Responses to Femoral Gland Secretions by Visually Adept Male and Female Collared Lizards

Abstract

Although visually transmitted social signals are well documented in many diurnal iguanians, including collared lizards, secretory femoral glands also suggest a role of chemical signals in intraspecific communication. We conducted laboratory trials to test the extent to which male and female collared lizards responded by tongue-flicking femoral gland secretions, neutral (water), and odoriferous (cologne) control substances, males distinguished self-secretions from those produced by unfamiliar rival males, and females distinguish secretions from unfamiliar vs. familiar males. Both males and females spent similar amounts of time in four arena quadrants each with a Petri dish treated with one of the four test compounds. Males gave more tongue flicks/trial to secretions produced by unfamiliar rivals and cologne than they tongue-flicked their own secretions and water. By contrast, the number of tongue flicks by females on control substances and familiar and unfamiliar males was similar. Results support the hypothesis that femoral gland secretions function in intrasexual signaling among male collared lizards, perhaps allowing them to distinguish unfamiliar rivals. Females tongue-flicked secretions from familiar and unfamiliar males with similar frequency that was high relative to that of males, suggesting a possible role of secretions in assessment of males. Ours is the first evidence of a signaling role of femoral gland secretions in collared lizards and adds to a growing body of evidence that chemical signaling has evolved in diurnal lizards that also have highly developed visual-based signaling.