Ailanthus Webworm Moth: All You Need to Know – Quick Guide for Curious Minds

The Ailanthus Webworm Moth is a fascinating insect with unique characteristics that set it apart from other moths. Its vibrant colors and distinctive patterns make it easy to identify. Found in various parts of the United States, this moth plays an interesting role in its ecosystem. Originating from the tropics, the Ailanthus Webworm Moth (Atteva aurea) can now be spotted down the far north. The adults are known for their striking orange forewings adorned with white spots and black outlines, oftentimes resembling tiny flower patterns. Their larvae feed the Tree-of-Heaven (Ailanthus altissima), which is native to China. Quick Facts:

• Size: About half an inch in length
• Color: Orange forewings with white and black details
• Food Source: Tree-of-Heaven leaves (for larvae)
• Distribution: United States, particularly in South Florida

Even though the majority of Ailanthus Webworm Moths are found in southern Florida and other tropical areas of North America, their adaptable nature is helping them to spread to new areas. On one hand, the moth’s larvae help control the population of an invasive tree species, but on the other hand, a higher moth population could lead to a decline in native plants or have other unforeseen consequences.

Ailanthus Webworm Moth Overview

Atteva Aurea

The Atteva aurea, commonly known as the Ailanthus Webworm Moth, is a small, colorful insect. Notable traits of this moth include:

• Long, thin body
• Orange forewings with white spots outlined in black
• Curved mouthparts (labial palps)
• Tufted head scales
• Filamentous antennae

This moth has a wingspan of around 1/2 inch and often holds its wings tight against its body when not in flight.

Ermine Moth

The Ailanthus Webworm Moth is an Ermine Moth, belonging to the family Attevidae. Some characteristics of Ermine Moths include:

• Bold colored wings
• Striking patterns
• Small size

Here’s a comparison table of the two entities:

Trait	Atteva Aurea (Ailanthus Webworm Moth)	Ermine Moth (Family Attevidae)
Size	Small (1/2 inch wingspan)	Small
Color	Orange with white spots outlined in black	Bold colors
Pattern	White spots resembling flowers	Striking patterns
Family	Attevidae	Attevidae

Life Cycle

Eggs

The life cycle of the Ailanthus Webworm Moth begins with the female moth laying eggs, generally on the underside of leaves¹. Hatching occurs within 2 weeks and marks the start of the caterpillar stage¹.

Caterpillars

The caterpillars of the Ailanthus Webworm Moth are slender and colored brown to almost black and may have four white dots on each segment. They feed on Ailanthus tree leaves, which is how they got their name.

Pupa

After the caterpillar stage, the Ailanthus Webworm Moth enters the pupa stage¹. This typically occurs in the soil, where the caterpillar forms a cocoon for metamorphosis¹. The pupa stage takes place throughout the winter months¹.

Adult Moth

The adult Ailanthus Webworm Moth is a small insect that is characterized by its long, thin body and its unique wing pattern². The adult moths emerge in the summer and are usually seen around late June and early July¹. To put it in a nutshell, the Ailanthus Webworm Moth goes through four stages in its life cycle:

• Eggs: laid on the underside of leaves, hatch within 2 weeks¹
• Caterpillars: slender, brown to black, with possible white dots²
• Pupa: occurs in soil, during winter months¹
• Adult Moth: emerges in summer, with distinctive orange and white spotted wings⁴

Habitat and Distribution

Host Plants

The Ailanthus Webworm Moth is primarily associated with the Tree of Heaven, an invasive species from China. This moth also feeds on other trees such as the Paradise Tree (Simarouba glauca), and Simarouba amara.

• Common host plants:
  • Tree of Heaven
  • Paradise Tree
  • Other Simarouba species

Geographical Range

The Ailanthus Webworm Moth is native to tropical areas, including Costa Rica and Southern Florida. However, it has expanded its range in response to the spread of its primary host, the Tree of Heaven. The moth can now be found throughout North America, particularly in Eastern Canada and the United States. Urban areas and nurseries with Ailanthus trees are hotspots for Ailanthus Webworm Moth populations.

• Native range:
  • Southern Florida
  • Costa Rica
• Expanded range:
  • North America
  • Eastern Canada
  • Urban areas with Ailanthus trees

Comparison Table:

Feature	Tree of Heaven	Paradise Tree
Latin Name	Ailanthus altissima	Simarouba glauca
Origin	China	North America
Invasive Status	Invasive Species	Native Species
Ailanthus Webworm Moth	Preferred Host	Secondary Host

Pollination and Ecological Role

Pollinator Interactions

The Ailanthus Webworm Moth also plays a key role in pollination. As they gather nectar from flowers, they inadvertently transfer pollen between plants, supporting plant reproduction. Some key points about their role as pollinators include:

• Active during the day and night.
• Attracted to pale or white flowers with fragrance.

Invasive Species Impact

As mentioned above, the moth’s caterpillar stage feeds on the foliage of invasive Ailanthus trees, which can help in controlling their spread. Here’s a quick comparison of the pros and cons of this relationship:

Pros	Cons
Helps control invasive trees	May inadvertently spread the trees
Reduces foliage of Ailanthus	Limited impact on tree populations

Conclusion

In summary, the Ailanthus Webworm Moth is an interesting creature with both pollination and ecological roles, benefiting the environment by controlling invasive tree species while also serving as a valuable pollinator.

Footnotes

1. Fall Webworm: Insect & Disease Fact Sheets: Forest Health – Maine ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸
2. Ailanthus Webworm | NC State Extension Publications ↩ ↩² ↩³ ↩⁴
3. Ailanthus Webworm Moth – Field Station ↩
4. Ailanthus Webworm Moth | Missouri Department of Conservation ↩ ↩²

Ailanthus Webworm – Letters from Readers

The Ailanthus Webworm is one of the most famous insects that our readers talk about and ask to know about. Over the last two decades, we have received dozens of emails from our readers asking us to identify this beautiful insect.

We have reproduced some of the best ones with some beautiful images for you to have a look.

Letter 1 – Ailanthus Webworm

What type of beauty is this? Kate Hi Kate, This little moth is an Ailanthus Webworm, Atteva punctella.

Letter 2 – Ailanthus Webworm

sexy bug spends the night Location:  Granite, MD August 29, 2010 1:38 pm Hi Bugman! You’ll be pleased to know nothing was squashed in the making of this inquiry. We were painting the upstairs bedroom yesterday and opened the window to get some ventilation. We closed the door behind us and left the light on all night, but our window had no screen. We hosted quite the unintentional bug party last night, and this handsome fellow stuck around to check out what we were having for breakfast. So what is it?? Thanks! hostess with the mostest

Nevermind! Found it on the site. We cleared our property of lots of invasives (plants) last year and replaced them with natives so it’s good to meet a bug who is a kindred spirit! Thanks for your time :0) Dear Hostess with the Mostest, We are happy to hear that you identified this Ailanthus Webworm, and also that you are replacing invasive plants with native species.  You will need to be very diligent to ensure that the Ailanthus does not return if that was one of the plants you removed.  Ailanthus or Tree of Heaven might be the greatest threat to native habitats in North America right now.  This large weed tree from China spreads by both roots and seeds, and a tree that is cut will just sprout back as a grove.  It can survive in cold, hot, wet, or dry climates.

Letter 3 – Ailanthus Webworm

Kind of moth??? Location: Goshen Indiana July 12, 2011 12:54 am Dear Bugman, I was outside with my dog and this big one flew into my house. I thought the corporation was beautiful but have no idea what kind it is. It was attracted to our outside light here in Northern Indiana. It has Orange and white strips on its wings and body the underside of its wings is jet black. It has 6 black legs that have very tiny white and yellow spots. I couldn’t find anything on BugGuide but at the same time, I can’t use that site well. If you have any info. please feel free to let me know thanks so much. Signature: freaked by bugs

Dear freaked by bugs, You are correct.  The Ailanthus Webworm is a moth.  Populations of the Ailanthus Webworm appear to be benefitting because of its namesake, the introduced Ailanthus tree or Tree of Heaven, a noxious weed tree that spreads rapidly once it has been introduced to an area. Thank you so much for identifying it for me. Now my 6 yr. old knows what to call it for show n tell (he will take a picture of course not the actual bug). Tami Hager

Letter 4 – Ailanthus Webworm

Subject: What is this? Location: Virginia July 3, 2014 7:36 pm Hi! Just wondering what this was. Thought the coloring was awesome and it struck my curiosity. Our backyard is wooded and when opening the door to let our dog in and out moths and fireflies usually sneak in, however, this is the first bug I’ve seen a color like this! Here is a photo of it on my bathroom mirror. Thanks! Signature: Kim

Hi Kim, This pretty little moth is an Ailanthus Webworm.

Letter 5 – Ailanthus Webworm

Subject: Beetle colored like a flower Location: Occoquan, Virginia July 8, 2014 9:45 pm Hello, i noticed this interestingly colored Beetle on the side of my sliding glass door frame near the outdoor light. I have never seen this species before. It has a beautiful floral-looking pattern. I have no idea if that is his wing pattern or body color. I did not want to disturb it. It was there in the morning and stayed all day. I’m figuring it is a Nocturnal species. Any help in Identification would be greatly appreciated. Thank you Signature: Mr. Joe Shukay

Hi Joe, This Ailanthus Webworm is a moth, not a beetle.

Letter 6 – Ailanthus Webworm

Subject: Beautiful Bug On Wind Chimes Location: Danville, Kentucky June 26, 2015 6:12 am Please help us identify this beauty we found on our wind chimes in Danville, KY (USA) on June 25, 2015. Thank you. Signature: Natalie

Dear Natalie, This lovely moth with its intricately patterned wings is an Ailanthus Webworm.

Letter 7 – Ailanthus Webworm

Subject: Beetle Location: Northeast Ohio, Youngstown July 30, 2016 5:33 pm Found this bug in my kitchen… It’s 8:30 PM EST in northeast Ohio on July 30, 2016. It’s about 75 degrees Fahrenheit, and we’ve been having some unusually warm and humid weather. Just wondered what this little guy is. 🙂 Signature: Mindy

Dear Mindy, This is an Ailanthus Webworm Moth, a species with caterpillars that feed on the leaves of the invasive Ailanthus Tree or Tree of Heaven.  On a totally different note, did you go to see Hillary Clinton speak at East High School today?  We have relatives in the Youngstown area, including mom who is 87 and lives in Campbell, Ohio, where our editorial staff was born and raised.  We have also been closely following the Mill Creek Park drama, and we personally feel it is very unfortunate when we hear how mismanagement has resulted in controversial and unfair job terminations there, and how the park is falling into a very sad state due to lack of proper staffing.

Letter 8 – Ailanthus Webworm

Subject: I think it’s a rattlebox moth, but… Location: Boynton Beach, Florida October 13, 2016 9:43 am Hello, What’s That Bug! I think I photographed an ornate bella moth (or rattlebox moth) but it just doesn’t look right to me. The black and white patterns along the sides are very different from the “normal” rattlebox moths seen in our area and it also appears to have touches of purplish black on the back of the neck. This bug was photographed at Seacrest Scrub Natural Area in Boynton Beach, Florida. What do you think? Is it a rattlebox moth that has just decided to be “different”? Thanks for helping us identify all things creepy and crawly – and in this instance, wildly colorful! Signature: Ann Mathews

Dear Ann, This is an Ailanthus Webworm Moth, NOT a Rattlebox Moth. Thank you so much for correcting me on the identity of this bug. I’ll let the natural area land manager know – this may be a new species for Seacrest Scrub Natural Area. Appreciate all you do! Ann Mathews Palm Beach County Department of Environmental Resources Management Hi again Ann, Though this is a native species, it has adapted to eating the invasive, exotic Tree of Heaven, Ailanthus altissima, which might have gotten established in the Seacrest Scrub Natural Area.  If that is the case, those in charge should attempt to eradicate this noxious tree that is invading native open space across the continent. Once again, thanks for the additional information about this moth. Our Department works hard to keep the natural areas free of invasive, nonnative plants. However, this particular natural area is surrounded by homes landscaped with lots of exotic plants – so I suspect the adult moths feed in the natural area while the caterpillars feed in the yards adjacent to the natural area. Ann Mathews

Letter 9 – Ailanthus Webworm

Subject:  Beautiful Bug Geographic location of the bug:  Alexandria, VA Date: 08/03/2019 Time: 08:54 AM EDT Your letter to the bugman:  I saw this very little guy/gal near my mailbox. Not sure what it is, but the pattern was so pretty. How do you want your letter signed:  Alex

Dear Alex, Over the years we have gotten many submissions commenting on the intricate beauty of the colors and markings of the Ailanthus Webworm moth.

Letter 10 – Ailanthus Webworm

Subject:  Colorful little moth Geographic location of the bug:  Central New Jersey Date: 08/06/2019 Time: 07:52 PM EDT Your letter to the Bugman:  Saw this pretty little moth on my siding this evening. Any idea what it is? Thank you. How you want your letter signed:  Barbara

Dear Barbara, A high-quality close-up is required to appreciate the intricate beauty of the Ailanthus Webworm.  Your image is perfect. Thank you so much for your very fast and informative reply! I love your site.

Letter 11 – Ailanthus Webworm Moth

I GIVE UP A friend in Ozone Park, NY sent this out to our E mail group asking “Name this bug” (He don’t know either, it was in front of his house he says). I’ve scoured your site and BugGuide without success (I’m totally clicked out). I’ve accused Bob of having his young daughter paint the bug to throw us off the scent. When I check “Beetles” they have 6 legs, same with flies, etc. etc. but this one only has 4 legs. Dragonfly? No luck there either, I’m perplexed in California. Robert teGroen Oak Run, CA Hi Robert, This pretty little moth is the Ailanthus Webworm.

Letter 12 – Ailanthus Webworm Moth

Subject: Bug On My Car Hood Location: Roseland, NJ October 29, 2012 9:31 am Hi, I Saw this bug on my car hood today. I Have never seen it before. I live in Roseland, NJ, and was hoping for an ID Signature: Ernie

Dear Ernie, This is an Ailanthus Webworm Moth.  We hope all is well there in New Jersey and that you have weathered the wrath of Sandy.

Letter 13 – Ailanthus Webworm Moth

Subject: What’s this beauty? Location: New Jersey July 15, 2013 3:58 pm Found him hanging out at our house. Was curious to know what type of insect it was. Signature: Heather

Hi Heather, This is an Ailanthus Webworm Moth, and we haven’t posted a new photo of this species this year, so your excellent photo is a nice example of a recent sighting.

Letter 14 – Ailanthus Webworm Moth

Subject: What is this bug? Location: Ohio October 21, 2013 2:07 pm Can’t find this insect anywhere. It looks like a long lightning bug with a very intricate design on the wings. Signature: Rob

Hi Rob, This is an Ailanthus Webworm Moth, Atteva punctella, a native Ermine Moth that has expanded its original range because its caterpillar adapted to eating leaves of the invasive, exotic Ailanthus or Tree of Heaven.  Sadly, the caterpillars will never do enough damage to the tree to help control the spread of that noxious weed species throughout the civilized world.

Letter 15 – Ailanthus Webworm Moth

Subject: orange, black and white bug ID Location: Harrisonburg, VA August 15, 2015 2:42 pm Hi – This pretty bug has been sitting on the same rattlesnake master bloom for a couple of days. It is located in a new pollinator plant garden in a riparian buffer area of a park in Harrisonburg, VA. The photo was taken on August 14, 2015. Thanks for your help! Signature: Adrie

Dear Adrie, This is an Ailanthus Webworm Moth.

Letter 16 – Ailanthus Webworm Moth

Subject: What is this Location: Northern ct August 24, 2015 7:31 pm Found in derby ct , just curious , newbie to the bug world. Signature: Andre

Dear Andre, In the past two weeks, we have identified numerous Ailanthus Webworm Moths, but because of time restrictions, we have not published those submissions.  Your images are quite nice, and since you are a newbie to our site, we decided to post your request in the hope it will help others to identify this lovely Ermine Moth.

Letter 17 – Ailanthus Webworm Moth

Subject: Whats this bug? Location: Northeast PA November 18, 2015 8:38 am I am near the Wilkes Barre area in Northeast Pennsylvania today is November 18th 2015 and saw this bug on a metal electrical box outside of my home. Signature: Ken Urian

Dear Ken, This is an Ailanthus Webworm Moth, Atteva aurea, a native Ermine Moth whose caterpillars have adapted to eating the leaves of the noxious weed Trees of Heaven, but alas, the moths are unable to control the spread of the tree that is invasive.

Letter 18 – Ailanthus Webworm Moth

Subject: What is this bug? Location: Buenos Aires, Argentina April 19, 2016 3:01 pm Dear bugman, I saw this bug at home yesterday for the first time ever, and I have no idea what it is. I hope you can help me identify it! I’m in Argentina and fall is just starting here. It’s been very humid and rainy for the past couple of weeks. Signature: Mercedes

Dear Mercedes, This sure looks like a North American Ailanthus Webworm Moth, Atteva aurea, to us.  Based on this Zoo Keys article, we believe your species is Atteva pustulella.  According to Eco Registros, the latter species is found in Argentina.

Letter 19 – Ailanthus Webworm Moth

Subject: Just curious Location: Dayton, Ohio near the Miami River July 5, 2016 7:10 pm This bug was on my car door after I parked at a riverside park during lunch just south of downtown Dayton, Ohio today. I’ve never seen anything like it. It was about 3/4 of an inch long, less than 1/4 inch wide. Yellow-orange with ‘flowers’ of round white petals trimmed in brown. Can you tell me what it is? Thanks! Signature: Deb

Dear Deb, This pretty little native Ermine Moth is an Ailanthus Webworm Moth.  Though the moth is native, the namesake plant, Ailanthus or Tree of Heaven is not.  Sadly, the feeding of the caterpillars has no negative impact on the invasive Tree of Heaven.

Letter 20 – Ailanthus Webworm Moth

Subject: Anyone know what this is? Location: Astoria, Queens July 18, 2016 9:30 pm Hi! Saw this on a wall in NYC… Never seen anything like it… Thanks! Signature: Ben

Dear Ben, This pretty little Ermine Moth is commonly called an Ailanthus Webworm Moth.