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University of New Orleans Theses and Dissertations

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Articles 1 - 13 of 13

Full-Text Articles in Other Ecology and Evolutionary Biology

Chromosome Number Evolution, Phylogeography, And The Effects Of Climate Change On Species Distributions In Polyploid Plant Systems, Courtney H. Babin Aug 2022

Chromosome Number Evolution, Phylogeography, And The Effects Of Climate Change On Species Distributions In Polyploid Plant Systems, Courtney H. Babin

University of New Orleans Theses and Dissertations

Polyploidy, a term used to describe organisms with cells having more than two paired sets of chromosomes, is a significant driver of diversification among land plants. Over a century of research has advanced our understanding of polyploidization in some taxa, but polyploid organisms remain understudied. In this dissertation, I investigate chromosome number evolution, phylogeographic structure, genetic differentiation, and the effects of climate change on ploidy level distribution using polyploid plant systems. In the first chapter, I inferred a molecular phylogeny of Allium, an economically important genus that includes cultivated crops and ornamentals, to investigate evolutionary transitions in chromosome number …


Structure And Evolution Of Lizard Immunity Genes, Trent Santonastaso Aug 2020

Structure And Evolution Of Lizard Immunity Genes, Trent Santonastaso

University of New Orleans Theses and Dissertations

One of the most important gene families to play a role in adaptive immunity is the major histocompatibility complex (MHC). MHC class II loci are considered to be the most variable loci in the vertebrate genome, and studies have shown that this variability can be maintained through complex co-evolutionary dynamics between host and parasite. Despite the rich body of research into the MHC, there is comparatively little understanding of its genomic architecture in reptiles. Similarly, loci associated with innate immunity have received little attention in reptiles compared to other vertebrates. In the first chapter, we investigated the structure and organization …


A Change In Grain? Diet Induced Plasticity In The Generalist Grasshopper Melanoplus Differentialis, Austin M. Culotta Dec 2018

A Change In Grain? Diet Induced Plasticity In The Generalist Grasshopper Melanoplus Differentialis, Austin M. Culotta

University of New Orleans Theses and Dissertations

Phenotypic plasticity is favored in heterogeneous environments in which alternative phenotypes can exploit alternative resources. However, it’s not clear whether phenotypic plasticity is useful in environments that become more homogenous over an organism’s life cycle. I studied a population of grasshopper Melanoplus differentialis that experiences high resource diversity as nymphs but low resource diversity as adults to determine if individuals can undergo diet-induced morphological plasticity in head shape to increase biting ability and ingestion of hard diets. Insects on a soft diet were larger and had greater bite force than those on a hard diet. Head structures related to chewing …


Conflict, Constraint, And The Evolution Of The Multivariate Performance Phenotype, Ann M. Cespedes Phd Dec 2017

Conflict, Constraint, And The Evolution Of The Multivariate Performance Phenotype, Ann M. Cespedes Phd

University of New Orleans Theses and Dissertations

Performance is key to survival. From day-to-day foraging events, to reproductive activities, to life-or-death crises, how well an organism performs these tasks can determine success or failure. Selection, therefore, both natural and sexual, act upon performance, and performance demands on individuals shape a population’s morphological and physiological trait distributions. While studies of morphological adaptations to ecological pressures implicitly center on the idea that responses to selection improve performance via changes in morphology, the relationships between morphology, performance, and fitness are not always well understood. In this dissertation, I investigate these relationships explicitly, as well as determine the effects that different …


Wing Shape Variation In The Mimetic Butterfly Papilio Dardanus (Papilionidae) And Its Unpalatable Nymphalid Models, Miles Hegedus Dec 2017

Wing Shape Variation In The Mimetic Butterfly Papilio Dardanus (Papilionidae) And Its Unpalatable Nymphalid Models, Miles Hegedus

University of New Orleans Theses and Dissertations

Papilio dardanus displays female-limited polymorphic mimicry of multiple model species. Butterfly wing shape is species-specific and can influence mimetic signaling, but has not been characterized in this species. We used elliptical fourier analysis to investigate whether mimetic P. dardanus female forms have converged on the wing shape of their respective models. Although both models and mimics varied in forewing and hind wing shape, we found no evidence of forewing shape convergence between them. Overall, forewings did not differ in shape between sexes in P. dardanus, nor in four non-mimetic Papilio used for comparison. Similarly, there were no hind wing …


Size-Dependent Patterns Of Reproductive Investment In The North American Invasive Plant Species Triadica Sebifera (L.) Small (Euphorbiaceae), Courtney H. Babin May 2017

Size-Dependent Patterns Of Reproductive Investment In The North American Invasive Plant Species Triadica Sebifera (L.) Small (Euphorbiaceae), Courtney H. Babin

University of New Orleans Theses and Dissertations

Knowledge of sex allocation trade-offs with tree growth in insect-pollinated woody plants is limited, particularly in invasive plants. This study examined patterns of growth and reproductive investment in a North American invasive plant species, Triadica sebifera, I hypothesized that the energy limitations of smaller trees may result in the production of more male reproductive structures that are energetically less costly. Diameter at breast height was a significant predictor of seed and catkin mass and regression can describe these relationships across sites. Seed and catkin mass were positively correlated across sites. The relationship between the seed mass:catkin mass ratio and …


The Origin And Expansion Of The Eastern Red Fox, Adrienne Egge Kasprowicz May 2016

The Origin And Expansion Of The Eastern Red Fox, Adrienne Egge Kasprowicz

University of New Orleans Theses and Dissertations

When new populations are first identified in a region there are multiple potential sources: introduction of a non-native species, extra-range expansion of a nearby population, or demographic growth of a previously unnoticed species. Red foxes were absent or rare in the mid-eastern portion United States until the late 1800s. Their origins potentially include natural population increase/expansion, translocations from Europe, and, eventually, 20th century fur farming. In this study I attempt to identify the relative impact of native expansion versus human mediated introductions of both colonial era European foxes and early 20th century fur-farm foxes on the establishment of red …


Arthropod Abundance And Diversity In Restored Longleaf Pine Savannas At Abita Creek Flatwoods Preserve, Cara B. Nighohossian May 2014

Arthropod Abundance And Diversity In Restored Longleaf Pine Savannas At Abita Creek Flatwoods Preserve, Cara B. Nighohossian

University of New Orleans Theses and Dissertations

The objective of this study is to determine whether changes in arthropod community structure in restored longleaf pine savannas corresponds to differences in vegetation structure often associated with burn frequency. Longleaf pine savannas are fire-maintained ecosystems characteristic of the southeastern United States and have experienced severe declines (around 97%) since European settlement. Changes in fire regime have been instrumental in the declines. Restoration of these ecosystems has involved reinstitution of periodic burnings to promote and maintain vegetative characteristics of the savannas. This study investigates trends in arthropod communities from areas heavily invaded by hardwood shrubs against those dominated by longleaf …


Statistical And Comparative Phylogeography Of Mexican Freshwater Taxa In Extreme Aquatic Environments, Lyndon M. Coghill Dec 2013

Statistical And Comparative Phylogeography Of Mexican Freshwater Taxa In Extreme Aquatic Environments, Lyndon M. Coghill

University of New Orleans Theses and Dissertations

Phylogeography aims to understand the processes that underlie the distribution of genetic variation within and among closely related species. Although the means by which this goal might be achieved differ considerably from those that spawned the field some thirty years ago, the foundation and conceptual breakthroughs made by Avise are nonetheless the same and are as relevant today as they were two decades ago. Namely, patterns of neutral genetic variation among individuals carry the signature of a species’ demographic past, and the spatial and temporal environmental heterogeneity across a species’ geographic range can influence patterns of evolutionary change. Aquatic systems …


Fish And Decapod Community Structure In Estuarine Habitats Of The New Orleans Land Bridge, Including A Description Of The Life Cycle Of Tarpon (Megalops Atlanticus) In Southeastern Louisiana, William Stein Iii May 2013

Fish And Decapod Community Structure In Estuarine Habitats Of The New Orleans Land Bridge, Including A Description Of The Life Cycle Of Tarpon (Megalops Atlanticus) In Southeastern Louisiana, William Stein Iii

University of New Orleans Theses and Dissertations

Estuarine marshes are generally considered to be productive but not necessarily diverse ecosystems. During 24 consecutive months, I collected 65,000 fishes and decapods comprising over 65 species from the New Orleans Land Bridge, an estuarine salt marsh. My research details the distribution of nekton across five contiguous but geomorphically different regions, which I defined as “Areas”. This factor “Area” was significant in explaining community composition differences in 11 of the 24 months I evaluated. That is, during those 11 months community structure was different among the Areas. Specific “month” was also found to be a significant factor as community structure …


Fish Assemblage Dynamics And Red Drum Habitat Selection In Bayou St. John And Associated Urban Waterways Located Within The City Of New Orleans, Louisiana, Patrick W. Smith Mr. May 2012

Fish Assemblage Dynamics And Red Drum Habitat Selection In Bayou St. John And Associated Urban Waterways Located Within The City Of New Orleans, Louisiana, Patrick W. Smith Mr.

University of New Orleans Theses and Dissertations

Bayou St. John (BSJ) and City Park Lakes and Lagoons (CPLL) are urban waterways in New Orleans, Louisiana. I studied habitat selection of red drum in BSJ, and fish assemblage change in BSJ and CPLL over 40 years. Temperature was found to be the best predictor of red drum habitat selection in Bayou St. John, while salinity and change in depth also were found to be good predictors for certain sites. Potential prey item abundance did not appear to influence habitat selection. Using data from 1971 – 2010, nearshore habitats in CPLL were affected by Hurricane Katrina, but have sense …


Bycatch Of The Lake Pontchartrain Basin Inshore Shrimp Fishery And Its Effect On Two Sea Catfish Species: The Gafftopsail Catfish (Bagre Marinus) And The Hardhead Catfish (Ariopsis Felis), Scott P. Eustis Dec 2011

Bycatch Of The Lake Pontchartrain Basin Inshore Shrimp Fishery And Its Effect On Two Sea Catfish Species: The Gafftopsail Catfish (Bagre Marinus) And The Hardhead Catfish (Ariopsis Felis), Scott P. Eustis

University of New Orleans Theses and Dissertations

In Lake Pontchartrain Basin, commercial fishing in estuarine habitats impacts many non-target species collected as bycatch. I investigated the bycatch assemblages collected by commercial vessels and compared these to assemblages collected by typical fishery-independent methods. I compared assemblages using analysis of similarity (ANOSIM) and determined important species by weight and abundance using similarity percentages analyses (SIMPER). I also examined differences in size-class distributions by gear type using density kernel plots and Mann-Whitney U tests. The two gear types collected significantly different assemblages (ANOSIM R = 0.522, p = 0.001) and gear type explained more composition differences than other factors such …


Metabolism And Cryo-Sensitivity Of Domestic Cat (Felis Catus) And Cheetah (Acinonyx Jubatus) Spermatozoa, Kimberly Terrell Aug 2011

Metabolism And Cryo-Sensitivity Of Domestic Cat (Felis Catus) And Cheetah (Acinonyx Jubatus) Spermatozoa, Kimberly Terrell

University of New Orleans Theses and Dissertations

Teratospermia (ejaculation of ≥ 60% structurally abnormal spermatozoa) is prevalent among felids facing extinction risk, including the cheetah. This trait also occurs in certain domestic cat populations, providing a valuable research model. Multiple components of sperm function are disrupted in teratospermic cats, and even structurally normal spermatozoa from these ejaculates may be functionally compromised. Teratospermic ejaculates are highly sensitive to damage during cryopreservation, limiting the success of genome resource banking programs for species conservation. Although both teratospermia and cryopreservation are linked to disruptions in multiple energy-dependent sperm processes, the metabolism of these cells has not been investigated. This project explored …