Meeting Abstract
Evolutionary arms races between predator and prey drive the evolution of life. These races do not occur in isolation, but involve complex interactions between organisms, and with their environments that shape the outcomes. Understanding how these interactions constrain or promote adaptive evolution is a fundamental problem in biology. In teleost fishes, body shape and spine length have evolved synergistically to overcome the gape-limitation of predators. Here we reveal a breakdown of this evolutionary synergy in an iconic group of coral reef fishes. Our phylogenetically informed analyses show that deep-body shapes are highly conserved, while spine lengths and other defensive traits have evolved adaptively in relation to foraging strategy. Species that obligately graze on corals have reduced defensive morphologies, suggesting environmental constraint and a reliance on protection from corals. Moreover, we show that transitions to solitary behavior result in consistent shifts to more robust defenses. The shift is most pronounced in benthic hunters, highlighting the higher risk of predation faced by species with this foraging strategy.
