In recent decades, anthropogenic disturbance in natural ecosystems has led to successive invasions by non-native species with negative consequences for native biodiversity and natural ecosystems. While a great deal of research has been done on the later stages of an invasion, few studies have examined the initial response of native taxa to invaders, and the role antipredator behavior plays in mediating interactions between non-native predators and native prey. Often invasions bring into contact species with no common evolutionary history, thus these native taxa may be naïve to the threat posed by the invaders. Behavioral plasticity may allow naïve prey to respond adaptively to novel non-native predators during these interactions and, as a result, behavior may play a key role in promoting the survivorship of prey under a novel predation threat.

By comparing the behavioral response of native prey species to native and recently introduced predators, new insights can be gained on the predatory threat posed by these novel invaders and which native taxa may be more vulnerable to invaders.

In Everglades National Park, fourteen predominantly predatory fishes have invaded and proliferated within the past forty years. Due to the threat these species pose to the native environment, there is a growing need for a better understanding of how these non-native predators interact with native Everglades fishes and macroinvertebrate. In a series of aquaria experiments, we examined the antipredator response of three abundant marsh prey species (mosquitofish Gambusia holbrooki, flagfish Jordanella floridae, and grass shrimp Palaemonetes paludosus) to a native predator (warmouth Lepomis gulosus) and to the recent introduced predator, the African jewelfish Hemichromis letourneuxi.

Results/Conclusions

Results showed that while L. gulosus and H. letourneuxi may have similar predator rates, and that certain prey could experience a release from predation in mixed predator treatments, the antipredator responses of the prey to the novel, non-native predator were similar to the responses exhibited to the native predator, despite prey having no experience with jewelfish. This suggests that these prey are relying on general cues for predator detection. Additional behavioral data suggests that J. floridae rely on visual predation cues to form a response, while G. holbrooki and P. paludosus rely on a combination of chemical and tactile cues for predator detection. Final results from this research will provide an understanding of the sensory information used by native prey to maximize their chances of survival when threatened by novel predators.