Personality-dependent passage behaviour of an aquatic invasive species at a barrier to dispersal

Abstract

Intraspecific variation in personality traits is increasingly recognized as an important determinant of invasion success and is associated with the dispersal ability of several invasive species. However, previous studies have focused on the dispersal of invasive species through continuous habitats, despite the high levels of anthropogenic fragmentation in modern environments. This study investigated how personality influences the behaviour of aquatic invasive species at an anthropogenic barrier to dispersal, using the passage behaviour of American signal crayfish, Pacifastacus leniusculus , at an experimental Crump weir as a model system. Personality was characterized by determining the repeatability of boldness, activity and sociability, with correlations between traits indicating behavioural syndromes, while passage behaviour was quantified as motivation and subsequent ability to pass the weir. Boldness and activity were repeatable and positively correlated, indicating a boldness–activity syndrome. However, sociability was not repeatable and was therefore not classified as a personality trait, potentially as a result of the confounding effects of social hierarchy formation. Bolder individuals tended to be more motivated to pass the weir, although motivation was not related to activity. Few individuals passed the weir, and personality was not related to passage success. This study evidences the presence of behavioural syndromes in signal crayfish and demonstrates that personality can influence the motivation of invasive species to expand their range in a fragmented habitat. Although no relationship with passage success was observed, the higher levels of motivation in bold individuals may lead to differential passage success in natural situations where the time to attempt passage is not constrained by experimental conditions. • Signal crayfish personality and barrier passage behaviour were assessed. • Boldness and activity, but not sociability, were repeatable personality traits. • Crayfish demonstrated a boldness–activity behavioural syndrome. • Bolder crayfish were more motivated to pass the weir, but were not more successful. • Activity and sociability were not related to crayfish passage behaviour.