A parallel geographical mosaic of morphological and behavioural aposematic traits of the newt, Cynops pyrrhogaster (Urodela: Salamandridae)

Abstract

Aposematic animals advertise their unprofitability to potential predators with conspicuous coloration, occasionally in combination with other life-history traits. Theory posits that selection on functionally interrelated aposematic characters promotes the unidirectional evolution of these characters, resulting in an increase or decrease in the effectiveness of the signal. To test whether this prediction applies on a microevolutionary scale, the intra- and interpopulational variations in aposematic coloration, behaviour (which enhances the effectiveness of the coloration) and body size of newts, Cynops pyrrhogaster (Urodela: Salamandridae), were investigated. A parallel geographical mosaic of variation in aposematic coloration and behaviour among populations, independent of body size, was found. Newts on islands displayed more conspicuous aposematic traits than those on the mainland, both morphologically and behaviourally. There was no significant relationship between variation in coloration and behaviour within populations. Male newts displayed more conspicuous coloration than females. Surveys of potential predators suggest that variable natural selection at a local scale, such as predation pressure, may primarily be responsible for the microevolution of variable aposematic traits in newts. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 97, 613–622.