Meeting Abstract
The evolution of morphological specializations across prey species might be driven by differences in the predators that species encounter. Species that are separated geographically often experience different predator regimes which might also require different predator-avoidance strategies. Amphidromous goby fishes provide a system that experiences a spectrum of predator regimes across their different habitats, making them an excellent system for studying how such regimes relate to prey morphology and behavior. For example, on the islands of Hawai’i and La Réunion, goby species that cannot climb live consistently with predators throughout their life. However, some goby species can climb waterfalls, which allows them to either live in predator-free (Hawai’i) or diminished-predator (La Réunion) environments as adults. We expected to find distinct body shapes across the adults from each regime, depending on the type of anti-predator strategy that each species prey used. Fish using a morphological strategy should have traits that physically hinder consumption by predators., whereas those using a kinematic strategy should have traits that assist in the production of thrust. To test these predictions, we used geometric morphometrics to quantify differences in body shape across six goby species that experience different predator regimes. We found that fish living consistently with predators have deeper bodies that would be harder to consume than those that can climb. Among climbing gobies, those that face diminished predation have longer posterior bodies, possibly allowing for a greater output of thrust compared to species from predator-free environments. These results support our prediction that morphology, and consequently the predator-avoidance strategy it facilitates, varies between predator regimes.
