Figure 4.

Variation in sperm swimming parameters (ALH, LIN and BCF) from three mouse species (M. musculus, M. spretus, M. spicilegus) incubated under non-capacitating conditions (mT-H medium) and capacitating conditions (mT-BH medium). Data are means ± SE (n = 7 in M. musculus, n = 8 in M. spretus, and n = 6 in M. spicilegus). Red squares: non-capacitating conditions, mT-H medium under air. Blue squares: capacitating conditions, mT-BH medium under 5% CO₂/air. (A–C) Lateral head displacement (ALH) (µm). (D–F) Linearity (LIN) (VCL/VSL) (%). (G–H) Beat cross frequency (BCF) (Hz). (A,D,G) M. musculus. (B,E,H) M. spretus. (C,F,I) M. spicilegus. Asterisks indicate significant differences (p < 0.05) between treatments for the same time in a Fisher post-hoc test. Different letters between times of incubation for the same treatment indicate statistically significant differences (p < 0.05) in a Fisher post-hoc test. If two time-points of an incubation share any letter, the differences between them are not significant. No letters were used when a time-point of an incubation did not show any significant effect in the dependent variable.