Field evidence for colour mimicry overshadowing morphological mimicry

1. Imperfect mimicry may be maintained when the various components of an aposematic signal have different salience for predators. Experimental laboratory studies provide robust evidence for this phenomenon. Yet, evidence from natural settings remains scarce. 

2. We studied how natural bird predators assess multiple features in a multicomponent aposematic signal in the Neotropical “clear wing complex” mimicry ring, dominated by glasswing butterflies. 

3. We evaluated two components of the aposematic signal, wing colouration and wing morphology, in a predation experiment based on artificial replicas of glasswing butterflies (model) and Polythoridae damselflies (mimics) in their natural habitat. We also studied the extent of the colour aposematic signal in the local insect community. Finally, we inspected the nanostructures responsible for this convergent colour signal, expected to highly differ between these phylogenetically distinct species. 

4. Our results provide direct eviden...