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Most land snails in order to ensure tlieir survival under adverse environmental conditions interrupt tlieir activity entering a state of dormancy. The transition from activity to dormancy is accompanied by several changes in the animais’ physiology. To identify these changes we examined the seasonal patterns in the biochemical composition and the LDH activity of three different tissues in four endangered land snail species. Additionally, within a phylogenetic framework we investigated the correlation of the measured parameters with the spatial and climatic variables of the sampling sites. Our results indicate that there are both differences and similarities in the pattern exhibited by the four species, depending on the physiological parameter investigated and the climatic conditions of the sampling sites, which sometimes have a significant effect on the seasonal pattern exhibited. Snails can successfully deal with the winter dormancy by maintaining high metabolite concentrations and stable water content whereas there is no indication of anaerobio pathways’ activation. At the same time, they deal successfully with the low humidity and high temperatures during the summer, but they are forced to maintain low metabolite concentrations and seem to activate anaerobio pathways to meet their energy demands. Therefore, from a biochemical perspective, it seems that winter is a less stressful period for snails compared to summer. According to the prevailing climate change scenarios, the Mediterranean region is going to exhibit a sudden transition towards a dryer and longer summer. This transition will exert a very high adaptation pressure on the already vulnerable Codringtonia species. Thus, it could be that this endemic Greek genus is truly on the verge of extinction.

Background Cornu aspersum is a quite intriguing species from the point of view of ecology and evolution and its potential use in medical and environmental applications. It is a species of economic importance since it is farmed and used for culinary purposes. However, the genomic tools that would allow a thorough insight into the ecology, evolution, nutritional and medical properties of this highly adaptable organism, are missing. In this work, using next-generation sequencing (NGS) techniques we assessed a significant portion of the transcriptome of this non-model organism. Results Out of the 9445 de novo assembled contigs, 2886 (30.6%) returned significant hits and for 2261 (24%) of them Gene Ontology (GO) terms associated to the hits were retrieved. A high percentage of the contigs (69.4%) produced no BLASTx hits. The GO terms were grouped to reflect biological processes, molecular functions and cellular components. Certain GO terms were dominant in all groups. After scanning the assembled transcriptome for microsatellites (simple sequence repeats, SSRs), a total of 563 SSRs were recovered. Among the identified SSRs, trinucleotide repeats were the predominant followed by tetranucleotide and dinucleotide repeats. Conclusion The annotation success of the transcriptome of C. aspersum was relatively low. This is probably due to the very limited number of annotated reference genomes existing for mollusc species, especially terrestrial ones. Several biological processes being active in the aestivating species were revealed through the association of the transcripts to enzymes relating to the pathways. The genomic tools provided herein will eventually aid in the study of the global genomic diversity of the species and the investigation of aspects of the ecology, evolution, behavior, nutritional and medical properties of this highly adaptable organism.