Intra-clutch offspring size variability in the freshwater zooplankter Daphnia magna

Intra-clutch offspring size variability is quantified and compared in nine European populations of the freshwater zooplankter Daphnia magna. Mean values for coefficients of variation for intra-clutch neonate body-length were low, and similar, within and between populations (range = 1.8 to 4.4%). There was little evidence that offspring size variability increased with increasing environmental uncertainty and, under 'common garden' laboratory conditions, maternal genotypes collected from more uncertain environments did not produce clutches with a greater range of offspring sizes. Maternal body-length and growth rate did not significantly correlate with offspring size variability. However, there was a marginally significant positive correlation between clutch size and offspring size variability when data across populations were poole