Environmentally-induced plasticity of life history parameters in the cladoceran Simocephalus vetulus

Key life history parameters significantly differed between two different clones of Simocephalus vetulus originating from different habitats, i.e. a fishless pool and a fish pond. The following fitness-related traits were studied: lifespan, age at first reproduction, interclutch period, number of clutches, and number of embryos. In general, in relation to the fish pond clone the fishless pool clone revealed longer lifespan and higher fecundity due to more frequent clutches, contributing to a higher fitness. Higher food quantities decreased the lifespan but did not alter fitness-related traits except for a shorter interclutch period. The Simocephalus clone from the fishless pool matured earlier in low food conditions, while the fish pond clone matured earlier in the high food conditions. The switch in food concentration between the subsequent generations significantly shortened the lifespan in the fish pond clone but revealed no effect in the fishless pool clone.