I say ants also, although mosquitoes are carrying all sorts of diseases now. Fire ants are not as big a problem to me as carpenter ants are. They live in the mulch and in my compost bin and they swarm and bite like crazy. Now I wonder if they aren't those crazy ants. I am going to have to take a closer look - which won't be hard, they are everywhere. I know of people who have died from fire ant bites, few die from mosquitoes so ants are the bad guys!