One finding that comes to mind is the fact that of the flies that do land on the zebra pelt, nearly all (75%) land on the black stripes. This suggests that something more is happening than just identifying the zebra as an unappealing target.
You also have experiments like this, where painting Japanese cows in zebra stripes was an effective fly deterrent, even though the flies there have no evolutionary history with zebras. (It's worth clicking just for the photo of the test cow.)
1. It's possible that Japanese flies are repelled for different reasons than African flies.
2. It's possible that flies are repelled both because the stripes interfere with the flies' vision in some way, and because the (African) flies prefer other animals.
Nice, thanks. The original article's claim that "Though the effect of stripes on flies is well-established, the source of the effect remains unexplained." is over-broad and incorrectly pessimistic.
You also have experiments like this, where painting Japanese cows in zebra stripes was an effective fly deterrent, even though the flies there have no evolutionary history with zebras. (It's worth clicking just for the photo of the test cow.)
https://journals.plos.org/plosone/article?id=10.1371/journal...