Spotted salamander egg masses

This webpage was a submission to Sigma Xi’s 2016 Student Research Showcase and was the winner of the Ecology and Evolutionary Biology Section

This work is now published in Ecology:

Functionality of the spotted salamander egg mass polymorphism
Amphibian eggs consist of ova surrounded by jelly layers that mediate interactions between the embryo and the surrounding environment. The spotted salamander, Ambystoma maculatum, exhibits a unique polymorphism in the structure and appearance of its egg masses. This polymorphism is genetically determined and is due to the occurrence of a unique protein in the outer jelly layer of the white egg mass morph. Based on the observation that the proportion of white egg masses in ponds across its range correlated with dissolved nutrient levels, I hypothesize that the white morph is adapted to ponds with low nutrient levels. I tested this hypothesis using two mesocosm experiments and by collecting field data from natural ponds at the University of Mississippi Field Station (UMFS). I found that larvae from white egg masses were larger upon hatching in low nutrient conditions than those from clear egg masses and that these differences persisted throughout the larval period. Additionally, higher proportions of white egg masses were found in ponds with low conductivity (an indicator of dissolved nutrient levels) at UMFS. These results support the idea that polymorphisms can be adaptations to, and are maintained by, environmental heterogeneity.


I also have a poster about this work and the above slides originally created for this submission archived on Figshare: