Land snails usually exhibit cycles of activity and dormancy (aestivation or hibernation). The transition between these two states is accompanied by a range of behavioural and physiological responses to ensure their survival under adverse environmental conditions. Furthermore, aestivation plays an important role in shaping species' distribution patterns. We examined the seasonal patterns in biochemical tissue composition in relation to aspects of behavioural ecology in three land snail populations: one mainland and one insular population of the widespread Helix aspersa and a population (sympatric with the latter) of Helix figulina, a congeneric species with a narrow and declining distribution. Helix figulina aestivates in underground borrows, while H. aspersa spends the summer under stones and may interrupt aestivation when conditions become favourable. Prior to aestivation H. figulina accumulates metabolic fuels, which it consumes later during summer, and at the same time loses substantial body water and increases lactate dehydrogenase (LDH) activity. The insular H. aspersa population follows a similar pattern (regarding metabolites and LDH activity), with the difference that water loss is limited. However, the mainland population of H. aspersa deviates from this model with energy metabolites and water levels showing little variation throughout the year, while LDH activity is reduced. These differences probably reflect the particular behavioural and physiological patterns adopted by each species. The specialist and range-restricted H. figulina shows a constant and more predictable seasonal pattern, which may be effective for surviving in its historical biogeographic range, but it seems to be more vulnerable to possibly changing environmental conditions. On the other hand the generalist and cosmopolitan H. aspersa adopts a more flexible pattern that compensates for the effects of adverse conditions during aestivation and permits a more effective exploitation of energy resources.

The aim of this work was to infer the phylogeny of the Greek endemic land-snail genus Codringtonia Kobelt 1898, estimate the time frame of the radiation of the genus, and propose a biogeographic scenario that could explain the contemporary distribution of Codringtonia lineages. The study took place in the districts of Peloponnese, Central Greece and Epirus of mainland Greece. Sequence data originating from three mtDNA genes (COI, COII, and 16S rDNA) were used to infer the phylogeny of the eight nominal Codringtonia species. Furthermore, the radiation time-frame of extant Codringtonia species was estimated using a relaxed molecular clock analysis and mtDNA substitution rates of land snails. The phylogenetic analysis supported the existence of six Codringtonia lineages in Greece and indicated that one nominal species (Codringtonia neocrassa) might belong to a separate genus distantly related to Codringtonia. The time frame of differentiation of Codringtonia species was placed in the Late Miocene-Pleistocene epoch. The dispersal-vicariance analysis performed indicated that most probably Codringtonia exhibited a north-to-south spread with the ancestral area being that of central Greek mainland, accompanied with duplication (speciation) and vicariance events. © 2011 Elsevier Inc.