Figure 4.

Effect of circadian forced desynchrony on sexual behavior of male rats during the dark phase. Percentage of LD24 control and LD22 desynchronized male rats that did not mount (A) and did not ejaculate (B) as a function of the time lapsed from the introduction of a receptive female. *p < 0.05, **p < 0.01. Log-rank values were calculated based on a Kaplan–Meier survival analysis. C, Mean ± SE copulatory rate in LD24 control and LD22 desynchronized males. Copulatory rate was calculated as the sum of mounting and intromission events divided by the time lapsed from the first mounting event until the first ejaculation event. Different letters denote statistical differences between groups (p < 0.05).