Detection of prey odors underpins dietary specialization in a Neotropical top-predator: how army ants find their ant prey

1. Deciphering the mechanisms that underpin dietary specialization and niche partitioning is crucial to understanding the maintenance of biodiversity. New world army ants live in species-rich assemblages throughout the Neotropics and are voracious predators of other arthropods. They are therefore an important and potentially informative group for addressing how diverse predator assemblages partition available prey resources. 2. New World army ants are largely specialist predators of other ants, with each species specializing on different ant genera. However, the mechanisms of prey choice are unknown. In this study, we addressed whether the army ant Eciton hamatum: 1) can detect potential prey odors, 2) can distinguish between odors of prey and non-prey, and 3) can differentiate between different types of odors associated with its prey. 3. Using field experiments, we tested the response of army ants to the following four odor treatments: alarm odors, dead ants, live ants, and nest materi...