PHENOTYPIC CHANGES IN THE PROGENY OF NUCELLA-LAPILLUS (GASTROPODA) TRANSPLANTED FROM AN EXPOSED SHORE TO SHELTERED INLETS

Nucella lapillus adults were transplanted from the exposed north Corni sh coast (Bude) to two sheltered inlets in south Devon (Dart Estuary a nd Plymouth Sound), sites where the native populations had ceased bree ding as a result of sterilisation by tributyltin (TBT) pollution. The transplants produced progeny, many of which survived to maturity and b eyond (6 + years). The shell form of Bude individuals is typical of an imals exposed to severe wave-action, i.e. of light construction with a large aperture to accommodate. a broad foot allowing for strong adhes ion. However, in contrast, the shell form of the progeny differed mark edly from that of their parents; they had the characters associated wi th development under sheltered conditions and subject to severe crab p redation, i.e. a robust structure and small aperture. Statistical anal ysis of the shell characters of the two generations indicated highly s ignificant differences. It is concluded these observations provide evi dence of the remarkable plasticity in the shell form of N. lapillus in that both 'exposed morph' and 'sheltered morph' can be produced by th e same gene pool when subject to the actions of the appropriate select ion pressures.