This is going to sound like the dumbest question but like are we any closer to understanding like how bugs pick their wing disguises? I know why, like I know they want camouflage, but how in the fuck do they get to the point they're creating scary eyes or OTHER bugs on their wings like what the fuck.... what the fuck??
Easier than it sounds!
Color pattern is one of the most variable things in any population; no two members of this species have EXACTLY the same markings, even if the markings still tend to look very remarkably like a couple of false flies. Some are even born with no markings at all, or extra blotches that totally ruin the effect!
So they probably started out as flies who had relatively ordinary spots on their wings, not anything surprising, and this would be what happened:
One day a predator hesitated, because it wasn’t sure whether to attack the body or one of the dark wing-spots. This meant this particular fly survived to have babies, passing on its genes for particularly dark and well-defined wing spots!
This may have become the norm for the average member of its species in a few generations of this happening, so long as it was effective on their most common natural predator, such as a jumping spider or another predatory fly (very common, it’s pretty much a fly-eat-fly planet)
Every generation still has a lot of variety in marking shape, positioning and color so all it takes is one with some branching lines (easy!) that a predator might mistake for “legs” even if they’re not perfect.
A little darker spot in the middle of it might also enhance the effect, giving the predator something conspicuous to be distracted by.
It still doesn’t need to look just like a picture of a fly to be effective, so long as it’s more confusing than the plain, ordinary spots they started with generations before! Which it probably is!
Flies make lots and lots and lots of babies, so you’re getting MILLIONS of slight variations every single year.
The wing markings aren’t the only thing that determine who lives and who dies, obviously, but if they make even 1% of a positive difference they are inevitably going to keep being refined by the eyes of their own predators.
Without knowing it, all their visually-oriented predators are gradually pushing the whole population to skew heavily in favor of all the most effective survival traits at once.
By this constant process of selection repeated probably a trillion times a century, the flies are bred for those amazingly convincing patterns as surely as if an intelligent force were hand-picking the best of them to breed.
It even works in the other direction, like maybe a fly is hatched whose markings are TOO detailed and maybe that’s actually bad for it, maybe it’s too easy for something to see it at a distance now. The trait inevitably hits a “sweet spot” and balances out.
This is going on with EVERY aspect of every living thing! Even every other aspect of this fly! Notice its real body and eyes are much lighter in color and probably blend with the surroundings better, so some predators probably see *only* the two fakes!
Not all fly species develop this same defense because not all of them have the same exact predators, and wing markings just aren’t always the first thing they genetically hit on! Maybe what worked for another fly was just getting faster, or seeing farther, or tasting bad, or having sharper bristles! With so many different predators whose methods can also change up over time, any species can go off in just about any direction that works…………or it falls behind and it goes extinct.
Basically there isn’t any difference at all between the way we humans consciously, deliberately breed animals for certain traits (like how we turned big dogs into tiny dogs or tasty fruit into tastier fruit) and what all species are doing to each other all day, every day by just trying to live. It’s a common misconception that “selective breeding” and “evolution” are different things but they’re not, evolution is positively nothing but what happens over tremendous periods of selective breeding, and anything at all that can kill an animal - be it another animal or the very weather - is one way or another selectively breeding it! Endlessly!
