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Articles 1 - 30 of 578
Full-Text Articles in Life Sciences
Prescribed Fire Effects On Microbial Communities And Functions In Managed Ecosystems, Viet Dao
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 …
Effects Of A Major Hurricane On Dynamics, Structure, And Composition Of Mississippi River Delta Forests, Lance C. Umlang
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
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 …
Integrated Pest Management And Behavior Of Stored Grain Beetles, Ethan Doherty
Integrated Pest Management And Behavior Of Stored Grain Beetles, Ethan Doherty
LSU Doctoral Dissertations
The lesser grain borer, Rhyzopertha dominica, and the rice weevil, Sitophilus oryzae, are two of the most destructive pests of stored rice. Their management has relied heavily upon fumigant insecticides. However, amid growing concerns that fumigant-resistant pests are becoming widespread, there is an urgent need for diversified management techniques and integrated pest management. Here, we explored management techniques and the behavior of these beetles. Host plant resistance toward both beetles was evaluated for 13 varieties of rice. We found large differences among varieties for both beetles in all resistance measures. We found that while nutritional components of a …
Genetic Dissection Of Alkalinity Tolerance In Rice (Oryza Sativa L.), Lovepreet Singh
Genetic Dissection Of Alkalinity Tolerance In Rice (Oryza Sativa L.), Lovepreet Singh
LSU Doctoral Dissertations
Alkaline stress is a major threat to rice production globally. The resources for genetic improvement of alkalinity tolerance in rice are limited. We performed genome-wide association study (GWAS) and QTL mapping integrated with whole genome sequencing and expression analysis to identify and confirm QTLs and candidate genes. We developed a near-isogenic line (NIL) population to fine map the two important QTLs. In GWAS experiment, we genotyped and phenotyped a panel of indica and japonica genotypes for alkalinity tolerance and identified genomic regions and candidate genes conferring alkalinity tolerance. Principal component analysis revealed that alkalinity tolerance score, shoot dry weight, and …
Neural Mechanisms Of Resiliency And Susceptibility After Repeated Social Defeat, Christy R. Wayne
Neural Mechanisms Of Resiliency And Susceptibility After Repeated Social Defeat, Christy R. Wayne
LSU Doctoral Dissertations
Social defeat is a powerful experience leading to drastic changes in physiology and behavior, many of which are negative. For example, repeated social defeat in vertebrates results in reduced reproductive success, sickness, and behavioral abnormalities that threaten individual survival and species persistence. However, little is known about what neural mechanisms are involved in determining whether an individual is resilient or susceptible to repeated social defeat stress. I used a resident-intruder experiment in the African cichlid fish, Astatotilapia burtoni, to create and investigate the behavior and neural correlates of these two opposing groups. Resilient fish used both searching and freezing behaviors …
Differences In Plant Hormone Responses Between Arabidopsis Thaliana And Schrenkiella Parvula Facing Lithium Toxicities, Jifeng Li
LSU Doctoral Dissertations
Investigating stress responses in plants is central to plant development studies and crop research. Identifying mechanisms of plant abiotic stress tolerance and adaptation will be keys to relieve the conflict between an increasing global population and declining agronomic land. Studies on extremophytes and their genetic responses to environmental stress are a way to help understand how and why these extremophile plants can develop well under extreme environments including high salinity and heavy metal toxicity. The studies herein first focus on comparative responses at the genetic level to lithium toxicity between Arabidopsis thaliana and Schrenkiella parvula. Based on elemental quantification …
Integrating Germplasm Repositories Into Oyster Aquaculture Systems At The Pathway, Center, And Network Levels, Sarah R. Bodenstein
Integrating Germplasm Repositories Into Oyster Aquaculture Systems At The Pathway, Center, And Network Levels, Sarah R. Bodenstein
LSU Doctoral Dissertations
Germplasm repositories offer many potential benefits to commercial farm operations, including preserving genetic resources and increasing production capabilities. Aquaculture industries have yet to take advantage of repository storage despite decades of research evaluating cryopreservation protocols. Eastern oysters (Crassostrea virginica), for example, are a useful research species when addressing this problem. Oysters are an economically important aquaculture species and a high-throughput cryopreservation method for oysters already exists. To address the gap between protocol research and commercial application a different approach is necessary that can analyze the requirements of repository development at multiple organizational levels. The goal of this dissertation was to …
The Characterization Of Selected Α- And Β-Carbonic Anhydrases Of Arabidopsis Thaliana, Hiruni Weerasooriya
The Characterization Of Selected Α- And Β-Carbonic Anhydrases Of Arabidopsis Thaliana, Hiruni Weerasooriya
LSU Doctoral Dissertations
Carbonic anhydrases (CAs) are zinc-metalloenzymes that interconvert two inorganic carbon (Ci) species, CO2 and HCO3-. In Arabidopsis thaliana, there are eight αCA genes, six βCA genes, three γCA genes, and two γCA-like genes. The majority of CA research in plants has focused on finding a link between CA activity and photosynthesis rates. Since the CA genes are expressed in different plant tissues and multiple CA isoforms are distributed among various organelles of the plant cell, I hypothesize that CAs facilitate CO2 diffusion among cell compartments and maintain Ci pools for carbon-requiring reactions by interconverting …
The Regulation Of Autoimmunity Genes In Pancreatic Β-Cells By Nf-Κb, Thomas Malone Martin
The Regulation Of Autoimmunity Genes In Pancreatic Β-Cells By Nf-Κb, Thomas Malone Martin
LSU Doctoral Dissertations
Type 1 diabetes (T1D) is an autoimmune disease where the immune system targets the pancreatic islet beta-cells, which are responsible for insulin production and secretion, leading to a state of insulin insufficiency. Many of the molecular details of disease onset and progression remain poorly understood, including key aspects of cytokine signaling. Therefore, we have examined some of the consequences of inflammatory cytokine signaling as a critical module relevant to T1D. Using interleukin-1 (IL-1) signaling as a well-defined paradigm for inflammation, we investigated key components of this signaling pathway in pancreatic beta-cells. We identified ICAM-1, one of the proteins expressed in …
Evaluating The Pesticide-Induced Outbreak Of Soybean Looper, Chrysodeixis Includens (Walker) (Lepidoptera: Noctuidae), In Louisiana Soybean, Scott Lee
LSU Doctoral Dissertations
Soybean looper, Chrysodeixis includens (Walker), has established itself as the primary lepidopteran defoliator in Midsouth soybean agroecosystems. Pesticide-induced outbreak events associated with this pest have been observed by soybean producers. The insecticides believed to prompt these incidents are routinely used for the control of other co-occuring pests, such as stink bugs. Outbreak conditions present soybean producers with conflicting management decisions for pests. Laboratory, greenhouse, and field experiments were conducted to provide a better understanding of insecticide usage impact on populations of C. includens and the arthropod community. To discern the potential mechanisms behind C. includens outbreak, a baseline for the …
The Global Transcription Factor Fur Is Activated By Binding A [2fe-2s] Cluster To Maintain Iron Homeostasis In Escherichia Coli, Chelsey Rene Fontenot
The Global Transcription Factor Fur Is Activated By Binding A [2fe-2s] Cluster To Maintain Iron Homeostasis In Escherichia Coli, Chelsey Rene Fontenot
LSU Doctoral Dissertations
Iron is an essential element for biological functions. Organisms have developed specific mechanisms to acquire, store, and export iron to manage intracellular iron homeostasis. These mechanisms are crucial not only for providing the cells with adequate iron for biological processes but also for ensuring that cells are not overloaded with excess iron, which is highly toxic. The Ferric uptake regulator (Fur) is a global transcription factor for maintaining intracellular iron homeostasis in bacteria. Previously, it was postulated that when the intracellular iron content is elevated, Fur binds ferrous iron to down-regulate the iron acquisition genes and up- regulate the iron …
Attentional Focus Effects On Motor Variability, Charlend Kenneth Howard
Attentional Focus Effects On Motor Variability, Charlend Kenneth Howard
LSU Doctoral Dissertations
Subtle changes in task instructions with associated changes of one’s focus of attention (FOA) can have measurable effects on performance and learning of complex motor skills (Wulf, 2013). The beneficial effects of adopting an external focus of attention (EF) have been well-documented in physical environments, and recently have also been demonstrated in virtual reality (VR) environments (Cochran, Aiken, Rhea, & Raisbeck, 2021; Yamada, Kuznetsov, Diekfuss, & Raisbeck, 2021). However, these studies primarily focused on performance outcomes (such as error and accuracy), with relatively less emphasis on movement coordination. Given that most human movements are motor abundant (more degrees of freedom …
The Impacts Of Immune Challenges On Fish Behavior And Physiology, Teisha King
The Impacts Of Immune Challenges On Fish Behavior And Physiology, Teisha King
LSU Doctoral Dissertations
For species living in dominance hierarchies, social rank dictates access to resources and often contributes to reproductive success. To ensure survival, individuals constantly evaluate trade- offs between crucial biological systems, like the reproductive and immune systems, depending on their social rank and physiological state. Little is known about how social species balance interactions between immune system function, fluctuations in social status and reproductive fitness, and the performance of behaviors necessary for maintaining social status when sick, particularly in fishes, the largest and most diverse group of vertebrates. My dissertation research uses a whole animal approach to examine how physiological profiles …
Effects Of Riverine Barriers On Avian Evolution In The Amazon Basin, Andre Eugene Moncrieff
Effects Of Riverine Barriers On Avian Evolution In The Amazon Basin, Andre Eugene Moncrieff
LSU Doctoral Dissertations
The high biodiversity found in the Amazon Basin has long captivated the attention of naturalists and evolutionary biologists seeking to explain its origins. Early observations by Alfred Wallace highlighted the role of rivers in delimiting the geographic ranges of many species; furthermore, where rivers narrow towards their headwaters, he noted that some species cross rivers freely. A major goal of this dissertation is to investigate how these and other observations about riverine barriers might inform our understanding of how speciation unfolds in Amazonia. My approach involved generating genomic data with dense geographic sampling for manakins in the genus Lepidothrix, …
Development Of Functional Markers For Resistance To Smut And Identification Of Genes Differentially Expressed In Response To Brown Rust In Sugarcane, Jose David Cortes
Development Of Functional Markers For Resistance To Smut And Identification Of Genes Differentially Expressed In Response To Brown Rust In Sugarcane, Jose David Cortes
LSU Doctoral Dissertations
Smut, caused by Sporisorium scitamineum and brown rust, caused by Puccinia melanocephala, are two of the most important diseases that affect sugarcane production in Louisiana and worldwide. Smut continues to cause losses in the breeding program in Louisiana. Therefore, a QTL analysis was conducted to identify molecular markers associated with resistance in F1 progeny (162) of a biparental cross between susceptible cultivar L 99-233 and resistant HoCP 96-540. Using 1,574 single-dose SNP markers, a total of 253 linkage groups (LG) were obtained with a genome coverage of 24,580.15 cM. Six QTLs were localized on five LGs. The highest …
The Effects Of Tillage And Cover Crops On Crop Yield And Soil Properties In Wheat Double-Cropping Systems, Peters E. Egbedi
The Effects Of Tillage And Cover Crops On Crop Yield And Soil Properties In Wheat Double-Cropping Systems, Peters E. Egbedi
LSU Doctoral Dissertations
This three-year study was conducted on a commerce silt loam soil at the Northeast Research and Experiment Station near St. Joseph, Louisiana to evaluate the following objectives: 1) evaluate crop yield response to tillage, winter, and summer cover crops in wheat double-cropping systems. 2) evaluate the effects of tillage, winter and summer cover crops on soil properties under different cropping systems. 3) quantify the economic benefits of double-cropping, cover cropping and monoculture systems under conventional and no tillage practices. A winter cover crop (WCC) mix (winter wheat (Triticum aestivum and Austrian winter pea (Pisum sativum) and summer …
Spatiotemporal Transcriptome Diversity And Responses To Salinity Tolerance In The Extremophyte Schrenkiella Parvula, Chathura Wijesinghege
Spatiotemporal Transcriptome Diversity And Responses To Salinity Tolerance In The Extremophyte Schrenkiella Parvula, Chathura Wijesinghege
LSU Doctoral Dissertations
Schrenkiella parvula is an extremophyte model related to the most widely studied plant model, Arabidopsis thaliana and Brassica crops in the mustard family (Brassicaceae). It can thrive in highly saline environments where the soil is enriched in Na+, K+, Li+, borates, and chlorides. Understanding how this extremophyte can survive high salinity with genomic adaptations can provide insight into developing stress resilient crops in the future. Gene expression of S. parvula in response to salt has been investigated using shoot and root tissue from mature vegetative-phase plants. However, prior studies have not examined the transcript …
The Applied Use Of Zein Nanoparticles In Agriculture, Colin Bonser
The Applied Use Of Zein Nanoparticles In Agriculture, Colin Bonser
LSU Doctoral Dissertations
Nanotechnology is a multifaceted and a promising strategy in agricultural pest management for the development of insecticides or insecticide carriers. Research has shown that nanoparticles increase stability and efficacy of entrapped chemical pesticides to prevent active ingredient degradation while improving chemical stability and solubility. The following work evaluated nanoparticles synthesized from biopolymers, materials that originate from renewable sources also have an increased biodegradability.
Work was conducted under laboratory, greenhouse, and field conditions to test the biopoloymers as possible insecticide and insecticide carriers. The primary biopolymer evaluated in the following studies was zein, although lignin and chitosan were also evaluated. Overall, …
Esterase Mediated Insecticide Resistance In The Southern House Mosquito, Culex Quinquefasciatus, Vivek Pokhrel
Esterase Mediated Insecticide Resistance In The Southern House Mosquito, Culex Quinquefasciatus, Vivek Pokhrel
LSU Doctoral Dissertations
Much is known about the development of insecticide resistance associated with targeted application against insect populations. However, off-target selection by applications of insecticides in agricultural and residential sites also impacts development of insecticide resistance and is understudied. Similarly, the impact of selecting one life stage of mosquitoes on the insecticide susceptibility of different life stages is largely unknown. The first part of this study shows that susceptibility to chlorantraniliprole, which is applied in rice and sugarcane fields in LA, decreased (5.7 to12-fold) in populations of Culex quinquefasciatus collected from near these fields compared to a reference field strain. In addition, …
Fish And Invertebrate Community And Trophic Structure In The Gulf Of Mexico Coastal Plains Watersheds Across Varying Hydrologic Connectivity., Erin Elizabeth Thayer
Fish And Invertebrate Community And Trophic Structure In The Gulf Of Mexico Coastal Plains Watersheds Across Varying Hydrologic Connectivity., Erin Elizabeth Thayer
LSU Doctoral Dissertations
Subtropical Northern Gulf of Mexico coastal plains watersheds tend to have mild seasonal temperature, low topography, and fine, mostly homogenous substrate sizes; these watersheds may not follow fish and invertebrate community patterns predicted by established lotic paradigms because those paradigms tend to describe communities in either temperate or tropical regions. However, the bases of most generally accepted lotic paradigms involve evaluation of allochthonous and autochthonous contributions to lotic ecosystems via three hydrologic connectivity dimensions including vertical (hyporheic and shallow groundwater), lateral (floodplain), and longitudinal (upstream and downstream). My dissertation goals were to explore these three dimensions within Louisiana coastal plains …
Identification Of Quantitative Trait Loci (Qtls) For Resistance To Bacterial Leaf Streak: Xanthomonas Translucens Using Qtl And Association Mapping In Three Populations Of Soft Red Winter Wheat, Benjamin Tyler Meritt
Identification Of Quantitative Trait Loci (Qtls) For Resistance To Bacterial Leaf Streak: Xanthomonas Translucens Using Qtl And Association Mapping In Three Populations Of Soft Red Winter Wheat, Benjamin Tyler Meritt
LSU Doctoral Dissertations
Bacterial leaf streak (BLS) and black chaff, caused by Xanthomonas translucens pv. undulosa (Xtu), can be a very destructive disease of wheat, especially in the warmer, wetter areas of the Southeastern U.S. Yield losses of up to 40 percent have been recorded in some cases in southern wheat growing regions. With no effective agronomic or chemical method of disease control, identification of genetic resistance is seen as a promising solution. Three soft red winter wheat populations (GAWN, ARK-SNP, and AGS 2060- AGS 2035 DH) representative of soft red winter wheat germplasm in the southeastern U.S. developed by …
The Risks Posed By Mosquito Ultra-Low Volume Applications To Procambarus Clarkii Production, Timothy Mcnamara
The Risks Posed By Mosquito Ultra-Low Volume Applications To Procambarus Clarkii Production, Timothy Mcnamara
LSU Doctoral Dissertations
Mosquito abatement has received much scrutiny due to concerns about the impacts of control applications on non-target organisms. In Louisiana, a great deal of this concern has come from crawfish farmers claiming mosquito abatement applications have damaged crawfish production. To determine which mosquito abatement practices and products pose a risk to crawfish production, we conducted a series of studies examining mosquito abatement practices in the vicinity of crawfish production fields and the impacts of common mosquito abatement product exposure on crawfish health and production. We found that mosquito ULV applications are the most likely to result in exposure to crawfish …
Effects Of Sensory Cues On Product Acceptability And Consumer Perceptions, Emotions, And Behavior, Cristhiam Gurdian Curran
Effects Of Sensory Cues On Product Acceptability And Consumer Perceptions, Emotions, And Behavior, Cristhiam Gurdian Curran
LSU Doctoral Dissertations
Visual and cognitive cues can affect overall liking (OL) and consumer perceptions, emotions, and behavior. The first study explored the effect of product color difference on the liking, perception, and purchase intent (PI) of cheese-flavored-tortilla chips (CFTC) formulations (A and B) on serving plates (plastic, foam, and paper). Color differences between formulations influenced crunchiness and saltiness liking and perception, which together with overall flavor liking and formulation, mainly determined CFTC OL. Although having similar fracturability (N) and sodium content, formulation A had higher crunchiness and saltiness likings. PI was influenced by crunchiness, saltiness, and OF liking with 37, 49, and …
Comparative Genomics And Virulence Studies Of Streptomyces Soil Rot And Scab Pathogen Species, Natasha Soares
Comparative Genomics And Virulence Studies Of Streptomyces Soil Rot And Scab Pathogen Species, Natasha Soares
LSU Doctoral Dissertations
Comparative genomic analyses were performed to gain insights into the organization and content of the genome of Streptomyces ipomoeae, the soil rot pathogen that infects sweetpotatoes. Unlike Streptomyces scab pathogens, the thaxtomin phytotoxin gene cluster (txt) in S. ipomoeae does not appear to reside within a genomic island and has diverged from its scab pathogen counterparts. Increased usage of the rare TTA codon, particularly for the txt cluster, suggests greater translational control by the bldA tRNA in S. ipomoeae. Orthologous gene searches and secondary metabolite profiling yielded ortholog groups and metabolite gene clusters that were exclusive …
The Effects Of Drought And Shade On Bottomland Hardwood Regeneration, Charles Joseph Pell
The Effects Of Drought And Shade On Bottomland Hardwood Regeneration, Charles Joseph Pell
LSU Doctoral Dissertations
Floodplain forests support a high diversity of tree species adapted to regenerate under fluctuating water and light availability. Regeneration regulates species composition, and shade and flood tolerance influence the likelihood of regeneration. Regeneration failure of shade-intolerant and flood-tolerant tree species commonly occurs in southcentral and southeastern floodplain forests of the United States, also known as bottomland hardwoods (BLHs). In many BLHs reduced flooding has resulted in a dryer floodplain. These changes in flooding are linked to recent shifts in species composition. The mechanisms controlling regeneration in BLHs and these composition shifts are poorly understood. In a controlled germination experiment, I …
Integration Of Remote Sensing Approaches For In-Season Nitrogen Management, Murilo De Santana Martins
Integration Of Remote Sensing Approaches For In-Season Nitrogen Management, Murilo De Santana Martins
LSU Doctoral Dissertations
Nitrogen (N) management is being conducted at flat rate in Louisiana due to practicality and convenience, but the price of N fertilizer and high breakeven costs are forcing producers to find ways to reduce costs and optimize N application. In this scenario, precision agriculture technologies, specifically the use of optical sensors on board of unmanned aerial systems (UAS) to variable rate N application on farm is showing a promising approach to save inputs and reduce environmental impacts. However, the general goal of this research was to develop and evaluate in-season N management approaches for N recommendation in corn (Zea …
Genetic Dissection And Qtl Pyramiding To Enhance Salinity Tolerance In Rice (Oryza Sativa L.), Sandeep Chapagain
Genetic Dissection And Qtl Pyramiding To Enhance Salinity Tolerance In Rice (Oryza Sativa L.), Sandeep Chapagain
LSU Doctoral Dissertations
Salinity is emerging as a major threat to rice production worldwide due to climate change and anthropogenic sources. We performed three different population development approaches using exotic salt tolerant donors in US rice backgrounds to identify the salt tolerant QTLs/genes and tolerant breeding lines. First approach involved development of a biparental introgression lines (ILs) population by utilizing a salinity tolerant donor ‘TCCP’ in an elite rice cultivar ‘Cheniere’ background and mapping of QTLs at germination, seedling, and reproductive stages A total of seven QTLs for five germination traits, 16 QTLs for seven seedling stage traits, and 30 QTLs for ten …
Evolution Of Freshwater Fishes In The Northern Neotropics, Diego Elias
Evolution Of Freshwater Fishes In The Northern Neotropics, Diego Elias
LSU Doctoral Dissertations
The northern Neotropics (NN) represents one of the most geologically-complex regions on the planet, composed of island-like geological blocks that have undergone multiple episodes of isolation and connectivity at various geological times. The riverscapes of the NN harbor a unique assemblage of freshwater fishes. In contrast to the freshwaters systems of South America, which are dominated by ostariophysan lineages, the aquatic systems of the NN are dominated by lineages of two families: Cichlidae (cichlids) and Poeciliidae (livebearers). It has been suggested that the geologically complex nature of the region allowed ancestors of cichlids and livebearers to colonize and radiate within …
Insights Into The Speciation Process From Genomic And Phenotypic Analysis Of An Avian Hybrid Zone In Amazonia, Glaucia Christina Del-Rio
Insights Into The Speciation Process From Genomic And Phenotypic Analysis Of An Avian Hybrid Zone In Amazonia, Glaucia Christina Del-Rio
LSU Doctoral Dissertations
Understanding the outcome of secondary contact is essential to shed light on the mechanisms governing species formation and maintenance. In Amazonia, closely related bird taxa with limited dispersal abilities are often separated by rivers, which presumably act as dispersal barriers. However, at the headwaters, rivers cease to be dispersal barriers, and this generates opportunities for secondary contact. In my dissertation, I studied genomic mechanisms associated with phenotypic differences, mitochondrial DNA structure, and putative reproductive barriers between two hybridizing Amazonian bird species in the genus Rhegmatorhina, a group of antbirds that find their arthropod prey exclusively by following army-ant swarms. …