Salinity, temperature and desiccation tolerance of intertidal gastropods Littorina quadricentus and Nodilittorina pyramidalis

Littorina quadricentus and Nodilittorina pyramidalis were subjected to different grades of salinity, temperature and desiccation to study their tolerance. In N. pyramidalis , the critical salinity level was 21 x 10 super(3) below which the animals exhibited a reduced activity and increased mortality. In L. quadricentus), below 24 x 10 super(3) sal. there was a sharp increase in mortality and decrease in activity. Animals of all size groups, in both species, responded similarly to varying temperature. Contrary to this, in desiccation tolerance experiments, larger forms withstood desiccation for a longer period than smaller forms in both species.