Are Webspinners Dangerous? Uncovering the Truth About These Insects

Webspinning spider mites are small arthropods more closely related to spiders and ticks than insects.

They are known for their webs and can be destructive pests in agriculture. However, are they dangerous to humans?

In comparison to other arachnids, webspinners are generally not a direct threat to humans, as their feeding habits focus on plants.

Their concern lies mainly within the agricultural sector, where they may cause damage to crops and reduce yields.

On the other hand, some spider species can pose risks to humans through bites, which may cause varying levels of discomfort or even an allergic reaction.

While webspinners may not be a direct danger to people, being aware of their impact on the environment and the potential risks associated with other arachnid species can help ensure a safe coexistence.

Through proper maintenance and care of outdoor spaces, we can minimize the potential for encounters with potentially dangerous arachnids and protect our crops and gardens from damage.

What Are Webspinners

Order Embioptera

Webspinners, belonging to the insect order Embioptera, are fascinating creatures found in tropical and subtropical regions across the world.

They inhabit every continent, except Antarctica, and can even be found on islands and in Virginia.

Morphology

These insects, part of the subclass Pterygota, exhibit unique physical traits that make them easily identifiable:

• Small size: Webspinners are generally small in size, ranging from 2 to 25 mm in length.
• Long antennae: They have long, filiform antennae which they use for navigation and sensing their environment.
• Modified front legs: Their front legs are specialized for spinning silk, their primary method of creating webs for protection and navigation.

Walking Sticks and Praying Mantises

Webspinners share some similarities with walking sticks and praying mantises, but there are key differences:

Feature	Webspinners	Walking Sticks	Praying Mantises
Size	2 – 25 mm	30 – 300 mm	30 – 100 mm
Legs	Modified front legs for spinning silk	Elongated legs for camouflaging	Raptorial forelegs for catching prey
Diet	Omnivorous; plant matter and small insects	Herbivorous; mainly leaves	Carnivorous; insects and small vertebrates
Habitat	Tropical and subtropical; webs in crevices and tree bark	Tropical, subtropical, and temperate; trees and bushes	Tropical, subtropical, and some temperate regions; grasses, bushes, and trees

While webspinners may appear similar to walkingsticks and praying mantises, their distinct characteristics set them apart from these other insects.

Webspinners in Nature

Habitat and Distribution

• Webspinners, also known as order Embioptera, are tropical and subtropical insects.
• They live in environments like moss, lichen, bark, and leaf litter.
• Webspinners can be found hiding in tunnels and chambers they create within their habitats.

Plant Material and Diet

• Webspinners primarily feed on plant materials such as dead leaves.
• Their diet consists of moss, lichen, and other similar organic materials.
• They use their silk-producing forelegs to spin protective webs as they consume plant matter.

Predators and Defense

• Webspinners have various predators, such as birds and larger insects.
• Among their defenses, they rely on their ability to escape quickly and remain hidden in their webs.
• Nymphs and adult webspinners can secrete silk from their abdomen, which they use to create barriers against predators.

Webspinners and Silk

Silk Production

Webspinners, insects from the order Embioptera, produce silk in a unique way compared to other arthropods.

Instead of using spinnerets like spiders, they have specialized silk ejectors on their front feet (tarsi) to produce silk.

Tunnel System

Webspinners construct elaborate tunnel systems to navigate their environment. These tunnels have the following features:

• Composed of silk and surrounding debris
• Multilayered chambers
• Used for protection, feeding, and breeding

These tunnels enable webspinners to travel safely and efficiently while remaining hidden from predators.

Parental Care

Parental care is an interesting aspect of webspinners’ behavior. Female webspinners are known to provide care for their offspring by:

• Defending the nest from predators
• Sharing their silk galleries with the young
• Providing food resources

This attentiveness ensures a higher survival rate for the webspinner’s offspring.

Silk Galleries

Webspinners’ silk galleries have unique properties, such as high hydrophobicity which makes them water-resistant.

Silk from different webspinners exhibits distinct characteristics:

Webspinner Species	Gallery Silk Attributes
Antipaluria urichi	Highly hydrophobic
Other species	Varying properties

These silk galleries not only provide shelter but also serve as a base for the intricate tunnel systems mentioned earlier.

Physical Features and Characteristics

Flight and Legs

Webspinners are unique insects known for their silk-producing abilities, which they use for shelter and protection.

They’re generally harmless to humans, and their physical characteristics are worth noting.

• Wings: Male webspinners have wings, while females are wingless.
• Legs: Both have short legs, but only their forelegs have basitarsomeres for spinning silk.

Here’s a quick comparison of their flight and leg features:

Feature	Male Webspinner	Female Webspinner
Wings	Present	Absent
Legs	Short	Short
Silk spinning	Forelegs	Forelegs

Color and Flexibility

• Coloration: Webspinners showcase various shades of brown and grey, camouflaging them in their environment.
• Flexible bodies: Their flexible abdomen allows them to navigate their silk galleries with ease.

Eyes and Antennae

Webspinners’ sensory organs include:

• Compound eyes: These eyes provide a broad field of vision to locate food and detect threats.
• Antennae: Playing a vital role in sensing their surroundings, webspinners’ antennae can detect vibrations and even help with communication among their colony.

Distinct Webspinner Species

Black Webspinner

• Native to California
• Dark colored body

The black webspinner is native to California and can be found in gardens or other outdoor environments.

They have a distinct dark-colored body, which helps them blend into their surroundings.

Entomologists have studied these insects to understand their unique behavior and characteristics.

Aposthonia Ceylonica

• Found in India
• Lively colonies

Aposthonia ceylonica is a webspinner species found in India, commonly known for their lively colonies.

When observed by science, the insects display distinctive behavior that sets them apart from other species.

Oligotoma Nigra

• Saliva used for web spinning
• Spider-like appearance

The Oligotoma nigra species, often mistaken for a spider due to their similar appearance, have a unique attribute: they use their saliva to spin intricate webs.

Their head structure and movements also contribute to the spider-like perception.

Comparison table

Feature	Black Webspinner	Aposthonia Ceylonica	Oligotoma Nigra
Location	California	India	Various regions
Coloration	Dark	Variable	Dark brown to black
Web Spinning Mechanism	Not specified	Not specified	Saliva
Social Behavior	Not specified	Lively colonies	Not specified

Are Webspinners Dangerous?

Webspinners and Humans

Webspinners are small arthropods closely related to spiders and ticks¹.

They pose no direct threat to humans, as they do not bite or cause pain. In general, webspinners are safe and should not be a concern for people.

Households and Gardens

Webspinners can be found in yard environments, particularly around trees and areas with moisture¹.

These creatures can become a nuisance in households and gardens when they spin webs on trees or other plants.

It’s important to note that they can damage certain plants, such as those with a diameter larger than 2½ inches².

Preventive Measures

To prevent webspinners from becoming a problem in your yard or garden, consider the following:

• Keep the area clean and free of debris
• Regularly inspect and maintain trees and plants
• Control moisture levels in the environment¹

By taking these preventive measures, you can help keep your yard and garden safe from potential webspinner infestations.

Comparison: Webspinners vs. Other Common Pests

Pests	Bite or Sting	Damage to Plants	Vector for Disease
Webspinners	✗	✓	✗
Mosquitoes	✓	✗	✓
Aphids	✗	✓	✓
Spider Mites1	✗	✓	✗

Conclusion

In conclusion, webspinner are not dangerous to humans.

These small insects are known for their silk-producing abilities, which they use to create silk galleries in soil or plant debris.

While they may seem similar to spiders due to their silk-spinning behavior, webspinners are not venomous and do not pose a threat to people.

They feed on plant material and detritus, playing a role in breaking down organic matter in their environment.

Footnotes

1. https://extension.usu.edu/pests/uppdl/files/factsheet/web-spinning-spider-mite97.pdf ↩ ↩² ↩³ ↩⁴
2. https://www.law.cornell.edu/uscode/text/18/930 ↩

Reader Emails

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

Letter 1 – Webspinner Dynasty

Subject:  Love Webspinners (the saga continues)
Location:  Henderson, Nevada
December 21, 2014
Hi Daniel,
Sorry this is so long but I have an update on my Webspinner Dynasty ;-).
I had to create a Family Tree to keep them all straight.  The tree goes as follows:

1.  Wilma 12/20/12 – the bravest and least skittish.  Wilma tunneled out from the toilet base and often stood up at the end of the tunnel looking for a male. 

I still don’t know how she came to be in my bathroom to begin with, though we did discover a hole in the exterior of the house on the porch that matched the area of the toilet.

2.  Wanda 7/1/2013 – Wilma’s daughter created through asexual reproduction.  Wanda was skittish and would stay only in the grout space I called the “front yard”.

3.  Wendy 9/1/2013 – Wanda’s daughter created through asexual reproduction.  Wendy was also skittish but would peek over the grout wall of the “front yard”.

4.  Wynona 11/21/2013 – the adventurer/explorer.  Wynona was Wendy’s daughter created through asexual reproduction.  Wynona was awesome to observe.  She built and almost connected a tunnel completely around the outside of the base of the toilet. 

She also started a tunnel up the front of the toilet a couple of inches.  She nearly connected the “front yard” to the other grout space area I called” the backyard”.  Wynona was all over the place.

5.  Wylie 3/13/2014 – I saved Wylie from a water-dish on the back porch.  He would have drowned but revived after I saved him with my finger. 

I wasn’t sure if he would find Wynona but I placed him at the opening of the tunnel going up the front of the toilet and to my surprise he immediately twisted himself around to go down the tunnel.

6.  Walt – another male webspinner saved from the water-dish on the back porch.  I introduced him to Wynona’s front yard where he immediately disappeared under the linoleum.

7.  Winnie 4/4/14 – Winnie was skittish and possibly the daughter of Wylie or Walt and Wynona.

8.  Willie – another male webspinner rescued from the water-dish that disappeared under the toilet through the front yard grout area.

On 4/19/14 I had to call in a plumber to replace the wax ring on the toilet and I was worried about Winnie, Willie and any possible off-spring.  When the plumber picked up the toilet – I told him to not harm any bugs found underneath. 

(I don’t know what he thought was under there but he jumped back after he pulled up the toilet – LOL!)  I did see Winnie hiding against the grout wall of the linoleum and then she went under the linoleum before I could catch her.   If bugs can be surprised she certainly seemed surprised.  A few days later, Winnie appeared.

On 7/2/14 I saw a Spider Intruder.  A couple of times over the last year and a half, different  black house spiders would find their way to the web-tunnels around the toilet. 

I worried that the spiders  would eat the webspinners so I would catch them to put them outside.  The last one got away under the toilet so my husband sealed the hole on the porch and I waited for several days before seeing a webspinner alive and well.

9 & 10.  TWINS:  Wilfred & Willard – 7/21/14.  Until the twins made an appearance, I had never seen 2 webspinners at one time.  I believe the twins were Winnie and Willie’s offspring.  I was fairly sure they were males because they made appearances as immature light brown webspinners. 

The females only showed themselves as black adults, no doubt looking for mates.  Also, the young webspinners could turn around in the web tunnels which is a male behavior and which females never do.

11.  ACTUALLY TRIPLETS!!:  Enter Wilbert.  Another immature male webspinner.

13.  Wilda – Not sure if Wilda started out as a male and then became a female or if she was a 4th offspring of Winnie and Willie.   Wilda always stayed around the back-yard grout area.

14.  Wally – 7/12/14 rescued Wally from the water-dish and put him in the back-yard grout area where he disappeared looking for Wilda.

15.  Waldo – 7/19/14 offspring of Wally and Wilda.  Another light brown immature male.  Waldo was ready to fly on 8/15/14 so I caught him and released him outside.

16.  Wilbur – 8/13/14 offspring of Wally and Wilda.  Wilbur also stayed in the backyard grout area.  Wilbur was ready to fly by 9/16/14 so I caught him and released him on the rose bush in the front yard.

Apparently, Wilbur was the last of the dynasty.   I can’t believe how much I miss them.  I’m working on a webspinner children’s book which may help children to realize the value of a bug. 

The webspinners were with me from 12/20/12 until 9/16/14 – almost 2 years!!  I’ve learned that it is possible to get attached to specific insects and that they have their own unique personalities and habits.

Thought you’d like to know ;-).  I’m attaching a few pictures (this time 😉 ):

1.  Wynona building the tunnel up the front of the toilet.
2.  The “twins in tandem” in Wynona’s web that goes around the base of the toilet.
3.  Waldo saying “goodbye” as I released him outside.
Always,
Kathi

Hi there Kathi,
Thanks so much for your wonderful update on your Webspinner dynasty.  Good luck with your book.  As with your previous Love Webspinners submission, we are tagging this posting with the Bug Humanitarian Award.

Letter 2 – Webspinners

Subject: Love Webspinners
April 20, 2014 12:46 pm
I have a female webspinner under my toilet and have had at least one since December 2012.  They are cute insects and very endearing.  I’ve had 4 or 5 generations and each is unique in the direction they take their web tunnels and how they behave. 

They can reproduce without a male and I’ve named each one.  The most recent is Wynona and I’ve found and saved 2 different males and “introduced” them to Wynona’s web where they’ve disappeared. 

The first male, Wylie,  was successful in mating since a baby was seen 3 weeks later in the web tunnel that Wynona built around the base of the toilet.  I think each generation lives approximately 6 months.  They supposedly molt 3 times before attaining adulthood. 

They are supposed to be very social and take good care of their young. I’ve never seen two at the same time.  I watch Wynona run back and forth in her tunnel (females never turn around but males can) and sometimes she extends her tunnels outwards or up the toilet bowl a few inches. 

The first webspinner, Wilma, built a tunnel a couple of inches from the toilet outward and even built a chimney at the end which she would rise out of to “look around” seeking a male. 

She was the bravest and least skittish of the generations. I’d put a small drowned gnat in Wilma’s web every few days or so and watch as she ate them (even though everything I’ve read says they are herbivores). 

I think they survive on the springtails and algae that must be in the humid area around the toilet.  I’d never seen them before and it took 3 months to solve the mystery.  I refuse to let anyone harm them. 

I discovered they must have tunnels under the linoleum around the toilet because the last male disappeared under the linoleum looking for Wynona or one of her daughters. 

If you find one – get a good magnifying glass and watch it – they spin their web tunnels upside down at times and are very interesting to watch.  When they wave their front legs around (spinning webs) – they look like they are waving at you with baseball mitt paws. 

They are the coolest bugs around.  I’d love to catch her and relocate her to a terrarium but I’m afraid the move would kill her or separate her from her family and she wouldn’t have easy access to the food-source (algae or springtails), if that is what they are eating.
Signature: Kathi

Hi Kathi,
We wish you had sent an image, but since you did not, we are illustrating your posting with a Webspinner image from our archives. 

We are also tagging you with the Bug Humanitarian Award for allowing your Webspinners to cohabitate with you in your home.  You did not provide a location for your sighting.

Hi Daniel,
Thank you for the Humanitarian award.  I live in Henderson, Nevada.  If I can find a good picture of one of my webspinners, I’ll send it to you. Meanwhile, the one from your collection is a great male webspinner ;-).
Thanks for putting up such a great website.
Always,
Kathi

Letter 3 – Webspinners

Subject:  Long ant like bug
Geographic location of the bug:  Phoenix, Arizona
Date: 07/09/2018
Time: 12:52 AM EDT
Your letter to the bugman:  I found two of these in my kitchen, and can’t find a match anywhere. The closest i found was a snakefly larva, but it didn’t match completely
How you want your letter signed:  James

Dear Dave,
These are benign Webspinners in the insect order Embiidina, and according to BugGuide:  “slender, usually brownish insects that may have wings (males) or be wingless (some males and all females); body of male flattened; body of female and immature more cylindrical; tarsi 3-segmented; basal segment of front tarsus greatly enlarged for producing silk from hollow hairs issuing on the basal and middle segments; cerci 2-segmented (but left cercus of some males 1-segmented).”  You might enjoy our Webspinner Dynasty posting.

Letter 4 – Webspinners swarming around lights

Subject:  Swarming around lights inside
Geographic location of the bug:  California’s Central Coast
Date: 08/06/2018
Time: 01:54 AM EDT
Your letter to the bugman:  For the last several days a few of these bugs have been showing up inside our house. This evening, a huge group was swarming every light we had on.

Can you tell me what this is? We have screens on all of our windows, so I’m concerned about how they are getting in. Appreciate your help if you can share any info. Thanks!
How you want your letter signed:  Amy

Dear Amy,
This is a benign Webspinner in the insect order Embiidina, and you have already discovered what BugGuide remarks:  “winged males of some species come to lights.” 

BugGuide also notes:  “rapid runners, often run backwards; live in colonies (in galleries of spun silk) and exhibit limited maternal care for eggs and young.” 

We don’t provide extermination advice, but you can try dimming the lights, keeping lamps away from windows and checking the screens for access points.