Alternative behavioural strategies and hormone profiles of male tawny dragon lizard colour morphs (#709)
Multiple and discrete colour morphs may persist within a population when they represent different fitness optima, manifested as alternative life history, behavioural reproductive or ecological strategies. We tested whether male throat colour morphs of the tawny dragon lizard, Ctenophorus decresii, potentially exhibit alternative strategies by assessing differences in morphology physiology and behaviour. We measured body size and condition, performance (measured as bite force), corticosterone and testosterone hormone profiles, conspecific aggression and predator response (flight distance) of morphs in a wild population. Morphs do not differ in their morphology, condition, performance or hormonal profiles however morphs do show morph-specific behavioural differences. Similar to findings in other throat colour polymorphic lizards (Uta stansburiana, Ctenophorus pictus and Podarcis melisellensis) in which orange/red colour morphs adopt a dominant strategy, in C. decresii the orange morph shows consistently high aggression to all conspecific coloured model intruders. The grey morph shows the lowest levels of conspecific aggression and boldness in the face of predators implying a cautious strategy while the aggression of the yellow morph was conditional on the colour of the intruder. We discuss the implications of these differences in behaviour for possible mechanisms maintaining this colour polymorphism.