Riband wave

Riband wave
Idaea aversata, sitting on a nettle leaf
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Lepidoptera
Family:	Geometridae
Genus:	Idaea
Species:	I. aversata
Binomial name
Idaea aversata Linnaeus, 1758

The riband wave (Idaea aversata) is a moth of the family Geometridae. It is an abundant species in Europe, the Near East and North Africa, its distinctive outline familiar at lighted windows.

Description

The species has a wingspan of 30–35 mm. The wings are buff or cream with dark fasciae (bands). Two main forms exist, equally abundant: one has darker shading between the central fasciae (as in the picture), the other (designated ab. remutata) has not. The ground colour of the wings is whitish yellow to ochre. Some specimens have a red-orange tone colouring. The pattern elements are dark brown and clearly shown. On the forewings there are three crosslines; on the hind wings there are two crosslines. The outer cross line has a significant outward angle near the costa. The area between the middle and outer cross line is dark brown. The discal flecks are small and inconspicuous, they may also be missing. Small marginal dots lie at the outer edge and can make almost a narrow marginal line.

Distribution

Almost all of Europe to the Ural mountains. Records are few in the Iberian Peninsula and the Balkan peninsula. The North border is Northern Sweden and Northern Finland. The northernmost parts of Russia and a few areas of Russia's Northwest of the Caspian Sea are excluded. In North Africa (Eastern Algeria and Tunisia), there is a smaller presence belonging to a separate subspecies (Idaea aversata indeviata Prout, 1935). Outside Europe, the distribution area extends from northern Turkey up to the Caucasus, from there via Central Asia, Siberia and Northeast China to Japan. The occurrence in Japan however be regarded as subspecies (Idaea aversata japonica Inoue, 1955). A small, isolated occurrence in southern Turkey is remarkable.

Biology

The adults fly at night from June to August, occasionally later , and are attracted to light.

The larva is brown, tapering towards the front, and feeds on a variety of plants including bedstraw, chickweed, dandelion and knotgrass. The species overwinters as a small larva.

1. ^ The flight season refers to the British Isles. This may vary in other parts of the range.

External links

• Riband wave at Markku Savela's Lepidoptera pages

References

Chinery, Michael Collins Guide to the Insects of Britain and Western Europe 1986 (Reprinted 1991)

Skinner, Bernard Colour Identification Guide to Moths of the British Isles 1984