Entomology Commons^™

Landscape Genetics Of The Gulf Coast Tick, Amblyomma Maculatum, Sara Simmons Benham

Biological Sciences Theses & Dissertations

Connectivity among populations helps to maintain genetic diversity, population stability, and resilience. The Gulf Coast tick, Amblyomma maculatum, is a vector of the pathogen Rickettsia parkeri. Persistence of tick populations with high rates of R. parkeri infection poses health risks to humans and animals. Mitochondrial haplotypes were characterized by sequencing a fragment of the mitochondrial 16S rRNA gene. A comparative study of A. maculatum and Amblyomma americanum was conducted to identify similar and unique patterns between the species within the same region. Next, I compared A. maculatum sites across three different regions of the United States. This work …

Determination Of The Presence Of Rickettsia Spp. And Borrelia Spp. Carried By Tortoise Ticks From Madagascar, Anna Phan

Biological Sciences Theses & Dissertations

Ticks were removed from three species of Malagasy tortoises, Astrochelys yniphora, A. radiata, and Pyxis arachnoides (comprising two subspecies P. a. arachnoides and P. a. oblonga), between 2012 and 2015. The ticks were presumed to be from the genus Amblyomma. Ticks were morphologically identified and then checked molecularly to confirm their classification or identify any ticks that could not be morphologically identified. Molecular identification was done via end-point PCR that amplified tick cytochrome oxidase (CO1) and tick 12S rRNA genes. Ticks were screened via a real-time polymerase chain reaction assay for the presence of Rickettsia spp. …

Molecular Candidates For Blocking The Transmission Of Vector-Borne Diseases, Ashish Naresh Vora

Biological Sciences Theses & Dissertations

Vector-borne diseases (VBDs) require urgent attention as they have a high mortality rate, with 700,000 people dying in a year as of 2017. So far, extremely few reliable vaccination strategies and solutions have emerged. Transmission blocking vaccines are one among many solutions available to manage the control of VBDs. These require identification of both vector and pathogen molecules that play important roles in the transmission, dissemination and establishment of VBDs. Our strategy is to characterize these candidates that play important roles in vector-host-pathogen interactions. This manuscript presents two such studies identifying the participation of two arthropod molecules in vector-host-pathogen interactions. …

Foraging Behavior Of Spring Bees And Their Agricultural Implications, Michael D. Gregory

Biological Sciences Theses & Dissertations

Colony Collapse Disorder has greatly reduced honey bee populations in the last decade. Native bees have been largely neglected in research, and their floral preferences may have agricultural implications because native bees ameliorate the demand to rely solely on non-native bees. In this work, pollinator visitation to flowers with manipulated ultraviolet floral patterns was monitored. Populations of wild showy golden-eye in Colorado, plus cultivar populations of black-eyed Susan and lawn populations of buttercups in Virginia were monitored for pollinator landings to compare preference for unmanipulated ultraviolet-absorptive floral guide preferences. Another number, a proxy for pollen load, was manipulated on strawberry …

Strawberries (Frag X Anan) Are Bigger When Native Mason Bees (Osmia Lignaria) Are Experimentally Added To Small Farms, Laura A. Campbell

Biological Sciences Theses & Dissertations

Agriculture is the cornerstone of our economy, and pollination plays a vital role in nearly all non-wind pollinated crops. Declining honey bee populations have caused a more diligent investigation into using solitary bees for crop pollination. The native, solitary Orchard Mason Bee has shown to successfully pollinate almonds and apples, but there has been little work conducted on their effectiveness as a low fruit crop pollinator. This study assesses their effectiveness as a small strawberry farm pollinator, and preferences for nesting materials. Mason bee cocoons and nest homes made with different materials (bamboo, Phragmites, or wood) were supplemented on …

A Hitchhiker’S Guide To Invasion Biology: Describing The Ecological Mechanisms Underlying The Range Expansions Of Two Ixodid Tick Species, Robyn M. Nadolny

Biological Sciences Theses & Dissertations

Increasing incidence of many tick-borne diseases have been linked to recent expansions of tick species distributions. Many tick species are expanding their ranges because of anthropogenic changes in the landscape, shifting climatic variables, and increasing populations of suitable host species and tick habitat. Few empirical studies have been performed, however, investigating the ecological mechanisms underlying these range expansions. Ticks are parasitic organisms that disperse across landscape by hitchhiking on hosts, but must then survive in the environment for long periods of time between bloodmeals. Two species of ixodid tick, Ixodes affinis and Amblyomma maculatum, are simultaneously expanding their ranges throughout …

Determining The Prevalence And Distribution Of Tick-Borne Pathogens In Southeastern Virginia And Exploring The Transmission Dynamics Of Rickettsia Parkeri In Amblyomma Maculatum, Chelsea L. Wright Thompson

Biological Sciences Theses & Dissertations

Tick-borne pathogens are an increasing threat to human and animal health worldwide. In the United States, cases of Lyme disease, spotted fever rickettsioses, ehrlichiosis and anaplasmosis are on the rise. Factors related to emergence include appearance of a new pathogen, recognition of an existing pathogen and environmental changes that result in new exposure events. Despite the rise in tick-borne disease incidence within many states, including Virginia, there is a paucity of data related to the prevalence and distribution of ticks and tick-borne pathogens.

The first aim of this dissertation research was to determine the tick-borne pathogen composition within tick populations …

Perch Selection By Male Dragonflies (Odonata, Anisoptera) Related To Competitive Ability And Species Composition, Jessica L. Beard

Biological Sciences Theses & Dissertations

Males of many species of dragonflies (Odonata, Anisoptera) establish territories in aquatic habitats where they compete with other males for access to food and females. Territorial males typically perch on emergent vegetation and chase rival males who intrude into their territories. This dissertation research examined the role of male size in perch height selection, position on the perch, and competitive ability. Four hypotheses were tested: 1) Dragonfly species would vary by size and that territorial species would show sexual size dimorphism (SSD), 2) Perch height selection would be related to dragonfly size, 3) Position on the perch would be related …

The Role Of Chemical Attractants In The Use Of Tick Traps For Life Stages Of Tick Species Ixodes Scapularis, Dermacentor Variabilis And Amblyomma Maculatum, Pamela C. Kelman

Biological Sciences Theses & Dissertations

Amblyomma maculatum, Ixodes scapularis and Dermacentor variabilis are three of the hard-bodied ticks found in the United States. This study explored three aspects of the appetence process of these tick species: attraction, desiccation survival, and locomotive activity. The first portion of this work was to improve one of the standard methods used for collecting ticks from the environment, the tick trap. To determine the attractants needed to capture all life stages of the three chosen species of ticks in the field using tick traps, a series of experiments were conducted using laboratory-reared larval, nymphal and adult A. maculatum, I. scapularis …

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 …

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 …

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 …

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 …

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, …

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 …

Aphytophagy In The Miletinae (Lycaenidae): Phylogeny, Ecology, And Conservation, John Mathew

Biological Sciences Theses & Dissertations

Less than 1% of all Lepidoptera are aphytophagous; of these, a considerable proportion is found in the family Lycaenidae. The aphytophagous Lycaenidae are believed to have arisen from a mutualistic template involving ant attendance. With this association firmly in place, it is a relatively simple shift to exploitation, either of the ants themselves, through active carnivory on the brood/trophallactic feeding from adults, or by carnivory on ant-tended homopterans, with little to no interference by the ants. Among lycaenids, aphytophagy has arisen several times; most spectacularly in the subfamily Miletinae, where all of the approximately 150 species are presumed or known …

Factors Affecting Nitrogen Fixation Rates In Termites (Isoptera: Rhinotermitidae: Reticulitermes) And Termite Nitrogen Contributions Of Forest Ecosystems, Anthony Duane Curtis

Biological Sciences Theses & Dissertations

Termites host symbiotic bacteria that fix atmospheric nitrogen, which makes termites important in the biogeochemical cycling of nitrogen in ecosystems. The objective of this study was to estimate annual nitrogen contributions by termites by examining seasonal rates of nitrogen fixation, seasonal abundance of different termite castes and their nitrogenase activity, the effects of dietary nitrogen on nitrogenase activity, and low oxygen and high carbon dioxide atmospheres on termite nitrogenase activity, and the accuracy of mark-recapture studies to estimate termite population size.

Termite nitrogen fixation rates were monitored monthly for 10 Reticulitermes Holmgren colonies from June, 1993, to December, 1995. Rates …

Pheromonal Composition Of Two Species Of African Amblyomma Ticks: Similarities, Differences And Possible Species Specific Components, Thomas Lem Price Jr.

Biological Sciences Theses & Dissertations

Two species of bont ticks, Amblyomma hebraeum and Amblyomma variegatum, common to Africa have been studied to compare types and quantities of compounds known or believed to serve as components of the attraction-aggregation-attachment pheromone (AAAP). A complex of attraction, aggregation and attachment pheromones are used by these ticks to detect hosts, mates and perhaps minimize interspecific breeding. Solvent extraction of pheromone emitting ticks followed by Gas Chromatography and Mass Spectrometry revealed little difference in the composition of the AAAP in these two species. However, subtle differences in the relative makeup of the pheromonal blend are noted, suggesting that such differences …

Evidence For The Sensory Receptor(S) Of The Mounting Sex Pheromone In Two Species Of Ixodid Ticks, Dermacentor Variabilis (Say) And Dermacentor Andersoni Stiles, James Stephen Phillips

Biological Sciences Theses & Dissertations

The foreleg claw sensilla were determined to be the receptors of the female contact sex pheromone, MSP (mounting sex pheromone), in D. variabilis, D. andersoni and A. americanum male ticks. In all three tick species, the claw sensilla consists of six anteriorly-directed setae arranged in three symmetrical pairs, two each on the opposite sides of the apotele of the claw and one on the ventral side. Behavioral bioassays and morphological study of these setae revealed that only the dorsal and middle (= lateral) pairs of claw sensilla are mechanogustatory, while the ventral pair are strictly mechanoreceptors. The dorsal and …

Evidence For The Role Of Ecdysteroids In The Genital Sex Pheromone Of Two Species Of Hard Ticks, Dermacentor Variabilis (Say) And Dermacentor Andersoni Stiles, Demar Taylor

Biological Sciences Theses & Dissertations

Neutering of part-fed females virtually eliminated copulatory behavior in Dermacentor variabilis and D. andersoni males. Extracts from the anterior reproductive tracts (ART) of part-fed (7 days) females restored the male copulatory behavior in conspecific neutered females, suggesting the presence of a genital sex pheromone (GSP). Similar extracts from unfed females did not restore the behavior, suggesting that the pheromone was produced during feeding. Perception of the GSP by sensillae on the male cheliceral digits was confirmed by electrophysiological techniques.

Ecdysteroids, specifically ecdysone and 20-OH-ecdysone were shown to be present in the anterior reproductive tracts in excess of amounts that could …

A Taxonomic Survey Of The Family Gyrinidae (Coleoptera) Of The State Of Virginia, Jerrold R. Harris

Biological Sciences Theses & Dissertations

The aquatic insect fanua of Virginia is not very well known. This is especially true of the order Coleoptera. There are few taxonomic studies on the families of Coleoptera found within the state, and one of the least known is the family Gyrinidae. It is the intent of this study to determine what species of Gyrinidae are found within the state and where they are found. Collections of the beetles were made throughout the state from March to December.

Twenty-one species of Gyrinidae were identified in Virginia, nine species of Dineutus and 12 species of Gyrinus. The family is distributed …

Life History Patterns Of Dytiscidae In A Temporary Pool, Annabel C. Blanco

Biological Sciences Theses & Dissertations

The Dytiscidae are one of the most distributed families of aquatic Coleoptera. In addition, they comprise one of the largest families in the order. With the exception of some European species, research in the ecology/life history of the Dytiscidae has been limited.

The patterns of appearance and disappearance of Dytiscidae were studied for one growing season, February to June, 1983, in a temporary pool in the Great Dismal Swamp. Fourteen species of larvae and twenty-four species of adults were collected. Definite temporal patterns were evident in larvae of Laccophilus spp., Laccornis difformis, Liodessus affinis, Uvarus granarius, Agabetes acuductus, and Hoperius …

Sex Pheromone Activity In The Foveal Glands In The Two Species Of Ixodid Ticks: Dermacentor Andersoni (Stiles) And Dermacentor Variabilis (Say), Lynn Anne Collins

Biological Sciences Theses & Dissertations

Sex pheromone activity in the foveal glands of female Dermacentor andersoni (Stiles) and Dermacentor variabilis (Say) is described. Autoradiography revealed the accumulation of ³⁶Cl in the foveal glands of females during their first 120 hours of feeding on a ³⁶Cl-labeled host. Emissions collected from these females contained a ³⁶Cl-labeled product. This product, however, was absent in emissions collected from the same females with their foveae dorsales obstructed.

Accumulation of ³⁶Cl in the foveal gland, in conjunction with the release of a ³⁶Cl-labeled product through the foveae dorsales, suggest localization of sex pheromone activity within these …

The Ecology Of The Dominant Tick Species In The Northwestern Portion Of The Dismal Swamp National Wildlife Refuge, Mary Keith Garrett

Biological Sciences Theses & Dissertations

Elements of the ecology of the two dominant man-biting ticks were studied during 1971-1973 in two locations in Southeastern Virginia, namely, what is now the Dismal Swamp National Wildlife Refuge and Newport News City Park. Tick species composition, relative abundance, density, and distribution in the two areas were compared. In addition, the Dismal Swamp locality was used as a test area for studies on the survival of native, lab reared and translocated Dermacentor variabilis (Say) and Amblvomma americanum (L.) in relation to selected abiotic factors. The Newport News locality served as a control area for these studies.

The species …