Size-specific swimming behavior of Daphnia pulex

Body length affects several aspects of the behavior of quietlyswimming Daphnia pulex Swimming and sinking rates were measuredat 0.033 s intervals during the ‘hops’ characteristicof Daphnia swimming behavior Larger animals swim faster, covermore distance, and produce more powerful swimming strokes. LargerDaphnia also sink faster, but the sinking rate scales as lengthto the 0 58 power, far lower than the power of 2 00 predictedby Stokes Law considerations. The number of hops s^–1 wasindependent of body size, although a theoretical analysis predictshopping rate (antennal beat frequency) should increase as bodylength squared. Turning behavior, measured as the ratio of displacementto total distance, during 5 s, is also independent of body sizeIndependence of several parameters of body motion and body sizeimplies that factors other than simple mechanics affect Daphniaswimming behavior