Electronic Theses and Dissertations

Identifier

2665

Date

2016

Date of Award

4-24-2016

Document Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Biology

Committee Member

Helen J. K. Sable

Committee Member

Michael H. Ferkin

Committee Member

Matthew Parris

Abstract

Consistent, intraspecific variation in behavior, termed animal personality, has been demonstrated in a wide variety of taxa. While the theoretical ecological and evolutionary implications of personality have been recognized, there are critical gaps in knowledge. For example, though behavior may be less repeatable over time, few studies have measured long-term consistency. I determined long-term repeatability of neophobia and examined factors that may influence neophobia. Then, I tested whether'bold' behavior was consistent across contexts and related to stress-physiology, as predicted by the coping style model. While personality limits behavioral plasticity, individuals still may adjust their behavior based on environmental conditions. I investigated how a change in environmental risk may influence neophobia and whether an individual's stress-response influences their reaction to risk. Finally, I compared the relationships among personality, learning, and stress-physiology to determine if differences in performance on learning tasks were related to personality. I investigated neophobic behavior, as it can be assayed in situ in free-living Florida scrub-jays, Aphelocoma coerulescens. Neophobia was repeatable in individuals. Older birds were more neophobic, which may be due to selective mortality on bolder individuals. Boldness near a novel object correlated with boldness in a non-novel context, but was not related to stress-responsiveness. In a separate study, individuals were more neophobic after a "predation attempt" (i.e., standardized capture and restraint) and the effect was conditional on physiological profile, with low stress-responders the most hesitant to approach anovel object after capture. When I examined cognition, I found that individuals experienced a trade-off in performance between types of learning which correlated with personality. Corticosterone exposure during the nestling period was correlated with learning as an adult. Low levels of corticosterone were associated with better associative learning performance and high levels with better reversal learning performance. These findings provide evidence that variation in sensitivity to environmental conditions, as reflected by an individual's personality, underlie the strategy individuals use to perform cognitive tasks (i.e., cognitive style). Overall, the results of this dissertation contribute to gaps in knowledge of animal personality and demonstrate that the Florida scrub-jay provides a suitable model for further investigation of the causes and consequences associated with personality.

Comments

Data is provided by the student.

Library Comment

dissertation or thesis originally submitted to the local University of Memphis Electronic Theses & dissertation (ETD) Repository.

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