Silver Υ

The silver Y is a medium-sized moth with a wingspan described in the range of 30-45 mm. The wings are intricately patterned with various shades of brown and grey serving as camouflage. In the centre of each forewing there is a silver-coloured mark shaped like a lower case Y (y) or a lower case Greek letter gamma (γ). There are several different forms with varying colours depending on the climate in which the larvae grow.

Technical description and variation. P. gamma Forewing purplish grey, with darker suffusion in places; the lines pale silvery edged on both sides with dark fuscous, the outer line indented on vein 2 and submedian fold, as in circumflexa; the oblique orbicular and the reniform conversely oblique and constricted in middle, both edged with silvery: the median area below middle blackish, containing a silvery gamma; the subterminal dentate and indented, preceded by a darker shade; hindwing brownish grey with darker veins and a broad blackish terminal border: aberrations due to difference in ground colour are ab. pallida Tutt, in which the ground colour is whitish grey, with the markings appearing darker and more sharply defined; ab. rufescens Tutt where it is yellowish red, with the gamma mark pale golden, also the lines and edges of stigmata, and the whole underside reddish: and ab. …

The species is widespread across Europe and over almost all the Palearctic including North Africa. It is resident in the south of its range and adults fly almost throughout the year. In spring variable numbers migrate north reaching as far as Iceland, Greenland, and Finland. A second wave of migrants arrives in the summer. In central Europe and the British Isles adults are present in significant numbers from May onwards with numbers dwindling in late autumn as they are killed off by frosts. Some individuals fly south again to winter around the Mediterranean and Black seas.

Silver Y moths can produce two or three generations in a year with a fourth generation when conditions are particularly good. The eggs are laid on the upper or lower surface of leaves. They are whitish in colour and hemispherical in shape with deep ribbing. They hatch after three to four days (longer in cool conditions). The adults fly from late spring to autumn. The larvae are about 30 mm long, have three pairs of prolegs and are usually green with whitish markings. They feed on a wide variety of low-growing plants and have been recorded on over 200 different species sCloveruch as Urtica dioica, clover, and crops such as the garden pea (Pisum sativum), sugar beet (Beta vulgaris), and cabbage (Brassica oleracea). The pupa is green at first, gradually darkening to black. The adults mate one or two days after emerging from the pupa and start laying eggs one to five days later. They die three to nineteen days after emergence.