Date of Award


Document Type

Open Access Thesis


Biological Sciences

First Advisor

Blaine Griffen


Spatial location within aggregations (i.e. periphery, central) is of biological significance to gregarious animals. Because these positions are a potential consequence of consistent individual behavioral differences, or personality, a better understanding of potential mechanisms concerning personality is central to predicting an individuals’ location. To determine the effects of individual personality on the dynamic spatial positioning of Uca pugilator while herding, field data collection and agent-based modeling were employed. Individuals were assayed to establish their personalities and returned to the field for observation as a means of identifying location preference within selfish herds. There was a significant difference between the extreme personalities and the proportion of time spent on the edge of the herd. The active individuals were at the periphery ~50% more of the time than less active individuals. An individual-based model qualitatively replicated these field results by applying the mechanism of activity level as an indicator of individual personality. This suggests that differences in personality-dependent movement are sufficient to explain the spatial positioning of individuals within selfish herds. This study enhances our understanding of the possible mechanisms that govern group movement, and has implications for modeling population dynamics that can be influenced by individual personality.

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