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 sibirica Prunus sibirica Prunus sibirica, called Siberian apricot (), is a species of shrub or small tree native to eastern China, Japan, Korea, Mongolia, and eastern Siberia. It is in the genus "Prunus" in the rose family, Rosaceae, one of several species whose fruit are called apricot, although this species is rarely cultivated for its fruit. The species was named by Carl Linnaeus in 1753. The species is highly genetically diverse. It grows in the form of a small tree with spreading branches and reaches a height of . It is very frost resistant and can survive temperatures down to .