Hi,
It seems to be random like the pieds.
But since you are going to be looking at the animal for 30 odd years or so it makes sense to me to pay a little extra for the one you think looks the best.
I would also pay extra for one that had a look I wanted to use in a project - say blackbacked ( the "barbed wire" look ) or reduced. I want one with nothing but black dots or crosses down the back, no pattern on the side at all, to mix with a reduced lemon pastel ( if I can find one ) to try and make my dream bumblebee.
dr del