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Full-Text Articles in Ecology and Evolutionary Biology

Friends Or Foes: Interpreting The Relationship Between Two Synoptic Small Mammals In Southeastern Virginia, The Hispid Cotton Rat (Sigmodon Hispidus) And Eastern Harvest Mouse (Reithrodontomys Humulis), Sarah A. Crawford Apr 2013

Friends Or Foes: Interpreting The Relationship Between Two Synoptic Small Mammals In Southeastern Virginia, The Hispid Cotton Rat (Sigmodon Hispidus) And Eastern Harvest Mouse (Reithrodontomys Humulis), Sarah A. Crawford

Biological Sciences Theses & Dissertations

Relatively little is known about the relationship between the hispid cotton rat (Sigmodon hispidus) and the eastern harvest mouse (Reithrodontomys humulis). Literature on these two syntopic genera in other areas of the United States suggests that competition may exist; however, both species seem to be greatly affected by environmental changes, making it difficult to draw any definite conclusions. Live trapping and microhabitat data collected from 2 old fields in Chesapeake, Virginia over a 9-year period were used to assess the biotic and abiotic influences on space use by these two species. Each I-ha plot consisted of 2 live traps placed …


Carrion Beetle (Coleoptera: Silphidae) Carcass Selection: Effects Of Carcass Mass And Site Fidelity, Jonathan M. Schmude Apr 2013

Carrion Beetle (Coleoptera: Silphidae) Carcass Selection: Effects Of Carcass Mass And Site Fidelity, Jonathan M. Schmude

Biological Sciences Theses & Dissertations

This study investigated reproductive behaviours of the carrion beetles (Coleoptera: Silphidae) of southeastern Virginia. Carrion beetles have been known to have ranges of carcass masses used for reproductive behaviors. In this study, pitfall traps were baited with 25g, 50g, or 75g of a cat food/mackerel mixture and left to decay and attract beetles for one week to investigate if any Silphidae species prefer a single mass over another. This study investigated the carcass bait mass that is used on the subfamily and species level, and how the beetle mass plays a role in preference. The study also investigated the effect …


Investigations Of Phytoplankton Diversity In Chesapeake Bay, Todd Arthur Egerton Apr 2013

Investigations Of Phytoplankton Diversity In Chesapeake Bay, Todd Arthur Egerton

Biological Sciences Theses & Dissertations

Characterizing the diversity of a community in relation to environmental conditions and ecosystem functions are core concepts in ecology. While decades of research have led to a growing comprehension of diversity in many ecosystems, our understanding in aquatic habitats and microbial organisms remains relatively limited. Phytoplankton represent a diverse and important group that contribute approximately half of global primary productivity and are intrinsically connected to changing environmental conditions, especially in systems as dynamic as estuaries. To better understand the ecological processes governing phytoplankton composition and diversity, spatial and temporal patterns of environmental parameters and their relation to the algal community …


Basin Isolation And Oceanographic Features Influencing Lineage Divergence In The Humbug Damselfish (Dascyllus Aruanus) In The Coral Triangle, Jeremy M. Raynal Apr 2013

Basin Isolation And Oceanographic Features Influencing Lineage Divergence In The Humbug Damselfish (Dascyllus Aruanus) In The Coral Triangle, Jeremy M. Raynal

Biological Sciences Theses & Dissertations

The Coral Triangle (CT) is a hotspot for marine species diversity as well as for intraspecific genetic diversity. Here, nuclear RAG2 and mitochondrial D-Loop genes were used to identify deep genetic divergence among Dascyllus aruanus (Linnaeus, 1758) populations across relatively short scales within the CT. Mitochondrial clades different by greater than 20 mutational steps were geographically isolated from one another across the distance between Java and the Lesser Sunda Islands, and also east and west across the Philippines. Evidence for population structure in the Sulu Sea and at the Lesser Sunda Islands is also identified. The results suggest that the …


Comparative Phylogeography Of The Emperor Snappers Lethrinus Lentjan And Lethrinus Harak (Lethrinidae: Percoidei) In The Coral Triangle, Andrew B. Hines Apr 2013

Comparative Phylogeography Of The Emperor Snappers Lethrinus Lentjan And Lethrinus Harak (Lethrinidae: Percoidei) In The Coral Triangle, Andrew B. Hines

Biological Sciences Theses & Dissertations

Many questions remain regarding the origins of the well-known peak in marine biodiversity found in the Coral Triangle. Barriers to gene flow may promote lineage diversification and provide the potential for speciation contributing to the high biodiversity in this area. Population structure was examined in two species of Emperor Snappers (Lethrinidae), Lethrinus harak and Lethrinus lentjan. These species were selected because they share similar life-history traits and geographic distributions, but differ in their habitat preferences. Specimens were collected from within the Coral Triangle as well as other localities across the Indo-Pacific. To investigate phylogeographic patterns and structure a hypervariable …


Uncoupling Between Dinitrogen Fixation And Primary Productivity In The Eastern Mediterranean Sea, Eyal Rahav, Barak Herut, Noga Stambler, Edo Bar-Zeev, Margaret R. Mulholland Mar 2013

Uncoupling Between Dinitrogen Fixation And Primary Productivity In The Eastern Mediterranean Sea, Eyal Rahav, Barak Herut, Noga Stambler, Edo Bar-Zeev, Margaret R. Mulholland

OES Faculty Publications

In the nitrogen (N)-impoverished photic zones of many oceanic regions, prokaryotic organisms fixing atmospheric dinitrogen (N2; diazotrophs) supply an essential source of new nitrogen and fuel primary production. We measured dinitrogen fixation and primary productivity (PP) during the thermally stratified summer period in different water regimes of the oligotrophic eastern Mediterranean Sea, including the Cyprus Eddy and the Rhodes Gyre. Low N2 fixation rates were measured (0.8-3.2μmol N m-2 d-1) excluding 10-fold higher rates in the Rhodes Gyre and Cyprus Eddy (~20μmol N m-2 d-1). The corresponding PP increased from east to west (200-2500μmol …


The Population Dynamics Of Two Rodents In Two Coastal Marshes In Virginia, Robert K. Rose, John A. March Jan 2013

The Population Dynamics Of Two Rodents In Two Coastal Marshes In Virginia, Robert K. Rose, John A. March

Virginia Journal of Science

The communities of small mammals were evaluated for 13 months with capture-mark-recapture methods in two Spartina-Juncus marshes of the Atlantic coast in Northampton County, Virginia. Small mammals were trapped for three days each month using live traps placed on floats on two study grids. Two rodents were numerically dominant (~90% of small mammals) there: marsh rice rat, Oryzomys palustris, and meadow vole, Microtus pennsylvanicus. Monthly estimates of population density were greater for rice rats (peak: 45/ha) than for those of meadow voles (peak: 30/ha). Survival rates were generally low, especially for rice rats, indicating highly vagile populations. Both …


Wintering Eiders Acquire Exceptional Se And Cd Burdens In The Bering Sea: Physiological And Oceanographic Factors, James R. Lovvorn, Merl F. Raisbeck, Lee W. Cooper, Gregory A. Cutter, Micah W. Miller, Marjorie L. Brooks, Jacqueline M. Grebmeier, Angela C. Matz, Cortney M. Schaefer Jan 2013

Wintering Eiders Acquire Exceptional Se And Cd Burdens In The Bering Sea: Physiological And Oceanographic Factors, James R. Lovvorn, Merl F. Raisbeck, Lee W. Cooper, Gregory A. Cutter, Micah W. Miller, Marjorie L. Brooks, Jacqueline M. Grebmeier, Angela C. Matz, Cortney M. Schaefer

OES Faculty Publications

During late winter (March) in the Bering Sea, levels of Se in livers and Cd in kidneys of spectacled eiders Somateria fischeri were exceptionally high (up to 489 and 312 µg g−1 dry mass, respectively). Comparison of organ and blood samples during late winter, early spring migration, and breeding suggests that the eiders’ high Se and Cd burdens were accumulated at sea, with highest exposure during winter. High exposure may have resulted from high metabolic demands and food intake, as well as concentrations in food. In the eiders’ remote wintering area, their bivalve prey contained comparable Se levels and …


Ontogenetic Shifts In Resource Allocation: Colour Change And Allometric Growth Of Defensive And Reproductive Structures In The Caribbean Spiny Lobster Panulirus Argus, Joshua R. Anderson, Angelo J. Spadaro, J. Antonio Baeza, Donald C. Behringer Jan 2013

Ontogenetic Shifts In Resource Allocation: Colour Change And Allometric Growth Of Defensive And Reproductive Structures In The Caribbean Spiny Lobster Panulirus Argus, Joshua R. Anderson, Angelo J. Spadaro, J. Antonio Baeza, Donald C. Behringer

Biological Sciences Faculty Publications

Resource allocation theory predicts a disproportionately large allocation of resources to defensive structures during early ontogeny in organisms that are subject to more intense predation at smaller than at larger body sizes. We tested this prediction on the Caribbean spiny lobster Panulirus argus, which exhibits a negative relationship between predation risk and body size with a high natural mortality of smaller individuals. Independent allometric growth analyses demonstrated that numerous defensive structures (e.g. orbital horns, segments supporting the antenna, the tail fan) display negative allometric growth throughout ontogeny. We interpret these findings as lobsters investing disproportionately more resources to defensive …


Genetic Population Structure Of Us Atlantic Coastal Striped Bass (Morone Saxatilis), David T. Gauthier, Corinne A. Audemard, Jeanette E. L. Carlsson, Tanya L. Darden, Michael R. Denson, Kimberly S. Reece, Jens Carlsson Jan 2013

Genetic Population Structure Of Us Atlantic Coastal Striped Bass (Morone Saxatilis), David T. Gauthier, Corinne A. Audemard, Jeanette E. L. Carlsson, Tanya L. Darden, Michael R. Denson, Kimberly S. Reece, Jens Carlsson

Biological Sciences Faculty Publications

Genetic population structure of anadromous striped bass along the US Atlantic coast was analyzed using 14 neutral nuclear DNA microsatellites. Young-of-the-year and adult striped bass (n = 1114) were sampled from Hudson River, Delaware River, Chesapeake Bay, North Carolina, and South Carolina. Analyses indicated clear population structure with significant genetic differentiation between all regions. Global multilocus F-ST was estimated at 0.028 (P < 0.001). Population structure followed an isolation-by-distance model and temporal sampling indicated a stable population structure more than 2 years at all locations. Significant structure was absent within Hudson River, whereas weak but significant genetic differences were observed between northern and southern samples in Chesapeake Bay. The largest and smallest effective striped bass population sizes were found in Chesapeake Bay and South Carolina, respectively. Coalescence analysis indicated that the highest historical gene flow has been between Chesapeake Bay and Hudson River populations, and that exchange has not been unidirectional. Bayesian analysis of contemporary migration indicated that Chesapeake Bay serves as a major source of migrants for Atlantic coastal regions from Albemarle Sound northward. In addition to examining population genetic structure, the data acquired during this project were capable of serving as a baseline for assigning fish with unknown origin to source region.


First Record Of Pond Sliders (Trachemys Scripta Scripta And T. S. Elegans) At Fredericksburg, Virginia With Observations On Population Size, Age And Growth, Werner Wieland, Yoshinori Takeda Jan 2013

First Record Of Pond Sliders (Trachemys Scripta Scripta And T. S. Elegans) At Fredericksburg, Virginia With Observations On Population Size, Age And Growth, Werner Wieland, Yoshinori Takeda

Virginia Journal of Science

We conducted a turtle mark-recapture program within a 160 m stretch of the Fredericksburg Canal with standard, baited hoop nets from May to July 2012 to determine if a population of the introduced Red-eared Slider (Trachemys scripta elegans) and Yellow-bellied Slider (Trachemys s. scripta) are established in this area. We captured and marked nine Red-eared Sliders (1 male, 8 females) and estimated a population size of 23 individuals. Most were reproductively mature. The established population in the canal may be a source of introduction into the Rappahannock River.


The Small Mammals Of Two Dune Communities In Southeastern Virginia, Robert K. Rose, Justin L. Sweitzer Jan 2013

The Small Mammals Of Two Dune Communities In Southeastern Virginia, Robert K. Rose, Justin L. Sweitzer

Virginia Journal of Science

Small mammals were surveyed using live and pitfall traps between the primary and secondary dunes at two locations on the shores of the Chesapeake Bay near the Atlantic Ocean: Little Creek Amphibious Base in Norfolk and Joint Expeditionary Base Fort Story in Virginia Beach, Virginia. Captures were dominated by house mice (Mus musculus) in interdunal habitats with sparse grass, whereas white-footed mice (Peromyscus leucopus) were found primarily in shrubby live-oak thickets on the tops of dunes. Hispid cotton rats (Sigmodon hispidus) were present only at Fort Story, and then only in patches of dense …


Effect Of Laser Ablation Depth In Otolith Life History Scans, Renée R. Hoover, Cynthia M. Jones Jan 2013

Effect Of Laser Ablation Depth In Otolith Life History Scans, Renée R. Hoover, Cynthia M. Jones

OES Faculty Publications

Life history scans of fish otoliths are bringing new insight into the structure, connectivity, and movement of fish populations. Data obtained from such scans, however, possess in-herent limitations that have not yet been fully addressed or understood. For example, several investigators have noted delays in otolith elemental uptake that do not appear to reflect habitat exposure. We hypothesized that the 3-dimensional structure of otoliths may produce sampling artifacts in the results obtained from laser ablation scans. To test this hypothesis, we sampled sagittal otoliths from juvenile Atlantic croaker Micropogonias undulatus with laser ablation inductively coupled plasma mass spectrometry to obtain …


Phosphorus Cycling In The Sargasso Sea: Investigation Using The Oxygen Isotopic Composition Of Phosphate, Enzyme-Labeled Fluorescence, And Turnover Times, Karen Mclaughlin, Jill A. Sohm, Gregory A. Cutter, Michael W. Lomas, Adina Paytan Jan 2013

Phosphorus Cycling In The Sargasso Sea: Investigation Using The Oxygen Isotopic Composition Of Phosphate, Enzyme-Labeled Fluorescence, And Turnover Times, Karen Mclaughlin, Jill A. Sohm, Gregory A. Cutter, Michael W. Lomas, Adina Paytan

OES Faculty Publications

Dissolved inorganic phosphorus (DIP) concentrations in surface water of vast areas of the ocean are extremely low (<10 nM) and phosphorus (P) availability could limit primary productivity in these regions. We explore the use of oxygen isotopic signature of dissolved phosphate (δ18OPO4) to investigate biogeochemical cycling of P in the Sargasso Sea, Atlantic Ocean. Additional techniques for studying P dynamics including 33P-based DIP turnover time estimates and percent of cells expressing alkaline phosphatase (AP) activity as measured by enzyme-labeling fluorescence are also used. In surface waters, δ18OPO4 values were lower than equilibrium by 3–6%, indicative of dissolved organic phosphorous (DOP) remineralization by extracellular enzymes. An isotope mass balance model using a variety of possible combinations of …


Conus: First Comprehensive Conservation Red List Assessment Of A Marine Gastropod Mollusc Genus, Howard Peters, Bethan C. O'Leary, Julie P. Hawkins, Kent E. Carpenter, Callum M. Roberts Jan 2013

Conus: First Comprehensive Conservation Red List Assessment Of A Marine Gastropod Mollusc Genus, Howard Peters, Bethan C. O'Leary, Julie P. Hawkins, Kent E. Carpenter, Callum M. Roberts

Biological Sciences Faculty Publications

Marine molluscs represent an estimated 23% of all extant marine taxa, but research into their conservation status has so far failed to reflect this importance, with minimal inclusion on the authoritative Red List of the International Union for the Conservation of Nature (IUCN). We assessed the status of all 632 valid species of the tropical marine gastropod mollusc, Conus (cone snails), using Red List standards and procedures to lay the groundwork for future decadal monitoring, one of the first fully comprehensive global assessments of a marine taxon. Three-quarters (75.6%) of species were not currently considered at risk of extinction owing …


Habitat Availability And Heterogeneity And The Indo-Pacific Warm Pool As Predictors Of Marine Species Richness In The Tropical Indo-Pacific, Jonnell C. Sanciangco, Kent E. Carpenter, Peter J. Etnoyer, Fabio Moretzsohn Jan 2013

Habitat Availability And Heterogeneity And The Indo-Pacific Warm Pool As Predictors Of Marine Species Richness In The Tropical Indo-Pacific, Jonnell C. Sanciangco, Kent E. Carpenter, Peter J. Etnoyer, Fabio Moretzsohn

Biological Sciences Faculty Publications

Range overlap patterns were observed in a dataset of 10,446 expert-derived marine species distribution maps, including 8,295 coastal fishes, 1,212 invertebrates (crustaceans and molluscs), 820 reef-building corals, 50 seagrasses, and 69 mangroves. Distributions of tropical Indo-Pacific shore fishes revealed a concentration of species richness in the northern apex and central region of the Coral Triangle epicenter of marine biodiversity. This pattern was supported by distributions of invertebrates and habitat-forming primary producers. Habitat availability, heterogeneity, and sea surface temperatures were highly correlated with species richness across spatial grains ranging from 23,000 to 5,100,000 km(2) with and without correction for autocorrelation. The …


Heritable Melanism And Parasitic Infection Both Result In Black-Spotted Mosquitofish, Lisa Horth, David Gauthier, Wolfgang Vogelbein Jan 2013

Heritable Melanism And Parasitic Infection Both Result In Black-Spotted Mosquitofish, Lisa Horth, David Gauthier, Wolfgang Vogelbein

Biological Sciences Faculty Publications

Male Gamhusia holhrooki (Eastern Mosquitofish) express a heritable pigmentation polymorphism approximate to 99% of males are silver, and only approximate to 1% have a melanic, black-spotted pattern. Sex-linkage, an autosomal modifier, and temperature control the expression of this heritable melanism. In many teleosts, melanin also accumulates around the site of parasitic invasion. We have identified black-spot disease in wild mosquitofish from their native habitat. Here, we demonstrate convergence upon the black-pigmented phenotype through two means: 1) heritable melanism, and 2) melanic spotting on the silver genotype that results from infection with immature encysted trematodes. Females are silver and express greater …


Does Pitcher Plant Morphology Affect Spider Residency?, Marc A. Milne, Deborah A. Waller Jan 2013

Does Pitcher Plant Morphology Affect Spider Residency?, Marc A. Milne, Deborah A. Waller

Biological Sciences Faculty Publications

Spiders are often found as residents in association with Sarracenia purpurea ( Purple Pitcher Plant). Many spiders choose web locations based on environmental cues such as vegetation structure and composition, prey density, temperature, and humidity. To determine if spiders use cues from the Purple Pitcher Plant to build their webs, we conducted a field study using variants of the plant that separated various morphological features: nectar, pigment, and the presence of prey. There was no difference in spider residency across all treatments and no difference in male/female or mature/immature residency. Linyphiids were the most common residents, possibly due to pitcher …


Bacterial Colonization And Extinction On Marine Aggregates: Stochastic Model Of Species Presence And Abundance, Andrew M. Kramer, M. Maille Lyons, Fred C. Dobbs, John M. Drake Jan 2013

Bacterial Colonization And Extinction On Marine Aggregates: Stochastic Model Of Species Presence And Abundance, Andrew M. Kramer, M. Maille Lyons, Fred C. Dobbs, John M. Drake

OES Faculty Publications

Organic aggregates provide a favorable habitat for aquatic microbes, are efficiently filtered by shellfish, and may play a major role in the dynamics of aquatic pathogens. Quantifying this role requires understanding how pathogen abundance in the water and aggregate size interact to determine the presence and abundance of pathogen cells on individual aggregates. We build upon current understanding of the dynamics of bacteria and bacterial grazers on aggregates to develop a model for the dynamics of a bacterial pathogen species. The model accounts for the importance of stochasticity and the balance between colonization and extinction. Simulation results suggest that while …