AN EPHEMERAL SEX-PHEROMONE OF FEMALE HOUSE MICE (MUS-DOMESTICUS) - PHEROMONE FADE-OUT TIME

Male mice will emit ultrasounds to at least two chemosignals present i n female mouse urine: a) an ephemeral unconditioned stimulus (UCS) pre sent in freshly voided urine and b) a conditioned stimulus (CS) that r emains after the UCS has disappeared. In this study, four phases exami ned the time frame over which the UCS disappeared. Urine that had been aged for either 12, 15, 18, or 24 h was compared for vocalization eli citation with fresh urine (which contains the UCS) and metabolic cage- collected urine (which does not). Under the conditions utilized, signi ficant pheromone fade-out occurred between 15 and 18 h.