Spiny orb weaver spiders can be a nuisance around homes and gardens due to their webs and appearance. While these spiders are harmless and beneficial in controlling other pests, some people may prefer to discourage their presence.
There are various methods to deter spiny orb weaver spiders from your property. Gently removing their webs, controlling their food sources, and modifying the outdoor environment can help create a less inviting space for these spiders. Additionally, using natural or chemical repellents may aid in managing their population.
For instance, you can:
- Regularly sweep or brush away webs from surfaces and plants
- Reduce exterior lighting to decrease the number of insects that attract spiders
- Keep vegetation trimmed to minimize suitable web-building locations
While implementing these strategies, remember that spiny orb weavers can be helpful in controlling mosquito and fly populations. Choosing to tolerate their presence might be beneficial for a more balanced ecosystem in your garden.
Identifying Spiny Orb Weaver Spiders
Appearance and Characteristics
- Shape: Spiny orb weaver spiders have a distinct rounded abdomen.
- Abdomen: The abdomen features noticeable spines or spikes.
These spiders are known for their unique web-building skills, creating spiral-shaped webs that can be quite large.
Species and Varieties
There are several species and varieties of spiny orb weaver spiders, including:
- Gasteracantha cancriformis (Crab-like Spiny Orb Weaver)
- Micrathena gracilis (Spined Micrathena)
- Micrathena sagittata (Arrow-shaped Micrathena)
Size and Color Patterns
Spiny orb weaver spiders exhibit size and color variations:
Species | Size Range | Color Patterns |
---|---|---|
G. cancriformis | 5-9mm | White, black, yellow |
M. gracilis | 3-6mm | Black with white markings |
M. sagittata | 4-7mm | White or yellow with black tips |
By keeping these details in mind, identifying spiny orb weaver spiders becomes easier.
Habitats and Behaviors
Living Environment
Spiny orb weaver spiders mostly dwell in trees, shrubs, and gardens. They have the ability to create webs near windows or light fixtures, which can be found in various locations across the United States.
Examples of their habitat:
- Trees: oak, maple, or pine
- Gardens: rose, vegetable, or flower
- Light fixtures: outdoor lamps, porch lights
Diet and Hunting Patterns
These spiders are predators that feed on different types of prey. They consume various insects like flies, mosquitoes, and ants. Their hunting patterns involve spinning webs to capture and devour these creatures.
Spiny orb weaver spider’s diet includes:
- Flies
- Mosquitoes
- Ants
Mating and Reproduction
Mating in spiny orb weaver spiders is an essential part of their life cycle. They usually mate during late summer or early fall. After mating, female spiders lay their eggs on strong, safe webs to ensure the survival of their offspring.
Pros and cons of their mating process:
Pros:
- Efficient reproduction
- Offspring protection
Cons:
- Short lifespan for the male spider
Comparison table of spiny orb weaver vs. another spider species:
Feature | Spiny Orb Weaver Spider | Another Spider Species |
---|---|---|
Habitat | Trees, shrubs, gardens | Windows, buildings |
Diet | Insects | Insects |
Hunting Patterns | Web spinning | Web spinning |
Mating Season | Late summer or early fall | Spring or summer |
Benefits and Risks
Advantages of Spiny Orb Weavers
- Spiny orb weavers are beneficial insects that help control the population of flies and other pests in gardens, fields, and forests.
- They are not aggressive and rarely bite humans.
Potential Threats and Dangers
- Although their bites are not dangerous, their venom can cause mild symptoms like pain, redness, and itching in some individuals.
- Large webs can be a nuisance, particularly if they obstruct pathways or other high-traffic areas.
Comparison | Spiny Orb Weavers | Other Spiders |
---|---|---|
Benefits | – Controlling pests – Non-aggressive |
Varies depending on the species |
Potential Side Effects | – Mild bite symptoms | Ranges from mild symptoms to severe reactions depending on the species |
Note: Not all spiny orb weaver species share the same traits. Some specific examples:
- Basilica Orbweaver Spider: They have a unique web structure with a dome shape, and their bodies feature red, white, black, and yellow markings.
- Spinybacked Orbweaver: This species has a crab-like appearance and is sometimes referred to as a crab-like spiny orb weaver.
Prevention and Control
Exclusion Methods
- Install screens and seal gaps: To prevent spiny orb weaver spiders from entering your home, install screens on windows and doors, and seal gaps around pipes and other openings.
- Manage outdoor lighting: Spiders are attracted to insects that gather around exterior lighting. Use motion-activated or yellow-tinted lights to minimize insect attraction.
Natural Strategies
- Bush and tree maintenance: Regularly trim bushes and trees near your home to reduce the habitat for orb weaver spiders.
- Cleanliness: Keep your environment clean and clutter-free, making it less appealing for spiders.
- Predators: Encourage natural predators like birds and other arachnids by providing birdhouses or creating a suitable habitat for them in your yard.
- Region-specific tips: If you live in Florida or other regions with high spider populations, natural strategies may be especially helpful in preventing and controlling infestations.
Some pros and cons of natural strategies:
Pros
- Environmentally friendly
- Low or no cost
Cons
- May not provide complete control
- May require ongoing maintenance
Professional Pest Control
In case of severe infestations, consider hiring a professional pest control company to eliminate spiny orb weaver spiders from your property. They may use chemical treatments or other methods.
Comparison Table
Exclusion Methods | Natural Strategies | Professional Pest Control | |
---|---|---|---|
Pros | Effective in preventing access to homes | Environmentally friendly, low cost | Expertise, comprehensive |
Cons | May require some investment (e.g. screens) | May not provide complete control | Chemical use, expensive |
By following these prevention and control methods, you’ll be well-equipped to manage spiny orb weaver spiders and create a comfortable living space.
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 – Orchard Spider and Crablike Spiny Orb Weaver
Hi There! I want to offer you some bugs and spiders, free!!!!!!
I Love your website and I also love spiders and insects and all the critters on earth! I am a photographer { hobby-not professionally} and have some photographs that I would love to donate to your website, free, {taken by me, so not stolen from any sites. If you can use them. I will be happy…and think that I have quite a few you may enjoy. I use a canon eos digital rebel, with macro, so my shots are not too shabby, though I am still working on not jumping and losing my focus when the spiders decide to jump in my lens: haha! I am Terri S. Heisele, and the pictures I give you are stamped, so you may probably be able to see the date stamp and info in properties if you right click them. I have re-sized them a bit and you may need to re-size as well to fit your site if you want to use them. I saw you had no photo of a spider that a lady asked about that looks like it has a smiley face on it….so maybe you can update your site with my photo…? I am including a spiny orb weaver {or two} and some odd little spider, tiny, that I photo’d on my own hand-then same spider much clearer on a stone patio table. I hope you enjoy using them, and please feel free to ask me if you need any specific species in Florida { EXCEPT ANY MEMBER OF THE COCKROACH FAMILY} as it is the one species I will run thru a wall to get away from! {not kidding!haha} I am a copyrighted photographer on the site Caedes.net known as Madmaven, and the photo I am submitting to you today of the “smiley face spider” and also one pic of my spiny orb spiders are on CAEDES, so don’t be alarmed, as they belong and are copyrighted to me, and my name in full is on site under madmaven. I hope you like these, and feel free to ask for my help anytime! FREE! 🙂 Best Wishes,
Terri S. Heisele
in St. Petersburg, Florida
PS: Your wonderful site helps me id many insects before I post them, so THANK YOU! I also love that you help educate people on all the wonderful living creatures around us!
Hi Terri,
Thanks for your letter and generous supply of images. For now, we only have time to post two of the spider images. The smiley faced spider you sent is actually an Orchard Spider in the genus Leucauge. The spiny spider can also be thought of as having a smiley face, and that is the Crablike Spiny Orb Weaver, Gasterocantha cancriformis.
Letter 2 – Crablike Spiny Orbweaver from Costa Rica
Subject: Little Yellow Fellow (spider)
Location: Costa Rica (Pital)
November 30, 2013 7:32 pm
I have been seeing these spiders for years, and there are a few different colors, but i cant seem to find the ”real” name for it. Could you guys help me?
Signature: Vince Nisly
Hi Vince,
As you indicated, the Crablike Spiny Orbweaver, Gasteracantha cancriformis, has multiple color variations, which include various combinations of yellow, black, white and even red. See BugGuide for some of the color variations. This is a harmless species that poses no threat to humans.
Letter 3 – Crablike Spiny Orbweaver from Dominican Republic
spider from the Dominican Republic
Location: Dominican Republic
March 18, 2011 1:25 pm
this was taken by a friend on March 15 2011 who is living in the Dominican Republic. It seems like a spider because of the web (though the web itself is quite dilapidated) but such small legs…maybe they’re folded in?
Signature: M. Arzt
Dear M. Arzt,
Your spider is Gasteracantha cancriformis, commonly called the Spinybacked Orbweaver or Crablike Spiny Orbweaver, though BugGuide also includes this list of common names: “Crab Spider, Spiny Orbweaver Spider, Crab-like Orbweaver Spider, Crab-like Spiny Orbweaver Spider, Jewel Spider, Spiny-bellied Orbweaver, Jewel Box Spider, and Smiley Face Spider.” The most common color variation for this species is white with black legs and markings and red spines.
Letter 4 – Spiny Orb Weaver from Argentina: Actinosoma pentacanthum
Spider
The Itsy Bitsy Spider sat on a waterplant, next to the pond in Buenos Aires, Argentina, The sneaky, weirdy guy, knelt down for a shot and Itsy Bitsy Spider smiled in response! Anyway, just wondering what this cute little guy is called!
Thanks a lot,
Cris
Hi Cris,
Wow, what a great photo of a great spider. We know it is one of the Orb Weavers, but have never seen the species. Looks like it might be related to the Micrathena spiders. We might be able to locate something more concrete in web searching.
Update January 25, 2016: Actinosoma pentacanthum
Thanks to a comment that just arrived, we are able to put a name to this stunning image from a ten year old posting. Insekten and FlickR both verify the name Actinosoma pentacanthum.
Letter 5 – Crablike Spiny Orbweaver: Color Variation from West Indies
Gasteracantha cancriformis
Hi Daniel and Lisa,
Here is a shot taken on our trip to Nevis, West Indies at the end of April this year. I am assuming this is Gasteracantha cancriformis , even though it has two less spines than the images from the US. There were a whole lot of these neat little spiders in their big scraggly-looking webs, spun across the back patio of one of the hotel rooms we stayed in, which was close to the beach. All of the spiders had yellow abdomens. I would not been able to recognize this spider, if not for reading your site, so thanks!
best,
Susan J. Hewitt
Hi Susan,
We are not thoroughly convinced that this Crablike Spiny Orbweaver is Gasteracantha cancriformis, but we are pretty certain the genus is correct. G. cancriformis has quite a bit of individual variation, so perhaps you are correct. The coloration on your specimen is stunning.
Yes, it is kind of different from the US specimens. On Wikipedia someone has attempted to list all the Gasteracantha species worldwide, and that list gives G. cancriformis as the only “New World” species. However it also lists a subspecies, Gasteracantha cancriformis gertschi , as the US taxon, so maybe that is why it looks a bit different? The other possibility is that at least in the case of snails, some of the Caribbean islands have had the opportunity to develop local forms and even endemic species, having been rather isolated for so long. Come to think of it I can e-mail a friend of a friend who is doing a doctorate on spiders at University of the West Indies, and see if she knows.
Update from a Spider Expert: (06/08/2007)
Hi Susan,
It is no bother. That is Gasteracantha cancriformis. Although the ones you saw were yellow they vary in colour so that some are white, red, orange or totally black. This the most common tropical species and is most likely the only species in the Lesser Antilles. With respect to the number of spines there are usually 6 spines but the anterior pair may have broken off or may be minute. Hope this is informative. Regards,
Jo-Anne N. Sewlal,
Dep’t of Life Sciences
University of the West Indies
St. Augustine, Trinidad and Tobago
Letter 6 – Crablike Spiny Orbweaver Egg Sac
Subject: Looks like an egg sac
Location: South East NC
September 11, 2016 8:14 am
Hi, found this inside the rain deverter on my husbands truck this morning.
Do you know what it is?
Thank you!
Signature: Suzanne
Dear Suzanne,
The first thought that passed through our mind when we looked at your image is that this might be the egg sac of a spider, and we followed that supposition, which quickly led us to the Featured Creatures site and a nearly identical image of the Egg Sac of a Crablike Spiny Orbweaver or Spinybacked Orbweaver Spider, Gasteracantha cancriformis. The egg sacs are described on Featured Creatures as being: “Ovate egg sacs, 20 to 25 mm long by 10 to 15 mm wide, are deposited on the undersides of leaves adjacent to the female’s web from October through January. The egg mass consists of 101 to 256 eggs, with a mean of 169 (based on 15 egg masses). After the eggs are laid on a white silken sheet, they are first covered with a loose, tangled mass of fine white or yellowish silk, then several strands of dark green silk are laid along the longitudinal axis of the egg mass, followed by a net-like canopy of coarse green and yellow threads. Eggs are frequently attacked by specialized predators, primarily Phalacrotophora epeirae (Brues) (Diptera: Phoridae), and occasionally Arachnophago ferruginea Gahan (Hymenoptera: Eupelmidae) (Muma and Stone 1971). Eggs take 11 to 13 days to hatch, then spend two to three days in a pink and white deutova stage before molting to the first instar.” A similar image can be found on Nature Closeups and on BugGuide.
Letter 7 – Crablike Spiny Orbweaver from Malaysia
Subject: Spiny orb-weaver
Location: Ulu Belum, Perak, Malaysia
January 4, 2013 2:24 am
Hi bugman,
what is this spesies?
Signature: Asyraf
Dear Asyraf,
This is a Crablike Spiny Orbweaver in the genus Gasteracantha, and we located one very similar looking spider on the Jungle Asia website, however it is only identified to the genus level.
Hi Daniel and Asyraf:
It is probably Gasteracantha kuhli, a Spiny Orbweaver native to southern Asia from India to Japan and including Southeast Asia. It also appears under the synonym G. kuhlii, but I believe the accepted name only has one “i”. To confuse the issue, I also found several sites that included photos from Asia of what looked to be the same spider, but that identified it as G. cancriformis. Both species are somewhat similar and both are characterized by six prominent abdominal spines, but G. cancriformis is a New World species (southern USA to South America). I suspect these are probably further incidents of online misidentifications. According to Wikipedia… “It has also been sighted in the Whitsunday Islands, Australia and Palawan, Philippines, as well as Kauai in the Hawaiian Islands.” These observations also may be based on erroneous identifications or, alternatively, G. cancriformis has been getting around. To me, G. cancriformis looks different enough that I would go with the native species, G. kuhli. Regards. Karl
Letter 8 – Crablike Spiny Orbweaver: Gasteracantha fornicata
An Australian Red & Yellow Spide
Hi There,
I saw this pretty spider while walking through the Atherton Tablelands in Northern Australia. I’ve been searching the internet and trying to find out what it is! A friend suggested that I check your site out and ask. I know you’re swamped but if you’ve a moment, please help and thanks in advance! Cheers,
Jennifer
Hi Jennifer,
This spider looked enough like one of the Crablike Spiny Orbweavers in the genus Gasteracantha that we tried a web search. We quickly found a photo of Gasteracantha fornicata on Wikipedia, and it appears to be a perfect match to your spider.
Letter 9 – Crablike Spiny Orbweaver from Kenya
Subject: Interesting Kenyan Spider
Location: Kenya
September 17, 2014 10:25 am
What kind of spider is this? We live in Machakos, Kenya. He looks to be half crab.
Signature: Marc Jordan
Dear Marc Jordan,
This appears to be an Orbweaver in the genus Gasteracantha, and North American members of the genus are known as Crablike Spiny Orbweavers. We located a very similar looking individual from Tanzania on FlickR, but it is only identified to the genus level and another image on FlickR is identified as possibly Gasteracantha versicolor. According to the images on Encyclopedia of Life, it is a highly variable species. Thorn Spider appears to be an accepted common name.
Letter 10 – Dewdrop Spider and Crablike Spiny Orb Weaver
pictures you don’t have yet!
Hi there! While perusing your site, I noticed you didn’t have any photos of the dewdrop spider. These minuscule kleptoparasites were all over the webs of our golden orbweavers last summer. There were sometimes as many as ten in one web. Also, I know you have loads of spiny orbweavers, but I didn’t see any that were yellow. My husband and I found this one while hiking with friends in Bastrop State Park, Texas. Keep up the great work!
Milly from Texas
Dewdrop Spider | Crablike Spiny Orb Weaver |
Hi Milly,
Thanks for sending us your great photos. Researching the Dewdrop Spider led us to information on an Australian species, Argyrodes antipodianus. More searching led us to Nick’s Spiders and a North American species, Argyrodes elevatus. BugGuide lists three genera of spiders under the category Argyrodes, Argyrodes, Faiditus, and Neospintharus, because they have not yet been separated to the genus and species level. The Dewdrop Spider of Australia gets its common name from the silvery abdomen which gives it the appearance of a dewdrop. It is also called a Quicksilver Spider. Your yellow Crablike Spiny Orb Weaver, Gasteracantha cancriformis, is not as common as the white form of the species.
Letter 11 – Spiny Orb Weaver from Africa
African Spider
November 4, 2009
While I was in Tanzania I happened upon a rather beautiful spider spinning is web. I think it is an African Horned Orb Weaver?
Gary Onstad
Tanzania
Dear Gary,
This is one of the Spiny Orbweavers, but we are uncertain of the species. We have been posting some old letters and your lovely photo caught our eye.
This is not kuhli, but cranciforms. If you had bothered to read the French website that you posted you’d note at the bottom that a diagnosic mark for kuhli are the 4 large distal spots on right and left of abdomen (their words not mine). The picture the poster posted does not have these markings, hence we have cranciforms and NOT kuhli.
To my knowledge Gasteracantha cancriformis is not found in Malaysia. I am a little bit confused about Luc’s comment, that this one is Gasteracantha cancriformis. I am pretty sure that this one Gasteracantha kuhli as suggested by Karl.
Devil crab orbweaver
The depicted spider is Actinosoma pentacanthum, a 5-spined orbweaver. 🙂
Thank you for identifying this ten year old posting. We have updated it with the information you provided.
I have one of these “smiley face” spiders by my back door that took over a web from the former tenant (a beautiful Golden Spider) what are they & is it normal for them to take over/evict other spiders or is it possible that my Golden Orb spider moved on?