Behaviourally-mediated learning ability in an invasive marine fish

Abstract

Invasive species can have profound impacts in non-native environments, the mechanisms behind which are often unclear. Learning and memory are notably two traits that may facilitate their impact. Behavioural traits can subsequently mediate learning ability in invasive species, the interaction between which may provide means by which to both better understand and manage invaders. We evaluated this relationship in lionfish (Pterois volitans), a species introduced to and invasive in the western Atlantic Ocean. We trained lionfish in a food reward task and assessed the degree to which behavioural traits and navigation strategy influenced their performance. We then evaluated memory retention by subjecting fish to training breaks of 5 to 42 days. Lionfish exhibited high inter-individual variability in learning. Half of the lionfish tested learned to navigate the maze, whose performance was strongly mediated by behaviour. Learning ability was positively correlated with boldness, exploratory tendency, and speed of task completion, but irrespective of spatial navigation strategy. However, fast exploratory fish trained in the complex navigation strategy had difficulty adapting to changing environmental conditions, indicative of a speed-accuracy trade-off. Lionfish were able to remember the location of the food reward for up to 6 weeks. Behavioural-mediated learning may help explain and understand the high impact of lionfish and other non-indigenous species in their invaded range and may elucidate spatiotemporal context-dependencies in their ecological impact.