One of the first things I did after my first week out with the rig last spring was to change the standard white bulbs to amber, as that was my thinking also. Finding amber bulbs wasn't hard (at any auto parts store), and I quickly switched them.
Well, the first week with the amber bulbs over the doors was good. Hardly any insects congregating over the doorways, and I thought..."ok, this'll work."
Moved the rig about 200 miles away for the next week, and the bugs were back. As I continued moving around the next few weeks, pretty much the same result no matter where I went.
After getting back home where I could make a few other convenience mods to the rig... I ordered some blue bulbs over the internet and decided to give them a shot.
Took the rig back out for a few trips... and while there are always a few flyin' critters that still wanna hang out above my doorways, I'm pretty sure that there aren't near as many as there used to be. Of course, that could just be a subjective guess... but I think they work better. Your mileage may vary...