Abstract Predation is a critical ecosystem process that shapes the structure and functioning of biological communities. However, due to its intermittent nature, fast pace and general unpredictability, predation is difficult to observe and quantify. Therefore, we commonly rely on indirect metrics or proxies of predation, which reflect the outcome of predation events but do not allow for inference about the predator's decision‐making process or predation rates. In terrestrial ecosystems, lifelike prey replicas have allowed ecologists to gain a broad understanding of predator choice, predation intensity and their drivers. Yet in aquatic ecosystems, few scalable, interactive predation assays have been developed. We introduce Goby Gummies , a customizable, edible prey model developed for aquatic ecology. Gummies are constructed using an inert, edible medium that can be cast into any desired shape (in our case, a goby fish), dyed various colours and supplemented with edible material to introduce variation in nutritional profiles. As such, goby gummies are a cheap, sustainable, high‐throughput assay that can be tailored to a variety of aquatic ecosystems. We performed two pilot studies to test goby gummies in a natural setting on coral reefs in Belize during which gummies were reliably consumed by a range of predatory fishes. First, we show that gummies supplemented with fishmeal were preferred by predators over agar‐only gummies, but the strength of this preference was dependent on their coloration, suggesting an intriguing interplay between external appearance and internal composition. Second, we compared fish‐supplemented gummies to squidpops, a previously developed predation assay for marine systems. Goby gummies were consumed first more frequently and eaten at quicker rates than squidpops and consistently attracted carnivorous predators, whereas squidpops were frequently consumed by herbivorous parrotfishes. Our results highlight that goby gummies provide a new predation assay tool in aquatic ecosystems that permits the exploration of many exciting questions surrounding prey and predator traits and their interplay. We envision goby gummies to kindle a diverse range of impactful studies across disciplines that mirror those conducted in terrestrial ecosystems.
Hemingson et al. (Thu,) studied this question.