Meeting Abstract
Within groups, many individuals maintain distinct behavioral phenotypes, or temperaments, with some being reliably more exploratory, social, aggressive, active, or bold than others. These temperaments can influence individual survival, reproductive success and offspring survival i.e. fitness. While research has been conducted on characterizing temperament traits among species, there is still little information on the underlying physiological mechanisms. The objective of this study was to determine the relative stability of multiple behavioral traits and identify underlying physiological profiles. To identify the five temperament categories discussed by Reale et al. (2007) we conducted five behavioral tests repeated 3 weeks apart in a sample of 54 Sprague-Dawley rats. We used the Novel Social Arena, Novel Object Arena, Partner Preference, Social Interaction and Resident Intruder tests. To measure stress physiology, we conducted an acute restraint test and measured glucocorticoid (CORT) responses. Innate immunity and basal CORT were measured during an 8-hour period after injecting rats with lipopolysaccharide. To measure adaptive immunity, rats were injected with keyhole limpet hemocyanin (KLH) and relative hindfoot swelling (RHS) measured in response to re-exposure 29 days later. Specific behaviors were correlated across time in similar tests suggesting stable temperaments. Lower levels of exploration, activity, and sociability were associated with higher CORT reactivity. Additionally, lower levels of exploration, boldness, and sociability were associated with higher RHS following KLH re-exposure. Our findings suggest that some temperaments are more consistent than others and that physiological mechanisms differ with each behavioral phenotype. This may account for differential temperament fitness across environments.
