Sustained Anxiety-Like Behavior in Crayfish Exposed to Thermal Burn

Abstract

Both invertebrates and vertebrates make immediate simple reactions to noxious stimuli; a tail flip to escape is a typical example in crayfish. More complex sustained emotional responses, such as anxiety or fear, can be demonstrated in many vertebrates but until recently have not been seen in crustaceans. Several recent studies have found sustained anxiety-like behavior (ALB) in crayfish in response to electric shock and social bullying, and this behavior can be suppressed by anti-anxiety medications. In this study, crayfish were subjected to a thermal burn stress, and then observed for ALB in an established model (light-dark maze). Stressed animals spent almost all of their time in the dark zone, in contrast to unstressed crayfish, who demonstrated normal crayfish exploratory behavior. In this model, crayfish clearly demonstrated ALB in response to stressful burn. This research has implications for humane treatment of crustaceans.