Experimental evidence for snails dispersing tardigrades based on Milnesium inceptum and Cepaea nemoralis species

Dispersal abilities in animals contribute to their local genetic variability and species persistence. However, the mechanisms facilitating a short-distance migration of small organisms remain underexplored. In this study we experimentally tested the role of land snails for a fine-scale transmission of tardigrades. We also check the ecological relationship between these two groups, by testing the impact of snail's mucus on tardigrades in anhydrobiosis. All the experiments were conducted under laboratory conditions. As model organisms, we used a tardigrade species Milnesium inceptum and a snail species Cepaea nemoralis. The selection of the experimental animals was dictated by their co-occurrence in natural habitats and similar atmospheric conditions required for them to remain active. Results of our experiments support the assumption that snails may transfer active tardigrades for short distances. On the other hand, the effect of the snails mucus on tardigrade recovery to active life after anhydrobiosis was negative. Death rates of tardigrades in anhydrobiosis (tun) were higher when affected by mucus compared to mucus-free tuns.