Figure 2
(a) Trajectories of free-swimming sperm under the no–flow condition. Rheotaxis sperm are those with head angle within ±22.5° of flow direction (i.e., horizontal image axis), as labeled by red arrows. Blue arrows label non-rheotaxis sperm. (b) Trajectories of sperm under fluid flow. (c) Percentage of rheotaxis sperm from six independent experiments (n = 342 for no flow and n = 440 for fluid flow condition). *Represents significant difference (p = 7 × 10−7 by two tailed t-test).
