Millions of years back, they apparently grabbed the genes for making carotenoids directly from a carotenoid-producing fungus. And then incorporated those genes into the aphid genome.
These structural changes on the protein's surface kick off a cascade of events that affect the expression of genes, such as those that turn carotenoid production on and off.
Go green, like honeydew melons, green peas, spinach, and collards to supply important carotenoids that reduce the risk of cataracts and macular degeneration.