Bug FAQHorned Spanworm Moth
Nematocampa resistaria · Order: Lepidoptera · Family: Geometridae
Also called: Bordered Chequer, Filament Bearer, Horned Spanworm
Source: Wikipedia
The horned spanworm moth has a wingspan of about 2 cm and lives across North America. Its caterpillars feed on a wide range of trees and shrubs, which can harm garden plants and forest trees. Adults fly from spring to late summer, with one to many generations depending on latitude.
Source: Wikipedia
How to recognize it
It is called the horned spanworm moth, also known as the filament bearer or bordered thorn, and belongs to the Geometridae family.
Source: Wikipedia
Size
The wingspan ranges from 19 to 25 mm.
Source: Wikipedia
What it eats
Caterpillars eat leaves of many deciduous and coniferous trees and shrubs, including fir, spruce, willow, birch, hazel, strawberry and carrot.
Source: Wikipedia
Life cycle
Adults are on the wing from May (April in the deep south) through August, with one generation in the north, two in the middle states, and several in the south.
Source: Wikipedia
Lookalikes
It was formerly grouped with the Eurasian species Nematocampa limbata.
Source: Wikipedia
Where it is found in the US
Recorded in 46 of 51 states and DC. Most records: Texas, New York, Vermont, Massachusetts, Pennsylvania, Michigan, Ohio, Wisconsin.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Status: native in North America; native in Canada; native in United States. Source: iNaturalist
Months it is reported in the US
Source: GBIF
More photos
Questions people ask
Do horned spanworm moth larvae damage trees?
Yes, the caterpillars feed on many tree and shrub species and can defoliate them.
Source: Wikipedia
When can I see adult horned spanworm moths?
Adults are active from spring through late summer, roughly April or May to August.
Source: Wikipedia
Same family (Geometridae)
Willow BeautyPeribatodes rhomboidaria
Pale BeautyCampaea perlataDamages trees, gardens or crops
Large Lace-border MothScopula limboundataDamages trees, gardens or crops
Riband WaveIdaea aversata
Yellow Shell MothCamptogramma bilineata
Large Maple Spanworm MothProchoerodes lineolaDamages trees, gardens or cropsSources
- Wikipedia: https://en.wikipedia.org/wiki/Nematocampa_resistaria
Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia
Text written 2026-10-22 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-22.