Diversity and behavior of sea slugs (Heterobranchia) in the rocky tide pools of Conero Riviera (western Adriatic Sea)

Rocky tide pools are transition environments whose communities are affected by sudden temperature, salinity and nutrient fluctuations. Furthermore, these environments are exposed to multiple stressors and can be easily altered by human trampling. In particular, specific studies on rock pool heterobranchs communities are lacking for the Mediterranean Sea. In this study, the community of Heterobranchia (Mollusca: Gastropoda) living in an anthropized rock pools system in western Adriatic (Ancona, Italy) has been investigated and a first checklist of the sea slugs in this urbanized areas is provided. During the four months survey, a total of 452 specimens, belonging to 19 species and 12 families was recorded. Notable findings were the first record of Placida dendritica for the Conero Riviera, and the first records of Doto cervicenigra and Ercolania viridis for the western Adriatic Sea. Identification of trophic categories showed a diversified assemblage in terms of food sources mirroring a surprising species diversity. Moreover, we provide here the description of a peculiar behavior possibly used by sea slugs to cope with the stressful conditions within this semi-closed system.