Seasonal and diurnal migration patterns of the spider (Araneae) fauna of coastal grey dunes

The study of the grey dune species' phenology patterns revealed interesting data on the occupation of this xerotherm habitat by several spider species groups. Apparently stenotopic erigonid species are totally absent during t he summer months. A possible explanation for this phenomenon is the lack of suitable prey (Collembola). Larger species of the Gnaphosidae, Thomisidae, Salticidac, Lycosidae and Arancidae are present during the summer. Of thes e Haplodrassus dalmatensis characterised by clear seasonal migration from t he litter border zone, where the juvenile development takes place, to the o pen grey dune as reproduction habitat. The smaller stenotopic erigonid spec ies (Typhochrestus digitatus. Pelecopsis nemoralis) do not show a clear sea sonal but instead a diurnal migration between these two habitats in their a dult phase.