This lovely little Cabbage White butterfly (Pieris rapae) really stands out against the beautiful flowers of the 'Santa Cruz' Oregano. It might seem unsafe, for a small creature, to be so visible in a habitat garden full of other creatures; but the white color sends a warning to visual predators.
Birds with some experience know that this butterfly is distasteful! That's because the white coloration in the wings comes from a waste product called a pterin; but instead of being excreted, the compound is used to color the wings. Pterin is just one of several types of pteridines which are closely related to uric acid, and chemically very similar to the white paste in bird droppings.
The larvae feed on Cabbage family plants, many of which contain mustard oil glycosides and sulfur compounds; these chemicals are passed on to the adult stage, where they are sequestered in the wings of the butterfly and add to the very disagreeable taste of this little creature!