Behavioural analysis of the American bullfrog (Lithobates catesbeianus): personality, behavioural syndromes and the effect of chronic exposure to thermal stress on behaviour

Abstract

Recently, regarding behavioural studies, the expression of consistent individual differences (CID), also known as personality or temperament, has received attention from several different areas of research. Furthermore, the expression of behavioural syndromes - correlations between different suites of behaviour (e.g.: exploration-aggression) - have also been verified. Studies on personality have identified its relevance in several ecological contexts, e.g., dispersion, biological invasion, and antipredatory response. In the recent scenario of anthropic environmental change and global warming, it is thought that personality differences can be important to understand how these changes affect, for instance, species distribution, as well as contributing to the development of novel conservation strategies. For such, ectotherms are excellent animal models due to their dependence on different microclimates necessary for maintaining their body temperature inside their thermal tolerance limits. However, experimental studies involving different temperature regimes are mostly focused on acute exposures, hindering predictions on how a scenario of constant and permanent change in temperature would affect variables such as behaviour. The aim of this project is to characterize personality and behavioural syndromes in adult males of the American bullfrog (Lithobates catesbeianus), focusing on the behaviours of activity, boldness, and exploration, as well as analyzing how chronic exposure to different temperatures and thermal stress affects behaviour in these animals. Furthermore, we will analyze how behavioural variables correlate with physiological variables, namely, plasma corticosterone levels and plasma bacterial killing ability, a measure of innate immunity, allowing us to correlate behavioural changes and thermal stress.