As I understand it, visual symmetry is generally a bad thing when trying to camouflage oneself. Supposedly the human eye more easily spots symmetrical objects, and presumably other animals do as well, since sport hunters seem to find that military-style camouflage principles work successfully for them. Now, there are plenty of animals with cryptic coloration, whether to avoid predation or to prey more successfully, yet it seems that almost all of them retain a bilaterally symmetrical color pattern. It’s obviously not impossible to breed asymmetrically colored animals, as any visit to the dog pound demonstrates, so why don’t more animals have disruptive, asymmetrical face patterns like those used by military snipers? It seems like this would give them a significant edge over their more symmetrical kin at concealing themselves effectively.
The only reason I can come up with for why this doesn’t happen is because of sexual selection: bilateral asymmetry could suggest a physical disorder, which would appear unattractive to potential mates, and so such a coloration pattern would never have a chance to establish itself. Yet this obstacle clearly wasn’t a deal-breaker for the fiddler crab or the hooded seal. Is there some other principle at work that tends to prohibit asymmetrical camouflage in animals?
I am not aware of anything other than developmental constraints that would cause this.
However, it should be pointed out that, except for moths and a few other animals that rest on tree bark, both sides of the symmetrical pattern are often not going to be visible to a predator.
Also, it would be simple enough to disrupt a symmetrical pattern by holding the wings or legs on either side of the body at different angles. Few insects seem to do this, so that it would seem the advantage is probably insignificant.
I think perspective may play a part in it. To a large animal, like a person, the collection of leaves, twigs, and trees in a forest seems random. And so an asymmetrical camoflage appears to work best. But to a smaller animal, like a leaf hopper insect, it’s world is full of symmetry. Leaves, flowers, and branches all have their own patterns. Each flower has so many petal of a particular shape; leaves are generally symmetrical folded lengthwise and come at regular intervals on the plant stem. Likewise, branches, though less patterned than flowers and leaves, generally have branches in an alternating pattern and a steady distance apart with a steady tapering. Perhaps it is in the creature’s best interest then to adopt a symmetrical camoflage to fit into its environment.
Also, perhaps asymmetrical camoflage could result in an animal with excellent camoflage on the left, but none on the right. The right color blotches on one side but none on the other.
Human made camoflage asymmetrical, but it is carefully planned and designed to look random and natural from all sides no matter how you cut the clothe.