Ecology and Evolutionary Biology Commons^™

Evolution Of Nematode Prey Chemotaxis Behavior Across Different Environments, Hailey R. Smith

Honors Theses

Climatic conditions in the near future are projected to be warmer, with more frequent and intense weather events. This will substantially alter the environments in which organisms must integrate specific information to find essential resources. Many organisms rely upon chemical signals to orient towards attractive resources through a mechanism called chemotaxis. How different environmental conditions, like temperature, impact this process will be important to understand as environments change. I conducted a laboratory evolution experiment with the model nematode Caenorhabditis elegans to see how success in chemotaxis assays changes over time when selected under different temperature regimes (normal laboratory temperature, increased …

Effects Of Increased Salinity On Mississippi Coast Bacterial Community Composition And Diversity, Clifton C. Wade

Honors Theses

Bacterial communities are important to ecosystem function in coastal environments, but the response of these communities to short term increased salinity conditions is understudied. This study utilized a microcosm setup to investigate the response of coastal seawater bacterial communities to three treatments: an unamended seawater control, a reference treatment that received reverse osmosis (RO) water, and an elevated salinity treatment that received artificial seawater dissolved in RO water. Microcosms were sampled four times over a five-day period to analyze the effects of time under different salinity conditions on the seawater bacterial community. 16S rRNA gene sequencing was used to analyze …

Ectomycorrhizal Fungal Identity Strongly Influences Soil Properties Relative To Pine Presence And Soil History In A Pine–Eucalyptus System, Braedan Watters

Honors Theses

Invasive Pinus radiata has increasingly spread into native ecosystems in the Southern Hemisphere, including Eucalyptus forests in Australia, where it forms novel hybrid forest systems in which invasive and native tree species coexist. The success of these invasions is closely tied to ectomycorrhizal fungi (EMF) such as Rhizopogon spp., yet the relative roles of pines versus their fungal symbionts in altering soil properties remain poorly understood. This study investigated the independent and interactive effects of soil history (Pinus or Eucalyptus), EMF identity, and pine presence on soil properties using a controlled factorial experiment. Soil from beneath either Pinus …

Quantifying Genetic Diversity In Nematode Feeding Rate, Jacob King

Honors Theses

Understanding how populations persist under changing environmental conditions is a central question in ecology and evolutionary biology. Variation in traits related to resource acquisition may play a key role in determining population survival when resources are limited or fluctuate over time. In this study, I investigated how variation in feeding-related traits influences population persistence using a combination of computational modeling and laboratory experiments. I developed a stochastic, individual-based consumer–resource model to simulate population dynamics across varying levels of trait variance and resource regimes. Across 60,000 simulated populations, increased trait variation consistently reduced extinction risk and extended persistence time, although the …

Beat Behind The Bark: Investigating The Effects Of Music Tempo On Canine Physiological And Psychological States, Marley Lanier

Honors Theses

This study explores how the tempo of music, measured in beats per minute (BPM), affects dogs' heart rate and oxytocin levels, adding to past research that shows that music affects physiological and behavioral states in dogs. Being able to understand these effects holds practical implications for improving overall well-being in canines in environments such as homes, shelters, and clinical environments. Using a within-subjects design, the dogs were exposed to slow and fast versions of one instrumental track, along with a white noise baseline condition before each randomized condition. Heart rate was recorded continuously throughout the session, and oxytocin saliva samples …

Bottles, Butterflies, And Biomass: Recycled Glass Sand, Microbial Additions, And Herbivory Effects On Milkweed Growth, Kealey Skinner

Honors Theses

Plant-soil-microbe interactions are integral components of ecological networks and drive ecosystem function from the bottom-up. Whereas herbivores regulate ecosystem function from the top-down, having opposing and potentially complementary effects on ecosystem function. My thesis sought to understand how below-ground microbial communities contribute to herbivore preference and plant biomass across varied soil substrates. My thesis asked: how do substrate and soil microbial communities influence herbivore preference and plant biomass accumulation on swamp milkweed (Asclepias incarnata)? To address this question, seedlings of A. incarnata were sown in 2.5 cm wide × 10 cm deep pots filled with either natural beach sand or …

Evaluating Fungal Endophytes Inoculation As A Mechanism For Salt Tolerance In Juncus Roemarianus, Rani Badve

Honors Theses

Salinity stress is increasing in coastal and estuarine ecosystems due to increasing temperatures and the reduction of freshwater inputs via precipitation pattern changes. Elevated salinity can negatively affect plant survival, threatening the stability of coastal wetlands and the ecosystem services they provide. Juncus roemerianus is a common and dominant marsh plant in the Northern Gulf Coast that lives in varying salinities. Growing evidence suggests that root-associated fungal endophytes may contribute to enhanced stress tolerance; however, the response of fungal communities to salinity remains poorly understood.

This study evaluated how salinity influences the abundance and diversity of culturable root-associated fungal communities …

Acute Effects Of The Psychoactive Pollutant Fluoxetine On The Antipredator Behavior Of The Gulf Killifish (Fundulus Grandis), Semyra Reus

Honors Theses

Pharmaceutical contaminants are increasingly prevalent in aquatic environments, yet their sublethal effects on ecologically relevant behaviors remain poorly understood, particularly in estuarine systems. Selective serotonin reuptake inhibitors (SSRIs), such as fluoxetine, are of particular concern due to the conserved role of serotonin in regulating behavior across vertebrates. Here, we investigated how acute exposure to environmentally relevant concentrations of fluoxetine influences anti-predator behavior in Gulf killifish (Fundulus grandis), a key estuarine fish commonly found in saltmarsh habitats. Killifish were exposed to control (0 ng/L), low (17.8 ng/L), and high (596 ng/L) fluoxetine concentrations and subsequently tested in the presence …

Discovering The Genetics Underlying Speciation Traits In Heuchera (Coral Bells), Tajinder Singh

Honors Theses

Hybridization is a key evolutionary mechanism for generating biological diversity, ultimately shaping diversification and adaptation of plant lineages in natural and agroecosystems.  Our understanding of the frequency, distribution, and significance of hybridization is rapidly increasing, but the external driving forces that dictate why certain species hybridize, and others do not remain obscure. The physical traits that shape gene flow and trait sharing among species are likely to be among the key factors that directly control hybridization. Gene flow in most plants is mediated by pollinating insects and thus by pollination syndromes, which are suites of floral traits that have evolved …

Developing A Range Prediction For The Imperiled Florida Harvester Ant (Pogonomyrmex Badius) Using Species Distribution Modeling, Noah Williamson

Honors Theses

The Florida Harvester Ant (Pogonomyrmex badius) was once widespread and commonplace throughout the sandhills of the Southeastern United States, providing key ecosystem services, such as seed dispersal and soil aeration. Over recent decades, however, Florida Harvester Ant populations have declined in some areas. Current literature postulates that Red Imported Fire Ants (RIFA), and the insecticides used to manage them, as well as further human encroachment onto their habitat, all likely contributed to Florida Harvester Ant population declines. Thus, to better protect these organisms, pursue data-driven conservation efforts, and guide management practices, more information about their nest site selection, as well …

Variable Hybridization Rates Between F2 Fundulus Notatus Females, Jordan Tanaka

Honors Theses

Hybridization between two related species has been widely observed and offers a lens into complex evolutionary processes. Endogenous and exogenous factors affect hybrid fitness and diversification, and pre-zygotic and post-zygotic barriers affect species’ ability to hybridize. Female mate choice is a pre-zygotic isolation mechanism which is known to be more significant than male mate choice in many species, a trend which is linked to females often investing more energy into offspring. Detailing the ways in which these mechanisms operate is integral to understanding hybridization on a larger scale. The species examined here, Fundulus notatus and Fundulus olivaceous, are closely …

Evaluating The Environmental Parameters Impacting Spawning Movement Of Gulf Sturgeon (Acipenser Desotoi) In The Bouie River System., Olivia St. Germain

Honors Theses

The anadromous Gulf Sturgeon (Acipenser desotoi) is federally listed as “threatened” and is natal to seven rivers from Louisiana to Florida. Only one spawning reach for Gulf Sturgeon natal to the Pascagoula River has been verified via the collection of eggs and larvae; a reach of the lower Bouie River. This reach is anthropogenically modified by four gravel mining formations, hereafter referred to as pits. The greater depths associated with this area have prompted previous researchers to suggest that Gulf Sturgeon may over-summer in pit formations instead of migrating to downstream holding areas in the Pascagoula River after spawning. The …

Climate Change And Species Interactions Jointly Shape Migration Timing And Growth At A Critical Ontogenetic Transition In Juvenile Sockeye Salmon, Margaret E. Veatch

Honors Theses

Climate change is shifting the timing of biological events globally, but the mechanisms linking environmental variation to phenological changes are poorly understood in many systems, particularly those where individuals undergo ontogenetic habitat shifts. Here, I examined the join influence of climate-driven environmental variability and species interactions migration timing and body size at migration in juvenile sockeye salmon (Oncorhynchus nerka) in Lake Aleknagik, Alaska, using a multi-decadal dataset (1967–2024). Migration timing varied widely among years and was best explained by a combination of ice-out phenology, epilimnetic temperature, and fish densities in littoral habitats. Juvenile sockeye salmon migrated earlier in …

Assisted Reproductive Technologies For Southern Cricket Frogs (Acris Gryllus), Audrey Grace Koltz

Honors Theses

Amphibians are facing the most drastic biodiversity declines of all vertebrates, with an estimated 41% of amphibians threatened with extinction. Captive breeding programs employ a variety of assisted reproductive technologies including environmental manipulation, hormonal therapies, artificial fertilization, and gamete preservation to augment vulnerable populations and optimize genetic diversity. Amphibians require a species-specific combination of environmental, social, and physiological cues to reproduce, which makes universal and successful captive breeding programs especially elusive. Here, I investigate assisted reproductive technologies for a small frog species, the southern cricket frog (Acris gryllus). Establishing successful methods for southern cricket frogs may yield promising results for …

A Search For Transcriptional Cofactors Of Gcm/Repo Involved In Determining Glia Cell Fate In Drosophila Melanogaster, Nivedha Kosalram

Honors Theses

In Drosophila melanogaster, the mechanism influencing the differentiation of glia and neurons is directed by a key transcription factor known as glial cells missing (gcm). gcm is a crucial regulator of cell fate decision, functioning as a binary switch to direct glial fate in gcm- positive cells and neuronal fate in gcm-negative cells (Jones, et.al, 1995; Hosoya, et.al, 1995; and Vincent, et.al, 1996). In addition to directing gliogenesis, gcm and its homolog gcm2 facilitate the determination of macrophages and tendon cells, highlighting that gcm acts with supplementary factors to induce various signaling pathways in different contexts (Jones, 2005; Johnson, et …

Ghosts In Glass: Ghost Crabs As Judges Of Glass Sand For Coastal Restoration, Emily Parrish

Honors Theses

Over 60% of the Gulf of Mexico coastline is actively eroding, which has resulted in thousands of miles of lost coastline over the last 100 years. This drastic loss of coastal land highlights the dire need for coastal restoration across the entirety of the Gulf Coast. A vital aspect of restoring these eroded areas is replenishing eroded substrate, traditionally conducted through offshore dredging of substrates which comes with high economic and ecological costs. Recycled glass sand may be able to fill this role and reduce our reliance on dredging while lowering the amount of glass waste entering landfills each year. …

Determining The Influence Of A Low-Head Dam On Macroinvertebrate Communities In The Bouie River, Natalie Santiago

Honors Theses

The Bouie River is a tributary of the Leaf River and belongs to the Pascagoula River watershed, the latter of which has no flow impediments in the form of sills or dams. The Bouie River has been heavily altered in the lower 10 river kilometers (rkm) from aggregate mining (creating a series of deep gravel pits) and the presence of an earthen and concrete low-head dam (sill) located 6 rkm from the mouth of the river. However, despite these alterations, the immediate stretch of river below the low-head dam is a known spawning habitat for diadromous fish species, including the …

Sibship Analysis Of Fall And Spring Spawn Gulf Sturgeon Eggs In The Choctawhatchee River, Florida, Lyric Mccullouch

Honors Theses

The Gulf sturgeon (Acipenser oxyrinchus desotoi) is an anadromous species that inhabits rivers along the northern Gulf of Mexico. Facing challenges from overfishing and habitat alteration, the Gulf sturgeon is listed as threatened under the Endangered Species Act. This study investigated the genetic distinctiveness of fall and spring spawning groups of Gulf sturgeon in the Choctawhatchee River, a critical habitat for the species. In this study, I used microsatellite loci to analyze Gulf sturgeon eggs previously collected in the fall and spring of 2019 and 2020. The goals of this study were to verify the genetic identity of …

Seasonal Detection Of Coliphages In Freshwater Bodies At Coastal Carolina University, Ella Caldwell

Honors Theses

Bacteriophages, commonly referred to as phages, are non-living viruses that only infect bacteria. As the most abundant biological entities on Earth, understanding their role in regulating microbial populations is essential. This ongoing research aims to identify naturally occurring bacteriophages that could effectively control bacteria blooms. The primary objective of this study is to detect coliphages on Coastal Carolina University's campus and determine their viral families. Coliphages are a subgroup of bacteriophages that specifically infect coliform bacteria. Water samples were collected across multiple sites on campus, and polymerase chain reaction (PCR) was employed to amplify the viral DNA from the potential …

Designing An Optimal Thermal Preference Arena For Southern Cricket Frog (Acris Gryllus) Juveniles, Eleanor E. Briggs, David M. Phillips Jr.

Honors Theses

Climate change has been altering ecosystems across the world at a substantial rate, disrupting the delicate ecophysiological relationships between ecosystems and the organisms that live in them. Ectotherms, such as amphibians, rely on external temperatures to behaviorally thermoregulate, making it especially imperative to study their thermal biology. Thermal preference, which assesses the environmental temperature an organism would seek out in the absence of external stimuli, provides valuable information about an amphibian’s thermal biology and can be used to predict the effects of climate change on a species or population. A commonly used method to measure thermal preference is an arena …

Effects Of Direct And Indirect Predator Cue Intensity On Foraging Decisions In A Deer Mouse, Peromyscus, Nicholas G. Levinson

Honors Theses

Ecologists developed optimal foraging theory as a framework to understand how an animal may spend minimal time to maximize resource intake. A giving-up density (GUD) is a metric of the density of remaining food in a food patch at which an animal decides foraging is no longer economical. This study aims to test how the intensity of direct and indirect predator cues alter foraging patterns of deer mice. To measure GUD, I used depletable food patches deployed in the “upper woods” on the periphery of Colby College. To simulate direct predator cues, 1 mL of fox urine was applied on …

Development Of A Course-Based Undergraduate Research Experience (Cure) Using The Bess Beetle, Sreya Maddali

Honors Theses

Participating in scientific research has increasingly been important in helping students develop necessary science learning skills, like critical thinking. One way of introducing students to these experiences is a Course-based Undergraduate Research Experience (CURE). CUREs enable students to improve in similar ways to internships and are more accessible to students from diverse backgrounds. The goal was to create a CURE centered around ecological genetics, using the Bess Beetle (Odontotaenius disjunctus) as the focal organism of a 16-week course. This species was selected because of its wide geographic range and divergent genetic lineages based on mitochondrial cytochrome oxidase subunit 1 (COI) …

Bioinformatic Comparison And Salinity Tolerance Of Various Cyanobacterial Strains, Lucie Rowe

Honors Theses

Cyanobacteria are an abundant and diverse group of photosynthetic prokaryotes with a long evolutionary history, which presents challenges for comprehensive taxonomic classification. Phylogenies were traditionally constructed based on the highly conserved 16S rRNA gene, but research has increasingly relied upon whole genome sequencing to elucidate evolutionary relationships, despite increased cost and time. In this thesis, publicly available genome sequences of various cyanobacterial strains were utilized to determine if the whole rRNA region, which includes the 16S, 23S, and 5S genes as well as the spacer regions between, could provide accurate, yet cost/time efficient representations of their evolutionary relationships. From phylogenetic …

Lmpact Of Salmonella Enterica Effector Proteins On Plant Physiology And Immunity, Sara Qader

Honors Theses

Salmonella enterica serovar Typhimurium are primarily recognized as pathogens associated with foodborne illnesses in humans. Salmonella also can colonize plant tissue effectively. The pathogen relies on type III secretion systems (T3SS) to infect mammals and plants successfully and counteract the immune response. Understanding the molecular mechanisms underlying Salmonella’s interactions with plants is essential for developing effective strategies to reduce its impact on human health and agriculture. Effector proteins, known for their role in modulating host-pathogen interactions, have been implicated in the virulence and pathogenicity of Salmonella. However, their specific functions and contributions to Salmonella’s interactions with plants remain largely unknown. …

Fiddler Crab Gut Microbiomes As An Indicator For Eutrophication Due To Waste-Water Contamination In Estuaries, Madison L. Geraci

Honors Theses

Estuaries are unique biogeochemical zones in coastal systems that provide a myriad of ecological functions: providing habitat for critically important fishery species, diverse species of plants and animals, and contributing to nutrient cycling. Estuaries are vulnerable to anthropogenic stressors as they are intersections between marine and terrestrial communities and are often the hotspot of coastal development and activity. Estuarine sediments act as repositories for anthropogenic contaminants, including excess nutrient runoffs and waste-water pollution that can cause states of eutrophication. Microorganisms are sensitive to these environmental changes, presenting a unique opportunity of being useful bioindicators of environmental stress. Isolating microorganisms from …

Survey Of The Bolctes From Fish River Nature Preserve, Noah T. Nelson

Honors Theses

Boletes are a special kind of mushroom inside of the Kingdom Fungi that are distinguished from other mushrooms by their uniquely pored hymenium, as opposed to gills. Many boletes are ectomycorrhizal, meaning they are mutualists with vascular plants, and thus beneficial to the overall health of the terrestrial ecosystem. Some are well-known for their edibility and are of economic importance. In the United States 59 genus-level clades comprising 290 operational taxonomic units have been reported. The southeastern US and Gulf Coast regions however are less researched and recorded for their mushroom ecology. In Alabama, only 56 bolete species have been …

Mate Choice Between Two Species Of Topminnows From Dissimilar Hybrid Zones, Chloe Davis

Honors Theses

Understanding the origins of reproductive isolation between closely related species is foundational to evolutionary and ecological research. Recent reviews have documented contemporary hybridization between a large portion of species. A greater knowledge of reproductive isolation and its components are vital to expanding conservation efforts for threats such as those to species persistence and community processes. However, there is a lack of clear understanding of how isolating mechanisms evolve throughout many systems where hybridization is prominent. Individuals within the Fundulus notatus species complex (F. notatus, F. olivaceus, and F. euryzonus) readily hybridize at many contact zones replicated throughout their …

Influences Of Sex, Morph, And Weather On Roosting Distributions In Overwintering White-Throated Sparrows (_Zonotrichia Albicollis_), Rebecca Stephens

Honors Theses

Habitat choice influences survival by affecting access to resources, shelter from predators, mating opportunities, and numerous other costs and benefits. As such, habitat conservation is crucial, especially for migratory songbirds which are declining primarily due to habitat destruction. White-throated Sparrows (Zonotrichia albicollis) are a well-studied migratory songbird, but little is known about their roosting behaviors or how those behaviors are affected by sex, color morph, or weather. To determine this, we tracked White-throated Sparrows to their roosts, determined core home ranges, and analyzed the average distances of roost sites to the home range centroids according to these factors. …

Northern Shrimp In The Gulf Of Maine And The Impacts Of Climate Change, Alicia Hober

Honors Theses

Northern Shrimp (Pandalus borealis) populations within the Gulf of Maine collapsed in 2011 following the first year that sea surface temperature surpassed 10ºC. The population collapse resulting in a moratorium in 2014. The waters of the Gulf of Maine have been rising at a rate of 0.045ºC per year, changing predator distribution, prey distribution, as well as Northern Shrimp biological variables. There has been very little recovery to the Northern Shrimp stock despite the fishing moratorium and the answers behind the collapse and lack of recovery remains enigmatic. Therefore, this two-chapter study includes a literature review and a …

Modification Of Marine Snail Microhabitats By Canopy-Forming Algae, Eleanor Mcgrath

Honors Theses

Brown algae, including the canopy-forming macroalgae Fucus distichus, are declining in abundance around the world due to stressors associated with climate change. Local extinction of Fucus impacts the intertidal community through cascading effects as the ecosystem loses a dominant primary producer at the base of the food web. However, Fucus is not only a resource species; it is also an ecosystem engineer. This thesis investigates the effect of Fucus extinction on the abundance of two herbivorous marine snails, L. saxatilis and L. obtusata, with a focus on the role of Fucus as a habitat- modifier. Specifically, I explored: …