For those looking to breed beautiful mourning cloak butterflies, it is important to know that their caterpillars have stinging hair. Let’s learn more about it and what to do if you get stung.
Nymphalis antiopa, or mourning cloak, is a large butterfly found in North America. These beautiful butterflies live for almost ten months, more than most others.
The larval stages of mourning cloak butterflies are known as spiny caterpillars. These caterpillars are known for their spiny body. When these spines come in contact with human skin, they can cause pain, severe infection, blistering, and other problems.
So, it’s better to avoid touching these fuzzy caterpillars. In this article, we will talk more about these caterpillars.
What Does the Mourning Cloak Caterpillar Look Like?
Mourning cloak caterpillars are 2 inches long (on average) and have a very striking appearance.
These caterpillars have black bodies, with reddish-orange dots found in every segment of their body.
Their entire body is covered with hair and black-colored spines with white dots on them.
It’s common to see a dozen large spiky caterpillars in one place because the butterflies lay their eggs in a bunch, and they all hatch together.
Is This Caterpillar Poisonous?
Yes, it is a poisonous bug. The Spiny Elm caterpillar (as it is otherwise known) is a stinging caterpillar that has urticating spines on its body.
Some of these hairs or spines can get attached to your skin when you touch this caterpillar.
These spines release a small amount of toxin inside your body, which can cause irritation, redness, swelling, and in some cases, an allergic reaction.
If you have weak immunity or are sick, the reaction might be severe and may need immediate medical attention.
So, mourning cloak caterpillars are poisonous, and you must avoid touching their venomous spines as much as possible.
Is It Dangerous To Humans?
Yes, the spiny caterpillar can sting humans, which can be a bit dangerous if the person is allergic to insect stings.
We are listing below some of the symptoms which you may face after exposure to the venomous spines of the mourning cloak caterpillar:
- Redness in skin
- Skin irritation
- Shortness of breath
- Difficulty in eating
If you touch the eyes or nose after touching this stinging caterpillar, then symptoms like coughing, nose bleed, sneezing, and mouth pain can also happen.
You need to remove the hairs immediately from your body after touching the caterpillar’s venomous spines. Use a small tweezer to extract the spine and throw it away afterward.
The symptoms may continue for a few minutes or up to a few days. If it continues for more than one day, you need to visit your doctor.
Does It Bite?
The mourning cloak caterpillars may be poisonous, but they don’t have powerful biting mouthparts. So they will not bite you.
These caterpillars have mandibles that they use to eat leaves and plant parts, but these mandibles cannot cause much of a dent in human skin.
How To Treat The Symptoms of Exposure to Urticating Spines?
If a person has a mild reaction after touching the venomous caterpillar’s hair, the treatment can be done at home.
You need to follow the below steps for doing home treatment at home.
- Remove the tiny hairs of the mount cloak caterpillar immediately. You can do this by using tape.
- You can place a tape strip on the area of your body that is exposed to caterpillar hairs.
- Pull the tape to remove all the hair.
- Wash the area gently with soap and water.
- If that area still itches, then you can put a paste of baking soda and water over it. But if it will not work, then apply hydrocortisone cream over the area.
- If you have blisters in that area, then contact your doctor immediately.
What Other Damage Does It Do?
Newly born mourning cloak caterpillars eat the leaves of trees like willows, cottonwood, and elms. They even feed on flowers like knapweed and scabiosa, which can cause significant damage to your yard.
The adult mourning cloak drinks the nectar of plants like red maple and milkweed. They even eat decaying fruits in your garden and consume tree sap.
Some signs of mourning cloak caterpillar damage are rolling leaves, holes on leaves, eggs, and excreta. They might even bore into the wood, which can cause a lot of damage to the tree.
Other Poisonous Caterpillars
#1. Giant Silk Worm Caterpillar
There are various species of giant silkworm caterpillars, but two species, the Buck moth and Io moth, have poisonous spines.
Buck moth Caterpillar
The buck moth caterpillar is brown to purple-black with various yellow spots. The entire body of this caterpillar is covered with black-colored spines.
You will commonly find them in oak or willow trees and mainly from spring to summer season in a year.
Io Moth Caterpillar
The Io moth caterpillar is usually light green or yellow. You will find a red line on both sides of these species. These caterpillars eat plants like corn, oak, apple, and roses.
#2. Flannel Moth Caterpillar
There are various Flannel moth caterpillars, but the most common ones with stinging hairs are the puss moth caterpillar and black wave flannel moth caterpillar.
Puss Moth Caterpillar
A Puss caterpillar is a one-inch caterpillar covered with long soft brown hair throughout the body. But
venomous spines are found just below these long hairs, which can cause irritation and blisters on your body at a slight touch.
Black Wave Flannel Moth Caterpillar
The sting of the black wave flannel moth caterpillar is not as dangerous as a puss caterpillar.
These caterpillars usually feed on hardwood plants, which you commonly see in the summer.
Frequently Asked Questions
#1. Are mourning cloaks rare?
Mourning cloaks are not rare. They are found in many places across Asia, North America, and Europe. They are rare in Britain, where they are also known as Camberwell beauty.
The behavior of these beautiful butterflies is quite interesting. When the weather gets cold, they hide in rocks and holes in trees, overwintering as adults.
But during the summer months, they come out and fly again in search of food.
#2. Are mourning cloaks endangered?
No, it is not an endangered species.
Mourning cloaks are quite common in the United States. But it is rarely seen in some parts of the World like Britain and the Gulf states.
These butterflies are quite beautiful. They feed on the nectar of the flowers of their host plants, including wild roses, black willow, and others.
#3. How long does a mourning cloak butterfly?
They live for almost ten months, more than other butterfly species. It is a large, distinctive butterfly with wings extending up to 3 to 3.5 inches.
When they close their wings, their body looks like they are wearing mourning cloak, which is the reason behind their name.
#4. Why are they called mourning cloaks?
The mourning cloak butterfly’s colors resemble that of a traditional cloak or loose garment worn by people who have lost their loved ones.
Mourning cloak butterflies are a sight to behold in the summer and spring seasons. However, those looking to breed them should be aware that the caterpillars have stinging hair.
We have discussed the steps to follow if these caterpillars’ hairs come in contact with your skin. However, the best policy is to wear gloves when handling them.
We thank you for reading this article!
Over the years, we have been fortunate to receive many emails from our readers detailing the mourning cloak caterpillars.
Go through the treasure trove of pictures and information in the letters below.
Letter 1 – Mourning Cloak Caterpillar
Black Spikey Caterpillar
Dear What’s That Bug,
My son and I found this black spikey caterpillar in the backyard eating some cottonwood leaves. It is mostly black with a lot of tiny white dots, tiny white hairs, and long black spikes all over its body. It also has five pairs of orange feet and rust colored spots down the middle of its back. We think it looks similar to a mourning cloak caterpillar that we saw on your site. Is that what it is? Thank you
You are correct in your identification of this Mourning Cloak Caterpillar..
Letter 2 – Mourning Cloak Caterpillar
hi bugman.. I came home to find the wall outside my backdoor in Southern Cal. covered with these beasties. They all seemed to be climbing up to my roof and appeared more rarely around other outside walls.
Do I need to call the exterminator? Or should I make peace with them? My dog hasn’t noticed them yet.
Los Angeles, Ca.
This is a Mourning Cloak Caterpillar which will become a lovely brown butterfly with cream colored wing edges and blue spots. The caterpillars feed on elm, willow, poplar and occasionally the floss silk tree.
Letter 3 – Mourning Cloak Caterpillar
I know you are busy, take a look if you can
Hi guys, attached is a photo of a caterpillar I’m trying to ID. I posted it on bug guide too. I also am sending over some other photos I took and posted on bug guide and you can use them onb your site too if you want to. Today I learned on your site the things I was calling silverfish were actually house centipedes and they eat other bugs in the house. Cool. I also read they can produce a painful bite. Not cool. Generally speaking, I’m not a bug killer (we have a “backyard safari” bug vacuum) and all tresspassers are released. Since I’m a high school teacher I always make it a point to set an example when we have a bug intruder in our classroom and make sure it is tossed out the window. Is there a way to post pics to the site like bug guide or do people just mail them to you?
Dear Unknown Teacher,
Since we are control freaks about the aesthetics of our site, we do not allow visitors to post. Imagine what we might find? We do not want Jenna to appear on our homepage one day. This is a Mourning Cloak Caterpillar.
Letter 4 – Mourning Cloak Butterfly Caterpillar
These little guys…
Found these little guys climbing out of my Chinese elm tree, here in Southern California. I watched for over an hour as at least 15 climbed down, one by one. Can you tell me what kind they are, and what they feed on? Thanks.
This is a Mourning Cloak Butterfly Caterpillar. They were feeding on the leaves of your Chinese Elm and they left the tree to find a good place to pupate. Mourning Cloaks are lovely purplish black butterflies with cream colored wing edges and blue spots.
Wow! Thanks so much for taking the time to answer my e-mail. Our entire evening had been centered around these caterpillars. My children and I carefully collected them as they came out of the tree thinking we would watch then release them as butterflies. Since I wasn’t sure what they fed on and didn’t want them to starve, I placed them back at the base of the tree. I tried looking online several times to identify, but had no luck. I even woke in the middle of the night thinking of them….funny. Anyway, it was SO NICE to find your e-mail with the answer, and the kids (2 & 4) were amazed with the pictures and facts I was able to then find on the internet. Thank you for helping keep our interest “peaked”. All that right in our own back yard! So cool. Take care.
Letter 5 – Mourning Cloak Caterpillar
SoCal Caterpillar, Agraulis vanillae?
Location: La Crescenta/Montrose California
March 14, 2012 3:45 pm
Hi Bugman! I came across a caterpillar today and tried figuring out what it was. Due to just moving here from Florida, I’m sure my area has tons of new bugs (including the giant black widow I found a while back!!) It looked like an Agraulis vanillae BUT it’s a bit different. It’s black/gray with 2 tight red/orange striped along its back. The spikes are NOT clumps of hairs, but actual single spikes.
I took 2 photos. 1 is on the concrete of my porch where I found it. The other is where I put it; a white rose tree.
Please forgive my photos. All I had near me was my phone, but I think the photos are good enough.
Signature: Thank you!
Though your caterpillar resembles that of the Gulf Fritillary, Agraulis vanillae, it is actually that of a Mourning Cloak, a lovely large purplish, black butterfly with creamy wing edges and blue spots. Mourning Cloak Caterpillars feed on native willows but they are very content to feed upon the leaves of cultivated Chinese elm as well.
Letter 6 – Mourning Cloak Caterpillar
Location: Denison, Texas
April 5, 2012 6:08 pm
I have seen about 13 of this in one afternoon crawling around. Is this a mourning cloak? Can they hurt you?
You are correct. This is a Mourning Cloak Caterpillar. They can often be present in great numbers as you have witnessed. According to the Auburn University webpage on Stinging Caterpillars: “Several species of nymphalid larvae bear conspicuous bristled or multi-branched spines similar to those found on some stinging caterpillars. One species, the spiny elm caterpillar (larva of the mourning cloak butterfly), is reported to possess urticating spines.” According to BugGuide: “Caution: Do not touch the larva; its spines may cause a stinging sensation if handled.”
Letter 7 – Mourning Cloak Caterpillars
Subject: Centipede? In SoCal
Location: southern california
March 23, 2016 5:58 pm
Hi! my wife and I just got a new puppy, and as we were taking him out to the restroom he saw the attached bugs in our tree. we have noticed them dead on our front porch and crawling on our fence as well. Theres ~100 in the tree. We just need it identified to see if its poisonous and how to rid them of our yard so our pup doesn’t have the opportunity to eat them! Its spring, in southern california, been hot the past week.
While we do have Centipedes in southern California, your images depict Mourning Cloak Caterpillars, and though they may deliver a slight sting if carelessly handled, they are harmless. There is no need to eradicate them from your tree. They may climb to the eaves of your home in groups to form chrysalides. Mourning Cloak Caterpillars will eventually metamorphose into lovely adult Mourning Cloak butterflies. Some years, when conditions are favorable, the Mourning Cloak Caterpillars can be quite numerous. Their local native host is willow, but they have adapted to feeding on the leaves of Chinese elm in California.
Letter 8 – Mourning Cloak Caterpillar
Subject: catepillar, bug, and spider
Location: Shore of Hells Canyon Reservoir, Oregon side
May 18, 2016 8:32 am
My son took these photos of some interesting invertebrates in our campsite. The vegetation is blackberry, rose, and common hackberry for trees.
We would love to know what species these are or any information you could give us.
Signature: Barbara Webb
This is a wonderful image of a Mourning Cloak Caterpillar, and we will be posting it to our site to help our readership identify them in future encounters. Your other insects are an immature Katydid and an Orbweaver spider.
Letter 9 – Mourning Cloak Caterpillar
Subject: ? Butterfly Larva
Location: southeast Michigan in June
June 17, 2017 6:06 pm
I am a hopeless butterfly enthusiast who came across this interesting caterpillar crawling along the
paved trail in our state park. I am familiar with the common butterflies found in our area, but my
research provided no matches for this larva. It was clearly in the wandering stage, seeking out a place to pupate. I hope you will be able to solve my little mystery. I would love to know to which
species it belongs! Many thanks in advance.
Signature: Kathy Genaw
Our Automated Reply: Thank you for submitting your identification request. Please understand that we have a very small staff that does this as a labor of love. We cannot answer all submissions (not by a long shot). But we’ll do the best we can!
In the interest of not wasting your valuable time, I want to let you know that I
was able to identify my butterfly larva. It is a Mourning Cloak caterpillar!
Thank you for the great work you do!
We are thrilled to post your image of a Mourning Cloak Caterpillar. Theyy do wander in search of a suitable site to undergo metamorphosis, and we have several images in our archive of Mourning Cloak chrysalides under the eaves of homes.