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- Title
- GENETIC AND PHENOTYPIC EVOLUTION IN THE ORNATE CHORUS FROG (PSEUDACRIS ORNATA): TESTING THE RELATIVE ROLES OF NATURAL SELECTION, MIGRATION, AND GENETIC DRIFT.
- Creator
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Degner, Jacob, Hoffman, Eric, University of Central Florida
- Abstract / Description
-
Understanding how migration, genetic drift, and natural selection interact to maintain the genetic and phenotypic variation we observe in natural populations is a central goal of population genetics. Amphibians provide excellent model organisms for investigating the interplay between these evolutionary forces because amphibians are generally characterized by limited dispersal abilities, high philopatry, and are obligately associated with the areas around suitable habitats (e.g. breeding ponds...
Show moreUnderstanding how migration, genetic drift, and natural selection interact to maintain the genetic and phenotypic variation we observe in natural populations is a central goal of population genetics. Amphibians provide excellent model organisms for investigating the interplay between these evolutionary forces because amphibians are generally characterized by limited dispersal abilities, high philopatry, and are obligately associated with the areas around suitable habitats (e.g. breeding ponds). Thus, on relatively small geographic scales, the relative effects of all of these evolutionary forces can be studied together. Here, we study the interaction of migration, genetic drift, natural selection, and historical process in the ornate chorus frog (Pseudacris ornata). We report the development and characterization of 10 polymorphic microsatellite genetic markers. Number of alleles per locus ranged from 2 to 21 averaging 9.2 and expected heterozygosities ranged from 0.10 to 0.97 averaging 0.52. However, in an analysis of two populations, three locus-by-population comparisons exhibited significant heterozygote deficiencies and indicated that null alleles may be present some loci. Furthermore, we characterized genetic structure and historical biogeographic patterns in P. ornata using these microsatellite markers along with mitochondrial DNA sequence data. Our data indicate that in these frogs, migration may play a large role in determining population structure as pairwise estimates of FST were relatively small ranging from 0.04 to 0.12 (global FST = 0.083). Additionally, we observed an overall pattern of isolation-by-distance in neutral genetic markers across the species range. Moreover, our data suggest that the Apalachicola River basin does not impede gene flow in P. ornata as it does in many vertebrate taxa. Interestingly, we identified significant genetic structure between populations separated by only 6 km. However, this fine scale genetic structure was only present in the more urbanized of two widespread sampling localities. Finally, in this study, we demonstrated that there was a significant correlation between the frequency of green frogs and latitude. There was a higher frequency of green frogs in southern samples and a lower frequency of green frogs in northern samples. However, when we interpreted this phenotypic cline in light of the overall pattern of isolation-by-distance, it was apparent that the neutral evolutionary forces of genetic drift and migration could explain the cline, and the invocation of natural selection was not necessary.
Show less - Date Issued
- 2007
- Identifier
- CFE0001721, ucf:47319
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0001721
- Title
- GENETIC DIFFERENTIATION AMONG FLORIDA POPULATIONS OF DIADEMA ANTILLARUM.
- Creator
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Chandler, Luke M, Hoffman, Eric, University of Central Florida
- Abstract / Description
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This project used molecular genetic markers (microsatellites) to determine the amount of genetic diversity within populations and whether significant differentiation exists among Florida populations of the long-spined sea urchin, Diadema antillarum. Specifically, this project aimed to (1) compare genetic diversity of D. antillarum from six populations in south Florida ranging from Biscayne Bay, the Florida Keys, and Dry Tortugas, and (2) determine whether two broodstock populations of D....
Show moreThis project used molecular genetic markers (microsatellites) to determine the amount of genetic diversity within populations and whether significant differentiation exists among Florida populations of the long-spined sea urchin, Diadema antillarum. Specifically, this project aimed to (1) compare genetic diversity of D. antillarum from six populations in south Florida ranging from Biscayne Bay, the Florida Keys, and Dry Tortugas, and (2) determine whether two broodstock populations of D. antillarum contain variation indicative of native Florida populations. Together, these questions can address whether broodstock populations contain the genetic variation necessary to meet the Florida Fish and Wildlife Conservation Commission�s (FWC�s) genetic policies for reintroduction throughout south Florida. Global FST among native populations was 0.0004 with a highest pairwise FST of 0.0025 between the Upper Keys and the area west of Key West, showing an overall trend of little natural differentiation between populations. Global FST for all populations inclusive of the broodstock samples was 0.0019 with a highest pairwise FST between a native population and broodstock of 0.0066 between Dry Tortuga and Mote�s broodstock, indicating little differentiation resulting from captive breeding. Average allelic richness and heterozygosity ranged from 22.6�24.4 and 0.937�0.956, respectively, for each population. Two-way ANOVAs comparing genetic diversity between native and broodstock populations showed no statistical difference in allelic richness (F= 3.892, p= 0.0535) or heterozygosity (F=1.43, p=0.237). The computer program STRUCTURE estimated the most likely number of genetic clusters to be k=1, inclusive of broodstock populations, further indicating a lack of differentiation either among native populations or between native and broodstock populations. These data suggest that captive-bred individuals of D. antillarum could be used for reintroduction as part of a plan to re-establish healthy urchin populations throughout the Florida Keys.
Show less - Date Issued
- 2016
- Identifier
- CFH2000044, ucf:45558
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFH2000044
- Title
- ESTIMATING DIET AND FOOD SELECTIVITY OF THE LOWER KEYS MARSH RABBIT USING STABLE ISOTOPE ANALYSIS.
- Creator
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Gordon, Matthew, Hoffman, Eric, University of Central Florida
- Abstract / Description
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Understanding the effect of food abundance on feeding behavior can benefit conservation efforts in many ways, such as to determine whether impacted environments need food supplementation, whether different locations of threatened species contain different food abundances, or whether reintroduction sites are missing key components of a species' diet. I studied the relationship between feeding behavior and food abundance in the Lower Keys marsh rabbit (Sylvilagus palustris hefneri), an...
Show moreUnderstanding the effect of food abundance on feeding behavior can benefit conservation efforts in many ways, such as to determine whether impacted environments need food supplementation, whether different locations of threatened species contain different food abundances, or whether reintroduction sites are missing key components of a species' diet. I studied the relationship between feeding behavior and food abundance in the Lower Keys marsh rabbit (Sylvilagus palustris hefneri), an endangered subspecies endemic to the lower Florida Keys. Specifically, my study set out to measure the relative abundance of the primary plants within the natural habitat of the Lower Keys marsh rabbit and estimate the proportion of each of these plants within the rabbit's diet. With this information, I tested the following hypotheses: first, the Lower Keys marsh rabbit selectively feeds on specific plants; second, that diet does not differ among sites; and third, that diet is not affected by food abundance. Using stable isotope analysis, I determined that two plants were prominent in the rabbit's diet: a shrub, Borrichia frutescens, and a grass, Spartina spartinae. These two species were prominent in the rabbit's diet in most patches, even where they were relatively rare, suggesting the rabbits are indeed selectively feeding on these species. In addition, although diet did differ among patches, selective feeding was apparent in all cases. Overall, this study determined that certain food types are important food sources for the federally endangered Lower Keys marsh rabbit and that these rabbits do not feed on plants based on plant abundance. This knowledge can be directly applied to reintroduction and restoration efforts for the Lower Keys marsh rabbit. More generally, the methods used in this study can be applied to other species of concern in order to address questions associated with diet requirements and foraging behavior.
Show less - Date Issued
- 2010
- Identifier
- CFE0003471, ucf:48952
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0003471
- Title
- TAXONOMY VERSUS PHYLOGENY: PHYLOGEOGRAPHY OF MARSH RABBITS WITHOUT HOPPING TO CONCLUSIONS.
- Creator
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Tursi, Rosanna, Hoffman, Eric, University of Central Florida
- Abstract / Description
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Subspecific taxonomic designations solely based on morphological characters can often lead to erroneous assumptions about the evolutionary history of populations. This study sought to investigate evolutionary questions and conservation implications associated with morphological subspecific designations of island populations. To this end, I focused my attention on the Lower Keys of Florida, a unique chain of islands with well-known geologic history and rich in endemic, endangered subspecies. I...
Show moreSubspecific taxonomic designations solely based on morphological characters can often lead to erroneous assumptions about the evolutionary history of populations. This study sought to investigate evolutionary questions and conservation implications associated with morphological subspecific designations of island populations. To this end, I focused my attention on the Lower Keys of Florida, a unique chain of islands with well-known geologic history and rich in endemic, endangered subspecies. I employed genetic analyses to evaluate historical variation and contemporary restriction of gene flow between the endangered Lower Keys marsh rabbit (Sylvilagus palustris hefneri) and its sister mainland taxa. A Bayesian phylogeny using 1063 base pairs of the mitochondrial cytochrome b gene did not recover reciprocal monophyly of the three named subspecies, and a 95% statistical parsimony haplotype network showed haplotypes being shared among subspecies. Furthermore, clustering analyses using 10 microsatellite loci identified a break within the Lower Keys, separating the western Lower Keys from the island of Big Pine Key. Surprisingly, Big Pine Key grouped with mainland populations and exhibits higher genetic diversity than the western Lower Keys islands. These unexpected findings suggest either a stepping-stone colonization pattern or recent gene flow between the mainland and Big Pine Key via natural dispersal or undocumented man-mediated transfers. Although these results suggest that subspecies designations within S. palustris are unwarranted, this study supports the designation western Lower Keys population as a discrete unit of conservation with regard to both DPS and ESU criteria. The importance of using several lines of evidence to uncover the evolutionary history of populations and implications for the conservation of island populations are discussed.
Show less - Date Issued
- 2010
- Identifier
- CFE0003418, ucf:48380
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0003418
- Title
- USING LANDSCAPE GENETICS TO ASSESS POPULATION CONNECTIVITY IN A HABITAT GENERALIST.
- Creator
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Hether, Tyler, Hoffman, Eric, University of Central Florida
- Abstract / Description
-
Understanding the nature of genetic variation in natural populations is an underlying theme of population genetics. In recent years population genetics has benefited from the incorporation of landscape and environmental data into pre-existing models of isolation by distance (IBD) to elucidate features influencing spatial genetic variation. Many of these landscape genetics studies have focused on populations separated by discrete barriers (e.g., mountain ridges) or species with specific...
Show moreUnderstanding the nature of genetic variation in natural populations is an underlying theme of population genetics. In recent years population genetics has benefited from the incorporation of landscape and environmental data into pre-existing models of isolation by distance (IBD) to elucidate features influencing spatial genetic variation. Many of these landscape genetics studies have focused on populations separated by discrete barriers (e.g., mountain ridges) or species with specific habitat requirements (i.e., habitat specialists). One difficulty in using a landscape genetics approach for taxa with less stringent habitat requirements (i.e., generalists) is the lack of obvious barriers to gene flow and preference for specific habitats. My study attempts to fill this information gap to understand mechanisms underlying population subdivision in generalists, using the squirrel treefrog (Hyla squirella) and a system for classifying 'terrestrial ecological systems' (i.e. habitat types). I evaluate this dataset with microsatellite markers and a recently introduced method based on ensemble learning (Random Forest) to identify whether spatial distance, habitat types, or both have influenced genetic connectivity among 20 H. squirella populations. Next, I hierarchically subset the populations included in the analysis based on (1) genetic assignment tests and (2) Mantel correlograms to determine the relative role of spatial distance in shaping landscape genetic patterns. Assignment tests show evidence of two genetic clusters that separate populations in Florida's panhandle (Western cluster) from those in peninsular Florida and southern Georgia (Eastern cluster). Mantel correlograms suggest a patch size of approximately 150 km. Landscape genetic analyses at all three spatial scales yielded improved model fit relative to isolation by distance when including habitat types. A hierarchical effect was identified whereby the importance of spatial distance (km) was the strongest predictor of patterns of genetic differentiation above the scale of the genetic patch. Below the genetic patch, spatial distance was still an explanatory variable but was only approximately 30% as relevant as mesic flatwoods or upland oak hammocks. Thus, it appears that habitat types largely influence patterns of population genetic connectivity at local scales but the signal of IBD becomes the dominant driver of regional connectivity. My results highlight some habitats as highly relevant to increased genetic connectivity at all spatial scales (e.g., upland oak hammocks) while others show no association (e.g., silviculture) or scale specific associations (e.g., pastures only at global scales). Given these results it appears that treating habitat as a binary metric (suitable/non-suitable) may be overly simplistic for generalist species in which gene flow probably occurs in a spectrum of habitat suitability. The overall pattern of spatial genetic and landscape genetic structure identified here provides insight into the evolutionary history and patterns of population connectivity for H. squirella and improves our understanding of the role of matrix composition for habitat generalists.
Show less - Date Issued
- 2010
- Identifier
- CFE0003204, ucf:48580
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0003204
- Title
- EXPRESSION LEVELS OF VIRULENCE GENES IN GROUP A STREPTOCOCCI: A RESPONSE TO AEROSOLIZED PROPYLENE GLYCOL.
- Creator
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Costello, Michael S, Hoffman, Eric, Moore, Sean D., University of Central Florida
- Abstract / Description
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Electronic cigarette usage is becoming increasingly prevalent among school age children and young adults. A known bactericidal agent, propylene glycol, is often used as a carrier for nicotine, flavoring, and additional constituents of electronic cigarette juice. This study examined the relationship between propylene glycol and virulence gene expression in Streptococcus pyogenes, a respiratory tract pathogen commonly found in school-age individuals. A variety of virulence genes controlled by...
Show moreElectronic cigarette usage is becoming increasingly prevalent among school age children and young adults. A known bactericidal agent, propylene glycol, is often used as a carrier for nicotine, flavoring, and additional constituents of electronic cigarette juice. This study examined the relationship between propylene glycol and virulence gene expression in Streptococcus pyogenes, a respiratory tract pathogen commonly found in school-age individuals. A variety of virulence genes controlled by the three stand alone regulators mga, RofA, and Rgg/RopB were sampled in an effort to understand the pathway by which virulence is affected. The genes chosen encode C5a peptidase, fibronectin binding protein, hyaluronate lyase, NAD glycohydrolase, Streptococcal pyrogenic exotoxin A and B, streptodornase, streptokinase, Streptolysin O, and Streptolysin S. No significant change in gene expression was observed, but a novel method to test the effects of aerosols on cells was developed. This method can be used in the future to observe the effect of aerosols, including commercial electronic cigarette juice, on both bacterial and mammalian cells.
Show less - Date Issued
- 2016
- Identifier
- CFH2000106, ucf:46048
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFH2000106
- Title
- Pine, aphids, and parasitoid wasps: patterns of cospeciation and host switches in a tri-trophic system.
- Creator
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Bass, Amber, Sharanowski, Barbara, Fedorka, Kenneth, Hoffman, Eric, University of Central Florida
- Abstract / Description
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Ecological interactions may drive speciation events, and the processes that drive these speciation events can leave behind patterns in the phylogenies of interacting taxa. These patterns have been studied extensively in herbivores and host plants, as well as parasites and their hosts, but rarely in tri-trophic systems. Here, we examine three closely related groups of interacting taxa, including parasitoid wasps (Pauesia), aphid herbivores (Cinara), and pine trees (Pinus) to determine if the...
Show moreEcological interactions may drive speciation events, and the processes that drive these speciation events can leave behind patterns in the phylogenies of interacting taxa. These patterns have been studied extensively in herbivores and host plants, as well as parasites and their hosts, but rarely in tri-trophic systems. Here, we examine three closely related groups of interacting taxa, including parasitoid wasps (Pauesia), aphid herbivores (Cinara), and pine trees (Pinus) to determine if the patterns between each interacting taxa indicate that cospeciation or host switches are more dominant. We create phylogenies of Cinara and Pauesia in the southeastern United States using ddRADseq data and analyze publicly available data for Pinus. Most Cinara and Pauesia were specialized, with no species utilizing more than three hosts, indicating that this system is well suited to cophylogenetic study, and host interactions likely play a role in the speciation of these taxa. Pauesia was slightly more specialized on Pinus, suggesting phytochemistry may constrain the host breadth of these wasps and lead to coevolutionary patterns between Pauesia and Pinus. Distance-based cophylogenetic analyses suggest that aphids and pine, and wasps and aphids have dependent phylogenies, but these analyses differ in regards to wasps and pine. However, event-based methods show that cospeciation events and host switches both present, often in nearly equal proportions, and duplications and sorting events occurred at a lower frequency if at all. Both Cinara and Pauesia require revisions and the development of updated taxonomic resources for identification. This system presents an ideal model group to study coevolutionary patterns and multi-trophic community dynamics across macro- and microevolutionary time scales.
Show less - Date Issued
- 2019
- Identifier
- CFE0007430, ucf:52707
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007430
- Title
- The Evolution of Peristenus (Hymenoptera: Braconidae): Taxonomy, Phylogenetics and Ecological Speciation.
- Creator
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Zhang, Yuanmeng, Sharanowski, Barbara, Hoffman, Eric, Savage, Anna, Marcus, Jeffrey, University of Central Florida
- Abstract / Description
-
Parasitoid wasps are ecologically and economically important as biological control agents. However, little is known about the diversity, distribution and biology of most hymenopteran parasitoids due to their small size, morphological conservatism, and complex life styles. The focus of my PhD research was to investigate the evolution and speciation of euphorine braconid wasps, using a combination of multilocus phylogenetics and population genomic techniques combined with traditional taxonomy....
Show moreParasitoid wasps are ecologically and economically important as biological control agents. However, little is known about the diversity, distribution and biology of most hymenopteran parasitoids due to their small size, morphological conservatism, and complex life styles. The focus of my PhD research was to investigate the evolution and speciation of euphorine braconid wasps, using a combination of multilocus phylogenetics and population genomic techniques combined with traditional taxonomy. The three data chapters of my dissertation are divided into different taxonomic ranks of euphorine braconids, focusing on genera, species, and populations. For chapter 2, I built a multilocus phylogeny of the tribe Euphorini with extensive taxa sampling around the globe. I confirmed the monophyly of Peristenus and Leiophron, two important biological control agents, and provided updated generic concepts and identification resources to aid applied researchers. In Chapters 3 and 4, I focused on cryptic species within the Peristenus pallipes complex in North America. I used an integrative taxonomic approach to resolve the taxonomic confusion within the Nearctic Peristenus pallipes complex (Chapter 3), then I used ddRADSeq to examine their evolutionary relationships with their Lygus hosts (Chapter 4). My dissertation provided a comprehensive analysis of Peristenus at multiple taxonomic ranks using phylogenetics and population genomics, providing insights into their evolutionary history that can be extrapolated into other groups of parasitoid wasps. The results from these studies also advanced our understanding of this group of animals of theoretical, economical, and conservation importance.
Show less - Date Issued
- 2018
- Identifier
- CFE0007272, ucf:52194
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007272
- Title
- Seascape genetics and rehabilitation efficiency in the Florida manatee.
- Creator
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Hall, Madison, Worthy, Graham, Weishampel, John, Hoffman, Eric, Dyer, Rodney, University of Central Florida
- Abstract / Description
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The Florida manatee (Trichechus manatus latirostris) was recently downlisted federally from (")endangered(") to (")threatened(") despite acknowledgments of remaining threats to long term population persistence. Challenges to future manatee conservation include, but are not limited to, increases in frequency of harmful algal blooms, intensifying anthropogenic disturbance, and loss of warm-water habitat. The goals of this dissertation were 1) to assess threats to the manatee via a comprehensive...
Show moreThe Florida manatee (Trichechus manatus latirostris) was recently downlisted federally from (")endangered(") to (")threatened(") despite acknowledgments of remaining threats to long term population persistence. Challenges to future manatee conservation include, but are not limited to, increases in frequency of harmful algal blooms, intensifying anthropogenic disturbance, and loss of warm-water habitat. The goals of this dissertation were 1) to assess threats to the manatee via a comprehensive, long-term (1973-2016), retrospective analysis of the manatee rescue and rehabilitation partnership (MRRP) and 2) to use seascape genetics analysis to examine whether abiotic, biotic, or anthropogenic seascape variables could significantly describe genetic distance patterns in space for this genetically depauperate population. Results from the MRRP analysis revealed that anthropogenic threats were the most significant reason for manatees to be rescued and rehabilitated. Manatees rescued due to watercraft injuries spent long periods in recovery before succumbing or being released resulting in significant expense to the rehabilitation system. Additionally, the seascape genetics analysis indicated that watercraft activity best explained spatial genetic patterns in the manatee population. It is established that anthropogenic use of watercraft negative affects manatees through the mechanisms of sub-lethal injury and mortality, and these results suggest there may be further negative impacts via the disruption of population genetic connectivity. Future management practices should seriously consider manatee/vessel interactions as watercraft strikes are costly for management, place pressure on the manatee population, and could disrupt population gene flow with potentially dire consequences. Mitigating anthropogenic impacts on the Florida manatee population is critical for future conservation and should be a primary focus.
Show less - Date Issued
- 2019
- Identifier
- CFE0007647, ucf:52465
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007647
- Title
- Beyond building a tree: Phylogeny of pitvipers and exploration of evolutionary patterns.
- Creator
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Fenwick, Allyson, Parkinson, Christopher, Hoffman, Eric, Crampton, William, Wiens, John, University of Central Florida
- Abstract / Description
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As generic and higher-scale evolutionary relationships are increasingly well understood, systematists move research in two directions: 1) understanding species-level relationships with dense taxon sampling, and 2) evaluating evolutionary patterns using phylogeny. In this study I address both foci of systematic research using pitvipers, subfamily Crotalinae. For direction one, I evaluate the relationships of 96% of pitvipers by combining independent sets of molecular and phenotypic data. I...
Show moreAs generic and higher-scale evolutionary relationships are increasingly well understood, systematists move research in two directions: 1) understanding species-level relationships with dense taxon sampling, and 2) evaluating evolutionary patterns using phylogeny. In this study I address both foci of systematic research using pitvipers, subfamily Crotalinae. For direction one, I evaluate the relationships of 96% of pitvipers by combining independent sets of molecular and phenotypic data. I find the inclusion of species with low numbers of informative characters (i.e. less than 100) negatively impacts resolution of the phylogeny, and the addition of independent datasets has no effect on or a small benefit to confidence in estimated evolutionary relationships. Combined evidence is extremely useful in evaluating taxonomy; I use it with South American bothropoid pitvipers. Previous work found the genus Bothrops paraphyletic, but no study had included enough species to propose a taxonomic resolution. I resolve the relationships of 90% of bothropoid pitvipers, and support the paraphyly of Bothrops as previously defined, but find it consists of three well-supported clades distinguished by distinct habitats and geographic ranges. I propose the division of Bothrops sensu lato into three genera.To address research direction two, I investigate the change in reproductive mode from egg-laying (oviparity) to livebearing (viviparity) in vipers, as well as the expansion of pitvipers through South America. I resolve the phylogeny and the divergence times for subgroups of interest then use model comparison and ancestral character state or geographic range estimation to trace the evolution of reproductive mode or geographic range across evolutionary history. For vertebrates, the predominant explanation for the evolution of reproductive mode is Dollo's Law of unidirectional evolution. This law has been challenged for a number of characters in different systems, but the phylogenetic methods that found those violations were criticized. I find support for unidirectional evolution in two analyses and rejection of it in others, and therefore do not reject Dollo's Law for the evolution of reproductive mode in vipers. In the case of geographic range, dozens of hypotheses have been proposed to explain the great biodiversity in South America, but tests of these hypotheses are lacking. I define specific time- and space-based predictions for seven hypotheses based on geological and climatic events (-) uplift of the Andes Mountains, saltwater inundation of inland areas, change in river flow, and Pleistocene climate changes. I find some support for half of the hypotheses, including one allopatric, one parapatric, and one based on climate change. I conclude that the evolution of South American pitvipers is extremely complex. Through fulfillment of both systematic research directions, I generated new knowledge about pitvipers and evolutionary processes. My methods of evaluating evolutionary patterns provide frameworks for different research questions in these areas, and I suggest that other researchers apply similar techniques to evaluate other portions of the Tree of Life.
Show less - Date Issued
- 2012
- Identifier
- CFE0004535, ucf:49236
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004535
- Title
- Life history response to infection and the potential for dishonest signals in the ground cricket, Allonemobius socius.
- Creator
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Copeland, Emily, Fedorka, Kenneth, Hoffman, Eric, Crampton, William, University of Central Florida
- Abstract / Description
-
In order to maximize fitness, individuals must partition their limited resources among competing physiological processes, creating negative statistical associations between processes known as (")life-history trade-offs("). Evidence indicates that individuals tend to decrease their reproductive investment when confronted with a significant immunological challenge in order to increase investment in immune defense. This trade-off is often accompanied by a significant decrease in the sexual...
Show moreIn order to maximize fitness, individuals must partition their limited resources among competing physiological processes, creating negative statistical associations between processes known as (")life-history trade-offs("). Evidence indicates that individuals tend to decrease their reproductive investment when confronted with a significant immunological challenge in order to increase investment in immune defense. This trade-off is often accompanied by a significant decrease in the sexual signal, which provides an honest signal of the male's infection status to potential mates. However, if individual residual reproductive value is low, they may instead increase their reproductive investment to maximize reproductive success before the end of their life (a.k.a. terminal investment). Here, we investigate the potential for terminal investment in the ground cricket Allonemobius socius by inoculating males with varying dosages of an immune challenge. We predicted that both high dose and advanced male age would induce terminal investment. Furthermore, we predicted that terminally investing males would produce a dishonest signal by increasing their signaling effort. We found that upon infection We found that upon infection, young males and old males differentially alter their reproductive strategy. Young males exhibited the classic deceleration of reproductive effort. However, old males increased their calling song energetics and decreased their parental investment (nuptial gift size), suggesting that old males are dishonestly signaling their condition to the female.
Show less - Date Issued
- 2012
- Identifier
- CFE0004529, ucf:49249
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004529
- Title
- Indirect estimates of gene flow and conservation implications in the striped newt (Notophthalmus perstriatus).
- Creator
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May, Sarah, Hoffman, Eric, Parkinson, Christopher, Johnson, Steve, University of Central Florida
- Abstract / Description
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This study used indirect methods to estimate patterns of gene flow in a rare salamander species, the striped newt (Notophthalmus perstriatus). First, we used combined genetic and ecological methods to determine whether populations that appear to exist in two regions separated by 125 km, exhibited genetic and ecological distinctness such that the regions demarcate separate conservation units. Using mtDNA (cyt-b), we found that haplotypes were shared between localities within each region but...
Show moreThis study used indirect methods to estimate patterns of gene flow in a rare salamander species, the striped newt (Notophthalmus perstriatus). First, we used combined genetic and ecological methods to determine whether populations that appear to exist in two regions separated by 125 km, exhibited genetic and ecological distinctness such that the regions demarcate separate conservation units. Using mtDNA (cyt-b), we found that haplotypes were shared between localities within each region but none were shared between regions. Niche-based distribution modeling revealed significant differences in the ecological setting between the two regions. In combination, the absence of evidence for recent genetic exchange and model-based support for differing ecological conditions utilized by newts between regions provides evidence that eastern and western populations are both distinct and significant. This study suggests a framework to evaluate discreteness and significance among populations for assessment of distinct population segments (DPSs which can be used as a conservation tool for many species. Second, we used microsatellites to characterize patterns of population connectivity, genetic differentiation, and effective population size in N. perstriatus. We assessed these patterns by testing several a priori hypotheses regarding the influence of gene flow and genetic drift on the distribution of genetic variation among and within populations. Interestingly, several of our results did not conform to our hypotheses. For example, our assessment did not reveal a significant pattern of isolation by distance among populations in this study. Additionally, we found that effective population sizes and genetic diversity of isolated populations were higher than expected. We discuss our results relate to our a priori hypotheses and we address the general question of why this species exhibited patterns contrary to what we expected given previous data on this taxon and other studies of similar taxa
Show less - Date Issued
- 2011
- Identifier
- CFE0004481, ucf:49311
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004481
- Title
- Evolution Through the Search for Novelty.
- Creator
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Lehman, Joel, Stanley, Kenneth, Gonzalez, Avelino, Wiegand, Rudolf, Hoffman, Eric, University of Central Florida
- Abstract / Description
-
I present a new approach to evolutionary search called novelty search, wherein only behavioral novelty is rewarded, thereby abstracting evolution as a search for novel forms. This new approach contrasts with the traditional approach of rewarding progress towards the objective through an objective function. Although they are designed to light a path to the objective, objective functions can instead deceive search into converging to dead ends called local optima.As a significant problem in...
Show moreI present a new approach to evolutionary search called novelty search, wherein only behavioral novelty is rewarded, thereby abstracting evolution as a search for novel forms. This new approach contrasts with the traditional approach of rewarding progress towards the objective through an objective function. Although they are designed to light a path to the objective, objective functions can instead deceive search into converging to dead ends called local optima.As a significant problem in evolutionary computation, deception has inspired many techniques designed to mitigate it. However, nearly all such methods are still ultimately susceptible to deceptive local optima because they still measure progress with respect to the objective, which this dissertation will show is often a broken compass. Furthermore, although novelty search completely abandons the objective, it counterintuitively often outperforms methods that search directly for the objective in deceptive tasks and can induce evolutionary dynamics closer in spirit to natural evolution. The main contributions are to (1) introduce novelty search, an example of an effective search method that is not guided by actively measuring or encouraging objective progress; (2) validate novelty search by applying it to biped locomotion; (3) demonstrate novelty search's benefits for evolvability (i.e. the abilityof an organism to further evolve) in a variety of domains; (4) introduce an extension of novelty search called minimal criteria novelty search that brings a new abstraction of natural evolution to evolutionary computation (i.e. evolution as a search for many ways of meeting the minimal criteria of life); (5) present a second extension of novelty search called novelty search with local competition that abstracts evolution instead as a process driven towards diversity with competition playing a subservient role; and (6) evolve a diversity of functional virtual creatures in a single run as a culminating application of novelty search with local competition. Overall these contributions establish novelty search as an important new research direction for the field of evolutionary computation.
Show less - Date Issued
- 2012
- Identifier
- CFE0004398, ucf:49390
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004398
- Title
- Testing for Isolation in Florida Raccoons (Procyon lotor) Using Phylogenetics and Population Genetic Structure.
- Creator
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Trujillo, Alexa, Hoffman, Eric, Fedorka, Kenneth, Parkinson, Christopher, University of Central Florida
- Abstract / Description
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Molecular data are useful in determining if populations are isolated and for species delimitation. Researchers and managers currently recognize five subspecies of raccoons (Procyon lotor) in Florida, based largely on perceived geographic isolation due to the island ranges of four subspecies. In this study, I provide the first estimate of phylogenetic relationships and population divergences within Florida raccoons using a molecular dataset. I analyze the mitochondrial control region,...
Show moreMolecular data are useful in determining if populations are isolated and for species delimitation. Researchers and managers currently recognize five subspecies of raccoons (Procyon lotor) in Florida, based largely on perceived geographic isolation due to the island ranges of four subspecies. In this study, I provide the first estimate of phylogenetic relationships and population divergences within Florida raccoons using a molecular dataset. I analyze the mitochondrial control region, cytochrome b gene, and eight nuclear microsatellite loci to test two hypotheses: 1) the five, morphologically and geographically-defined subspecies of raccoon in Florida represent genetically distinct populations and (2) due to differing range sizes and habitat variation between island and mainland subspecies, the four island populations should exhibit reduced levels of genetic diversity and smaller effective population sizes compared to the mainland population. My results indicate no evidence of historical differentiation between the subspecies, but suggest a recent restriction of gene flow among three clusters of raccoons. The three clusters do not correlate to traditional geographies for subspecies identification. I provide evidence of reduced genetic diversity in island populations of raccoons compared to their mainland counterparts. These data stress the importance of using multiple lines of evidence when naming taxa to avoid misinforming the taxonomy.
Show less - Date Issued
- 2015
- Identifier
- CFE0006233, ucf:51069
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006233
- Title
- Climate Change and the Evolution of Insect Immune Function.
- Creator
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Perry, Danae, Fedorka, Kenneth, Jenkins, David, Hoffman, Eric, University of Central Florida
- Abstract / Description
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Insects are ectothermic organisms that have physiological, behavioral and life-history traits directly influenced by their environment. Investigations have shown that many insects use melanin to permanently darken their cuticles in cooler or drier climates to improve thermoregulation and desiccation resistance. Melanin is a major component of pathogen defense in insects. This suggests that environmentally driven adaptive changes in cuticular melanin may non-adaptively shape insect immune...
Show moreInsects are ectothermic organisms that have physiological, behavioral and life-history traits directly influenced by their environment. Investigations have shown that many insects use melanin to permanently darken their cuticles in cooler or drier climates to improve thermoregulation and desiccation resistance. Melanin is a major component of pathogen defense in insects. This suggests that environmentally driven adaptive changes in cuticular melanin may non-adaptively shape insect immune function. This hypothesis has been referred to as climate-related Cuticle Dependent Immune Investment (climate-related CDII). Climate-related CDII also suggests that a warming climate could lead to the evolution of a weakened melanin-based immune response due to direct selection for lighter cuticles. Climate-related CDII has not been investigated with regard to climate change. Using Drosophila melanogaster, the first part of this study investigated if the documented pattern of lowered immune function in warmer temperatures offsets the expected gain in metabolic rate. The second part of this project investigated how a warming thermal environment will affect the evolution of insect immune function by quantifying changes in melanization and immune function over multiple generations in a changing thermal environment. In the first investigation there was evidence for weakened immune function in males, while females saw an offset by gaining a metabolic boost. The second investigation showed evidence that warming treatments evolved lowered overall immune function. This project gives evidence that insect immune function has the potential to be weakened by increasing temperatures. Insect immune function is a major contributing factor to insect abundances. A decrease in beneficial insects or an increase in harmful insects or pathogens they vector could have detrimental environment and human health consequences.?
Show less - Date Issued
- 2017
- Identifier
- CFE0006638, ucf:51256
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006638
- Title
- Advanced castes at the outset of eusociality in wasps (Vespidae).
- Creator
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Piekarski, Patrick, Sharanowski, Barbara, Carpenter, James, Hoffman, Eric, University of Central Florida
- Abstract / Description
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A dominating and widespread view is that evolutionary change is gradual and waits upon mutation. Likewise, it is thought that workers and queens of eusocial insects diverged gradually and stepwise. That is, rudimentary castes preceded advanced castes. This paradigm hinges on eusociality having evolved once in Vespidae, and primitively eusocial paper wasps lacking ontogenetic caste biasing (differentiation of castes during larval development). Using a phylogenomic approach this study shows...
Show moreA dominating and widespread view is that evolutionary change is gradual and waits upon mutation. Likewise, it is thought that workers and queens of eusocial insects diverged gradually and stepwise. That is, rudimentary castes preceded advanced castes. This paradigm hinges on eusociality having evolved once in Vespidae, and primitively eusocial paper wasps lacking ontogenetic caste biasing (differentiation of castes during larval development). Using a phylogenomic approach this study shows strong evidence for two origins of eusociality in vespid wasps, wherein one origin is likely characterized by the sudden appearance of castes with physiological, and perhaps even morphological, differences established before adulthood (i.e. advanced castes). Ontogenetic caste biasing was likely present at the outset of eusociality in the most recent common ancestor of paper wasps, yellowjackets and hornets. This suggests that the definitive, non-temporal castes of eusocial wasps evolved from interactions between mothers and daughters, rather than same generation females. These results challenge the idea that castes began with only rudimentary differences. A model of stepwise caste divergence, which assumes an independent mutation event for each phenotypic caste difference, is unwarranted. It is hypothesized that phenotypic plasticity and cryptic genetic variation may explain how some eusocial societies emerged, and began with advanced castes. The results suggest that evolution can produce alternative phenotypes with many aspects of the phenotype being discrete at the outset. Thus, the emergence and divergence of castes in eusocial vespids was not necessarily a gradual process.
Show less - Date Issued
- 2017
- Identifier
- CFE0006640, ucf:51240
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006640
- Title
- The behavior of humans and wildlife with respect to roads: insights for mitigation and management.
- Creator
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Grace, Molly, Noss, Reed, Weishampel, John, Hoffman, Eric, Johnson, Steve, University of Central Florida
- Abstract / Description
-
Road ecology is the study of how roads and wildlife interact. Traditionally, road ecologists have primarily focused on one effect of roads: roadkill. Though roadkill can have devastating effects on wildlife populations, roads have sub-lethal impacts that are gaining more and more attention from the scientific community. These sub-lethal impacts include noise, light, and chemical pollution as well as altered habitat structure, which can all influence animal behavior. In this dissertation, I...
Show moreRoad ecology is the study of how roads and wildlife interact. Traditionally, road ecologists have primarily focused on one effect of roads: roadkill. Though roadkill can have devastating effects on wildlife populations, roads have sub-lethal impacts that are gaining more and more attention from the scientific community. These sub-lethal impacts include noise, light, and chemical pollution as well as altered habitat structure, which can all influence animal behavior. In this dissertation, I applied a behavioral ecology framework to study specific lethal and sub-lethal road effects with the goal of improving mitigation efforts. In Chapters 1 and 2, I evaluated how human behavior may be modified to reduce wildlife-vehicle collisions; traditionally efforts have been made to modify wildlife road crossing behavior. I found that Roadside Animal Detection Systems, which warn drivers when animals are near the road, are successful in reducing crash risk; however, care must be taken to ensure that drivers do not become acclimated to the warning system. In Chapters 3 and 4, I evaluated how traffic noise affects subadult growth and adult abundance and communication of anuran amphibians (frogs and toads), a taxon widely recognized as one of the most negatively impacted by roads. I found that through traffic noise alters tadpole behavior, it does not appear to have a negative effect on their growth. Traffic noise does, however, negatively affect adult anuran abundance. My results indicate that this reduction in abundance is caused by the interference of traffic noise with anuran communication.
Show less - Date Issued
- 2017
- Identifier
- CFE0006595, ucf:51275
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006595
- Title
- Genetic structure and demographic analysis of Key deer (Odocoileus virginianus clavium).
- Creator
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Villanova, Vicki, Hoffman, Eric, Parkinson, Christopher, Fedorka, Kenneth, University of Central Florida
- Abstract / Description
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Recent improvements in genetic analyses have paved the way in using molecular data to answer questions regarding evolutionary history, genetic structure, and demography. Key deer are a federally endangered subspecies assumed to be genetically unique (based on one allozyme study), homogeneous, and have a female-biased population of approximately 900 deer. I used 985bp of the mitochondrial cytochrome b gene and 12 microsatellite loci to test two hypotheses: 1) if the Moser Channel is a barrier...
Show moreRecent improvements in genetic analyses have paved the way in using molecular data to answer questions regarding evolutionary history, genetic structure, and demography. Key deer are a federally endangered subspecies assumed to be genetically unique (based on one allozyme study), homogeneous, and have a female-biased population of approximately 900 deer. I used 985bp of the mitochondrial cytochrome b gene and 12 microsatellite loci to test two hypotheses: 1) if the Moser Channel is a barrier to gene flow, I should expect that Key deer are differentiated and have reduced diversity compared to mainland deer and (2) if isolation on islands leads to a higher probability of extinction, I should expect that Key deer exhibit a small population size and a high risk of extinction. My results indicate that Key deer are genetically isolated from mainland white-tailed deer and that there is a lack of genetic substructure between islands. While Key deer exhibit reduced levels of genetic diversity compared to their mainland counterparts, they contain enough diversity of which to uniquely identify individual deer. Based on genetic identification, I estimated a census size of around 1,000 individuals with a heavily skewed female-biased adult sex ratio. Furthermore, I combined genetic and contemporary demographic data to generate a species persistence model of the Key deer. Sensitivity tests within the population viability analysis brought to light the importance of fetal sex ratio and female survival as the primary factors at risk of driving the subspecies to extinction.
Show less - Date Issued
- 2015
- Identifier
- CFE0006058, ucf:50981
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006058
- Title
- Go with the flow: patterns of connectivity in low dispersal coral reef gobies (Coryphopterus spp.) throughout the western Atlantic.
- Creator
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Volk, Daniel, Hoffman, Eric, Ferreira, Carlos, Cook, Geoffrey, University of Central Florida
- Abstract / Description
-
Gene flow is an integral biological process that can mediate speciation. While many consider the ocean to be an open environment, there are many barriers that limit gene flow, particularly in the western Atlantic. I analyzed data from two widespread, coral reef fishes, the bridled goby (Coryphopterus glaucofraenum) and sand-canyon goby (C. venezuelae), throughout their range in the western Atlantic. Using two genetic datasets, mitochondrial DNA (mtDNA) and genomic SNPs, I investigated the...
Show moreGene flow is an integral biological process that can mediate speciation. While many consider the ocean to be an open environment, there are many barriers that limit gene flow, particularly in the western Atlantic. I analyzed data from two widespread, coral reef fishes, the bridled goby (Coryphopterus glaucofraenum) and sand-canyon goby (C. venezuelae), throughout their range in the western Atlantic. Using two genetic datasets, mitochondrial DNA (mtDNA) and genomic SNPs, I investigated the evolutionary history of these species and inferred the location and strength of putative barriers. My results suggest that several unique lineages have genetically diverged from one another in the presence of two major barriers. First, the Amazon River has isolated Brazil from the Caribbean and second, a unique lineage was found at an isolated oceanic island, Atol das Rocas, off the northeast coast of Brazil. Furthermore, minor barriers have caused slight genetic differentiation in each of the Caribbean species off the coast of Venezuela, while on the Brazilian coast, there are up to two barriers that separate three genetically unique areas. The stronger of the two barriers is located at Cabo Frio near an upwelling system and the weaker barrier coincides with the outflow of the S(&)#227;o Francisco River. Overall, this research highlights how barriers impact speciation and genetic structure within these gobies in the western Atlantic and more broadly, deepens our understanding about the role of oceanographic features in the speciation process.
Show less - Date Issued
- 2017
- Identifier
- CFE0006924, ucf:51690
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006924
- Title
- The Effect of Parental Population Density on Offspring Immune Function.
- Creator
-
Davis, Dana, Fedorka, Kenneth, Savage, Anna, Hoffman, Eric, University of Central Florida
- Abstract / Description
-
It is well known that an individual's environment, genetic code, and gene by environment interactions have an effect on its overall phenotype. However, there is a growing body of work that shows that parents can have an effect on their offspring's phenotype beyond the inherited genetic code. Studies have shown that parents may affect their offspring through physiological mechanisms such as egg provisioning and epigenetic effects and through behavioral mechanisms such as maternal care. In many...
Show moreIt is well known that an individual's environment, genetic code, and gene by environment interactions have an effect on its overall phenotype. However, there is a growing body of work that shows that parents can have an effect on their offspring's phenotype beyond the inherited genetic code. Studies have shown that parents may affect their offspring through physiological mechanisms such as egg provisioning and epigenetic effects and through behavioral mechanisms such as maternal care. In many of these cases, the parental effect is triggered by an environmental cue. Previous work has shown that density can impact immune function and cuticle color in insects - two phenotypic traits that are pleiotropically linked. Additional work has shown that parental density can have impacts on offspring immune function, as well. However, previous studies utilized insect species that show a strict density dimorphic phenotype where individuals reared at high densities exhibit increased immune function and much darker cuticles than their low density counterparts, which is not an accurate representation of most insect systems as most insect systems show a more continuous response to density effects. Also, previous work has not determined the parental origin of density effects on offspring immune function and cuticle color. It has been suggested that parental density effects may be due to maternal egg provisioning and that paternal effects may be minimal. However, knowledge of parental origin would give us a better insight into the possible mechanisms of these density driven parental effects and provide a direction for future research. In my study, we used Drosophila melanogaster in order to determine (1) if density affects immune function and cuticle color in a species that shows a continuous response to density, (2) if parental density affects offspring immune function and cuticle color, and (3) if the source of these parental effects are of a maternal origin only or if these effects are of a paternal origin, as well. We found that there is an effect of density on immune function and cuticle color in the parents in a more common insect system and parental density had an effect on offspring phenotype, as well. Most notably, we found that, in addition to the effects of maternal density, these parental effects on offspring phenotype were a response to paternal density, as well.
Show less - Date Issued
- 2017
- Identifier
- CFE0006580, ucf:51355
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006580
