Ecology and Evolutionary Biology Commons^™

Ecology Of Tenodera Sinensis And Tenodera Angustipennis (Mantodea: Mantidae) In Eastern Virginia, Cory A. Gall

Biological Sciences Theses & Dissertations

My study, conducted on the Wildlife Refuge located on Virginia's Eastern Shore, focused on the life history, ecology, and intra- and interspecies interaction of Tenodera sinensis and T. angustipennis. Field methods included capture-mark-recapture, species, sex, and developmental life stage identification, and recorded key developmental milestones. Also, to analyze food-limiting growth, a laboratory cohort was fed ad lib, with lab and field cohorts measured bi-weekly and their mean weekly growth was compared.

When compared to a lab cohort, Tsinensis field mantises were shown not to be growth limited by the abundance of prey. In 2011, the dates of several developmental stages …

Effects Of The Parasitic Dinoflagellate Hematodinium Sp. On Blue Crab (Callinectes Sapidus) Activity Predation And Habitat Selection, John M. Tiggelaar Ii

Biological Sciences Theses & Dissertations

The blue crab Callinectes sapidus occurs along the Atlantic and Gulf coasts of the United States, and in high salinity regions, they are subject to lethal infection by the parasitic dinoflagellate Hematodinium. In Virginia's seaside estuaries, the prevalence of Hematodinium infection of C. sapidus can sometimes exceed 50%, threatening the commercial fishery for this species. Indeed, other commercially important crustacean fisheries have approached collapse due to Hematodinium infections. Most studies of this host-parasite interaction have focused on epidemiology, host-pathogen dynamics, and pathogen transmission, and little is known about the impact of the parasite on host behavior and population dynamics. …

The Ecology Of The Timber Rattlesnake (Crotalus Horridus) In Southeastern Virginia, Scott M. Goetz

Biological Sciences Theses & Dissertations

Few studies have examined the relationship between forest canopy structure and the ecology of the timber rattlesnake (Crotalus horridus). I used radiotelemetry to compare the movements, activity range sizes and behaviors of timber rattlesnakes before and after a large-scale natural disturbance that opened a previously closed canopy. The disturbance was Hurricane Isabel which made landfall in northeast North Carolina and southeastern Virginia in 2003. Isabel created gaps in the canopy through tree blowdown, resulting in a 16.6% opening in the forest canopy at my study site, in southeastern Virginia. I compared six years of female tracking data from …

Effects Of 11 Years Of Co2 Enrichment On Root Biomass And Spatial Distribution In A Florida Scrub-Oak Ecosystem, Rachel Eilenfield Schroeder

Biological Sciences Theses & Dissertations

A Florida (USA) scrub-oak ecosystem was exposed to elevated atmospheric CO₂ in open-top chambers from 1996-2007. Minirhizotrons and ground-penetrating radar (GPR) were used to measure fine root (< 2 mm diameter) and coarse root (> 5 mm diameter) biomass, respectively. After 11 years of CO₂ enrichment, there was a trend of greater total root biomass under elevated CO₂. Fine root biomass exhibited a pattern of recovery and steady state throughout the study, with significant CO₂ stimulation observed only after disturbance. Greater root biomass under elevated CO₂ during recovery periods could result in greater carbon inputs belowground, alteration of the soil carbon …

Patterns Of Transience, Sex Bias, And Body Mass In Open-Habitat Rodent Populations, Stephen Edward Rice

Biological Sciences Theses & Dissertations

Rodents are assumed to live their lives in circumscribed (natal) areas with males being more prone to disperse than females and juveniles more prone to disperse than adults. To test these assumptions we examined the initial captures of geographic populations of hispid cotton rat, meadow vole, prairie vole, and marsh rice rat obtained through capture-mark-recapture methods. Capture records were obtained from Kansas and Illinois from long-term studies, and through live-trapping in Chesapeake, Virginia. I evaluated proportions of residents and transients, adults and juveniles, and males and females for significant differences among seasons, years, and geographic locations. The overall body masses …

Rats As Forest Pests In Southeastern Virginia: Girdling By The Hispid Cotton Rat Sigmodon Hispidus As A Significant Source Of Mortality Of Loblolly Pines (Pinus Taeda) In A Successional Pine Forest, Robyn M. Nadolny

Biological Sciences Theses & Dissertations

The hispid cotton rat (Sigmodon hispidus) is a common field rodent throughout the southeastern US, where volunteer loblolly pine trees (Pinus taeda) invade open space and begin the process of ecological succession from field to pine forest. Recent analysis of the diet of S. hispidus indicates that loblolly pine bark is stripped and eaten during the winter months. In this study, we explored the extent of rodent girdling on a 1.23 ha grid in a successional pine forest in southeastern Virginia. During the winter of 2005 we observed damage to 65% of trees in our study area, with 98% …

A Comparison Of Adrenal In Toad-Eating And Nontoad-Eating Snakes, Shabnam Mohammadi

Biological Sciences Theses & Dissertations

Toads are chemically defended by bufadienolides, a class of cardiotonic steroids lethal to most predators, including many snakes. Bufadienolides bind to Na+K +-ATPase, inhibiting their ability to transport ions. In cardiocytes, this inhibition cause arrhythmia and severely increased contraction strength, which, if prolonged, lead to death. However, several snakes are resistant to bufadienolides and consume toads with no ill effects. Adrenal glands produce hormones that are important for the maintenance of Na+K +ATPase, and may therefore play an important role in countering the negative effects of bufadienolides. Indeed, the toad-eating specialist Heterodon platirhinos has been known to possess enlarged, and …

Spatially-Explicit Agent-Based Modeling Of Ecosystem Change And Epizootiological Impacts On Caribbean Spiny Lobster, Panulirus Argus, Thomas William Dolan Iii

Biological Sciences Theses & Dissertations

Agent-based models explicitly incorporate interactions and variation at the individual level, just as in the real world. As a result, agent-based models are realistic, intuitive, and generally less complex mathematically than their analytical counterparts. Their primary disadvantage is the large amount of detailed data required to construct and parameterize them. Although the use of agent-based simulation is increasing in ecology, they are highly specific, so are rarely used for development of theory. To demonstrate the flexibility and utility of this approach I developed a multi-species, agent-based, spatially-explicit model of the spiny lobster nursery of southern Florida that incorporates changing salinities, …

The Mosquito (Diptera: Culicidae) Fauna Of The Blackwater Ecological Preserve: Effects Of Prescribed Burns And Habitat Type On Mosquito Abundance And Distribution, Norman A. Grefe Lll

Biological Sciences Theses & Dissertations

While mosquitoes (Diptera: Culicidae) are among the most studied of insect groups, much remains unknown about their distribution and response to environmental impacts such as prescribed burns. Blackwater Ecological Preserve, located near Zuni, Virginia, is a relict long leaf pine barren, parts of which undergo periodic prescribed burns to maintain and restore this fire-dependent ecosystem. To assess the impact of prescribed burns on mosquito activity and to determine associations between seasonal patterns of adult mosquito activity and habitat type, CDC light traps baited with dry ice were set (rom late April through October at Blackwater Ecological Preserve during the 2005 …

Carrion Beetles Of The Blackwater Ecologic Preserve: Community Structure Seasonal Patterns And Habitat Use, Amy L. Simons

Biological Sciences Theses & Dissertations

Carrion beetles (Silphidae) are important in the decomposition of carcasses in ecosystems. Two subfamilies, Nicrophorinae and Silphinae, differ in reproductive behaviors. The Nicrophinae, burying beetles, bury small carcasses to serve as food for the adults and their offspring. The Silphinae oviposit near larger carcasses. There is intense competition among all carrion beetles and other carrion feeders for carcasses, and beetle species have evolved seasonal activity patterns that minimize competition, such as when they are active and when they reproduce. Northern Silphidae communities are more diverse than southern communities, probably due to increased competition for carrion in the south.

This research …

A Test Of The Area Of Refuge Hypothesis In Indo-Pacific Marine Biogeography, Jonnell C. Sanciangco

Biological Sciences Theses & Dissertations

Many hypotheses have been proposed to explain the marine biogeographic patterns of species richness of the Indo-Pacific. One of these hypotheses suggests that available habitat area is the main predictor of species richness. This is the basis for the area of refuge hypothesis that attempts to explain the global maxima of species richness found in the Coral Triangle, the area encompassing mostly the Philippines, Indonesia, and Malaysia. This species-area effect also has habitat heterogeneity as a potential component. The purpose of this study is to test the effects of habitat availability predictors, such as shallow water area and coastline length …

Inter-Island Variability In Above And Belowground Plant Biomass In Interior Marshes On The Virginia Barrier Islands, Staci B. Blecha

Biological Sciences Theses & Dissertations

The Virginia Coast Reserve's Long Term Ecological Research (LTER) site is of great interest because the barrier islands have been migrating, rapidly at times, and are exceptionally dynamic. The barrier islands have tidal saltwater marshes on the lagoon side and freshwater marshes on the island interiors. In these interior marshes on North Hog Island, South Smith Island, and North Parramore Island, salinity and depth to water table were measured to determine if these factors were influencing biomass and biomass allocation patterns in the marsh. Hog Island had the freshest interior marshes (0 and 0.7 ppm), and the most diverse (H'=0.84 …

Body Size And Growth Patterns Of Microtus Pennsylvanicus (Ord.) In Chesapeake, Virginia, Sara E. Bell

Biological Sciences Theses & Dissertations

From Dec 2002-Feb 2008, a capture-mark-release study was conducted on 2 Chesapeake, Virginia populations of meadow voles (Microtus pennsylvanicus). The study sites were effectively 1 ha grids in old fields. Two modified live Fitch-type traps were placed at 12.5 m intervals on grids that were trapped for 3 days each month. In northern North America, voles have distinct breeding cohorts (spring and autumn), experience autumn and winter weight loss, demonstrate both delayed growth and sexual maturation in autumn-born young, have lifespans less than 15 weeks, and average about 35-50 g as adults. Chesapeake voles bred year-round, experienced no …

Interisland Variability Of Dune Plant Community Structure On Virginia's Barrier Islands, Justin K. Shafer

Biological Sciences Theses & Dissertations

The barrier islands of the Virginia Coast Reserve LTER site provide an opportunity to study interisland variability of dune plant communities. My research focused on the variation in biomass and diversity of communities among islands and dune positions. Grassy dunes of young, intermediate and old age were sampled on Smith, Hog, and Parramore Islands. Aboveground biomass was obtained from harvest plots, and roots were extracted from cores. Data were collected on depth to groundwater and total soil nitrogen. Variation in mean aboveground biomass was evident among the islands with the highest values on Hog Island, followed by Smith, then Parramore …

Ecological Interactions Between Spiders And The Purple Pitcher Plant, Sarracenia Purpurea, Marc Aaron Milne

Biological Sciences Theses & Dissertations

Spiders and harvestmen are commonly captured by or reside upon the carnivorous purple pitcher plant, Sarracenia purpurea. Although spiders and harvestmen are often known to be prey of S. purpurea, other ecological interactions between these arthropods and the plant are poorly understood. Studies were undertaken at three pitcher plant populations, two in Virginia and one in North Carolina, to assess the ecological relationships between spiders and harvestmen and S. purpurea. Multiple plots containing pitcher plants (treatment) and plots lacking pitcher plants (control) were created at these locations. Spiders and harvestmen were collected through five different techniques. Spatial, …

Impacts Of The Spotted Spiny Lobster (Panulirus Guttatus) On The Long-Spined Sea Urchin (Diadema Antillarum) And Patch Reef Communities In The Florida Keys, Meredith D. Kintzing

Biological Sciences Theses & Dissertations

Caribbean coral reefs have undergone a phase shift from a system dominated by corals to one where algae are pervasive. This shift was precipitated by the loss of herbivores, including the mass mortality of the long spined sea urchin (Diadema antillarum), coupled with disease and the recruitment failure of hermatypic corals. Diadema populations have recovered in some areas of the Caribbean, but are still below historical levels in the Florida Keys, likely due to low larval supply coupled with predation on juveniles. Lobsters are sea urchin predators in other systems and the spotted spiny lobster (Panulirus guttatus …

Biotic And Abiotic Characteristics Influencing Nest Location And Trophic Relationships Of The Fungus-Growing Ant Trachymyrmex Septentrionalis (Formicidae: Attini), Jonathan Paul Howell

Biological Sciences Theses & Dissertations

Trachymyrmex septentrionalis represents the only species of fungus-growing ant in the southeastern United States. T. septentrionalis cultivates a symbiotic fungus on which the ants feed. Worker ants collect plant and animal debris to feed the fungus. These ants are common in Florida, but increasingly scarce as they near the northern extent of their range in New Jersey. Colonies of T. septentrionalis occur in patches throughout Blackwater Ecological Preserve, a longleaf pine forest in southeastern Virginia. Blackwater Ecologic Preserve is a 129 hectare tract of land, located in Isle of Wight county, that is undergoing a regimen of controlled burning to …

Effect Of The Herbivorous Channel Clinging Crab (Mithrax Spinosissimus) On Patch Reef Algal Communities In The Florida Keys, Florida (Usa), Angela M. Mojica Osorio

Biological Sciences Theses & Dissertations

Coral reefs worldwide are undergoing dramatic habitat modification from coral to macroalgal dominance due to water pollution, coral diseases, global. warming, and the loss of herbivores. This phase-shift bas been particularly severe on Caribbean reefs due in large measure to the decline of piscine and echinoderm grazers, whose presence appears crucial for stemming the decline of coral reefs and enhancing their resilience. Virtually unknown, however, is the role of other macrograzers in coral reef ecosystems. This is the first study to examine the feeding ecology and grazer effect of the herbivorous West Indian spider crab (Mithrax spinosissimus) on inshore patch …

Ecology And Molecular Phylogenetics Of Hydnora (Hydnoraceae) In Southern Africa, Jay Francis Bolin

Biological Sciences Theses & Dissertations

The Hydnoraceae are a clade of root holoparasitic angiosperms that contain two small genera, Hydnora and Prosopanche. This study, focused on Hydnora, presents novel data regarding the pollination biology, germination ecology, parasite-host nutritional relationships, and the molecular systematics of this group. Experimental addition of the primary pollinator, Dermestes maculatus to Hydnora africana chamber flowers demonstrated beetle imprisonment during the carpellate stage. Changes in the inner surfaces of the androecial chamber allowed beetle escape after pollen release. Most beetles escaped, dusted with viable pollen, three days after pollen release. To investigate germination ecology, aqueous root extracts of host and …

Ecology Of Neotropical Arboreal Snakes And Behavior Of New World Mollusk-Eating Snakes, Julie M. Ray

Biological Sciences Theses & Dissertations

The Neotropics is a biologically diverse region that provides man opportunities for ecological and behavioral studies. I utilized the speciose ophidian fauna of central Panama to explore the general ecology of arboreal snakes, the defensive behaviors of the snake community, and the diet of mollusk-eating snakes. I studied arboreal species to understand interspecilic relationships in several morphometric characters and to examine preferences in habitat. There were significant morphometric differences in relative length of jaw, mass, tail length, and size at midbody. The arboreal realm was partitioned among species by distance to ground, distance to water, and diameter of the perch. …

A Phylogeny Of The Snappers (Lutjanidae; Percoidei) Inferred From Cytochrome B Sequence Data, Matthew R. Semcheski

Biological Sciences Theses & Dissertations

The Lutjanidae are economically and ecologically important fishes commonly known as snappers. A morphological study of Lutjanidae concluded that it contained four subfamilies and that together with the family Caesionidae, form the superfamily Lutjanoidea. Although this view was supported elsewhere in the literature, it was later contradicted, treating the caesionids as members of the Lutjanidae. In order to infer a phylogeny of genera within Lutjanidae, the complete cytochrome b gene (1140bp) of 21 lutjanid taxa was sequenced and analyzed along with 19 lutjanid, caesionid, and outgroup sequences obtained from GenBank. Data were analyzed for base composition stationarity and saturation. Phylogenetic …

Spatial And Trophic Dynamics Of A Macrofaunal Community On A High Energy Intertidal Sandflat, Sharon Ann Tatem

Biological Sciences Theses & Dissertations

Spatial and trophic interactions between macrofaunal species were studied in a high energy intertidal system during spring-summer low tides. Bioturbation by the enteropneust hemichordate, Balanoglossus aurantiacus (Girad), as evidenced by large fecal mounds, was a conspicuous feature on the sandflat Sediment characteristics were compared between ambient (non-fecal) and B. aurantiacus fecal mound types (fresh-oxidized, fresh-reduced, aged-oxidized, and aged-reduced). Fecal material was differentiated by age based on the presence or absence of mucus and the time of fecal deposition. The color of fecal material was used to assign oxidative state. Multiple isotopes (carbon, nitrogen, sulfur) were used to determine the origins …

Influences Of The Loggerhead Sponge (Spheciospongia Vesparium) And The Vase Sponge (Ircinia Campana) On Nearshore Hard-Bottom Community Development In The Florida Keys, Scott Donahue

Biological Sciences Theses & Dissertations

Sponges, octocorals, and stony corals are the dominant sessile fauna within shallow, hard-bottom communities in the Florida Keys, FL (USA). The sponge component of these communities is not well studied and has been cyclically decimated from as early as 1844, most recently in south-central Florida Bay in 1991 and 1992, in apparent association with phytoplankton blooms. The purpose of this research was to examine ways in which sponges may contribute to the maintenance of hard-bottom communities. Specifically, I investigated: 1) the effect of sponges and physical structures on local sea floor scouring and thus the potential for maintenance of hard-bottom; …

Microspore Wall Morphogenesis And Orbicule Ultrastructure Of Isoetes, Khalid Alarid

Biological Sciences Theses & Dissertations

The microspore wall morphogenesis and orbicule ultrastructure of Isoetes were studied using electron microscopy. Microspore wall morphogenesis in five species of Isoetes (I. appalachiana, I. engelmannii, I. hyemalis, I. piedmontana, and an undescribed species from York Co., VA, USA) was studied using scanning and transmission electron microscopy. Results show that they generally have the same developmental stages in terms of microspore wall morphogenesis. The mature microspore wall consisted of four layers: perispore, paraexospore, exospore and endospore. Paraexospore formation began during the tetrad stage. The exospore was then formed between the paraexospore and the plasma membrane. During the free spore …

Seasonal Variation In Diet Of The Cotton Rat (Sigmodon Hispidus) Based On Fecal Analysis, Lynn A. Walker

Biological Sciences Theses & Dissertations

Cotton rats, Sigmodon hispidus, live in oldfields, habitats with a variety of mostly herbaceous plants. Based on other studies, the hispid cotton rat eats predominantly grasses, but grasses rarely are the only food. Fecal samples were collected each month during an ongoing capture-mark-release demographic study of the rodent community at a location in southern Chesapeake, Virginia. In the lab, five fecal pellets per animal were stained, placed on a microscope slide, and covered with starch-gel medium and coverslip. Then a clear nail polish was applied to produce a semi-permanent slide. Using a microscope and a set of reference slides, plant …

Evidence For Disease Mediated Extinction: Correlation Between An Introduced Pathogen And Extinction Of Rattus Macleari On Christmas Island, Kelly B. Wyatt

Biological Sciences Theses & Dissertations

The Durham Collection and the Cambridge and Oxford University Museums provided the materials to investigate the possibility that the extinction of indigenous rats of Christmas Island was a result of disease introduced by infected ship rats (R. rattus) in 1899. The collections of H.E. Durham in 1901-1902 reveal that R. macleari was present on Christmas Island up to then and includes specimens of R. rattus together with specimens that exhibit characteristics of both R. rattus and R. macleari. Durham's notes indicate both R. rattus and R. macleari specimens were heavily infected with trypanosomes at the time of collection. In …

Modeling Habitat And Environmental Factors Affecting Mosquito Abundance In Chesapeake, Virginia, Alan Scott Bellows

Biological Sciences Theses & Dissertations

The models I present in this dissertation were designed to enable mosquito control agencies in the mid-Atlantic region that oversee large jurisdictions to rapidly track the spatial and temporal distributions of mosquito species, especially those species known to be vectors of eastern equine encephalitis and West Nile virus. I was able to keep these models streamlined, user-friendly, and not cost-prohibitive using empirically based digital data to analyze mosquito-abundance patterns in real landscapes.

This research is presented in three major chapters: (II) a series of semi-static habitat suitability indices (HSI) grounded on well-documented associations between mosquito abundance and environmental variables, (III) …

Molecular Phylogenetics Of Perciform Fishes Using The Nuclear Recombination Activating Gene 1, Andrew R. Mahon

Biological Sciences Theses & Dissertations

The order Perciformes contains one-third of all extant fishes in twenty different suborders and over 10,000 species. Few systematic investigations have been performed on this large group of fishes at the suborder level and their evolutionary history is widely recognized as problematic. This dissertation presents three studies: a molecular phylogenetic analysis of the putative suborders of the order Perciformes, an analysis of interrelationships of the families of the perciform suborder Percoidei, and a multi-gene investigation of the percoid superfamily Sparoidea.

The taxa sampled in this dissertation represent one of the most inclusive molecular datasets, to date, testing the monophyly of …

Behavioral Enhancement Of Onshore Transport By Postlarval Caribbean Spiny Lobster (Panulirus Argus), Jason Seth Goldstein

Biological Sciences Theses & Dissertations

The onshore transport of meroplanktonic marine larvae or postlarvae is often complex, involving both active (i.e., behavior, swimming) and passive (i.e., oceanographic elements) transport mechanisms. Behaviors that modify passive transport have presumably evolved to situate larvae in settlement habitats where survival is enhanced. Active transport mechanisms have not been described for the puerulus postlarvae of any species of spiny lobster, despite their extraordinary mobility and known preference for specific settlement habitats. In the Florida Keys, for example, Caribbean spiny lobster (Panulirus argus) pueruli travel from oceanic waters into coastal areas where they settle within bushy, red macroalgae. I …

Effects Of Elevated Atmospheric Co2 On Root Dynamics, Biomass And Architecture In A Scrub-Oak Ecosystem At Kennedy Space Center, Florida, Daniel Benjamin Stover

Biological Sciences Theses & Dissertations

A major gap in whole-plant ecology lies with our understanding of root system growth, function and distribution. Large belowground structures, in addition to fine roots, are of particular interest because of their role in carbon sequestration. Non-destructive methods, including ground-penetrating radar (GPR) and minirhizotron observation tubes, were used to investigate effects of elevated CO₂ on root biomass, dynamics (productivity, mortality, and turnover), root persistence and architecture in a fire dominated scrub-oak ecosystem. Open-top chambers have been exposed to elevated atmospheric CO₂ for the past eleven years at Kennedy Space Center, Florida. No significant sustained CO₂ treatment effects …