And here’s an answer!
Peppered Moth Evolution
Andrew, like danly said, that’s a great question about camouflage! Here is one take on it:
There is a distinction between self-awareness and mechanical sensory perception, but it’s a continuum.
To have true self-awareness, an animal would need an internal model of itself: “My abdomen is 580 nm yellow”, and it would have to compare itself to an external object: “That petal is 580 nm yellow; therefore I belong there”. Very few invertebrates show this level of self-awareness.
Instead of thinking about matching, these animals operate on simple behavioural rules shaped by natural selection:
- Example rule: “Move towards visual stimuli that produce low colour contrast”
- Example rule: “If your green receptors are stimulated, then stop and adopt a hunting posture”
To us watching the spider, it looks like the spider “knows” that it matches the petal, but internally, the spider is following mechanical stimuli that do not require any concept of self-colour.
For cuttlefish — which are some of nature’s most spectacularly coloured animals — the colour system is mostly automatic, but they can control it if they think about it, similar to our breathing.
So animals like the spider are not checking their reflection in a drop of water. For them, evolution bypasses the need for self-awareness. Natural selection favours individuals who run a kind of automatic program which puts them in places where they blend in. As animals get smarter (like cephalopods, and extending to humans), more thinking and self-awareness kicks in.
I’ve always wanted to see a walking stick. Maybe I have, without realizing it 
Found this assassin bug nymph in the jungle in North Sulawesi. Incredible camouflage work. I think it’s genus Acanthaspis
https://www.inaturalist.org/observations/404662988
This medium sized crab from intertidal sea grass beds on Bunaken Island North Sulawesi is a mind messing work of camouflage. It really cannot be seen except when it’s moving. If you look at the lower left part of the main mass you can make out the legs. The eye stalks are whitish centre right. The creature is facing to the right but fair enough if you can’t see it. It’s decorated in sand and dead sea-grass to the extent that its form cannot really be made out
