Number 35 • June 2, 2005 • Jeffrey K. Barnes

Ailanthus webworm moth
Order: Lepidoptera
Family: Yponomeutidae
Genus and sepcies: Atteva punctella (Cramer)

Ailanthus webworm moth Ailanthus webworm moth

In their native habitats of Central and South America, Ailanthus webworm caterpillars build communal webs in native trees of the family Simaroubaceae. The species has spread north through much of the United States, where its caterpillars utilize primarily an introduced simaroub, Tree of Heaven, Ailanthus altissima. Tree of Heaven is native to North China. It was planted extensively in Europe in the 1700s and soon made its way to North America, where it is now naturalized along fences, roads, and in waste places.

Ailanthus webwormThe colorful adult Ailanthus webworm moths are pollinators, often seen visiting flowers of many different species during daytime. They mate at dawn and lay eggs at dusk, primarily on fibrous substrates, such as the larval webbing. Larvae of various ages feed gregariously on leaves, flowers, seeds, and even bark. Cocoons are constructed within the webbing. The species is multivoltine, and it apparently does not diapause. It is unlikely that it overwinters in the northern part of its range. Rather, it migrates north across the United States to southern Canada each year.