Chemosensory Responses by Female Iberian Wall Lizards, Podarcis Hispanica to Selected Lipids Found in Femoral Gland Secretions of Males

Abstract

In many lizards, secretions of males are used in social behaviors, but it is almost unknown which specific chemicals are relevant in mediating these behaviors. Moreover, only a few studies have examined whether lizards can actually discriminate between different chemical compounds. We tested for differential chemosensory responses of female Iberian Wall Lizards, Podarcis hispanica, to two lipids (cholesterol and cholesta-5,7-dien-3-ol) found in femoral secretion of males, and which previous behavioral studies suggested may be relevant in female mate choice. The higher tongue-flick (TF) rates directed at cotton swabs containing these two lipids indicated that females detected and discriminated these chemicals from a control. There were no significant differences between responses to cholesterol and to the whole natural femoral secretion from males, probably because cholesterol is the major predominant component in secretions of males. The higher TF rates to cholesta-5,7-dien-3-ol than to cholesterol indicated that females discriminated these two steroids. Moreover, females seemed able to assess changes in concentration of cholesta-5,7-dien-3-ol and responded more strongly to higher concentrations. These results, together with the previous finding of female preference for areas scent marked by males with higher proportions of this steroid in their secretions, might support that cholesta-5,7-dien-3-ol was a “key” chemical that might be used by females to choose potential mates.