1. Post-maturation growth leading to indeterminate growth patterns is widespread in nature. However, its adaptive value is unclear. Life history theory suggests this allocation strategy may be favoured by temporal pulses in the intensity of mortality and/or the capacity to produce new tissues. 2. Addressing the origin of indeterminate growth and the variability of growth patterns, we studied the growth of duck mussels, Anodonta anatina, a pan-European unionid, in 18 Polish lakes. For each population...