Tuesday, August 23, 2011

Look Alike

Things always seem to slow down in the garden in August. It's so very very hot, with rain nearly every day, and we don't always seem to get out to see what's going on like we do in the cooler months. There's still plenty of activity, though, as we found when we turned over the oleander leaves and discovered some new caterpillars the other day.


Polka dots! We knew pretty quickly what these caterpillars were likely to be. Last year, we posted about the Spotted Oleander Moth (Empyreuma affinis), a Caribbean species that has been moving its range steadily north for the last 30 years or so. It feeds, as should be extremely obvious, on oleander (Nerium oleander).

The Spotted Oleander Moth is similar in appearance to the Common Oleander Moth, also called the Polka-Dotted Wasp Moth (Syntomeida epilais), both as adult moth and and as a caterpillar. The common oleander caterpillar is familiar to anyone who has oleander in their yards, as a bright orange caterpillar with black spiky hairs (click here to see a picture). The Spotted Oleander Moth caterpillar is also orange, but with white spots and mostly white hairs, with longer black hairs at the front and back.


All parts of the oleander plant are very toxic, so it seems likely that any caterpillars that feed on it would be toxic as well. The bright coloring of the spotted oleander caterpillar is a good indicator of that danger - it's a form of defense called "aposematism". These bright colors basically indicate to possible predators that the organism in question is likely to make them sick if eaten. The hairs of this caterpillar, or setae, are harmless to humans, but likely very irritating to anything trying to ingest it.


The common oleander caterpillar is a known pest on oleander plants, but the spotted oleander caterpillar shown here is not considered to be as destructive as they are not as gregarious. We found only three altogether on our oleander plants, so that seems true. 

Not that it matters to us. Since our yard is designed to attract wildlife, we rarely consider any new creatures to be pests in My Florida Backyard. This recent find was a good reminder that summer heat doesn't keep wildlife from visiting the garden, and it shouldn't keep us from visiting either!

6 comments:

  1. What an interesting post. I don't have any oleanders so do not have these critters visiting my gardens.

    The rain sure has been nice, but the heat and humidity keep me pretty much indoors. I really need to get out to take care of some things, but just do not feel like it.

    So glad that Irene is predicted further east of us.

    Have a great day ~ FlowerLady

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  2. I just spotted one of these covered in dew on an oleander plant on my morning walk in Bradenton, FL. I had never seen one before but it was so cute I HAD to photograph it and will be posting the pics on my blog. I will link to your post so that others can find out more information about these! Thank you for posting so I could identify this little cute critter! :)

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  3. I have one inside my screen between my window. It's made itself like a "woven" hammock to keep itself up in the top corner of the window. Every now and then it wiggles, (looks more like it's squeezing or scrunching), but if it's cocooning and I don't know if they do that, it's been at it for 3 days and there's barely any "silk" around it. Now I live in Melbourne and as far as I know we don't have any Orelander in our yard. I don't know what it's doing just chilling out in the corner of my window, lol, so if anyone knows, please, let me know.

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  4. I have one inside my screen between my window. It's made itself like a "woven" hammock to keep itself up in the top corner of the window. Every now and then it wiggles, (looks more like it's squeezing or scrunching), but if it's cocooning and I don't know if they do that, it's been at it for 3 days and there's barely any "silk" around it. Now I live in Melbourne and as far as I know we don't have any Orelander in our yard. I don't know what it's doing just chilling out in the corner of my window, lol, so if anyone knows, please, let me know.

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  5. We just picked this little guy up in the greater Orlando area. I am super excited for my 5 year old to see this process. Thanks for your blog, the caterpillar identification site didn't show this result, and it's definitely what we have. It wasn't on a plant, so we didn't know what it eats, and now we can go get it some food!

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