Not all warning colouration signals toxicity

Just don't bother BRIGHT colours in the natural world are often a warning. In the case of tiger snakes, blue-ringed octopuses, arrow-poison frogs, hornets and many other species, the warning is that the animal carries toxins that will sicken or kill. Thus it was that Alfred Russel Wallace, co-inventor of the theory of natural selection and an avid insect collector, proposed that the beautifully coloured Pachyrhynchus weevils of eastern Asia and Australia were dangerous. Yet, after spending hours...