Status‐signalling chemical badges in male Iberian rock lizards

Abstract

Summary 1.Male competition for females often results in the evolution of conspicuous male traits that signal fighting ability or dominance status. Most studies examining mechanisms allowing these traits to function as reliable status signals (or badges) have focused on conspicuous visual or acoustic traits. However, many animals communicate chemically, and chemical traits alone may also signal male dominance status. 2. We examined whether chemicals in femoral gland secretions of male Iberian rock lizards ( Lacerta monticola monticola Boulenger 1905) may signal dominance status. 3. In staged encounters, larger males were dominant over smaller ones. While controlling for male body size, males of higher dominance status produced femoral secretions with higher proportions of hexadecanol and octadecanol. 4. Tongue-flick assays showed that males were able to (1) discriminate, by chemosensory cues alone, the different concentrations of hexadecanol from other chemicals presented in femoral secretions; (2) respond aggressively towards hexadecanol while responding neutrally towards other chemicals; and (3) show differential chemosensory and aggressive behaviours towards hexadecanol according to their own dominance status. 5. These results suggest that hexadecanol may be a reliable status badge. Moreover, because hexadecanol elicits male aggressive behaviour, subordinate males signalling high status ('cheaters') may end up paying high fighting costs. In addition, males that had higher dominance status, and that allocated higher proportions of hexadecanol to femoral secretions, had greater T-cell immune responses. This result suggests a possible link between quality of the immune system, dominance status, and chemical signals.

Responses of female rock lizards to multiple scent marks of males: Effects of male age, male density and scent over-marking

“…For example, in many lizards, scent marks may give information on sex, body size, or age recognition (Aragón et al, 2001a;López and Martín, 2001;reviewed in Mason, 1992;Mason and Parker, 2010;Martín and López, 2011), or even provide more detailed information on morphological traits and health condition of the signaller (López et al, 2006;Martín et al, 2007a). This information seems important in intrasexual relationships between males Martín, 2002, 2011;Carazo et al, 2007Carazo et al, , 2008Martín and López, 2007;Martín et al, 2007b) and in female mate choice López, 2000, 2006a,b;López and Martín, 2005a;Olsson et al, 2003;Martín et al, 2007a). Therefore, scent marking a territory might initially be a simple and effective method to inform on the identity and characteristics of the male that defends that territory.…”

Chemical Constituents of the Femoral Gland Secretions of Male Tegu Lizards (Tupinambis merianae) (Family Teiidae)

“…This information may be used by females to select scent marks of some individual males, which suggests pheromonal mate choice (e.g., López, 2000, 2006a;López et al, 2002López et al, , 2003Olsson et al, 2003;López and Martín, 2005a). Compounds in femoral gland secretions may also provide information on fi ghting ability or dominance status to other males (Aragón et al, 2001;Carazo et al, 2007;Martín et al, 2007b).…”

Social control of unreliable signals of strength in male but not female crayfish,Cherax destructor

“…When the costs of fighting are high, it is mutually advantageous for opponents to passively establish dominance using signals of potential fighting ability (Maynard Smith, 1974;Sneddon et al, 1997;Martín et al, 2007). Agonistic interactions over resources should then be decided through an asymmetry of the signal, which represents an individual's resource holding potential (RHP) (Parker, 1974;Maynard Smith and Parker, 1976).…”