Genetic diversity of marine gastropods: contrasting strategies of Cerithium rupestre and C. scabridum in the Mediterranean Sea

Allozymic variation encoded by 25 gene loci was compared and contrasted in natural coexisting populations of the marine gastropods Cerithium rupestre and C. scabridum collected along the rocky beach of the northern Mediterranean Sea of Israel. C. rupestre showed considerably less genic diversity than C. scabridum. Results support the niche-width variation hypothesis as C. scabridum may be considered a species characterized by a broader ecological niche than C. rupestre. However, the extreme difference between the genic diversity of the 2 species might result from at least 2 sets of factors reinforcing each other, namely the ecological niche as well as the life zone and life history characteristics