When and where will strong biotic interactions arise within communities that receive biological invaders? For predatory invaders, existing prey selectivity data are of limited use for predicting future consumptive interactions because they are specific to the identity and relative abundance of species in a particular assemblage. We investigate whether the strength of consumptive interactions can instead be predicted based on a priori knowledge of morphological and behavioural traits that recur across species and are hypothesized to affect the predation process. To test this ‘traits-based’ approach, we conducted multi-species foraging trials with coral-reef fishes in the Caribbean, a diverse, trait-rich fauna for which interactions are likely shifting rapidly due to the introduction of predatory Indo-Pacific lionfish. We evaluated predictions about the combined effects of three behavioral traits—water column position of both predator and prey, anti-predator aggregation behavior of prey, and hunting strategy of predators—on successive phases of the predation process and ultimately the strength of consumptive interactions.
Results/Conclusions
Tracking predator and prey behaviors reveals that inter-specific variation in traits mediates encounter, attack, and capture rates. Behaviorally-driven bottlenecks at different stages of the process underpinned selective consumption by each predator species, and resulted in large differences in total predation mortality rates among prey species. Our analysis also suggests that unique behaviors exhibited by invasive lionfish, rather than naïve responses by prey, mediate their foraging success relative to native predators. Our results illustrate how incorporating a priori knowledge about foraging and anti-predator traits can improve predictions of the strength of emergent consumptive interactions caused by global change.