Intraspecific life-history variation in Lymnaea peregra (Gastropoda: Pulmonata). I. Field study

By comparing the dynamics of 3 neighbouring populations (Sheaf, Rivelin and Don) of Lymnaea peregra, the extent to which interpopulation differences in life history are due to environmental factors was examined. The Don population started breeding earlier, and had longer breeding seasons than the Sheaf and Rivelin populations. The Sheaf population was bivoltine while the Rivelin and Don populations were univoltine. Members of the summer cohort of the Sheaf population had higher growth rates and reproductive outputs. Sheaf and Rivelin snails had higher mortality rates than Don snails in winter. Lower temperatures and faster currents accounted for the higher mortality rates at the Sheaf and Rivelin sites. Food availability was important for growth rates and number of breeding bouts per year. -from Authors