Underlying tendencies of behaviour: Examining stress and anxiety in convict cichlid fish

Abstract

Animal behaviour varies across hierarchical levels made up of behaviours, personality traits, and behavioural types/syndromes. Stress coping style and anxiety are examples of behavioural types, or covariance of personality traits within individuals, and can be influenced by prior stress exposure. A common test used to measure anxiety in rodents is the elevated plus maze, and here an adapted version for use in fish (the submerged plus maze) was validated using the benzodiazepine diazepam. I show that fish spent more time in and entered more open arms of the maze after diazepam exposure than after vehicle exposure, mirroring validations used for the elevated plus maze. The submerged plus maze maintains construct validity for testing anxiety in fish. The effect of developmental stress exposure on adult convict cichlid fish personality traits and a behavioural syndrome was examined. At the individual level, significant effects of early life stress were not seen in adulthood on personality traits, though stress exposure did result in the disruption of the formation of an exploration-boldness syndrome that was present in the unstressed population. These results suggest that an exploration-boldness syndrome is the default syndrome in convict cichlids but may not have provided adaptive benefit for fish in the stressed population due to the level of predation stress in their developmental environment and was therefore not formed. I have demonstrated behavioural plasticity in response to environmental manipulations.