About Lythria purpuraria (Linnaeus, 1758)
Lythria purpuraria, commonly called the purple-barred yellow, is a moth species that belongs to the family Geometridae. Its distribution ranges from western Europe to Siberia, Russia, Ukraine, Turkmenistan, and Kazakhstan. The forewings of this moth are green-yellow, and they generally bear two red-purple transverse lines. This species is often confused with its sister species L. cruentaria, which also belongs to Geometridae. The confusion arises because both species occur in a range of sizes and display multiple different wing patterns. L. purpuraria and the four other species in the genus Lythria have genitalia structures that are very difficult to analyze and study. Adult Lythria purpuraria are active on the wing from April to June, with a second flight period from July to September. This is a day-flying species that produces two generations per year. The larvae of Lythria purpuraria feed on Polygonum aviculare, commonly known as prostrate knotweed.
