I was riding around Klamath Lake in Southern Oregon some years back on my SV before I added the windscreen. It turns out there is a particular kind of fat-bodied gnat that swarms for miles and miles... If I would have let their remains dry, I could have peeled them off in a solid (and thick) layer from my helmet, jacket, pants, gloves and bike. Pretty disgusting...
I was almost killed, on my old CB650, by a swarm of miller moths. They had swarmed around a street light, on a corner, and the road had become greased with them. I skidded out and barely made it between the light post and a fire hydrant, that was next to it. I managed to keep the bike upright over a big tree stump, I'm glad they cut it close to the ground, but had to lay it down when the next obstacle was as big as a house. It was a house. A small knee dent to the tank was the only damage. I shook like a leaf for about a half hour and had a couple smokes, before I could continue the ride. BUGS SUCK!