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 brigantina Prunus brigantina Prunus brigantina, called Briançon apricot, marmot plum, and alpine apricot, is a wild tree species native to France and Italy. It is the only apricot-like "Prunus" species native to Europe. The fruit is similar to the commercial apricot "Prunus armeniaca", and is edible. An edible oil produced from the seed, 'huile des marmottes', is used in France. Unlike the other closely related species known as apricots, the fruit is smooth rather than hairy. "Prunus brigantina" is considered a member of the apricot group, along with "P. armeniaca", "P. mandshurica", "P. mume", and "P. sibirica", but its genetic relationships