Behavioral Plasticity Across Non-Social Contexts in Female Green Swordtails, Xiphophorus Hellerii

Phenotypic plasticity is the ability of an individual to alter its phenotype in response to environmental change. Individuals that express plasticity in behavior can quickly respond to changes that occur in the environment. Therefore, individuals that exhibit behavioral plasticity can alter their behavioral expression to best match current environmental conditions. The degree and direction of behavioral plasticity may be influenced by variation in individual characteristics. Understanding how variation in individual traits affects behavioral plasticity, and, whether patterns of behavioral plasticity are consistent across behavioral contexts are important topics to explore as we try to better understand how plasticity evolves and is maintained. For the study, we tested female green swordtails (Xiphophorus hellerii) to determine whether individuals express behavioral plasticity in response to a predator in two non-social contexts: (i) environmental assessment and (ii) foraging. Specifically, we were interested in how behavioral plasticity varies among individuals that differ in size and maturation age, and whether individual behavioral plasticity is correlated across contexts. In both the environmental assessment context and the foraging context, females expressed predator-related behavioral plasticity in the same six behaviors. For one foraging-related behavior in the foraging context, small individuals expressed plasticity of the behavior, whereas large females did not. This result suggests that body size may influence predator-related plasticity in foraging. Maturation age did not significantly affect the expression of plasticity in any of the behaviors measured. In the six behaviors that were significantly affected by the predator treatment, we found no evidence of correlated plasticity across the two non-social contexts. The design of this study allowed us to take a detailed look at how females adjust their behaviors in an environmental assessment context and in a foraging context in response to predator presence. Continued exploration into these topics may yield valuable information on how behavioral plasticity evolves and is maintained within and across populations. Advisor: Alexandra L. Basol