I actually voted for size..but I am beginning to wonder more if it may not be the most important.
Doesn't it make sense that when trout for instance are feeding on scuds or sowbugs that there are different sizes of them being taken from the bottom or fish are seeing various sizes floating by? The fish are not going to encounter just a size 18, or a size 16 as they wait..Think about it like a crowded sidewalk, we see all sizes of folks walking by. IMHO they are feeding on all sizes, its just opportune what they hit. I also don't believe that fish are keying in on specific colors, only shades of colors. So maybe shape is the most important..the fish, in its infinite wisdom, which is very little, says to itself...now that looks like something I have eaten before. I know very little about entomology, or the cycle of these bugs, so I may be completely off base here. Now, a hatch may totally require the proper size. When there is a midge hatch, are all of the emerging insects the same size?....Dano