Increased predation risk modifies lizard scent-mark chemicals

Variation in environmental factors plays a central role on organisms' physiological changes. However, the physiological response to predation risk has rarely been investigated in reptiles. Chemical senses are important for intraspecific communication in squamate reptiles. In male lizards Iberolacerta cyreni the maintenance of relative proportions of lipids in femoral gland secretions is costly, which may ensure honest signalling of quality. We hypothesized that increased predation risk should compromise the maintenance of such lipid proportions, as both a fear response and escaping behavior can have physiological consequences. We simulated predator attacks and found that relative proportions of lipids in femoral gland secretions changed in disturbed lizards but not in control ones. Thus, predator-prey interactions may modulate relative concentrations of chemicals in scents of lizards. Potential consequences of this effect on intraspecific chemical communication are suggested.