Researcher ORCID Identifier


Graduation Year


Document Type

Campus Only Senior Thesis

Degree Name

Bachelor of Arts



Reader 1

Tessa Solomon-Lane

Reader 2

Brian Duistermars

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Rights Information

© 2022 Isabela P Harmon


Individual variation in community behavioral performance is composed of the interacting elements of behavior, neuroendocrine function, and neural gene expression. These factors are highly investigated in regard to adult social behavior, yet little is known about how their influence varies across developmental stages. Within our investigation, we studied juvenile and adult social status of Astatotilapia burtoni, a highly social African cichlid fish. A. burtoni adults form rich social hierarchies and display plastic status phenotypes. Dominant males are sexually viable, aggressive, territorial, and ornately colored in comparison to silver, non-territorial, non-aggressive, and reproductively unviable subordinate males. Little is known about the regulation of juvenile fish status relationships, despite the potential important mechanical similarities and differences with adults. We compared dominant and subordinate juveniles and adults at two states of social stability (unstable following one day and stable following seven days). The adult groups included two females for reproductive context. We collected behavioral, water-borne testosterone, and whole-brain transcriptome neuromodulator expression data. We found higher testosterone concentration in adults compared to juveniles, and in dominants compared to subordinates, with larger differences after seven day. We observed variation in BDNF, GHRH, androgen receptor, estrogen receptor paralogs, and GnRH expression based on social status, developmental stage, and community stability. There was a significant interaction between juvenile social status and behavior performance while adult behavioral performance was influenced by community stability. Additionally, dominants of both developmental stages performed greater territory duration and frequency. Overall, this study’s findings improve our understanding on what factors constitute individual variation in social behavior across social status, developmental stages, and community stability within social species.

This thesis is restricted to the Claremont Colleges current faculty, students, and staff.