Hawaiian Banana Butterflies…did they evolve mouths made to eat bananas…?
First a clarification: it’s the larvae (caterpillars) that eat banana leaves, and not the fruit. Caterpillar mouthparts are specialized for cutting and chewing, so the “jump” between eating one type of leaf to another leaf that is similar in consistency, thickness, etc. is not so dramatic. In fact the chemical differences are probably more important, so there must have been physiological changes that allow/drive these caterpillars to eat banana leaves. 1. I don’t think anybody saw the changes, since nobody was looking for them. Change is easy to see in retrospective, once it’s happened. But more importantly, a recent (2007) study based on molecular data estimates that the divergence of these specialized species happened “on the scale of millions, and not thousands, of years ago, suggesting that banana is a secondary host for these species, and that they originally diversified on native hostplants that may now be rare or extinct” (quote from
