I have a red helmet. It may be my imagination but insects seem to veer into my path while riding.
Possible but not likely. Most insects see lots of UV detail and contrast in addition to visible lightwaves. Although I remember something about the color blue and bumblebees.
I have a white helmet but during the spring I get bugs everywhere; in the helmet, down the jersey, in my ear, armpit, sock, legs and arms. It has everything to do with where and when you ride. Keep your mouth closed when riding near a flowering meadow and get good at taking your helmet off as soon as you hear the tell-tale impact. Yellow jackets will sting AND bite you as many times as they can before you get rid of 'em.