Chemical Polymorphism and Chemosensory Recognition between Iberolacerta monticola Lizard Color Morphs

Abstract

In the lizard Iberolacerta monticola, there are 2 discrete color morphs ("blue" vs. "green") that seem to have alternative reproductive strategies. Because scent marking of territories and chemoreception are important in social organization of these lizards, we explored whether there is also chemical polymorphism and chemosensory recognition between color morphs. Analyses by gas chromatography-mass spectrometry showed that adult males of different morphs had similar chemical compounds in femoral gland secretions, but the proportions of some shared chemicals were different; blue morph males had higher proportions of steroids and lower proportions of fatty acids than green males. Differential tongue-flick rates to scents from femoral secretions of males indicated that males were able to detect the scent of any male from a baseline odorless control (water) but did not discriminate between the scent of males of different morphs. In contrast, females detected and discriminated between scents of the 2 male morphs by chemical cues alone. We suggest that differences in males' chemical signals between morphs and the ability of females of discriminating chemically between male morphs might be required to maintain spatial behavior, social organization, and mate choice decisions and, thus, be important for the maintenance of alternative reproductive strategies and polymorphism in lizards.