Chemosensory Recognition of Familiar and Unfamiliar Conspecifics by Juveniles of the Iberian Wall Lizard Podarcis hispanica

Abstract

Chemosensory recognition of familiar conspecifics has been reported in studies with members of several lizard families and may be advantageous to distinguish between intruders and neighbors or group members. However, few species have been studied and information on the ability to discriminate between familiar and unfamiliar conspecifics by chemosensory means is lacking for most lizard families. In this paper we ask whether juveniles of the Iberian wall lizard Podarcis hispanica (Lacertidae), can discriminate between chemical signals from familiar conspecifics with whom they have shared a terrarium for several months and those from unfamiliar conspecifics housed in a different terrarium. Experimental trials were conducted by transferring juveniles to a test terrarium with a filter paper substrate. We tested the responses of lizards to paper substrates labeled by familiar cage‐mates, unfamiliar conspecifics, or unlabeled. Tongue‐flicks and other behaviors in response to pheromonal stimuli were recorded for 10 min Juveniles directed more chemosensory behavior towards paper substrates bearing chemicals from familiar conspecifics than towards similar paper substrates labeled by unfamiliar conspecifics. These results indicate that juveniles in this lizard species can recognize familiar conspecifics and discriminate between familiar and unfamiliar individuals using only chemical stimuli. We discuss the role of habituation in familiar conspecific recognition and review possible explanations of the functional significance of this type of discrimination in lizards.

Chemical self-recognition in the lizard Liolaemus fitzgeraldi

“…They sample and sense chemosignals through the tonguevomeronasal system (Font 1996), which allows them, for example, to recognize their partners (Bull 2000), and determine from a potential partner its body size (Lemaster and Mason 2002), body condition (Shine et al 2003), and mating status (Cooper and Pérez-Mellado 2002;O'Donnell et al 2004). In other social contexts, chemosignals can give detailed information about the fighting abilities of the owner (Labra 2006) and allow for the identification of the sex of the signalers (Cooper and Pérez-Mellado 2002), discrimination of familiar from unfamiliar individuals (Font and Desfilis 2002), mother-offspring recognition (Bull and Baghurst 1998), and self-recognition (Alberts 1992).…”

Chemical stimuli mediate species recognition in Podarcis wall lizards

“…The compounds involved may be present in femoral (Alberts, 1990(Alberts, , 1991Alberts et al, 1992) or cloacal gland secretions (Trauth et al, 1987;Cooper and Trauth, 1992), skin secretions (Weldon and Bagnall, 1987;Mason and Gutzke, 1990), or in faeces (Carpenter and Duvall, 1995;Bull et al, 1999;Labra et al, 2002). Although our study did not specifically address the source of chemicals involved in species recognition, the fact that a differential response was obtained for tongue-flicks directed at the substrate, but not for those directed at the terrarium walls or at the air, suggests that discrimination is based on non-volatile chemicals detected by vomerolfaction (Burghardt, 1980;Font and Desfilis, 2002). Since we did not observe any behaviour suggesting active marking by females, we assume that chemical marking by females is a passive process: females probably label paper substrates as they move around dragging their ventral surface, as has been described for juvenile P. hispanica lizards (Font and Desfilis, 2002).…”

“…Although our study did not specifically address the source of chemicals involved in species recognition, the fact that a differential response was obtained for tongue-flicks directed at the substrate, but not for those directed at the terrarium walls or at the air, suggests that discrimination is based on non-volatile chemicals detected by vomerolfaction (Burghardt, 1980;Font and Desfilis, 2002). Since we did not observe any behaviour suggesting active marking by females, we assume that chemical marking by females is a passive process: females probably label paper substrates as they move around dragging their ventral surface, as has been described for juvenile P. hispanica lizards (Font and Desfilis, 2002). Field observations suggest that, particularly in sand dunes such as those where these animals were collected, passive marking by females would probably be limited to vegetation or objects of anthropogenic origin, since sand is a moving substrate that presents a major challenge for chemical marking (Alberts, 1992).…”

Discrimination of conspecific faecal chemicals and spatial decisions in juvenile Iberian rock lizards (Lacerta monticola)

“…Pheromones also convey information about individual attributes, such as age (Martín and López 2006a) and sex (López and Martín 2005). In addition, lizard discrimination of conspecific chemicals is often functional in juveniles (Hanley et al 1999;Font and Desfilis 2002) and, in the common lizard (Lacerta vivipara), was shown to play a role in dispersal; philopatric and disperser juveniles differed in their responses toward conspecific chemical cues (Léna et al 2000;Aragón et al 2006a, b;Cote and Clobert 2007).…”