Figure 1.

Mating and aggressive behavior in Bmal1 KO males. A, Male mating assay: days until appearance of copulatory plug after introduction of an estrous WT female (n = 4, Student's t test). B, Serum T measurement in WT and Bmal1 KO males (n = 10–12, Mann-Whitney test). C, Mating behavior: total number of mounting attempts in 30 minutes during a mating trial with a receptive WT female (n = 9 intact, 3–4 GDX + T, one way ANOVA followed by Tukey post hoc). D, Aggression (resident): aggressive behavior during introduction of a WT male into the test subject's (resident's) home cage (n = 5–6 intact, 3–4 GDX + T). *, P < .05; **, P < .01.