It's the heat that attracts. Those look like red wasp nests. Been there, done that.There does seem to be a strange relationship between magnetic fields and some flying,stinging insects!
This summer we were working up on extension ladders, doing maintenance on medium voltage switches up 25' in the air... the cross bar that the switches are attached to is a square tube where the ends are sealed with a square plate, but the corners are notched out to... it was the perfect home for bees. We emptied every can of wasp killer we had by the end of the day. At times you'd be climbing the later, half way up look up and realize you're climbing into a haze of wasps. By the end of the day we'd be spraying at them mid flight while climbing up the ladder making it a contest. It was something, somehow managed not to get stung :thumbup: I also learned that bees love to make nests on the bottom of transformer throatsI think every single weather head on a pipe service I've pulled off has has a nest or 3 in them. I jump back everytime but so far (knock on wood) I've never ran into a live one! That day is going to come on top of an extension ladder fully extended I'm sure.