[What the study of seminal fluid proteins in Drosophila tells us about the evolution of reproduction]

Decrease in male fertility observed in the past decades have involved sperm quantity and quality disorders. However, decrease in quality or quantity of seminal fluid may also trigger drastic reduction of female and also male fertility. The present paper documents on the composition of seminal fluid, the consequences on sperm cells and on the physiological and behavioral effects towards females. The work evidences the crucial role of seminal fluid in the postcopulatory interactions between the sexes and illustrates the selective effects in the male-female coevolution.