TIME FOR LOVE
The time of physiological events over the course of the day-night cycle are regulated by circadian clock genes, such as Clk, per, tim and cyc. The authors of a paper published in Current Biology (L. M. Beaver & J. M. Giebultowicz, Regulation of copulation duration by period and timeless in Drosophila melanogaster. Curr. Biol. 14, 1492-1497, 2004) found that two among these genes, per and tim, also regulate the duration of copulation in male Drosophila melanogaster.