THE EFFECTS OF BOLDNESS ON THREAT-SENSITIVE DECISIONS IN FISHES

Personality describes the consistent, individual differences in the behaviour we observe among human and non-human models alike. One of the components of human and animal personality which has sparked interest, is the boldness trait. Boldness is the propensity to engage in risk taking behaviour, and as such, has important ecological impacts on the interactions between animals. By changing the amount of risk taking behaviour, boldness effectively alters the outcome of predator-prey interactions. Boldness may alter a prey’s decision between an antipredator response or continuing other important behaviours (e.g. foraging or reproduction) when faced with a predator. The difference in response may be the result of a changed perception in the amount of local risk, or due to a differential amount of information gathered from the environment. In either case, more information about local predators increases the likelihood that a prey will appropriately respond to a threat. In aquatic systems, prey often receive chemical information from the scent of predators or chemical released by conspecifics. Specifically, alarm cues are released following damage to the skin tissue of many prey species and thus are reliable indicators of risk. These alarm cues are often the first line of prey defense, as they degrade slowly and are passed through the aquatic medium in currents. Secondary information regarding local risk often comes from the visual cues associated with the sight of a predator or frightened conspecifics. This provides prey with reliable information about risk since the transmission distance of visual cues is limited in water and further lessened by vegetation and turbidity. My experiment demonstrates that boldness in fathead minnows (Pimephales promelas) is stable over shorter temporal scales, and subsequently, affects how minnows acclimate to their environment and respond to visual and chemical information on local threats. In low risk environments, personality and turbidity strongly affect the threat-sensitive response of minnows. Shy minnows demonstrate no antipredator response when in turbid water and bold minnows elicit a strong fright response in turbid conditions. In clear conditions, the opposite occurs with large fright responses in shy minnows and no response in bold minnows. Conversely, when minnows were exposed to high amounts of environmental risk through the exposure to alarm cues, they all elicit strong fright responses regardless of personality or turbidity. This is the first experiment to investigate the complex interplay of personality and multiple cue types on the threat-sensitive response of prey fish