floral fridays -- yellow first?

Is it just an accident of the daylilies that I've gotten? Or is there some bigger reason that the first blooms we have are yellows?

This week we saw our first blooms. First we had Happy Returns (Apps, 1986). Now, joining the party is Sweet Seneca Kisses (K. Rood, 2003). There's also a yellow noname, and another one that'll probably bloom tomorrow. We think it's Eenie Weenie (Aden, 1976) -- hopefully we'll have a better idea once it blooms. Now, we have lots of cultivars in lots of different colors. Reds. Oranges. Purples. And that includes a lot of bi-colors and multicolors.

Is there a reason the yellows come first? I can speculate that it takes less energy for a plant to make the pigments needed for a pale yellow flower than for a brighter or darker one. But that would just be me pulling explanations out of my butt. I wonder if other daylily enthusiasts see the same phenomenon?