Sunday, October 17, 2010


Laurel Sphinx Moths are found throughout Eastern North America. This one was photographed in August at work. It had been attracted to the mercury vapor light pointed out our flag. The next morning it was hanging from the Russian Sage. These are a modestly beautiful moth, certainly not extravagant in their coloring, or in their size, yet pretty just the same. They are sometimes called the Fawn Sphinx, which I assume comes from their fawn-like coloring. They are yellowish-brown in color, with dark margins on their forewings. There is also a bold white line on their forewings, and the hindwings are tan with a dark border. Their wingspan is up to 4 1/16 inches.


They can be found in woodland, yards and nurseries. They are often found around ornamental lilacs, which explains why I found a caterpillar of one of these moths hanging on my lilac bush. This particular moth was being used as a host to the brachonid wasps. Sphinx moth caterpillars are often chosen by these wasps as a host. Brachonid wasps are parasitoids, the females will use their ovipositor to lay eggs under the skin of the caterpillar. The eggs hatch and feed on the caterpillar from the inside. Once the caterpillar has been almost entirely devoured from within these tiny larvae will bore through the skin of the caterpillar and form capsule-like cocoons on the outside of the caterpillar. These tiny white, oval-shaped cocoons will remain on the caterpillar throughout its final days...within a week the wasps will hatch and shortly thereafter the caterpillar will die. It seems a horrific way to die, but it is a normal process in the life of the wasp and a means of biological control of the sphinx moths. 


The caterpillars of the laurel sphinx feed on lilac, privet, ash, fringe tree, and plants in the olive family. Adults will nectar at honeysuckle, and bouncing bet. They will be seen hovering over the blooms at dusk and late evening.

To say that these wasps are terrible is to say that the moths are good. In the case of these creatures neither is an apt description, they are merely doing what they do best, and that is survive by any means possible. In the case of the moth death is eminent, but the wasps will go on to carry out future generations. For me, as a naturalist and lover of all insects it was a rare and exciting glimpse into their lives.

8 comments:

  1. Had one with a more colorful body and wings on my patio fly in my house. It was huge, released it before the cats found a toy.

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  2. I'm with you on the good-bad dichotomy; i.e., I don't answer that question. but if some of these moths were to build up a huge population that would help control our invasive privet scourge, I'd be delighted!

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  3. Wow, those are some dramatic/pretty antennae!

    I also agree re: "good" "bad." I don't think those words are useful and I very seldom use them re: such things. They are clearly a judgmental statement, and I don't think that promotes learning or understanding. Things just "are."

    Anyhow, will be posting probably 3 pics of inverts tomorrow, 2 I shot in Joshua Tree NP yesterday, one I am afriad I may have imported 'cause I think it flew out of the trunk of my car when I arrived home and opened it.

    One of the inverts is possibly the MOST spectacular, blow your head of GORGEOUS crazy thing I've ever seen. Not the greatest shots 'cause it was flying, but one pretty good one. I'd LOVE it if you could visit and guess. =) xo

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  4. I can't wait to see your post tomorrow and try to identify your mystery insect. I love a challenge.

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  5. Love the parasitoid picture! Those are probably Cotesia coming out of that caterpillar... but that's just a wild guess haha.

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  6. Thanks Chris, I was so excited when I found this little caterpillar all decked out in its cocoon finery. Cotesia huh? I concur. :o)

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  7. i found a caterpiller and i am not sure if it is a luarel sphinx or not, but it has the stripes, and has begun to grow a horn in the back. but when i found it, it was not green, but a pinkish brown color. so, i think it might be dying. please help me figure out how to help it, and nourish it back to health so i can return it to it's natrall habitat. oh and also i live in weastern north america, and it said these caterpillars are found in the eastern part. so i don't really know what to think other that that i want to help it.

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  8. Sarah can you send me a picture of the caterpillar. Sphinx moths can look similar in the caterpillar stage. The fact that it is turning pinkish in color could mean it is just going through another molt. Some caterpillars change color as they grow. As far as telling you what to feed it I would need to see it first to identify it, then we can determine what it feeds on, or if it is getting ready to pupate and will not require any more nutrition.

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