Influence of trematode infections on in situ growth rates of Littorina littorea

The influence of various species of digenean trematodes on rile in situ gro wth rate of Littorina littorea (Gastropoda: Prosobranchia) from different h abitats was investigated. The main results showed: (1) that infections eith er reduced or had no significant effect on growth in comparison with uninfe cted snails; (2) that the same type of infection could have a differential effect on growth depending on the habitat/population from which the snails originated. These findings are consistent with the life history hypothesis expecting no or a stunting effect of trematode infections on the growth of longer-lived snails, but do also emphasize that growth rates following trem atode invasion can be significantly modified by environmental conditions, s uch as, food availability.