Filming VarWild: Satyrium w-album

The White-letter Hairstreak (Satyrium w-album Knoch, 1782)

The White letter Hairstreak is widespread in temperate Eurasia to Japan. In the Var (France) the butterfly flies from early May to August, in one generation. The White-letter Hairstreak spends most of their time around the canopy of Elm trees. The female lays isolated flattened "UFO" shaped eggs at the base of the terminal buds on branches older than two years, at all heights. The caterpillars hatches just before the flowering of the Elm trees, around mid-February. They feed first on flower buds than on the flowers, the fruit-seeds and leaf-buds. In their last stage they feed on leaves that develop 6 weeks after flowering.

Since 2014, unfortunately, virtually all elm trees die in the wide area of Draguignan. This die off is most likely caused by the Dutch elm disease (DED). DED is caused by a member of the sac fungi Ophiostoma ulmi (Ascomycota) affecting elm trees, and is spread by elm bark beetles Scolytus scolytus. Although believed to be originally native to Asia, the disease was accidentally introduced into America and Europe, where it has devastated native populations of elms that did not have resistance to the disease.

With the disappearing of the elm trees, the White-letter Hairstreak (Satyrium w-album) will also disappear from the heavily affected areas in the South of France. Annually the disease expanse very quickly, and there is little sight that this will be stopped in the coming years.