Ailanthus webworm

The Ailanthus Webworm (Atteva aurea) is an ermine moth now found commonly in the United States.^[1][2] It was formerly known under the scientific name Atteva punctella (see Taxonomy section). This small, colorful moth resembles a true bug or beetle when not in flight, but when in flight it resembles a wasp.^[3]

Ailanthus webworm
Atteva aurea feeding on Vernonia gigantea
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Lepidoptera
Family:	Attevidae
Genus:	Atteva
Species:	A. aurea
Binomial name
Atteva aurea (Fitch, 1856)
Synonyms
Deiopeia aurea Fitch, 1857 Poeciloptera compta Clemens, 1861 Oeta aurera Stretch, 1873 (misspelling) Oeta compta var. floridana Neumoegen, 1891 Atteva edithella Busck, 1908 Atteva exquisita Busck, 1912 Atteva ergatica Walsingham, 1914 Atteva microsticta Walsingham, 1914

Host plants

The ailanthus webworm is hypothesized to be native to South Florida and through the American tropics (as far South as Costa Rica), which contains their original larval host plants: Paradise Tree (Simarouba glauca) and Simarouba amara.^[4]

The Tree-of-Heaven (Ailanthus altissima), originally from China, has expanded across the United States, and is widely considered an invasive species.^[5] A. aurea is thought to have adapted to feed on and breed in A. altissima, which is in the same family (Simaroubaceae), which resulted in the expansion further North in the United States.^[6] This expansion of its range is what resulted in its common name.

Ailanthus webworm in Ailanthus altissima tree

Climate

This tropical moth is commonly seen in summer throughout the continental US, and occasionally eastern Canada (its northern limit is eastern Ontario and south-western Quebec beyond the host range). This species appears to be either adapting to colder areas, or staying further north due to changing climates.^[7]

Life cycle

Larvae produce nests on the host plant by pulling two or more leaflets around a network of loose webbing. Then they consume the leaflets and bark. The caterpillars have a wide, light greenish-brown stripe down their backs and several thin, alternating white and olive-green stripes along their sides. The range of colors is from light brown to dark black. The adult moth visits flowers, is diurnal, and is a pollinator. The life cycle from egg to egg can happen in four weeks. Due to this being a species from warmer areas, it lacks a diapause stage. Larvae can be found from mid-spring to a hard freeze. There may be many generations each summer with eggs being laid on the webs of other larvae. This can result in a communal web that has multiple generations - from eggs to various larva stages to pupae. Mating happens in the mornings with egg-laying apparently happening in the evening. Eggs are found individually, not in clusters, even though each web may contain many separate eggs.^[8]

Taxonomy

• 
  Atteva edithella, now considered a synonym of Atteva aurea
• 
  Atteva exquisita, now considered a synonym of Atteva aurea
• 
  Atteva ergatica, now considered a synonym of Atteva aurea
• 
  Atteva microsticta, now considered a synonym of Atteva aurea

Wilson et al. (2010) discovered that morphologically similar Attevid moths were assigned two different names, Atteva ergatica in Costa Rica and Atteva punctella in North America, but had identical DNA barcodes.^{[9][10][11][12][13][14]}