Use of the pond snail Lymnaea stagnalis (L.) in laboratory experi ments for evaluating macrophyte palatability

The possibility to use the pond snail Lymnaea stagnalis (L.) to assess the palatability of aquatic macrophytes in the laboratory was examined. The growth and the reproduction of this snail were studied in breeding aquaria and under laboratory conditions. The consumption rate of L. stagnalis was recorded for eight macrophyte species in one choice experiment and two non-choice experiments performed in two consecutive years. The breeding of L. stagnalis presented no difficulties. Within a few weeks, a single individual produced hundreds of young snails. In favourable conditions of temperature and water volume, these young specimens reached 30 mm shell length eight weeks after hatching. The feeding experiments demonstrated that the snails of this size can be used to accurately discriminate the palatability of macrophyte species. The feeding preferences of L. stagnalis did not significantly differ among the three experiments. The use of L. stagnalis as a model to study plant palatability in freshwater habitats is discussed from both a conceptual and a pragmatic point of view.