Cave Astyanax: Hunters or scavengers? Evidence from gut contents

Astyanax cave fish has been a particularly helpful model to study the role of evolutionary development and biological processes in caves. Despite a plethora of studies, it remains unclear what the food sources actually are for adult Astyanax in their natural cave environment. Gut contents of an eyeless specimen from Caballo Moro cave included a troglomorphic isopod and a water flea. This is the first instance where an actual stygobitic species has been reported to be a food item for adult Astyanax .  Furthermore, there is good evidence that this adult fish hunted and preyed upon live crustaceans. Up to now, it had been a conundrum as to why adult cave Astyanax presented Vibration Atraction Behavior when previous studies had only come our with bat guano in their gut contents. We report here that adult Astyanax can also be active hunters of crustaceans, which may vibrate at such frequencies.