Intraspecific life-history variation in Lymnaea peregra (Gastropoda: Pulmonata). II. Environmental or genetic variance?

Comparison of 3 neighbouring populations Lymnaea peregra demonstrated variation in a number of important life-history traits. Reproductive timing showed varying degrees of plasticity in the 3 populations; differences in this trait between populations were genetically determined. Juvenile growth rate, hatchling size, and age at onset of breeding were genetically controlled within some populations. Number of traits showing significant interpopulation and intrapopulation variations decreased from F₁ to F₂ generations. On a phenotypic basis, time to 1st reproduction was negatively correlated with size at hatching for 1 population. -from Authors