Found in many parts of America in later summer and fall.
The Saddleback Caterpillar Acharia (formerly Sibine) stimulea, is easier to recognise than the adult moth. This is unusual, and probably explained best by the fact that it is diurnal (active by day) and therefore easily seen by predators. The normal solution here is to be camouflaged, but in this case the caterpillar can sting and evolution has equipped it with a conspicuous warning! (In contrast the adult is nocturnal and well camouflaged.)
Eyespots
Many adult butterflies carry ‘eyespots’ on their wings. They fly by day and it is thought that the sudden ‘flash’ of a pair of ‘eyes’ unsettles predators. See the ‘Fish and Insects’ blog - eyespots. Adult moths (which normally fly by night) have no need for this sort of deception, and their caterpillars – if they are poisonous – usually carry the universal yellow/black warning markings. The Saddleback Caterpillar has evolved unique markings which work by giving potential predators a glimpse of a single large ‘eye’ and the further confusion of two ‘heads’. Any predator that goes on to eat a saddleback will be badly stung and probably ‘remember’ the distinctive pattern. (This will not help the individual that was eaten of course, but it will benefit the species.)
Nasty Sting
The caterpillars have stinging hairs all over their body, especially on the ‘horns’ that poke out at either end. These hairs can inject a venom from poison sacs carried at their base, and the very painful sting can cause humans problems for days.
Two Heads
The ‘double-ended’ look of the saddleback caterpillar has two uses. First there is probably an element of ‘confusion’ – the predator is left wondering which end to attack – and second there is the fact that any attack is likely to encounter the stinging hairs. The fleshy ‘horn’ might well be damaged, but it is not essential for life. The nasty sting is likely to discourage the would-be predator, and the experience might affect future behaviour.
Food Plants and Disrtibution
The Saddleback Caterpillar is found across much of Eastern North America. It is a solitary feeder and will feed on many trees and shrubs. It often lurks in the shade under leaves, and its striking pattern can make it irresistible for children. They should be warned not to touch it because the sting is as bad as that of a bee and the swelling, sick feeling and rash can last a long time.
There is at least one record of this caterpillar crossing the Atlantic – probably on imported plants – and stinging a French toddler . This is just one example of the way humans can affect the distribution of animals – other ways can be found here.
The copyright of the article Saddleback or Packsaddle Caterpillar in Other Insects is owned by John Blatchford. Permission to republish Saddleback or Packsaddle Caterpillar in print or online must be granted by the author in writing.
I brushed through one of my bushes, ironically called a burning bush, and
was suddenly screaming and cursing. The most excruciating bug delivered
ouch I've ever experienced. At first I thought it was the bush that did it
and was prepared to cut it down until my son found these vulgar creatures.
Now, I'm on a seek and destroy mission throughout my entire yard.
Aug 22, 2008 9:35 PM
Guest :
Can someone tell me if the saddleback caterpilar can be found in a moving
vehicle. Does the sting cause a reaction and swell the entire arm from the
wrist to the elbow with scabs forming over it looking like something from
outer space.
Aug 24, 2008 4:06 AM
Guest :
my neighbors found one of thses in the cornfeils behind their house abd
brought it home and showed me. i think they look like tiny pieices of art.
i didn't know they were poisonous until i looked the up on the web.
Aug 24, 2008 9:29 AM
Guest :
I was just stung by one of these guys on my finger. It hurts like a wasp
sting. It was attached to our side door and I merely brushed up against it
very lightly. It is still attached to the door. I used tape to pull out
the "stingers" and that has helped. I have sprayed it with wasp
killer foam. All I had. We have an Oak tree in this part of our yard. I
hope we don't find more. Ouch it really hurts
Aug 28, 2008 2:53 PM
Guest :
yea, I just accidently found one just by walking passed my tree (weeping
cherry tree )in the yard when it stung me as I brushed up againsted
it...it's not a plesent feeling..it does feel like a bee sting.
Aug 29, 2008 5:06 AM
Guest :
I latched onto one of these lastnight trying to pull of a dead looking
leaf. I thought I caught fire. The redness and swelling was enough so I
couldn't bend my fingers. It made my arm ache horribly clear up through my
elbow. As it spread I became alarmed and went to emergency carrying the
demon in a jar. They had never seen nor heard of such a thing. Today, the
swelling is gone, the fire is gone, but all my extremities are prickling.
It must get into your blood stream. Between yellow jacket holes, stink
horn, and a terrible attack to my face by a number of hornets, I'm ready to
burn down my yard. I'm becoming afraid of it. I took close up detailed
pictures of the intersting little slug if anyone is interested.
gramawphyl@juno.com
Aug 31, 2008 7:37 PM
Guest :
When I was rideing my lawnmower I scraped up the side of a snowball bush. I
did not relize that it was on there until I swung my arm back and fellt bad
sting. I took off to the house and cleaned the sting and brought the little
demon inside and set it on my sink and looked up to see if it was posuines.
when I founded out it was not deadly or swallon I took it back outside and
let it go
Sep 1, 2008 12:23 PM
Guest :
I just got stung! Wow it hurts. I was going to remove a dying caladium
leaf when I saw this cute colorful critter on my hand. Thought I would
walk over to show it to my husband when I felt the stinging and couldn't
get it off my hand fast enough. It feels like a spreading bee sting. The
stinging has spread to 3 of my fingers and I have chills! Don't think it
is so cute anymore!
Sep 1, 2008 12:25 PM
Guest :
Sep 2, 2008 1:47 PM
Guest :
My sisters found one of these and came to show me. And I accidentally
knocked over the container they had it in, so now the little beast is loose
in my house... -_-"
Sep 3, 2008 9:22 AM
Guest :
I found a Saddleback Caterpillar when I was picking some ripe tomatoes
(Long Island, New York). The bugger was sitting right on the Beefy tomato.
I glad I did not get stung. Very cool looking. Isn't nature wonderful.
Sep 3, 2008 9:25 AM
Guest :
I found a Saddleback Caterpillar when I was picking some ripe tomatoes
(Long Island, New York). The bugger was sitting right on the Beefy tomato.
I glad I did not get stung. Very cool looking. Isn't nature wonderful.
Sep 3, 2008 7:27 PM
Guest :
I went to go to work and put my key on my car while i put the kids in it
was still dark out and i was in a hurry. I went to grab my key s off the
car and i did not see the little demon on my car I must of laid my arm on
it when i got my key and stung me I was not sure what happen i got in my
car and started it and my whole arm was stinging So i got out and saw
somthing little and green on my car so I turn the flash light on that was
on my phone and saw it was a caterpiller I never know they could sting and
just thought it waqs all in my head. I then took my kids to my moms and by
the time i got there my arm was all swollen thats when my dad told me they
can sting.
Sep 7, 2008 3:12 PM
Guest :
I was just stung by one today
Sep 8, 2008 4:19 AM
Guest :
Yesterday I was pruning my blueberry bushes and brushed one with the back
of my thumb. Yikes that hurt! When I saw the culprit (actually there were
about ten)I thought my son's Pokemon had come to life (I might have been
delerious with pain). What an interesting little creature.
Sep 8, 2008 4:55 PM
Guest :
I was trimming my roses last eveing and thought I had hit a thorn. I
felt like my hand was on fire. I thought I had been stung by a wasp. After
applying a baking soda mix to the stings, I went to the rose bush and found
4 sadllebacks lined up on a single leaf. Didn't have a clue what they were,
but it was the worst pain I have felt for a long time
Sep 9, 2008 8:47 AM
Guest :
"Ouch" never saw anything like this. I found it on a hibacous
bush after it stung me. My hand is tingling now! After reading the website
I feel much safer. I put an ice pack on it!
Buttercup
Sep 17, 2008 12:11 PM
Guest :
YO i just found dat in my yard it was beautiful
Sep 17, 2008 6:27 PM
Guest :
We decided to catch these critters for my son to take to school to show his
class. That evening my daughter (3) decided to touch it...she screamed for
about an hour! I have never seen one before.
Sep 17, 2008 6:31 PM
Guest :
I was in the outhouse trying to do some business when I thought my insides
fell out and the devil himself set me on fire. One of those darn devils
crawled up near my tank...I ain't never ran so fast! Jumped in my car and
raced to the doctor-he found three of those bad boys lingering around. Watch out now...they might be pretty but they hurt like hell.
Sep 22, 2008 8:18 AM
Guest :
I was removing a Maple sapling from my garden and one of these was on it.
Fortunately, I just barely brushed it but it still got me. It burned like
a son of a gun. I immediately washed the area and poured alcohol on it.
It finally stopped stinging about fifteen minutes later. I now have a
small red line on my hand.
Sep 24, 2008 10:11 AM
Guest :
Yep...these things really hurt. I brushed up against it in the yard and
couldn't figure out what did it. It's a cross between a fire ant sting and
a bee sting. Using ice really helped but my whole finger hurts.
Oct 1, 2008 3:26 PM
Guest :
I am still stinging! I was pulling up some flowers and it stung me. I
couldn't find what it was and finally found this little critter and decided
to look it up on the internet. It hurts horribly. My whole arm is already
sore. I hope this doesn't last too long!
Oct 11, 2008 1:35 PM
Guest :
While pulling some weeds from around a "red tip patina" I
developed a burning sensation on both hands. Looking into the bush
(carefully) I found what I assumed to be the culprits - there were two! I
put my hands in water and applied a generous amount of meat tenderizer on
the burning areas. The pain subsided in about 15 minutes. I then went on
line and found this web site describing the saddlebacks that "got
me". SC
Oct 11, 2008 3:57 PM
Guest :
I was stung by one of these while moving my houseplants indoors. It is the
worst sting I have ever had. It is much worse than a bee or wasp sting. I
had a rash on my arm for over a week.
Oct 20, 2008 4:29 PM
Guest :
October 2008...We were hunting for geocaches in the woods of Kentucky and
my 11 year old son pushed a branch back and when he let go the branch
brushed him and on the mouth and he said"ow" I think something
pocked me. My husband looked at the leaf closer and found the saddleback
caterpillar there. My son's mouth started to swell and really hurt him.
We went to a bath room and rinsed off his mouth/lip which was now
quivering. He said it felt like a needle was shoved through his lip. It
took about 4 hours for the swelling to go down.
Dec 23, 2008 5:53 AM
Guest :
My 4 year old son had a run in w/ the saddleback ... his hand brushed up
against one eating from a rose bush. Needless to say my son won't go near
the bush again. We live in Myakka City Florida & have been florida
residents all our lives & never have seen this type of caterpillar.
Feb 21, 2009 6:17 PM
Guest :
Hey there's no point in killing those bugs. The poor creatures won't kill
you and they'll eventually become butterflies. We all need to be careful
when gardening or handling plants!
Feb 24, 2009 7:36 PM
Guest :
We were outside in our yard in Sept. of 2007. When we ran across this
creature. We took a picture until we could figure out later what kind of
bug it was. Then after having the picture lay around our house for over a
year our (7 year old) daughter brought a library book home from school. Out
of curiousity we looked in it and found the Saddleback caterpillar. We
looked on the web for more info. and found an article stating that it is
found across much of Eastern North America. We live in French Creek West
Virginia and was wondering if anyone could tell us in about what areas are
they not found in or could they be located anywhere across the United
States. Another reason is because in our daughters library book it states
this particular caterpillar is also either called or in the category of the
tropical Limacodid moth. Could someone give me an explaination on this. It
would be really appreciated. I myself or noone in our family has ever been
stung and after reading about them being able to sting we will remove any
we do find. When we found the first one in our yard on a leaf it was
touched but noone had gotten stung. I will be waiting on a response to
these questions that I have.
Jun 20, 2009 6:40 AM
Guest :
Goodness!! I have never heard of or seen one of these before. My 2 yr old
son was playing in the yard at his grandparents house (we just had some
storms and a lot of leaves and a few branches are in the yard)and all of
the sudden he started screaming and crying. He had gotten stung by one!!!
His foot is swelled and hes having to limp a little but is fine. Just be
careful after storms!
Jun 27, 2009 9:40 AM
Guest :
I just found one of these in front of my apartment here in New Orleans, LA.
It munched on African Iris for days, and now it is gone. What a beautiful
and haunting creature!
Jul 30, 2009 7:51 AM
Guest :
Ours seem to be partial to iris leaves. It is a memorable sting.... I've
gardened the same lot for 30 years and last year was the first time I'd
seen one/ met one up close and personal. This year when I brushed past
one, I knew the sting and also knew not to panic. They are beautiful!
Aug 15, 2009 6:55 PM
Guest :
Never thought I'd be looking up this odd, but really pretty, sort of, slug
of a stinging caterpillar. I was wondering what was eating my
vibernum--found it at the end of leaf, with a stinging finger. I'm used to
wasp stings, and it didn't look like a nasty spider, so I just went on to
study it. It didn't seem to mind me taking photos of it--like any other
slug, it doesn't just drop what it's doing, and figures I wasn't out to eat
it. Used to slugs, which I have no problem stamping out it's life, but I
gave this critter far more than my share of interest. Like a slug, it
wraps its yucky bod around the end of a leaf, swelling up and looking like
it's gonna puke. That's because it's eating it, to the last morsal. Then,
it pooped!!! on my unworn flipflop--like, what goes in its mouth is
immediately digested, goes through its digestive track (I guess it has a
digestive track), and then poops. After I took 100 or so photos of it, and
I decided it was just too pretty to stamp out its stinging life, I put it
down, far away from my condo's garden container garden. Very cooperative
study model, and I have the pics to prove it. The sting, BTW, is nowhere
as bad as a wasp's--a wasp's sting is the worst of stings, and lasts for
hours. This critter's sting was uncomfortable, but I have plenty of
hydrocortisone 1% if I thought I needed to self-treat, and it didn't get to
that level of agony. Far more interesting studying it then crying about
how it protects itself. No wonder birds don't like this garden--better and
safer feeds elsewhere; but I do get my share of pretty swallowtails and
monarchs, and moths.
Aug 24, 2009 9:21 AM
Guest :
Yep, well I had always heard that colorful creatures in nature were
something to stay away from....now I know why. I just slightly brushed up
against one when the little !**?$"" NAILED ME! Yes they do hurt
a little!!
Aug 30, 2009 4:17 PM
Guest :
Never saw it.... was picking blackeyed peas in our garden this evening and
suddenly felt a severe sting on the fleshy side of my thumb and palm.
Worse than a wasp sting. Immediately saw the caterpillar and looked it up
on the web. Took packing tape and pulled the barbs out, hopefully, used
soda and water, then Benadryl topically. Is feeling better, but still
stinging and red. Ouchy little buggers!
Aug 31, 2009 2:46 PM
Guest :
I got stung several times by 2 of these beasties while picking lima beans
in our vegetable garden in Winchester TN. I finally found the first one
under a leaf & carefully removed the leaf with beastie to show my
husband. Little did I suspect that there was another one waiting. It got
me too! I picked the rest of the limas wearing rubber gloves. The stings
hurt for awhile, but I did not get any visible skin reaction, but other
folks might be more sensitive to the venom.
Aug 31, 2009 5:50 PM
Guest :
Finding this strange and venomous and beautiful creature will change how I
dress and glove up for yardwork from now on......
Sep 1, 2009 4:44 PM
Guest :
I found one of these saddle back caterpilars in my flowering plum tree and
went to flick it off with my finger and another one hiding hit my hand and
the pain was as bad as a bee sting. It worried me because I am allergic to
bees. Washed it real good and put cortisone cream on it and the pain went
away in about 30 minutes. Never have seen these before and hope I don't
run into them again.
Sep 7, 2009 12:31 PM
Guest :
I was cutting down a small tree in our back yard and felt a slight sting.
I carried the tree to the house to cut up and place in the garbage can when
I felt a serious sting. I saw the caterpillar, and sprayed the inside of
the can with wasp and hornet spray. It killed the caterpillar. I took it
to Home Depot and the cashier stated that they recieved a shipmeny of crab
apple trees that was infested with them and had to destroy the trees. A
lady customer was stung by one.
Sep 8, 2009 11:24 AM
Guest :
My grandson had his first anaphylactic reaction to a wasp sting this
summer. Sunday he was at his aunt's playing and simply ran by a tree with
one of these little suckers on a leaf. At first we did not know why he was
screaming then we found the catapiller. By then he was breaking out in
whelps and starting to have problems breathing. Luckily we had his EpiPen
at hand. Never expected to react to a catapiller, especially such a pretty
one.
Sep 15, 2009 11:07 AM
Guest :
I went outside to get some limbs from my weeping willow tree to make new
starts when i was stung by something when i came inside i found 2
saddleback catepillars one small and one large on my willow branch,my kids
thought it was very fascinating and started taking photos ,not untill i got
online did i know they were poisonious,I still have whelps that sting and
itch but what does this mean for my tree?
Nov 5, 2009 5:16 AM
Guest :
I got stung by one of these bad boys last year but didn't know what had
caused me the agony until several days later when I showed my co-worker the
"stingers" (there were at least 20 of them)still in my arm. He
knew right away what they were from and told me about the saddleback
caterpillar. I thought for sure he was pulling my leg until I came home and
did some research online.
I had no idea there were such things
as venomous caterpillars. Unfortunately for me, I was unable to get the
stingers out using the tape method and other various methods I found
online. Mainly because I had continued to work (Landscaping) with these
things in the crook of my arm for days on end, embedding them further into
my skin. Although I did wash the area frequently and poured peroxide over
the wounded area several times daily, the burning, tingling, numbing and
slight muscle spasms never seemed to let up. In fact, sometimes the entire
left side of my body would ache and tingle and burn and contract, etc.
It also sometimes gave me chest pain to the point that I thought I
might be having a heart attack and thought about calling an ambulance
several times. However, I never did call the ambulance or go to the
hospital and continued my online research in fascination. I found out that
since the stingers were still in my arm, the venom was still being pumped
into my body and carried throughout my blood stream. It took me a full 2
weeks to finally completely remove ALL the stingers in my arm and I had to
literally dig them out with a needle and tweezers.
It was at
least a full 2 months before I completely recovered from the incident. The
pain, nausea and cramping, burning, tingling and numbing weren't constant
but they were persistent. I felt them daily for at least 2 months, but not
24/7. It would come and go. I'd be driving down the road on my way to a
clients house feeling just fine and then all of the sudden my left arm
would start tingling and burning and cramping, etc. Sometimes I would get
hot and dizzy and nauseous for a few seconds to a few minutes and sometimes
the burning would last anywhere from a few minutes to a few hours.
This wasn't just happening in my arm either, it was rather like a
jolt of electricity shooting through the entire left side of my body right
down to the foot, through my arm, neck, chest, etc. It was the weirdest
thing I ever experienced from an encounter with an insect, to say the
least.
But in the end, I still respect the beautiful insect.
Jun 20, 2007
