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

Abstract

Faeces play a role in intraspecific chemical communication in many vertebrates, including lizards. Here, we hypothesised that juvenile Iberian rock lizards (Lacerta (=Iberolacerta) monticola) use substrate-borne conspecific faecal chemicals to assess the social environment and base their spatial decisions. To test this hypothesis, we prepared chemical stimuli by dissolving faeces in an organic solvent (dichloromethane, DCM) and conducted chemosensory trials where we quantified latency to the first tongue flick (TF) and TF rates when young captive-borne juveniles were placed in an arena compartment whose substrate was labelled by (1) a control (DCM), (2) their own faecal chemicals, (3) faecal chemicals of another juvenile, (4) faecal chemicals of an adult female or (5) faecal chemicals of an adult male. Following TF observations, we removed a partition that separated the labelled compartment from a chemically unlabelled one, and recorded for 5 min when juveniles first crossed to the unlabelled compartment and total time spent in the labelled compartment. Each juvenile was tested with all stimuli in a randomised order. In addition, juveniles belonged to different families and were unrelated to and unfamiliar with faeces donors. Taken together, TF and spatial responses toward stimuli indicate that juveniles discriminated between faecal chemicals of conspecific juveniles, adult females and males, and that they avoided remaining in substrates labelled by adult male faecal chemicals. We suggest that juveniles assess the social environment based on conspecific faecal chemicals thus avoiding aggression and cannibalistic risks undertaken from encounters with adult males.

Chemical communication in the lacertid lizard Podarcis muralis: the functional significance of testosterone

“…), although there is some evidence that faeces, cloacal secretions and skin lipids may also contain socially relevant chemical stimuli (Cooper and Vitt ; Mason and Gutzke ; Cooper ; Labra ; Moreira et al . ). Epidermal glands of most lizards develop at the onset of sexual maturity, and their activity is often greatest in male lizards and during the reproductive season (Smith ; Cole ).…”

Scat on the doorstep: Refuge choice in a group‐living lizard is influenced by the presence of scat piles

“…For example, obtaining social information rather than territoriality may better explain group‐living otters’ ( Lontra canadensis ) strong investigative behaviours in response to foreign scat (Oldham & Black ). Similarly, some lizards appear to use chemical cues from scats to differentiate familiar and unfamiliar individuals (Bull et al ; Moreira et al ; Wilgers & Horne ). For example, like E. stokesii , E. striolata form aggregations, create scat piles and can discriminate between their own scats and that of conspecifics (Bull et al ).…”

“…In contrast to glandular secretions which are often costly to produce (Buesching et al ), chemical communication from defecation allows signallers to leave public signals at a low cost, which may reduce potentially high‐cost encounters whilst still conveying information on the marker’s social environment. In many taxa, faeces (scat) and urine have evolved to function secondarily as a method of chemical communication (Sprent et al ; Moreira et al ; Buesching et al ). This is well‐illustrated by latrines, defined as the repeated use of a specific site for defecation or urination (Irwin et al ).…”

“…Alternatively, scat‐piling may function as a social marker, playing a crucial role in the mediation of individual and group recognition (Chapple ; Bellamy ). Indeed, previous studies have shown that lizards can distinguish between familiar and unfamiliar conspecific scat (Bull et al ; Bull et al ; Bellamy ; Moreira et al ; Wilgers & Horne ). Despite this, few studies to date have focused on space use and refuge choice.…”

Caracterização quí­mica de secreções de glândulas pré-anais e femorais de espécies brasileiras de lagartos da famí­lia Teiidae (Squamata)

“…Embora os dados que revelam fezes como fontes de semioquímicos sejam conhecidos há décadas (DUVALL et al, 1987), pouco se sabe sobre o seu papel no comportamento social de lagartos e sobre a sua composição química. Machos jovens de Iberolacerta monticola (Lacertidae) são capazes de discriminar entre juvenis, fêmeas adultas e machos adultos apenas com base em informações químicas presentes nas fezes e evitam locais marcados por machos adultos, reduzindo o risco de encontros agonísticos e predação (MOREIRA et al, 2008). Um experimento comportamental, excluindo o caráter visual das pelotas fecais, revelou que machos adultos de Liolaemus tenuis (Liolaemidae) utilizam as informações químicas presentes nas fezes para autoreconhecimento (LABRA et al, 2002).…”