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. 2016 Aug 16;7:12452. doi: 10.1038/ncomms12452

Figure 3. Ovarian fluid enhances both nesting and sneaker male sperm characteristics.

Figure 3

Means for each time point and ovarian fluid treatment are represented for nesting male by circles and for sneaker males by triangles. The presence (blue) or absence (red) of ovarian fluid is represented by the colour of the symbol and lines. Error bars indicate the s.e.m. For all sperm characteristics examined except motility, the best-fit model (based on the hierarchical model and AIC comparison using ANOVA and AICctab from library bbmle in R) included treatment (with or without ovarian fluid), time (repeat) and the interaction between treatment and time (number of observations: n=32 males × two treatments × 5 observation points per male and treatment=320 data points). No significant effect of male type or interaction between male type and ovarian fluid treatment was found. For motility, the interaction between time and treatment was not significant. Statistical results of the linear repeated measures mixed effects best-fit models are summarized for each sperm characteristic (fit by maximum likelihood using lme from library nlme in R): (a) Motility (per cent of cells motile): (intercept F(158)=177.15 P<0.0001, treatment F(158)=106.33 P<0.0001, repeat F(126)=28.04 P<0.0001, interaction F(1)=3.02 P=0.084). (b) Curvilinear velocity (VCL): (intercept F(158)=312.21 P<0.0001, treatment F(158)=80.58 P<0.0001, repeat F(126)=42.62 P<0.0001, interaction F(1)=4.57 P=0.034). (c) Straightness (straight line velocity VSL/average path velocity VAP): (intercept F(158)=609.31 P<0.0001, treatment F(158)=147.77 P<0.0001, repeat F(126)=32.95 P<0.0001, interaction F(1)=26.54 P<0.0001). (d) Linearity (straight line velocity VSL/curvilinear velocity VCL):(intercept F(158)=545.97 P<0.0001, treatment F(158)=141.02 P<0.0001, repeat F(126)=41.51 P<0.0001, interaction F(1)=25.24 P<0.0001). Other measures of velocity (VSL, VAP) yield similar results.