Variation in the response of juvenile and adult gastropods (Lymnaea stagnalis) to cyanobacterial toxin (microcystin-LR)

Owing to the increasing public health problem related to the proliferation of toxin-producing cyanobacteria in aquatic ecosystems, we have investigated the response of the pond snail Lymnaea stagnalis exposed to 33 mu g/L microcystin-LR for 6 weeks, through its life traits (survival, growth, fecundity) and locomotion; uptake of microcystin-LR was also quantified in the snail body tissues. To study the potential plasticity of the response related to the development stage, snails were exposed to the toxin as sexually immature and mature. According to our results, microcystin-LR accumulated in snail tissues at a higher level in juveniles (7.96 ng/g fresh weight) versus adults (2.17 ng/g fresh weight). Whatever the age, survival, growth, and locomotion were not affected by the toxin, and fecundity of polluted adults was reduced by half. These results are discussed in terms of negative effects of aqueous microcystin-LR occurrence on the dynamics of natural populations of gastropods. (C) 2005 Wiley Periodicals, Inc.