Ecology and Evolutionary Biology Commons^™

Influence Of Genetic Relationships On The Spatial Distribution Of Breeding Eastern Wild Turkeys (Meleagris Gallopavo Silvestris) In West-Central Louisiana, Rachel D. Price

LSU Master's Theses

Eastern wild turkeys (Meleagris gallopavo silvestris) have a complex social system influenced by dominance hierarchies and exhibit seasonal variation in gregarious behaviors. Previous work has examined the influence of kin relationships on interactions between same sex conspecifics and flock associations, but information on how genetic relatedness influences interactions between individuals remains lacking. We constructed a dyad-based social network using high-resolution GPS data from 179 female and 68 male wild turkeys in west-central Louisiana during the 28-day period before a females’ 1^st nest initiation to quantify interaction probability based on genetic relatedness and age. Our findings suggest that …

Evaluating Eastern Wild Turkey (Meleagris Gallopavo Silvestris) Behavioral Ecology In The Southeastern United States, Chad Argabright

LSU Doctoral Dissertations

The wild turkey (Meleagris gallopavo spp.) is a game bird species in North America who are one of the great success stories in restoration and conservation. Wild turkeys were extirpated from most of their range in the early 20th century, but through habitat restoration and translocation efforts the population was restored to the point of being sustainably harvested in 49 U.S. States by the late 20th century. However recent declines in wild turkey population indices have necessitated ongoing research on the behavioral ecology of wild turkeys to help counteract these declines. East Texas specifically for the past century has …

Decoupling Of Reproduction And Lifespan Trade-Off In Caenorhabditis Elegans Through Microbial Programming, Nora M. Villafuerte

LSU Master's Theses

The microbiome is increasingly recognized as a major regulator of host physiology. Using the Caenorhabditis elegans model, we investigated how natural commensal bacteria modulate host reproduction and lifespan through internal egg hatching, a phenotype in which retained embryos hatch within the maternal body. Screening strains from the CeMbio collection identified four focal strains Ochrobactrum BH3, Lelliottia JUb66, Pantoea BIGb0393, and Enterobacter CEent1 that significantly increased internal egg hatching during the late reproductive period. This contrasts with pathogenic bacteria, which induce early-onset internal egg hatching. Across the focal strains, worms exhibited reduced total brood size but an expanded reproductive window relative …

Metacommunity Coupled Epidemiological And Biophysical Modeling Of An Emergent Coral Disease, Benjamin Holmes Farmer

LSU Doctoral Dissertations

Emerging infectious diseases pose imminent risk to the marine realm and coral reefs in particular. Since its emergence in 2014, stony coral tissue loss disease (SCTLD) has dramatically reduced living coral cover in Florida and charted a similar course in the Caribbean. SCTLD is by far the most severe coral disease in history and has driven highly susceptible species to local extinction, yet the mechanisms driving the regional epizootic are not well understood. Here, we developed reef-scale parameterizations of disease spread using model sites in the lower Florida Keys, developed extensive metacommunity habitat maps for the US Caribbean, and then …

Examining Private Landowner And Stakeholder Attitudes, Perceptions, And Knowledge Of Prescribed Fire In Louisiana, Chloe E. Crawford

LSU Master's Theses

Periodic fire was a primary driver of ecosystems across the Southeastern United States for millennia; however, fire suppression policies have become pervasive in the United States and led to increased fuel loads in forests as well as reduced biodiversity and reduced disease resilience. Prescribed fire presents a risk mitigation strategy and land management tool whereby practitioners can apply fire to the landscape in a controlled manner, thus reaping the benefits of fire while minimizing the risks associated with fire. Land in Louisiana is primarily privately managed and owned, so state-level conservation goals cannot be met without private landowner participation. As …

Stream Fish Assemblage Dynamics And Barriers To Aquatic Connectivity In The Ichawaynochaway Creek Watershed, Georgia, Usa, Jake R. Duhé

LSU Master's Theses

Stream fishes in the southeastern United States are adapted to hydrological disturbances such as droughts. However, this region is projected to experience increasingly frequent and severe disturbances that will elevate water demands given increasing agricultural and urban development. Further, road-stream crossings (RSCs) are abundant features in these streams that can exacerbate drought-mediated stream fragmentation and impede movements by many aquatic organisms, including fishes, when poorly constructed. These compounding effects may adversely affect the diversity and abundances of resident stream fishes, but their interactions remain poorly understood, warranting rigorous testing of how droughts and RSCs influence stream fish dynamics. I assessed …

Assessing Niche Differences Across The Dwarf Salamander Species Complex Of The Southeast Us, Sarah Roy

LSU Master's Theses

Characterizing niche differences in closely related species can provide valuable insights into the extent of ecological divergence between species, and the potential evolutionary processes behind speciation. This study builds the first ecological niche models for the Eurycea dwarf salamander species complex, which includes five species with varying distributions across the southeastern United States. Ecological niche models (ENMs) were built for each species using the machine-learning algorithm, MaxEnt. We used pairwise niche overlap analyses and statistical validation techniques to investigate potential ecological drivers behind species divergence and the degree of niche overlap among the five Eurycea species. We found an overall …

Mate Choice And Movement Ecology Of Plegadis Ibis In Louisiana, Ryan T. Klutts

LSU Master's Theses

In 1817, George Ord documented the first North American records of Glossy Ibis (Plegadis falcinellus), a species native to the Old World. Over the next 200 years, Glossy Ibis expanded its breeding range to include the Atlantic coast to southernmost Florida and thence up the Gulf coast to eastern Texas. Forty-five to 75 years ago, its range expansion brought it into secondary contact with White-faced Ibis (P. chihi) in Louisiana, a native species whose breeding range includes freshwater wetlands in Louisiana and eastern Texas. Hybridization between the two species resulted in a large hybrid zone in southern Louisiana, providing an …

A Phylogenomic Investigation Of The Historical Biogeography Of Livebearers (Cyprinodontiformes: Poeciliidae), Sheila Rodríguez Machado

LSU Doctoral Dissertations

The Neotropics contain several biodiversity hotspots and harbor the highest diversity of freshwater fishes globally. Yet, recognizing the patterns and processes driving this richness remains a challenge. Similarly, all groups and subregions have not received the same attention, especially in the genomics era. Addressing these knowledge gaps will help us to better understand the region’s evolutionary and biogeographic complexity. The goal of this dissertation is to examine phylogenetic and biogeographic patterns of Neotropical freshwater fishes, with emphasis on the Greater Antilles, across multiple taxonomic and geographic scales. To achieve this goal, I generated a genomic dataset of hundreds of ultraconserved …

Impacts Of Climate Change On Cannibalism And Disease Transmission In The Fall Armyworm, Kale Rougeau

LSU Master's Theses

Climate change may alter host-pathogen dynamics in terrestrial ecosystems due to rising global temperatures and carbon dioxide levels. Here, we examined cannibalism and disease transmission using the fall armyworm (Spodoptera frugiperda), an invasive agricultural pest, and its species-specific lethal baculovirus, Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV), under various potential challenges of climate change. We used three temperature treatments (cooler, optimal, warmer) based on the fall armyworm’s thermal performance curve to simulate a changing climate and four artificial diets with various protein-to-carbohydrate ratios (low, equal, high, standard) to manipulate resource quality from altered carbon dioxide levels. We found that higher …

History, Annotated Gazetteer, And Bibliography Of Ornithology In Kalimantan, Indonesian Borneo, Frederick H. Sheldon, Mohammad Irham, Daisy G. S. Kho, Erik Meijaard, Subir B. Shakya, Dewi M. Prawiradilaga, Sebastianus (Bas) Van Balen

Occasional Papers of the Museum of Natural Science, Louisiana State University

Kalimantan comprises nearly three quarters of the island of Borneo and is the place where scientific study of Bornean birds began. We describe the history of bird research in Kalimantan from its beginning, highlighting the ornithologists who explored the region and how their interests and methods changed over time, from a concentration on specimen collection, to examinations of community ecology, to conservation in the face of habitat change and species depletion, to the latest investigations using satellite, genetic, and digital technology. We also highlight some future directions for research, especially the need for more work on basic ecology and biogeography. …

Louisiana Graduate Network In Applied Evolution (Lagniappe): 2024-2025 End-Year Report, Kristina G. Little, Samuel B. Robison, Bret Blackmon

Reports

The Louisiana Graduate Network in Applied Evolution (LAGNiAppE) is a post-baccalaureate program funded by the National Science Foundation (NSF) and hosted by the LSU Department of Biological Sciences. In its second year, the program provides recent college graduates with a structured, immersive research experience designed to prepare them for graduate education and careers in STEM. This report presents findings from the 2024–2025 program year (cohort 2) and is based on comprehensive evaluation data collected from Scholars, mentors, and co-mentors. The 2024–2025 cohort engaged in a wide range of activities, including intensive bootcamp training, independent research projects, scientific presentations, weekly seminars, …

Co2 In Flowing Freshwaters: Macro Scale Database Compilation, Addressing Ph Bias In Co2 Estimates, And Quantifying Cross-Scale Interactions, Timothy R. Toavs

LSU Doctoral Dissertations

This dissertation focuses on carbon dioxide (CO₂) dynamics in flowing freshwaters, contributing to the growing body of knowledge about inland water carbon cycles. The research is structured into three main chapters, each progressing towards the objective of utilizing variability in flowing freshwaters to further understand carbon dynamics, anthropogenic land cover impacts, and potential impacts from a changing climate. Chapter one compiles a 30-year dataset of pCO₂ measurements from flowing freshwater systems across the contiguous United States. This dataset, referred to as CDFLOW, includes over 750,000 pCO₂ estimates from more than 35,000 locations. It serves …

Understanding Mechanisms For Coastal Marsh Sustainability In A Changing Climate, Ashley R. Booth

LSU Doctoral Dissertations

In the Chenier Plain of Louisiana and Texas, coastal marshes are subject to high rates of relative sea level rise (RSLR), restricted sedimentation, and declining elevation attributed to subsidence and decades of intensive management. These marshes were created via mineral sedimentation but now largely accrete via organic matter accumulation. This organic matter accumulation (OMA) – or the balance between plant productivity and decomposition – is essential for maintaining elevation and thus long-term sustainability. However, management for elevation is complicated by a poor understanding of how abiotic factors like flooding and salinity impact processes driving OMA and elevation. To better understand …

Evaluating Growth Of Coastal Grass In Recycled Glass Sand: Evidence For Safe Application In Coastal Restoration, Allison B. Huddleston

Honors Capstones

Louisiana’s coastal land loss results from complex interactions of anthropogenic and naturally occurring processes that impact sediment supply in the Mississippi river delta. Given the coastline's vital role in the state’s economy, Louisiana has made significant investments in coastal restoration projects, including planting native vegetation and adding borrowed sediments. The amount of sediment needed to maintain Louisiana’s existing coastline exceeds the available amount that could be extracted, and state officials have since identified this lack of sustainable sediment resources as a critical limitation for future restoration projects. One proposed solution to address this shortage is using recycled crushed glass cullet …

Effects Of Retinal Gonadotropin-Releasing Hormone On Reproductive Behavior And Retinal Activity In The Cichlid Fish, Astatotilapia Burtoni, Chase Anselmo

LSU Master's Theses

Many animals use visual signals to evade predators, forage for food, and communicate with conspecifics. Some animals that shift into and out of breeding stages, such as fish, can modulate their visual sensitivity to better adapt to changing internal and external conditions. Previous work in our lab demonstrated that females of the cichlid fish Astatotilapia burtoni have improved visual sensitivity when they enter reproductive readiness. However, little is known about how fish and vertebrates more broadly modulate visual sensitivity across their reproductive cycle. We hypothesized that the hormone and neuromodulator gonadotropin-releasing hormone (GnRH) could modulate visual sensitivity because GnRH is …

Louisiana Graduate Network In Applied Evolution (Lagniappe): 2023-2024 End-Year Report, Kristina Little, Samuel B. Robison, Bret Blackmon, Andrew R. Burns

Reports

The Louisiana Graduate Network in Applied Evolution (hereinafter; LAGNiAppE) was funded by a grant awarded through the National Science Foundation (NSF 22-506), as part of the Research and Mentoring for Postbaccalaureates in Biological Sciences (RaMP) grant program. The LAGNiAppE program provides training and mentorship to cohorts of recent college graduates from underrepresented groups interested in advancing their knowledge and research skills in evolutionary biology. Social Research and Evaluation Center (SREC) at Louisiana State University conducted the evaluation of LAGNiAppE, assessing program implementation and impact. The evaluation team at SREC employed a mixed methods design that included online surveys for scholars …

The Behavioral Specialization Of African Ant-Following Birds On Dorylus Driver Ants, Patricia F. Rodrigues

LSU Doctoral Dissertations

Ant-following birds, that forage on arthropods flushed by swarm raiding army ants, are an iconic phenomenon in tropical forests around the globe. Despite capturing the attention of naturalists for over a century, research on ant-following birds has largely focused on Neotropical species. Decades of research on Neotropical ant-following birds has revealed fascinating aspects of their specialization, including complex cognitive and behavioral adaptations that allow birds to locate and track nomadic army ants. Despite this breadth of research on Neotropical species, virtually nothing is known of the behavioral ecology of African ant-following birds, and it remains unknown whether they exhibit adaptations …

An Exploration Of The Drivers Of Intraspecific Variation In Arthropod Phenotypes, Jamie Phelps

LSU Doctoral Dissertations

Herein we explore the various forces that drive phenotypic variation in arthropods focusing on spatial and temporal differences as well as sexual dimorphism. We use both marine, Tigriopus californicus, and terrestrial, Melitaeini, organisms to investigate these forces.

Tigriopus californicus and Heat Hardening: The study explores how Tigriopus californicus, a copepod, adapts to thermal variation along the North American Pacific Coast. Researchers investigated intraspecific variation in heat hardening, measuring differences in upper lethal limits (ULLs) and potential fecundity costs across five populations. We found a cost of heat hardening: the size of the first brood produced after heat shock …

The Role Of Sexual Network Core Groups In Disease Epidemics, Jason Janeaux

LSU Doctoral Dissertations

Sexually transmitted infections (STIs) remain an economic and social burden, non-discriminately affecting sexually active individuals worldwide. The unique transmission of STIs is dependent upon host and pathogen life histories, as well as the underlying network structure of the host population. Within a population there is a group of individuals, the core group, that maintains STI presence and helps sustain ongoing transmission both within the core group and in the surrounding population. While the presence of these core groups is well documented, the criteria for inclusion into a sexual core group is not. In this dissertation, I explore common factors that …

Impact Of Containment And Elevation On Created Marsh Plant Community And Ecosystem Dynamics, Kevin R. Stoner

LSU Master's Theses

Coastal marsh restoration is increasing globally, as marshes are impacted by anthropogenic impacts. Billions of dollars are allocated to marsh restoration in the Mississippi River delta where wetland loss rates are extremely high. The recovery of structural and functional attributes of created marshes varies by attribute measured and project. Here, two marshes created in 2018 and one natural marsh were used to examine how variations in hydrologic connectivity and marsh elevation influence subsurface hydrology and salinity, vegetation community structure, soil properties, accretion, and denitrification. I established a comparative field study in a created marsh contained within a higher elevation containment …

Spatial Mapping Of The Benthic Community And How It Is Used To Research Effects Of Dredging In Louisiana's Lake Borgne., Meghan Johnson

LSU Master's Theses

Benthic communities are vitally important for healthy aquatic ecosystems across Louisiana’s coast. Specifically in Lake Borgne, ecologically important species of fish like the Gulf Sturgeon (Acipenser oxyrinchus desotoi) rely on benthic macrofauna as their main food source. The purpose of this study was to determine the spatial landscape of biodiversity and abundance of the benthic macrofauna community in Lake Borgne. Environmental conditions played a key role in community structure during the study period (fall 2021 through summer 2023) with a major drought occurring in 2023. In 2023, the decline in the abundance of most benthic invertebrates and in …

Effects Of Treated Effluent Discharge On Tree Water Use And Growth In A Cypress Swamp., Devin Schexnayder

LSU Master's Theses

Inundated baldcypress (Taxodium distichum) trees generally respond to secondarily-treated and disinfected municipal effluent additions with increased growth rates and reduced mortality. Yet, the effects of effluent additions on the water-use and functional traits of inundated mature baldcypress are poorly understood. Because increased tree growth is associated with increased water use, effluent additions may affect the water budget in coastal swamps by increasing water uptake from the rhizosphere due to increased tree transpiration. I used sap flux density (f_d) measurements to assess water-use traits and tree-level daily transpiration (E) in seven mature inundated baldcypress trees that had …

Settling Preference Of Nipponaclerda Biwakoensis (Hemiptera: Aclerdidae) On Phragmites Australis Stems, Alexia Catherine Desoto

LSU Master's Theses

Phragmites australis, a wetland grass that stabilizes the Louisiana coastline, has been undergoing a major die-off near the Mississippi River Delta (MRD) since the autumn of 2016. One suspected cause for this plant decline is the attack of an invasive scale insect, Nipponaclerda biwakoensis. We lack information on the host preference of the crawlers, the life stage that decides where to settle and when to start feeding on the plant. The objectives of this study were to identify what positions along the vertical stem N. biwakoensis prefers to settle and what host-plant traits may be influencing this choice. We recorded …

Prescribed Fire Effects On Microbial Communities And Functions In Managed Ecosystems, Viet Dao

LSU Doctoral Dissertations

Microbes (both fungi and bacteria) serve important ecosystem functional roles in nutrient cycling and decomposition, which affect ecosystem response following disturbances such as prescribed fire. A multitude of abiotic and biotic factors influence microbial community compositions, which then drive microbial ecosystem functions. The factors driving microbial communities further change due to fire disturbances and progression with time. Although prescribed fire is commonly used as a technique for ecosystem management, the effects of fire on microbial communities or their functions are simply understudied. Ecosystem management decisions tend to focus on plant and ecosystem post-fire responses. Thus, incorporation of fire effects on …

Parental Environnement Influences Offspring Gene Expression In The Olympia Oyster, Ostrea Lurida., Mark S. Yeats

LSU Master's Theses

The Olympia Oyster is the only native oyster species on the Pacific coast of North America. Seasonality in water temperatures across this threatened species’ broad and fragmented range has been linked to its development, reproductive timing, reproductive activity, growth, and survival rates. Recent evidence suggests parental environments can have carry-over effects on larval growth and respiration rates in response to temperature. In this study, we utilized transcriptomic methods to identify the underlying mechanisms of this cross-generation plasticity. Sequence libraries of adult ctenidia tissue and pooled larval replicates were extracted and spawned from hatchery raised oysters of the same parentage immediately …

Diving At High Altitude: O2 Transport And Utilization In The Ruddy Duck And Torrent Duck In The Andes, Kevin G. Mccracken, Graham R. Scott, Luis Alza, Andrea Astie, Ciska Bakkeren, Emil Bautista, Mariana Bulgarella, Rebecca Cheek G. Cheek, Beverly A. Chua, Neal J. Dawson, Alexis Diaz, Catherine M. Ivy, Peter B. Frappell, Cecilia Kopuchian, Sabine L. Laguë, John N. Maina, Violeta Muñoz-Fuentes, Elizabeth R. Schell, Matthew M. Smith, Ryan J. Sprenger, Pablo L. Tubaro, Elizabeth R. Schell, Matthew M. Smith, Ryan J. Sprenger, Pablo L. Tubaro, Thomas Valqui, Roy E. Weber, Daniela Wilner, Robert E. Wilson, Julia M. York, William K. Milsom

Occasional Papers of the Museum of Natural Science, Louisiana State University

Hypoxia and cold temperatures create unique physiological challenges for high-altitude organisms that can vary depending on lifestyle. While nearly all studies of air-breathing animals at high altitude are from terrestrial species, species that breath-hold dive underwater at high altitude encounter a very different set of selective pressures influencing their phenotype. The goal of this publication is to highlight the changes in O2 transport and utilization in high-altitude diving birds relative to divers at sea level, and the extent to which these changes are qualitatively distinct from phenotypic changes in non-diving species at high altitude. For example, while high capacities for …

Using Machine Learning To Measure Changes In Immunity Due To Climate Change In The Fall Armyworm, Spodoptera Frugiperda, Nathaniel T. Haulk

LSU Master's Theses

Object detection is a recent development that allows for the detection of multiple objects in photographs. Numerous machine learning algorithms have been developed for object detection. Here we sought to determine which algorithm performed best when relating to an organism's health and immunological response. The fall armyworm (Spodoptera frugiperda) is a major agricultural pest causing millions of dollars in damage to farmlands across the globe. With their recent spread into Africa and Asia, the need for understanding how best to control population outbreaks via biocontrol has increased. While viruses are a major biocontrol agent for controlling insect pests, we …

Effects Of A Major Hurricane On Dynamics, Structure, And Composition Of Mississippi River Delta Forests, Lance C. Umlang

LSU Doctoral Dissertations

Tropical cyclones recurrently influence coastal forests worldwide. Tree survival (resistance) and post-cyclone recruitment (resilience) can vary with cyclone intensity, producing differences in composition, arboreal structure, and dynamics among affected forests. Studies of tropical cyclone wind effects on coastal forests typically emphasize damage more than post-cyclone responses. We hypothesized that intense cyclones might produce large, stratum-dependent effects that prevent affected forests from returning to pre-storm conditions. We explored direct effects of major Hurricane Katrina and post-hurricane changes in oak-dominated bottomland and cypress/tupelo-dominated swamp forests within the inactive portion of the Mississippi River deltaic plain. Overall mortality was high (14-25%) but concentrated …

Productivity Of Wood Ducks, Black-Bellied Whistling-Ducks, And Hooded Mergansers Using Nest Boxes In Louisiana, Dylan L. Bakner

LSU Doctoral Dissertations

Resident female wood ducks (Aix sponsa) in the southeastern United States are managed through nest box programs, with the goal of enhancing local hunting opportunities. Historically, hooded mergansers (Lophodytes cucullatus) were the only other cavity-nesting waterfowl species in the southeastern United States known to use these nest boxes. However, the recent northward range expansion of black-bellied whistling-ducks (Dendrocygna autumnalis) has extended into the range of wood ducks and mergansers. All three species are brood parasites, potentially using one another as hosts for their parasitic eggs and impacting their reproductive output. My research evaluated the …