Jessica Hernandez, Ph.D.
Postdoctoral Project
How does mating system regime influence the evolution of host and parasite traits?
Parasites are an integral part of the natural world and have evolved multiple strategies to use host resources, evade host immune defenses, and achieve transmission to new hosts. Previous research has primarily explored either vertical (e.g., parent to offspring) or horizontal (e.g., between adults of the same generation) parasite transmission. However, many parasites are transmitted both vertically and horizontally, and the role of these different transmission modes in host and parasite evolution is not well understood. Discovering the causes and consequences of diverse parasite transmission modes will help us understand how parasites infect hosts and could help inform disease control strategies. For this project, I will integrate experimental evolution, transcriptomic, and mathematical modeling approaches to quantitatively assess host fitness, parasite fitness, and define key traits that drive co-evolutionary dynamics between host and parasite.
PhD Projects
Do pair-bonded social partners exhibit more similar cloacal bacterial communities than expected by chance?
We have a limited understanding of how fine-scale social interactions, such as social partnerships that occur during the breeding season, shape host-associated microbial communities. Further, most studies exploring the relationship between social behavior and microbial communities focus on the gut and skin. For this project, I used 16S rRNA amplicon sequencing to assess the similarity between the cloacal bacterial communities of pair-bonded social partners.
This research is published in PLoS ONE's Microbiome Across Biological Systems special collection. Article
Does sexual activity predict cloacal bacterial microbiome richness and structure?
Sexual activity, specifically copulations, is one way through which bacteria (beneficial, commensal, and/or pathogenic) can be transmitted between individuals. While considerable research has focused on the sexual activity or the microbiomes of animals, little research has explored the relationship between the two. For this project, I am using both observational and experimental approaches to assess if female sexual activity varies with aspects of the cloacal microbiome.
This research is published in Ecology & Evolution. Article
Collaborators
Dr. Ignacio Moore (PhD Advisor), Dr. Lisa Belden, Dr. David Haak, Dr. Joel McGlothlin, Dr. Jenifer Walke,
Dr. Daniel Medina, Dr. Camilo Escallón, Dr. Ben Vernasco, Emily Reasor, Taryn Smith, Catherine Hucul
Undergraduate Projects
(Sea turtle handling on behalf of conservancy, with necessary permits)
Is the presence of fungal and bacterial nest pathogens associated with Loggerhead sea turtle hatch success?
Sea turtles have inhabited this planet for more than 210 million years. Even today, they are among the largest reptiles in the world, but unfortunately, they are one of the most endangered animals. While bycatch, coastal development, predators, and pollution detrimentally impact sea turtles, another prominent threat includes opportunistic bacterial and fungal pathogens. For this project, I focused on the potential opportunistic pathogens Serratia marcescens and Fusarium solani.
Research presented at the Bald Head Island Conservancy research symposium
Collaborator: Dr. Sheila Mays
What are the effects of urbanization on hormone levels in male western fence lizards across urban and protected areas?
The expansion of urban areas at unprecedented rates poses a threat to native flora and fauna. In the latter case, some fauna may be able to survive and persist, while others fail to do so in such urbanized ecosystems. Bonier's Urban-Endocrine Hypothesis (2012) posits that endocrine traits (e.g., hormone levels) may contribute to an animal's ability to persist or not. For this project, I assessed the circulating hormonal concentrations of lizards across an urban-rural gradient in the Los Angeles basin.
Research performed for undergraduate experimental thesis
Collaborators: Dr. Kris Kaiser (Thesis Advisor), Dr. Brenna Gormally, Jon Feingold, Maria Caruso, Dakota Spear
Photo: Jarred Jones
Do Northern spring salamanders exhibit homing behavior following displacement?
Salamanders vary in their homing behavior following displacement events. Understanding the factors driving this variation is important because a salamander's ability to home may have significant consequences in terms of gene flow and the isolation of populations. For this project, I tested whether Northern spring salamanders exhibited homing behavior following a displacement event and to determine whether the behavior was influenced by the behavioral syndrome of the individual.
Research performed through the support of a NSF REU based at Hubbard Brook Experimental Forest
Collaborators: Dr. Jon Davenport, Dr. Windsor Lowe, Dr. Brett Addis (a Whitman alum!)
How do changing ice conditions affect the diet of penguins in Antarctica?
The goal of this project was to assess how changes in ice conditions as a result of climate change (i.e., glacier retreat) during the latter half of the twentieth century impacted the diets of penguins. We identified the species of fish consumed by three species of penguins (gentoo, chinstrap, adele) at two sites in Antarctica (Cape Shirreff, Copacabana) from 2009 to 2011.
Collaborators: Dr. Nina Karnovsky, Nai de Gracia, Davey Holmes, Weston Staubus, Scott Lindburg
Photo: Lara Asato