I never really thought about it until now, but translucency is a pretty efficient form of camouflage. Why waste energy on pigments that may not meet all your needs?
I spotted this common green darner (iNaturalist) in my tomato vines on a cold morning. It took me a little bit to realize what was right in front of me. Then my Master Naturalist brain kicked in.
My daily ritual of inspecting my vegetable garden includes some time spent looking for these:
As most growers of solanaceous plants know, a single one of these caterpillars can do a significant amount of damage to a tomato plant. And yet, due to their perfect coloration and patterns, they almost exactly mimic the curls, veins and shading of tomato leaves. Finding them can be difficult.
It’s a trick. There isn’t a hornworm in that photo, as far as I know. (I tend to look for the damage the hornworm does first, then find the worm from that.)
But take the hornworm off the tomato plant, and it sticks out like a… meal for a voracious wasp.
But if you can swing transparency like the dragonfly, your camouflage is almost perfectly adaptive without pigments or fancy mechanisms to change your coloration. Roost in any shrub or tree, and you’re mostly hidden provided your body also looks something like a twig or branch. Great for a wide-ranging generalist like the dragonfly. No need to spend time searching for the right host plants. Like this southern pink moth: