Satyrium pruni (Linnaeus, 1758)

Host plants:
The larvae feed on Prunus species, especially Prunus spinosa, but also Prunus padus and plums.

Habitat:
Satyrium pruni lives in hedges, on shrub-rich grasslands, bright riparian forests, coppice forests and rarely also gardens. Satyrium pruni prefers warm, but not too dry grassland/scrub biotopes and clear floodplain forests.

Life cycle:
The caterpillar overwinters in the egg shell. The eggs are brownish and thus not conspicuous and not so easy to find such as those of Satyrium spini or Thecla betulae. They are deposited singly or in small groups (usually 2, very rarely 3) on branches and twigs, but also on the trunk near the ground.
Thus it is additionally recommended to search for larvae (tapping) in order to detect Satyrium pruni. The larvae are observed especially on old blackthorn bushes, but soemtimes also on dwarf shrubs as long as they are able to bloom. They are rearly found together with those of acaciae (only small overlapping in ecological niches). The caterpillar moults three times, is mature in May and the adults mostly fly in June and early July (nowadays also more and more from late May). They usually fly around the bushes and trees that are interspersed in the hedges and occasionally suck on Ligustrum and Rubus.

Endangerment factors:
Despite its ecological plasticity, Satyrium pruni is endangered by the destruction of hedgerows and open forest areas as well as too rigid removal of shrub in grasslands. In areas with many shrub-rich dry grasslands as the Swabian Jura Satyrium pruni is still quite widespread and sometimes common.

Global warming seems to result in a shift: on the one hand Satyrium pruni spreads in formerly too cool regions as partially in the northern foreland of the Alps (Pre-Alps), on the other hand it is pushed back in some lowlands like the Upper Rhine Valley where some sites get too dry and hot.

Remarks:
The distribution extends from the Pyrenees (N-Spain) across central and Eastern Europe to east Asia (Korea, Japan). It misses largely in southern, Mediterranean Europe.