Bug FAQSingle-dotted Wave
Idaea dimidiata · Order: Lepidoptera · Family: Geometridae
Also called: Single-dotted Wave Moth
The single-dotted wave has a wingspan of about 13 to 18 mm. Its wings are brownish-yellow to slightly reddish-white with dark grey-brown markings, including a light wavy line and black discal spots. It lives in damp places like marshy woods, fens and river banks and flies at night from June to August.
Source: Wikipedia
How to recognize it
The wing colour ranges from brownish-yellow to slightly reddish-white with dark grey to dark brown pattern elements. The median band and crosslines may be incomplete or broken. Costal stains appear on the front edge of the forewing. A light wavy line runs near the inner edge, bordered by dark stains in the marginal area. Both fore- and hindwings have black discal flecks, often weaker on the forewings. Marginal stains are linked by a thin line.
Source: Wikipedia
Size
Wingspan is 13 to 18 mm.
Source: Wikipedia
When you see it
Adults are active at night from June through August, sometimes later.
Source: Wikipedia
Where it comes from
It is a Holarctic species found in the Western Palearctic and Nearctic regions.
Source: Wikipedia
Where it is found in the US
Recorded in 21 of 51 states and DC. Most records: New York, Washington, Oregon, Michigan, Vermont, Massachusetts, Ohio, Pennsylvania.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Status: introduced in North America; introduced in United States; introduced in Canada. Source: iNaturalist
Months it is reported in the US
Source: GBIF
More photos
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/Idaea_dimidiata
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.