
In 38 years, this is the first I have heard an observation like this. Sorry. You could be getting heavy dew over night that is trapping some insects perhaps.
+1. Can't say that I have every hear of this as well.
Todd's answer is a solid hypothesis. I am sure the birds will be loving all the extra activity.
We are new to our metal roof (about one month) and this forum. We are noticing lots of dead flying insects (flying ants, wood bees, etc. ) since our metal roof was installed. Many are on the roof itself, dead, and many are on the ground, where they'd come off after a rain. I noticed, a few times, while on a part of the roof, that flying insects were attacking it, repeatedly bumping into it..... is there some "science" to this? Are these insects attracted to the reflectivity of the metal? That is one theory I have. Any expert observations would be appreciated.