Term of Award

Fall 2019

Degree Name

Master of Science in Biology (M.S.)

Document Type and Release Option

Thesis (open access)

Copyright Statement / License for Reuse

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.


Department of Biology

Committee Chair

Emily Kane

Committee Member 1

Emily Kane

Committee Member 2

James Roberts

Committee Member 3

Christine Bedore

Committee Member 3 Email



Divergent selection pressures in populations that occupy different environments can result in phenotypic differentiation in traits that provide a local fitness advantage. Trinidadian guppy (Poecilia reticulata) populations are separated by physical barriers such as waterfalls which result in repeated shifts in selective pressures from predator avoidance in high predation environments towards resource competition in low predation environments. Such shifts in selection pressures have previously shown that a range of locally adapted morphological and behavioral traits are changed. However, the role of local adaptation on biting behaviors remains unclear. I analyzed morphological differences such as body length, jaw position, eye area and body depth to validate known differences between populations. I then filmed adult females from replicate high/low predation pairs while they used biting behaviors to feed on an agar substrate. I did not find divergence in either morphological or kinematic traits, suggesting a general lack of local adaptation, contrary to previous findings. A lack of divergence could be due to less pronounced morphological divergence in females, perhaps as a constraint of bearing young, and the absence of divergent selection on prey capture performance. In female guppies, morphology and performance are not locally adapted, and divergence may exist primarily in behavioral traits (consumption rates) as a result of competition in low predation environments.

Research Data and Supplementary Material


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