On a trip across the country I came across a store that had open doors to the outside. Hung up around the edges of the doors were zip lock bags full of water. The woman told us that it cut down on the flys that came into her shop. She said before the bags the flys made the shop pretty unbarable and after the bags there were only ever a few flys. She thought the reason had something to do with the air bubbles in the bags messing up the fly’s vision and it confused them. Has anyone else heard of such a thing, or would anyone have any idea why it might work?
I was reading about this somewhere very recently. . .if only I could remember where. Apparently, the light moving through the water causes lots of visual movement. The flies read this as high possibility of predators and steer clear. Or something like that. Bottom line is, it seems to work.
Maybe you read it here?