Plebejus (Vacciniina) optilete
Hostplant: Vaccinium uliginosum and Vaccinium vitis-idaea. It can probably use other species within Vaccinium. I used both mentioned in my breeding, but the larva seemed to do better on V.uligiosum.
Lifecycle and behavior: The female laid eggs on both upper- and undersides of the leaves. The eggs used 1 week to hatch. The larva hibernated as L3. They molted once after hibernation. The pupa used 9 days to hatch. The adult butterfly has its main flight period in June and July. Further north it can be on the wing into August.