Intraspecific variation in life history traits of the panamanian electric fish Brachyhypopomus Occidentalis
Date
2021-05-20
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Abstract
The purpose of this thesis was to investigate intraspecific variation of life history traits in the
electric knifefish Brachyhypopomus occidentalis under natural conditions, and to explore how
individuals optimize their reproduction and brain size under varying predation risks. In the first
chapter, I describe the reproductive biology of B. occidentalis, using several reproductive traits
selected in both females and males to provide insight on the reproductive effort of mature
knifefish. I provide field evidence supporting the hypothesis that predation risk environment
and geographical isolation drive variation in female reproductive strategies. In the second
chapter, I explore whether predation risk and drainage contributed to brain mass variation B.
occidentalis. I also explore how ontogenetic scaling relationships influence brain mass, and
how this association may have been affected by predation. I show that predation risk is an
important driver of brain mass variation and discuss the potential implications for the fish and
other highly encephalized vertebrates.
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Keywords
Life history, knifefish, brain mass, reproduction, expensive tissues