Atteva aurea (Ailanthus Webworm Moth)
Species Overview
Scientific name: Atteva aurea
Common name: Ailanthus Webworm Moth
Family: Attevidae
Native range: Originally native to southern Florida, the Caribbean, and Central/South America, where it feeds on native Simarouba species (Paradise Tree).
Expanded range: Now found across much of North America, including the Chicago region, largely due to its adoption of Tree-of-heaven (Ailanthus altissima) — a non-native, invasive tree introduced from Asia.
Identification: Small day-flying moth (~1–1.5 cm body length) with vivid orange forewings patterned with white spots edged in black; when at rest, wings fold tightly over the body, making it look like a slender beetle.
Ecological Role
In Native Range
Larval role: Herbivore of native Simarouba species; helps regulate foliage density, indirectly influencing canopy light and understory diversity.
Adult role: Nectar feeder and prey species for birds, predatory insects, and spiders.
In Chicago Region
Larval role: Feeds almost exclusively on the invasive Ailanthus altissima (Tree-of-heaven). This can slightly reduce Ailanthus vigor, but it’s not enough to control the invasive population.
Adult role: Opportunistic nectar visitor, but not a significant native pollinator because it doesn’t have a close coevolutionary relationship with local flora.
Food web: Provides food for insectivorous birds, predatory wasps, mantids, spiders, and predatory beetles.
Lifecycle (Chicago Area)
Egg Stage
Eggs laid on leaves or shoots of Ailanthus (or Simarouba in native range).
Hatch in a few days.
Larval Stage
Caterpillars feed gregariously, creating loose silk webbing over leaves and tying them together.
Feeding continues for ~2–3 weeks.
Pupal Stage
Pupation occurs inside the webbed leaves.
Adult Stage
Emerge as small, brightly colored moths.
Active during the day; often seen visiting flowers.
In Chicago, there are likely 2–3 generations between late spring and early fall, depending on temperature.
Host Plants
Larval Host Plants in Chicago
Primary: Ailanthus altissima (Tree-of-heaven) — non-native, invasive.
No known native Illinois plants are used as larval hosts here.
Adult Nectar Sources
Adults feed from a variety of small-flowered species, including native goldenrods (Solidago spp.), asters (Symphyotrichum spp.), and milkweeds (Asclepias spp.), though they don’t require these to complete their life cycle.
Native Plant Support in Chicago
Because A. aurea is tied to an invasive host plant here, there are no native host plants you can grow to directly support its reproduction without also supporting Ailanthus altissima, which is ecologically harmful. For Chicago gardens, conservation planting should focus on native moths and butterflies with native host plant requirements.
If Managing as a Non-Native Species
Since A. aurea’s larval host is an invasive tree, management aligns with Tree-of-heaven removal and predator encouragement.
Predators to Encourage
Insectivorous birds: Chickadees, nuthatches, warblers — supported by planting native trees/shrubs (Quercus, Prunus, Amelanchier).
Predatory wasps: Paper wasps (Polistes spp.), potter wasps — supported by nectar-rich plants like mountain mints (Pycnanthemum), wild bergamot (Monarda fistulosa), and Joe-Pye weed (Eutrochium purpureum).
Spiders: Provide undisturbed vegetation and avoid pesticides.
Predatory beetles: Ground beetles and lady beetles benefit from diverse plantings and leaf litter habitat.
Chicago Conservation Takeaway
Don’t plant or encourage Tree-of-heaven — it’s invasive and also a key host for the destructive Spotted Lanternfly (Lycorma delicatula).
If Ailanthus is present, removing it reduces both the moth’s breeding habitat and the spread of the invasive tree.
Plant diverse native species to support native Lepidoptera and their predators, rather than A. aurea.
