Seasonal variability in the palatability of freshwater macrophytes: a case study

Citation

Elger A, Barrat-Segretain M & Willby N (2006) Seasonal variability in the palatability of freshwater macrophytes: a case study. In: Caffrey J, Dutarte A A, Haury J, Murphy K & Wade P (eds.) Macrophytes in Aquatic Ecosystems: From Biology to Management: Proceedings of the 11th International Symposium on Aquatic Weeds, European Weed Research Society. Developments in Hydrobiology, 190. Amsterdam: Springer, pp. 89-93. http://link.springer.com/chapter/10.1007/978-1-4020-5390-0_13#

Abstract
The pond snail Lymnaea stagnalis (L.) was used for a laboratory assessment of seasonal variation in palatability of three freshwater macrophytes: Potamogeton lucens, Elodea canadensis and E. nuttallii. For each species, 2-5 populations were investigated in spring and in summer. Preliminary results showed that the feeding rate of similarly-aged snails bred under standard conditions was stable over time. In contrast, snail feeding rate on the three macrophyte species decreased from spring to summer, which was therefore interpreted as a decrease in plant palatability. This decrease was probably due to tissue maturation, as suggested by the concomitant increase in the dry matter content of leaves of the three species. The high palatability of the species studied during the spring may prove detrimental in cases of strong herbivore pressure, and could have consequences for macrophyte distribution among aquatic habitats.

Keywords
aquatic plants; dry matter content; herbivory; Lymnaea stagnalis; phenology