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1. The structure of local populations of a monophagous butterfly, the bog fritillary Proclossiana eunomia, was studied in a complex of suitable habitat patches separated by spruce plantations or fertilized pasture.2. An unexpected high level of adult movements between habitat patches was detected by a mark-release-recapture technique. Local populations were connected by adult movements across unsuitable habitats, leading to a metapopulation structure.3. This evidence of the metapopulation structure of a specialist butterfly challenges the supposed relationship between habitat specialization and closed, isolated populations.4. Males and females of P. eunomia exhibited different spatial behaviours; females were more likely to emigrate and dispersed further than males. These differences in spatial behaviour are related to the mating system.

The climate warming of the postglacial has strongly reduced the distribution of cold-adapted species over most of Central Europe. Such taxa have therefore become extinct over most of the lowlands and shifted to higher altitudes where they have survived to the present day. The lycaenid butterfly Lycaena helle follows this pattern of former widespread distribution and later restriction to mountain areas such as the European middle mountains. We sampled 203 individuals from 10 populations representing six mountain ranges (Pyrenees, Jura, Massif Central, Morvan, Vosges and Ardennes) over the species' western distribution. Allozyme and microsatellite polymorphisms were analysed to study the genetic status of these highly fragmented populations. Both molecular marker systems revealed a strong genetic differentiation among the analysed populations, coinciding with the orographic structure and highly restricted gene flow among them. The large-scale genetic differentiation is more pronounced in allozymes (F CT : 0.326) than in microsatellites (R CT : 0.113), but microsatellites show a higher resolution on the regional scale (R SC: 0.082) compared with allozymes (F SC : n.s.). For both analytical tools, we found private alleles occurring exclusively in a single mountain area. The highly fragmented and isolated occurrence of populations is supported by the distribution pattern of potentially suitable climate suggested by species distribution models. Model projections under two climate warming scenarios predict a decline of climatically suitable areas, which will result in the extinction of most of the populations showing unique genetic characteristics.