Ailanthus Webworm Moths: Beneficial Insects and Garden Gate Icons

Summary: Ailanthus webworm moths, beneficial insects by March and Garden Gate icons in October, control the tree of heaven and pollinate wildflowers and woodies.

Ailanthus webworm moth (Atteva aurea) with giant ironweed (Vernonia gigantea) flowers, near Cincinnati, Ohio: Greg Hume, CC BY SA 4.0, via Wikimedia Commons

Ailanthus webworm moths are beneficial insects of planned and wild ailanthus webworm moth gardens in Canada, Mexico and the United States, and Garden Gate icons in the magazine’s issue for October 2015.

Ailanthus webworm moths, beetle-like at rest and wasp-like in flight, benefit North American landscapes, March through October or November, by pollinating flowers while sipping tree nectars. Their larval, second stage as caterpillars contributes to healthy ecosystems by consuming edible bark, flowers, foliage, fruits and seeds on the tree of heaven (Ailanthus altissima). Reliance of all four stages in the lepidopteran’s life cycle and natural history upon the invasive, non-native tree of heaven dates only to the mid-19th century.

Globally warmed climate change and tree of heaven naturalizations extend ailanthus webworm moth ranges ever eastward and northward of an imaginary line from the Rocky Mountains.

The thorny bushes Castela emoryi, Castela peninsularis and Castela polyandra function as native woody food- and shelter-friendly hosts in planned and wild ailanthus webworm moth gardens. The paradise trees Simarouba aurea of Costa Rica and Simarouba glauca of Mexico get similar responsibilities as food- and shelter-hosting woodies in native southern habitat niches. The six natives have air-cleansing, soil-holding, wildlife-sustaining niches in dry forests and semi-arid deserts while tree of heaven does likewise in whatever American ecosystem it invades.

The lepidopteran’s scientific classification is from Asa Fitch, entomologist and natural historian of Salem, New York, in 1856, year of ailanthus webworm moth appearances in Georgia. Tree of heaven expansions southward from introduction into Philadelphia, Pennsylvania, in 1784 to Texas by 1856 jumpstart ailanthus webworm moths migrating northward from the forty-eighth state.

New World native Ailanthus webworm moths have become closely associated with Ailanthus altissima, known commonly as tree of heaven, an Old World native that has been extensively introduced and naturalized in the Americas: H. Zell, CC BY SA 3.0, via Wikimedia Commons

Sustainability in disturbed, polluted, stressed environments keeps tree of heaven available for in-store and on-line purchase and present in planned and wild ailanthus webworm moth gardens. Every four weeks at dusk, from as early as March to as late as August, adult females lay white eggs from that day’s dawn mating sessions.

The caterpillars manage communal lifestyles by spinning silken webs over host leaf surfaces to sustain that year’s spring through summer series of eggs, larvae and pupae. Master gardener and master naturalist wildlife mappers note basic black or brown body colors for all larval instars, except for very light brown first, newborn instars.

All instars otherwise offer a light green-brown, wide line along the uppermost side, thin olive and white stripes along each side, and white bristles and dots.

Ailanthus webworm moth pupae position themselves into apostrophe or comma shapes whose black or brown colors depend upon whether respective ambient temperatures are falling or rising.

Final, flying stages quit looking moth-like when at rest since ailanthus webworm moths hold their fore- and hind-wings tightly in, alongside the body except in flight. Black-and-white-headed, black-and-white-legged, black-bodied, day-active adults reveal one pair of heavy-weight, orange forewings, each decorated with eight black-encased white dots, and one set of light-weight brown hindwings. They sip nectar from hostplants and from bee-brush (Eysenhardtia texana), black-root (Veronicastrum virginicum), frost-weed (Verbesina virginica), goldenrod (Solidago), inkberry (Phytolacca americana) and shrubby boneset (Ageratina havanensis).

Ailanthus webworm moths, as beneficial insects and Garden Gate icons in planned and wild ailanthus webworm moth gardens, turn rules about moths as night-active pests upside-down.

Crucifixion thorn (Castela emoryi) is a food- and shelter-friendly shrub for Ailanthus webworm moths; crucifixion thorn shrub southwest of Arlington, Maricopa County, south central Arizona: Mike, CC BY SA 4.0, via Wikimedia Commons

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

Ailanthus webworm moth (Atteva aurea) with giant ironweed (Vernonia gigantea) flowers, near Cincinnati, Ohio: Greg Hume, CC BY SA 4.0, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Atteva_aurea_25.jpg

Ailanthus altissima, known commonly as tree of heaven, Baden-Württemberg state, southwestern Germany: H. Zell, CC BY SA 3.0, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Ailanthus_altissima_001.JPG

crucifixion thorn tree (Castela emoryi), southwest of Arlington, Maricopa County, Arizona: Mike, CC BY SA 4.0, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Castela_emoryi.jpg

For further information:

“075100 – 2401 – Atteva aurea – Ailanthus Webworm Moth – (Fitch, 1856).” North American Moth Photographers Group at the Mississippi Entomological Museum at Mississippi State University.
Available @ http://mothphotographersgroup.msstate.edu/species.php?hodges=2401

“Atteva aurea: Ailanthus Webworm Moth.” Encyclopedia of Life.
Available @ http://www.eol.org/pages/952311/overview

Barnes, Jeffrey K. 2 June 2005. “Ailanthus Webworm Moth.” University of Arkansas > Division of Agriculture > Department of Entomology > Arthropod Museum > Arthropod Museum Notes Number 35.
Available @ http://www.uark.edu/ua/arthmuse/ailamoth.html

Becker, Vitor O. September 2009. “A Review of the New World Atteva Walker Moths (Yponomeutidae, Attevinae).” Revista Brasileira de Entomologia 53(3): 349-355.
Available @ http://www.scielo.br/pdf/rbent/v53n3/07.pdf

Wilson, John; Landry, Jean-François; Janzen, Daniel; Hallwachs, Winnie; Nazari, Vazrick; Hajibabaei, Mehrdad; and Hebert, Paul. 17 May 2010. “Identity of the Ailanthus Webworm Moth (Lepidoptera, Yponomeutidae), a Complex of Two Species: Evidence from DNA Barcoding, Morphology and Ecology.” ZooKeys Volume 46, pp. 41-60. Dx.doi.org/10.3897/zookeys.46.406
Available via Pensoft @ http://zookeys.pensoft.net/articles.php?id=2199