Black hairstreak forewings. The most conclusive way to distinguish the two is by the row of black spots accompanying the orange band which the white-letter hairstreak never has. They spend most of their lives in the canopy or in dense scrub, feeding on honeydew, and very rarely come down to ground level. Eggs are laid singly on young blackthorn "Prunus spinosa" growth and it is this stage which hibernates. Although blackthorn is the main foodplant, wild plum "Prunus domestica" and other "Prunus" spp are occasionally used. The caterpillar hatches the following spring, at the end of April, just before the buds open
Prunus cerasus Prunus cerasus Prunus cerasus (sour cherry, tart cherry, or dwarf cherry) is a species of "Prunus" in the subgenus "Cerasus" (cherries), native to much of Europe and southwest Asia. It is closely related to the sweet cherry ("Prunus avium"), but has a fruit that is more acidic. The tree is smaller than the sweet cherry (growing to a height of 4–10 m), has twiggy branches, and its crimson-to-near-black cherries are borne upon shorter stalks. There are several varieties of the sour cherry: the dark-red morello cherry and the lighter-red varieties including the amarelle cherry, and the popular Montmorency cherry. The