Subject: 8-10 LARGE caterpillars on Crepe Myrtle tree in Central Florida
Location: Central Florida, USA
September 14, 2013 1:31 pm
Hello! Love your website (and bugs!!). Help please???
I have 8-10 fairly large caterpillars, about 4-6 inches long, BRIGHT yellow green with a dark red & white band on both sides & numerous spiny tufts on the dorsal & both sides. They are an impressive group, and currently feasting on the leaves & branches of an immature Crepe Myrtle tree. This is the 3rd day I have seen them.
I am in NE Orlando, in Central Florida. My house is adjacent to 2 lakes & a 10 acre wooded semi-marshy conservation area. I am new to this house, and have NEVER seen these before, although I have lived in Central Florida for 25+ years. These gorgeous guys have stripped most of the new & younger leaves from my Crepe Myrtle. Haven’t touched the flowers or the seeds or woody parts so far. They appear to have a stinging aspect, so I haven’t touched yet.
What are they, please?? Keying them out has proved difficult for me, and I appreciate your help and expertise. Are they moth or butterfly? Can I raise them??
Thank you VERY MUCH for any help!
Signature: Pat O

Io Moth Caterpillar

Io Moth Caterpillar

Dear Pat,
You have a healthy brood of Io Moth Caterpillars,
Automeris io, and they will metamorphose into lovely Giant Silkmoths with pronounced eyespots on the underwings.  Adult Io Moths exhibit sexual dimorphism.  The larger female Io Moths have brown upper wings while the male Io Moths have bright yellow upper wings.  You are correct that the caterpillars are capable of stinging.  We believe your estimate of 4-6 inches in length is a bit exaggerated, and we would put the mature caterpillars maximum length closer to 3 1/2 inches.  We are especially amused by the ruler in your photo which has the number side away from the camera.  You can raise Io Moth Caterpillars to maturity with little effort.  We would urge you to keep both the caterpillars and pupae outdoors, or at least in an area where they are the same temperature as the outdoors.  You do not want them to emerge early in a heated environment.  Adult Io Moths do not eat and they only live a few days, long enough to mate and reproduce.

Io Moth Caterpillar

Io Moth Caterpillar

Subject: 8-10 big green caterpillars in C Florida IDENTIFIED, i think!
September 14, 2013 2:48 pm
Just an update to my prior question concerning  the large bright green caterpillars I found on my Crape Myrtle tree.
I think I have identified them!  Using tips from other readers of your site, I backtracked the pests of Crape Myrtle  using HOSTS database of the Natural History Museum website (limited success, but a good start). was a good source also. Then went to Discover Life website ID guide.  Found them!! I think my hungry young guests are Automeris io larvae/caterpillars!! And yes, they DO sting……
I appreciate your website, and the opportunity & links to continue to learn.
Pat O

Ed. Note:  We didn’t realize that Pat had identified her Io Moth Caterpillars when we created the posting.


Location: Florida

4 Responses to Io Moth Caterpillars

  1. Danielle says:

    Thank you for this information. I have five on my brand new 6 ft crape myrtle tree. Almost all the leaves are gone now. What can I put them in so my daughter can watch them change?

  2. Sherry says:

    I don’t seem to be getting the answer I need. Will this lo moth caterpillar kill my crepe mertle tree?

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