Comment Re:Terrible summary (Score 2) 190
I half agree and half don't. Asking why the flies did not evolve to adjust is a good question; most animals do evolve to exploit readily available food sources, not to have seemingly random phobias of them, so there seems to be a large unanswered question. My problem with any evolutionary theory, though, that uses the word "why" is that it's implying causality from correlation, which is a science no-no.
It could be, for example, that flies have some other aversion to zebras -- for example they may have a more effective swatting tail -- and therefore the flies evolved an aversion to zebra stripes. Since we don't have any good tests of ancient fly behavior we can't truly know which came first. It could be that there was some third related causal element... for example if zebras stripes were an evolutionary advantage allowing them to hide from large predators in some particular foliage that appeared striped, and that foliage also housed animals that ate tsetse flies, the flies could have learned not to go near the striped surfaces for reasons unrelated to zebra. Or the two things (stripes and aversion to stripes) could have evolved as a coincidence.
Don't get me wrong, it's a good use of animal demographic data and a very interesting result. I also tend to believe that the result is correct: that the zebra evolved stripes because those with particularly dominant stripes were less prone to disease and problems brought on by fly bites, and this led to a positive selection for those striped traits. I'm just saying it's always going to be a leap to say there's a "why" that any particular evolutionary advance happened, because "why" is vulnerable to the "why not" counterargument, and it's unprovable because no experimentation can (reasonably) be done.