Relationship Between Imposex and Morphological Variation of the Shell in Nucella lapillus (Gastropoda: Thaididae)

The relationship between imposex and shell morphology of the common dogwhelk, Nucella lapillus, was examined in populations from North Wales. Degree of imposex, morphometry of the shell, habitat-exposure to wave action and substratum type were subjected to multivariate statistical analyses. Shell size increased significantly with increasing degree of imposex. This trend possibly is caused by a diversion of energy allocation from reproduction to shell growth when reproductive effort is blocked or disturbed by imposex.