardens and wooded areas. It’s helpful to familiarize yourself with some pictures to better identify them in your surroundings.

Size and Shape

Spiny orb-weaver spiders exhibit considerable differences in size and shape. Their large and rounded abdomen is one of their most defining features. Some key characteristics to assist with identification include:

• A large, bulbous abdomen often overlapping a bit with the cephalothorax
• Abdomen covered with spines or humps
• Shorter third pair of legs compared to the other legs

Here’s a comparison table detailing the features of a spiny orb-weaver spider:

By observing these features, you can accurately identify a spiny orb-weaver spider and distinguish it from other spider species.

Distribution and Habitat

Spiny orb weaver spiders can be found in various parts of the world, including North America, Central America, Asia, Africa, Australia, India, and Hawaii. They are typically found in forests and wooded areas, where they build their webs among trees and shrubs to catch flying insects.

The distribution of these spiders varies depending on the specific species. For example, the red spiny orb weaver (Gasteracantha cancriformis) is commonly found in the southeastern United States, particularly Florida, as well as in parts of Central America.

On the other hand, the spined micrathena (Micrathena gracilis) is more widespread throughout the United States, including in dense forests and woodlands. Some other species of spiny orb weavers can also be found in Asia, Africa, and Australia, showcasing their adaptability to various habitats.

As part of their habitat, they usually prefer:

• Warm and humid environments
• Places with an abundance of flying insects for food
• Tree and shrub-rich areas for web construction

Remember that while you may encounter spiny orb weaver spiders in many different regions, the specific species you’ll find will depend on the local environment and climate. In general, keep an eye out for their distinctive webs and spiny abdomens when exploring wooded areas and forests.

Behavior and Lifestyle

Spiny orb-weaver spiders are fascinating creatures with distinctive behaviors. They mainly reside in gardens and thrive during the warm months, from spring to early fall.

These spiders create impressive orb-shaped webs to catch their prey, which primarily consists of insects like flies, mosquitoes, and moths. They construct these webs using their silk to trap and immobilize their next meal.

Spiny orb-weavers are active during the night, which is when they build their webs and hunt for prey. As nocturnal hunters, they rely on their webs to entangle and incapacitate their victims.

One important aspect to note about these spiders is their venom. While orb-weaver spiders produce venom to subdue their prey, their bites are generally harmless to humans. They are not considered to be aggressive spiders and tend to only bite as a last resort in self-defense.

So, when you encounter a spiny orb-weaver spider in your garden, remember that they are helpful creatures that control insect populations and pose little threat to you. Simply observe and appreciate their unique lifestyle and web-spinning abilities.

Reproduction and Life Cycle

Spiny orb-weaver spiders exhibit sexual dimorphism: females tend to be larger and more colorful than males. During reproduction, the male carefully approaches the female and pairs with her on the web.

Females lay their eggs in small, well-protected egg sacs. These sacs provide a safe environment for the eggs to develop. After the eggs hatch, the spiderlings stay inside the sac for a short period before venturing out on their own.

Throughout their life cycle, these spiders molt several times as they grow. The process involves shedding the old exoskeleton and growing a new one, allowing them to increase in size.

Keep in mind, spiny orb-weaver spiders are not harmful to humans, having venom that is not medically significant to us. Regardless, it’s best to admire these remarkable creatures from a distance, respecting their space and natural habitat.

The Spider’s Diet and Predators

The spiny orb weaver spider has a diet mainly composed of small insects. Some common prey for this spider include flies, moths, beetles, and mosquitoes. These spiders play a significant role in controlling the population of these pests in a garden setting.

You might notice that the spiny orb weaver is quite efficient in capturing their prey. They use their intricate webs to catch insects, and their spines serve as a defense mechanism against predators. Some common predators of this spider are birds, larger spiders like the crab spider, and even certain wasps.

A quick comparison between spiny orb weaver and its prey:

The spiny orb weaver’s diet and its role as a predator make them quite beneficial to your garden. Their population control of pests might help keep your plants healthy and thriving.

Their Role in Ecosystem

Spiny orb weaver spiders play a vital role in maintaining a balanced ecosystem. These spiders help in controlling pests by catching and consuming various insects. As a result, they provide indirect benefits to your garden, citrus groves, and shrubs.

For instance, spiny orb weavers feed on insects like mosquitoes, flies, and plant pests such as aphids. These insects can harm your plants and transmit diseases, so having spiny orb weavers around can be advantageous. Here are some key roles these spiders play in the ecosystem:

• Insect control: They reduce harmful insect populations by catching them in their webs and consuming them.
• Pest management: Spiny orb weavers can be particularly beneficial in citrus groves, where they help control pests such as the Asian citrus psyllid.
• Plant protection: In shrubs and other vegetation, their presence reduces the number of plant-eating insects, promoting healthy plant growth.

In conclusion, while the bite from a spiny orb weaver spider might be mildly painful, it’s essential to remember their crucial role in the ecosystem. They are beneficial creatures that help manage pests and protect plants in various environments, including gardens, citrus groves, and shrubs. So, rather than being fearful of them, it’s important to appreciate their contributions to a balanced ecosystem.

Interaction with Humans

Spiny orb-weaver spiders are generally harmless to humans. They might build their webs near homes and gardens, but they rarely cause problems for residents. In fact, these spiders can even be considered beneficial, as they help control insect populations by feeding on various pests.

If you come across a spiny orb-weaver spider, it’s best not to disturb them. They are not aggressive and usually won’t bite unless provoked or accidentally squeezed. A bite from this spider is not considered medically significant. The venom, if any, is not strong enough to pose a serious risk to humans.

However, if you do happen to get bitten, you can expect a reaction similar to that of a mosquito bite. Some symptoms you might experience include:

• Redness around the bite area
• Slight swelling
• Itching or mild pain

To alleviate any discomfort, simply clean the bite area with soap and water, apply a cold pack, and take over-the-counter pain relievers or antihistamines as needed.

In conclusion, spiny orb-weaver spiders should not be feared by humans. They pose little threat to us and can even be beneficial in controlling pests in our surroundings.

Is the Spiny Orb-Weaver Spider Poisonous?

Comparing with Other Spiders

When you think of poisonous spiders, some infamous names like the black widow and the brown recluse may come to mind. However, the spiny orb-weaver spider is far less intimidating. These spiders are not considered venomous or dangerous to humans¹. Unlike the black widow or the brown recluse, the spiny orb-weaver is non-aggressive, and will not bite unless provoked².

Here’s a comparison table to give you a quick idea:

The Spider Bite: What to Expect

In the rare case that a spiny orb-weaver spider bites you, it may cause mild pain and swelling³. The bite is mostly harmless, and severe symptoms such as numbness, nausea or difficulty breathing are extremely unlikely⁴. Male and female spiny orb-weaver spiders both have venom, but it’s too weak to cause harm to humans⁵.

Are Their Webs Dangerous?

Spiny orb-weaver spiders create intricate and beautiful webs, yet they pose no threat to you⁶. You may accidentally walk into one while you’re outdoors, but there are no dangers associated with touching their webs.

Remember to simply appreciate these tiny creatures and their elegant webs from a safe distance, and you’ll have little to worry about.

Reader Emails

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

Letter 1 – Two Spined Spider: New Zealand Spiny Orb Weaver

strange spider beetle thing
hello,
a couple of hours ago my family and i came across an odd looking bug, it is quite small only about a cm in size about three times the size of a ladybug. it has from what i can tell 8 legs, a red body, a black ‘shell’ like thing on its back, with two small white spike like things coming of the ‘shell’. it also has a yellow ring around the bottom of the ‘shell’ . the back of its ‘shell’ however is yellow, theres thin lines of red separating the yellow on the ‘shell’ from the black. if it helps we are in New Zealand. if you need a photo i could try to take one, although i’m not sure if we’ll still have it depending on how quickly you reply. just so you know i’m obviously looking for the name of it
thanks a bunch
Tim

Hi Tim,
What we know immediately is that this is a Spiny Orb Weaving Spider. We need to do some research to see if we can identify the species. A quick search revealed nothing. There are two genera of Spiny Orb Weavers in the U.S.: Micrathena and Gasteracantha. Try searching there and let us know what you find.

Update: (01/19/2007) New Zealand Spiny Orb Weaver ID…
Hi there!
I did some searching on Google and found a New Zealand museum site with your spiny orb weaver. It calls it a Two-spined spider (Poecilopachys australasiae) and has some basic info about it.
http://www.tepapa.govt.nz/ResearchAtTePapa/Research/NaturalEnvironment/InsectsSpidersAndSimilar/SpidersWeb/What/Pages/Twospined.aspx
Regards, Matthew

Wow Matthew,
Thanks so much for your quick ID.

Broken Links Fixed
Broken links on your site
December 28, 2010 4:53 pm
Hi,
You have a couple of links to Te Papa’s website on your website, thanks heaps for that! I have recently noticed in our logs that some of these are broken, so I thought I’d report them to you to enable you to fix them.
These broken links came from a data migration when we upgraded our website. We are really sorry about it.
These are the 3 pages with broken links:
http://whatsthatbug.com/2007/12/29/two-spined-spider-from-new-zealand/
http://whatsthatbug.com/2005/12/21/two-spined-spider-new-zealand-spiny-orb-weaver/
http://whatsthatbug.com/2007/01/17/spiny-orb-weaver-from-new-zealand/
The new address of the two-spine spider on our website is the following:
http://www.tepapa.govt.nz/ResearchAtTePapa/Research/NaturalEnvironment/InsectsSpidersAndSimilar/SpidersWeb/What/Pages/Twospined.aspx
Thanks a lot for linking to us again!
Kind regards,
Florence Liger, webmaster at Te Papa
Signature: Florence Liger

Letter 2 – Spiny Orb Weaver from New Zealand

Is This A Spiny Orb Weaver
Dear Bugman
Can you help? I found this spider in my garden in Hamilton New Zealand on a Grisalenia plant. This spider is about the size of your small finger nail. I think it could be a Spiny Orb Weaver. Is this a native to New Zealand? Thanks
Tony

Hi Tony,
Back in December of 2005 we received a photo of this species also from New Zealand. We identified it as a Spiny Orb Weaver, but never identified the species. We tried to get a species again now, but once again, with no luck. Perhaps one of our readers can provide a more accurate species identification.

Update: (01/19/2007) New Zealand Spiny Orb Weaver ID…
Hi there!
I did some searching on Google and found a New Zealand museum site with your spiny orb weaver. It calls it a Two-spined spider (Poecilopachys australasiae) and has some basic info about it.
http://www.tepapa.govt.nz/ResearchAtTePapa/Research/NaturalEnvironment/InsectsSpidersAndSimilar/SpidersWeb/What/Pages/Twospined.aspx
Regards, Matthew

Wow Matthew,
Thanks so much for your quick ID.

Broken Links Fixed
Broken links on your site
December 28, 2010 4:53 pm
Hi,
You have a couple of links to Te Papa’s website on your website, thanks heaps for that! I have recently noticed in our logs that some of these are broken, so I thought I’d report them to you to enable you to fix them.
These broken links came from a data migration when we upgraded our website. We are really sorry about it.
These are the 3 pages with broken links:
http://whatsthatbug.com/2007/12/29/two-spined-spider-from-new-zealand/
http://whatsthatbug.com/2005/12/21/two-spined-spider-new-zealand-spiny-orb-weaver/
http://whatsthatbug.com/2007/01/17/spiny-orb-weaver-from-new-zealand/
The new address of the two-spine spider on our website is the following:
http://www.tepapa.govt.nz/ResearchAtTePapa/Research/NaturalEnvironment/InsectsSpidersAndSimilar/SpidersWeb/What/Pages/Twospined.aspx
Thanks a lot for linking to us again!
Kind regards,
Florence Liger, webmaster at Te Papa
Signature: Florence Liger

Letter 3 – Spiny Orb Weaver Jewelry

spider
Hi! My boyfriend knows I like spiders, so he gave me this necklace a while back. (I have since told him I like them ALIVE, not dead.) I haven’t found what kind of spider it is though. I think it may be a spiny orbweaver of some sort. Did I guess right? I love your site, by the way! The pictures people send in are absolutely lovely. More power to you and the creepy crawlies that we share the earth with!
Nicole

Hi Nicole,
We agree that this is a Spiny Orb Weaver, but do not know the species. These lucite encased spiders and insects that are used as pendants and key chains are produced in China with local specimens.

Letter 4 – Spiny Orbweaver from Brazil: Rubrepeira rubronigra

Subject: Spider
Location: Rio Negro River in Brazil
November 13, 2012 9:34 pm
Can you tell me a little about this spider? Can’t seem to find any info on it. Thank you
Signature: Sincerely

All we can say is WOW, that is a beautiful spider.  This is one of the Orbweavers in the family Araneidae, and it is most likely one of the Spiny Orbweavers from several genera that are already represented on our site.  It might also be a different genus.  Some Orbweavers get quite large, with a leg span close to that of a human hand, though most of the Spiny Orbweavers are smaller.  We wish you provided some size information.  When we have time, we will attempt a species or genus identification.  Perhaps while we are at work, one of our loyal readers will be able to come up with some helpful information.

Daniel, thanks for getting back to me. The Spider wasn’t so big, a little bigger than a 25 cent piece.
KB

Karl digs up another identification!!!
Hi Daniel and Sincerely:
Not only is this a gorgeous spider, it is also a rare find. It is an orbweaver (Aranaeidae), specifically a female Rubrepeira rubronigra. It appears to be distributed widely throughout northern South America, but is rarely photographed and poorly documented. The definitive paper on the species is by Herbert W. Levi and it makes a very interesting read. You can access the paper by following this link and then clicking on ‘Full-text PDF’. The genus Rubrepeira is a new one and it only has the one species. As far as I can tell the male of the species has not yet been described or even discovered, and there is speculation that the males are dwarfed. Excellent post! Regards. Karl
p.s. Daniel, the second link doesn’t always work on my computer for some reason. If it gives you problems you could try finding it yourself (it shows up numerous times on Google). The reference is:  Herbert W. Levi. The American species of the orb-weaver genus Carepalxis and the new genus Rubrepeira (Araneae: Araneidae). Psyche 98:251-264, 1991.

Thank Karl,
We downloaded the pdf.rubrepeira_026493

Letter 5 – Spiny Orbweaver from Brazil

Subject: spinyback orbweaver spider from Brazil
Location: Curitiba, Parana, Brazil
April 10, 2013 4:59 pm
Hey there,
I have been looking in the Internet for some hours now and couldn’t find out which orbweaver spider I have found here in our local park…
I saw that some other orbweavers from Brazil have been identified here…so…let’s give it a try =D
(I hope the one picture is sufficient!)
Greetings,
Signature: by Danny

Dear Danny,
We haven’t the time to research this at this moment, but we are posting your lovely image of a Spiny Orbweaver.  We hope to get a species or genus name for you soon, though we suspect it is in the genus Micrathena, which is represented on BugGuide.  It might even be a species represented on BugGuide that has a southern coloration.

Letter 6 – Spiny Orbweaver from Columbia: Micrathena lepidoptera

Micrathena
Location: Columbia
November 24, 2010 9:56 am
Hello
I’d like to know if it is possible to identify precisely this Micrathena. I guess it’s some variation of M. Gracilis, but cannot determine further. I suppose we need a specialist. Can you help me or direct me to such a specialist?
Signature: J-L

Dear J-L,
You are correct that this is a Spiny Orbweaver in the genus Micrathena, but we need to research the species and that takes time.  We just looked at the clock and realize there is no time for research this morning as we must rush off to work.  This is just the type of challenge that our faithful reader Karl undertakes quite often and we hope he can do a bit of research.

Thanks for the time taken to answer. I don’t *need* to know what it is exactly, and certainly not immediately.
But, as I searched the net and could not find any picture like that one, I’m just damn curious 🙂
Have a good day.
JL

Karl provides an identification
Hi Daniel and J-L:
I am not the specialist you seek but I was able to do some research. According to Sabogal and Florez (2000) there are 49 species of Micrathena in Colombia, but M. gracilis does not make it that far south. Fortunately your spider is quite distinctive. The compound spines place it in the lepidoptera Group, of which there are two species in Colombia. Only M. lepidoptera, however, has three sets of compound spines on the abdomen, and most of the other characteristics are consistent with your spider as well. I wasn’t able to find any online photos for comparison but you can try linking to a paper by Levi (1985) entitled “The Spiny Orb-Weaver Genera Micrathena and Chaetacis (Araneae: Araneide)” published in the Harvard University Bulletin of the Museum of Comparative Zoology (http://www.biodiversitylibrary.org/page/4313778#page/589/mode/1up). It has excellent descriptions and illustrations of this and many other Micrathena species. I can’t be certain of the identification but I believe that is it.  Regards.  Karl

Thanks for that. It looks like we have identification, then.
Pity there is no photographic catalog online 🙂
Thanks again for your time!
J-L

Hi again J-L,
But now there is some photographic evidence online thanks to your excellent photograph.

Letter 7 – Spiny Orbweaver from Nicaragua

Subject: Winged spider n Nicaragua?
Location: Nicaragua
November 17, 2015 1:15 pm
Hi Bugman! My daughter just sent this photo from Nicaragua. Could either have been in the Nueva Segovia Department up north or on the west coast. It was taken last week so about November 13, 2015. Is this a wild looking winged spider or is it a spider that has caught a butterfly or moth? Does it bite and of so, is it poisonous?
Signature: Parry

Dear Parry,
This is not a winged spider, but it is an Orbweaver.  We believe it may be a color variation of the highly variable Crablike Spiny Orbweaver, Gasteracantha cancriformis, and this image of an individual from Nicaragua on FlickR  looks similar to your individual.  We would not rule out that it might be a member of the genus Micrathena.

Letter 8 – Spiny Orbweaver from Panama: Micrathena schreibersi

Subject: Amazing Spider from Panama
Location: Panama, Central America
August 27, 2012 10:40 pm
Hello, My family and I just returned from a two week vacation in Panama, Central America. We spotted this beauty while on a hike near a town called El Valle. I was wondering if you could help ID it for us. Would his bite have been dangerous?
Signature: Fred