Phenotype

Currently, one of the most critical research priorities in wildlife science is to understand, describe, and predict how the unprecedented rate of climate change will impact organisms and ecosystems. This is particularly essential for thermally sensitive organisms that are already imperiled, such as turtles.
For all known turtle species, the nest incubation environment plays a critical role in many developmental processes which can directly influence a number of phenotypic traits, such as body size, mass, locomotor performance, behavior and even sex. Most chelonians (and all extant marine turtles) possess a mechanism known as temperature dependent sex determination (TSD), whereby gonads differentiate into ovaries or testes depending on the incubation temperature of the eggs during a critical period of embryonic development. The rapid rate of climate change highlights the need for a clear understanding of how potential changes in the nest environment will affect turtle development and hatchling phenotype. However, it is poorly understood how different environmental factors interact with the embryo’s own genetic program to produce a specific phenotype. My thesis aims to (i) provide a better understanding of the complex relationship between the developing embryo and the nest environment and its effect on hatchling phenotype, and (ii) offer a solution to the difficulties associated with identifying primary sex ratios in turtle species with TSD.

This research represents the first multi-year investigation of the feeding ecology of Gombe’s Cercopithecus populations. The main goal of this study was to identify dietary overlap and distinctiveness among the phenotypes in our study group, a mixed species group of guenons comprised of C. ascanius, C. mitis, and C. ascanius x C. mitis hybrids. Field assistants collected feeding data using ad libitum observations as well as instantaneous scan sampling at 30-minute intervals from July 2014 to December 2018. A total of 63 plant species were identified in our group’s diet. Results indicate that a significant difference exists between the diets of each phenotype. The results also found an unusually high percentage of invertebrate eating (54%) in our group. These findings suggest that invertebrates are an important food resource for the Gombe study group and may help facilitate coexistence in an environment where there are many sympatric primate species.