Colour patterns in müllerian mimetic species are strongly related to the evolution of chemical defences. One of the classic examples of mimicry is the Heliconius butterflies, where there is a high geographic variation of mimetic rings. Despite extensive research on the colouration and toxicity of this group of butterflies, the relationship between these two traits is still understudied, and whether the warning signal is quantitatively honest is unknown. In this study, cyanogenic compounds and colour contrasts of two mimetic rings were quantified under different light conditions and two models of bird vision. The correlation between these two variables was evaluated using linear models (lm). No correlation was found between colouration and toxicity, but there was a correlation between the latter and the species. In addition, variation was found between the chemical profiles of species in the same ring and between geographic locations. Other factors such as resource limitation (e.g. host plant) could explain the toxicity associated with the same colouration pattern.
