Adapted to an Invasive Tree

Ailanthus webworm moth, Cape Cod 2018 (photo by Bob Kroeger) The light makes black look blue.

18 August 2021

Here’s a beautiful moth we wouldn’t see if it weren’t for an invasive tree.

The ailanthus webworm moth (Atteva aurea) is a tropical ermine moth that relied on the paradise tree (Simarouba glauca) and Simarouba amara as its larval hosts. In the U.S. this limited the moth’s range to South Florida.

However in 1784 we began importing an Asian member of the Simaroubaceae family, the tree of heaven (Ailanthus altissima), because we thought it was pretty. We sold it as a landscaping tree for over 100 years. It became invasive and spread across the US and into Canada (map by state/province below).

Ailanthus range in North America (EDDMaps)

Ailanthus is also a host for Atteva aurea so the moth spread with the tree, earning it the common name Ailanthus webworm moth. This daytime moth now ranges from Florida to Texas and across eastern North America to Minnesota and Ontario.

It is really very beautiful …

… and tiny.

I’m not surprised I haven’t seen one yet.

But maybe I’ll find its webs on an Ailanthus tree.

Keep a look out for this gorgeous little moth that adapted to an invasive tree.

p.s. The blue color on the moth at top is just a trick of the light but it makes him even more beautiful.

(top photo by Bob Kroeger, remaining photos from Wikimedia Commons; click on the captions to see the originals)

1 thought on “Adapted to an Invasive Tree

  1. I saw one of these about three years ago in the parking lot of Lowe’s at the Waterfront. I had no idea what it was, so took a photo and did a little research. Quite a striking looking insect. Never saw one before or since.

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