How does a fish avoid being eaten by a bigger fish? Evolution could build up defenses such as spines or armor, or favor avoidance strategies such as quick reactions, swimming away and hiding. The rules of evolution are tough, so you cannot really have both, the argument goes.
But this hypothesis has been difficult to test in practice. Now Jennifer Hodge, a postdoctoral researcher working with Professor Peter Wainwright and colleagues in the UC Davis Department of Evolution and Ecology, College of Biological Sciences, has carried out a survey of hundreds of specimens of butterflyfish, carefully measuring their physical traits and defenses compared to feeding style.