A Beautiful Bug with a Not-so-beautiful Namesake

What’s in a name? That which we call a rose by any other name would smell as sweet.

~William Shakespeare

Ailanthus Webworm Moth on Joe Pye

These beautiful day-flying moths were common in the garden this weekend (click photos to enlarge)

I remember finding this beautiful little moth many years ago when I worked as a naturalist in state parks. When I looked it up in my field guide, I quickly discovered it was a type of Ermine Moth. Most of this group are white with small black spots, much like the winter coat of certain members of the weasel clan. But this one is quite different, looking like it is covered in a flower-patterned shawl. In fact, it is often mistaken for a beetle due to its habit of holding its wings tight against its body. Plus, unlike most moths, it is a daytime visitor to flowering plants. So, for many years, I referred to this as an Ermine Moth.

Ailanthus Webworm Moth on Joe Pye 1

Ailanthus Webworm Moth on Joe Pye Weed

Then, a few years ago, I wanted to use an image of one in a program, and when I looked it up in a newer moth field guide, I found that it has a much less desirable (in my opinion) common name, the Ailanthus Webworm Moth (Atteva aurea). In my early field guide, this moth was native only to south Florida, where its larvae feed on a tree found primarily in Central and South America. But the moth has spread and its larvae switched diets to its new namesake plant, the Tree of Heaven, or Ailanthus altissima. Tree of Heaven is in the same family as the original host plants, but is instead native to northern China. It was introduced to North America in the late 1700’s and has more recently spread across at least thirty states where it is now considered an aggressive pest plant that pushes out many native plants. As the moth adapted to its new host, it was also able to extend its range, and is now found over much of the eastern half of the United States and southern Canada. As the name implies, the larvae feed on Ailanthus leaves in silken webs they spin as a group. Unfortunately, the caterpillars have not proven to be effective in keeping this aggressive tree species in check.

Ailanthus Webworm Moth on Rosinweed

Ailanthus Webworm Moth on Rosinweed

In spite of its unglamorous name and the accompanying negative connotations, I still enjoy seeing this brightly adorned little moth. It can be quite common in late summer and early autumn, especially in fields with masses of goldenrod. The adults feed on nectar and can be seen this time of year slowly crawling along a variety of flowers along with bees, beetles, and a host of other busy pollinators.

 

2 thoughts on “A Beautiful Bug with a Not-so-beautiful Namesake

  1. Thanks so much for today’s blog! I love moths and yesterday on a hike around Apex Community Park Lake (Lake Pine) we found a gorgeous Imperial Moth. I had no camera with me but Bobby did so he got good photos. I just recently found out I have a Tree of Heaven on my farm in west Cary which will need to be destroyed. But before I do I will look for that wonderful little moth you wrote about today!

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