Life Sciences Commons^™

Browntail Moth (Euproctis Chrysorrhoea) Integrated Pest Management Program: Evaluation Of Monitoring Traps And Biopesticides, Sadia Crosby

Electronic Theses and Dissertations

Browntail Moth (BTM; Euproctis chrysorrhoea) is a non-native species currently outbreaking in Maine. BTM are polyphagous folivores and feed on a variety of woody plant species, including many economically and ecologically important ornamental and forest trees such as oaks and apples. Human health is also a concern as BTM larvae produce urticating hairs that can cause severe dermatitis in people. New monitoring and management programs are urgently needed, with the current population densities reaching a 100-year high.

The Maine Forest Service monitors BTM populations by visually assessing winter nest densities and defoliation patterns, both time and labor intensive. This …

A Social And Ecological Approach To Mosquito Species Distribution Across Land Use In Bangor, Maine, Megan L. Schierer

Electronic Theses and Dissertations

Mosquitoes are ubiquitous pests and infectious disease vectors. However, not all mosquito species bite humans, or are competent pathogen vectors between bloodmeal hosts. Along with climatic variables like temperature and rainfall, mosquito species distribution is determined by aquatic habitat availability for juvenile mosquito development, and terrestrial habitat and host availability for adult mosquitoes. There is variation in the preferred aquatic habitat for gravid female oviposition and subsequent larval development. Some mosquito species’ oviposition and development are associated with ephemeral water sources (e.g., floodplains), others prefer more permanent water sources (e.g., bogs or vernal pools). Other mosquitoes have evolved to occupy …

The Spatial Habitat And Seasonal Prevalence Of Blow Flies (Diptera: Calliphoridae) In Windsor-Essex County, On, Madison Laprise

Electronic Theses and Dissertations

Blow flies (Diptera: Calliphoridae) are important insects due to their role in carrion decomposition, myiasis, and forensic entomology. Many studies have observed generalized habitat preferences of the adult flies, such as shady and sunny, rural, and urban, and seasonal, but not explicitly based on the different nutritional resources. In contrast, this study examines the relationships between adult blow fly species prevalence across five land use types, three traffic volumes, three levels of roadkill density, and three seasons with a novel sampling protocol focused on predicted carrion resource availability. Blow flies were trapped at 44 locations across Windsor-Essex County, ON during …

The Black Soldier Fly, Hermetia Illucens Linnaeus (Diptera: Stratiomyidae): A Novel Approach To Combat Food Waste In Windsor-Essex., Patricia Obianuju Okpara

Electronic Theses and Dissertations

Within Ontario alone, approximately 3.7 million tonnes of organic food waste is generated yearly. This waste includes food scraps, wasted food, and plant wastes such as leaves, plant stems, and fruit. Most of it is transported to landfills for composting each year, but the use of landfills as a method of waste management is not sustainable. It adds strain to the environment by releasing harmful greenhouse gases and by demanding landfill space. The current protocols set by the Ontario government, while promising, do not address methods that support the safe disposal of organic waste and conversion into valuable end products …

Investigating Salinity Intrusion Effects On Sapelo Island, Georgia Using Benthic Macroinvertebrate Bioindicators, Raymond Paul Kidder Ii

Electronic Theses and Dissertations

Coastal wetlands are threatened by the compounding effects of sea level rise and historical land modification. Historically, much of Sapelo Island, Georgia was deforested and drained using a series of ditches and canals to create arable land fit for agriculture and to provide drainage to the inhabited parts of the island. Today, this network of artificial channels is believed to be facilitating the movement of saltwater from the nearby estuary into freshwater areas on the interior of the island. This study aimed to better understand the frequency and magnitude of salinity intrusion events along with their resulting impacts to the …

Light And Temperature Entrainment Of Two Circadian-Driven Behaviors In The Flesh Fly Sarcophaga Crassipalpis, Raven Ragsdale

Electronic Theses and Dissertations

Circadian rhythms dictate the timing of both once-in-a-lifetime adult emergence (eclosion) and daily locomotor activity rhythms in the flesh fly S. crassipalpis. Light cycles are considered the primary environmental time cue (zeitgeber), but the life history of S. crassipalpis suggests that temperature cycles (thermocycles) may also play a key role. This work evaluates the efficacy of thermocycling as a zeitgeber in S. crassipalpis. We found that shifting both light and temperature cycles of sufficient amplitude affect the phasing of eclosion and locomotor activity, but result in different patterns. Additional experiments suggest greater thermocycle sensitivity during the late metamorphic …

Biophysical Interactions And Social Perceptions Of Ixodes Scapularis (Acari: Ixodidae) Exposure Risk Due To Climate Change, Brittany Schappach

Electronic Theses and Dissertations

Increased temperature variances are being recorded in Maine due to climate change, contributing to increased densities of blacklegged ticks (Ixodes scapularis) and concomitant increase in reported cases of tickborne diseases across the state. Understanding the interactions between mean temperature and temperature variance in relation to overwinter tick survival is crucial in understanding the tick’s geographical expansion limits to create better prediction models for their expansion. The goals of this study were to determine the interacting microclimate effects of winter temperature variance and mean temperatures on tick mortality, which month nymphal blacklegged ticks experience highest mortality, and assess the connection between …

Risk-Prone And Risk-Averse Foraging Strategies Enable Niche Partitioning By Two Diurnal Orb-Weaving Spider Species, Mitchell D. Long

Electronic Theses and Dissertations

Niche partitioning is a major component in understanding community ecology and how ecologically similar species coexist. Temporal and spatial partitioning and differences in foraging strategy, including sensitivity to risk (variance), likely contribute to partitioning as well. Here, we approach this partitioning with fine resolution to investigate differences in overall strategy between two species of diurnal, orb-weaving spiders, Verrucosa arenata and Micrathena gracilis (Araneae: Araneidae), that share similar spatial positioning, temporal foraging window, and prey. Through field observation, we found that V. arenata individuals appear to increase spatial and temporal sampling to compensate for an overall risk-prone strategy that depends on …

Characterization Of Hemocytes In Amblyomma Americanum And Investigation Of Traf6’S Role In Proliferation Of Hemocytes In Response To Infection, Jacquelyn T. May

Electronic Theses and Dissertations

Amblyomma americanum is a medically important vector in the southeast United States. Cellular and molecular aspects of the immune system of this species were examined. To investigate cellular processes, hemocytes produced in response to gram-negative infection were characterized according to their ultrastructure. Four hemocyte types were identified: prohemocytes, plasmatocytes, type-I granulocytes, and type-II granulocytes. To elucidate molecular processes, we investigated AamTRAF as an immune-related gene by silencing the gene using RNAi then quantifying the hemocytes after inoculation with gram-negative and positive bacteria. It was found that silencing AamTRAF caused a decrease in hemocyte proliferation in response to gram-positive but not …

Survey Of Native Predatory Hemipterans And Assessment Of Nabis Americoferus Carayon (Hemiptera: Nabidae) As A Biological Control Agent Of Lepidopteran Tomato Pests, Andrew Laflair

Electronic Theses and Dissertations

Invasive species have become a grave threat to the economic viability of our global vegetable producers. Tomato pinworm Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) has expanded from its range originating from Peru to being established in nearly hundreds of countries, causing tomato production losses of up to 100% on occasion; however, it has not yet been found in Canada or the USA. Southwestern Ontario is a significant tomato producer making it a high risk from this invasive species. Efficient integrated control methods such as native biological control agents (BCAs) that avoid creating insecticide resistance are ideal. Surveys of Southwestern Ontario conservation …

Variation In Oviposition Behaviour Of Blow Flies (Diptera: Calliphoridae) Due To Relative Humidity And Intraspecific Interactions, Theresa Tran

Electronic Theses and Dissertations

Blow flies are usually the first insects to arrive at carrion, using it to oviposit or breed. The behaviour to search for and accept a carrion resource as suitable for oviposition is influenced by abiotic factors, particularly temperature and humidity, as well as by the presence of other insects. My thesis focuses on the influence of relative humidity (RH), combined with intraspecific interactions, on oviposition choices of three blow fly species Lucilia sericata (Meigen), Phormia regina (Meigen), and Calliphora vicina Robineau-Desvoidy (Diptera: Calliphoridae). Individual fly oviposition behaviour was measured on a temperature gradient (10-40°C) under high (75- 85%) and low …

Regenerative Agriculture Effects On Invertebrate And Bird Communities And Insect-Provided Ecosystem Services, Alex Michels

Electronic Theses and Dissertations

Conventional agricultural practices can have unintended consequences on the environment and wildlife. Insects and birds are declining at rapid rates around the world, and the current conventional agricultural paradigm is a major driver through habitat loss and the intensification of production. Invertebrates in agroecosystems provide services to both farmers and the rest of society. Regenerative systems may promote the functioning of an agroecosystem by influencing invertebrate abundance, diversity, and ecosystem services and mitigate bird and insect declines through conservation practices that increase soil health, reduce disturbances, and increase biological diversity. Here I address knowledge gaps of the effects of regenerative …

Investigating The Effect Of A Facultative Symbiont, Hamiltonella Defensa, On Pea Aphid, Acyrthosiphon Pisum, Fecundity And Behavior In Elevated Co₂ Atmospheres, Tyler J. Follman

Electronic Theses and Dissertations

As atmospheric carbon dioxide (CO₂) levels continue to rise, it is important to study how economically important organisms, like the pea aphid, Acyrthosiphon pisum, will react to these conditions. The pea aphid feeds on the phloem of crop plants like alfalfa, peas, and fava beans, where it not only directly harms the plant but also can spread plant viruses. A wide variety of factors can influence pea aphid fecundity and behavior. Some of these factors are abiotic, like atmospheric conditions, and some are biotic, like microorganisms with which the pea aphid has a mutualistic relationship. In this thesis, …

Mortality In Interspecific Hybrids Of Nasonia Vitripennis And Nasonia Giraulti, Bonnie Cobb

Electronic Theses and Dissertations

Nasonia is a parasitoid wasp genus that serves as an emerging model for studying speciation due to an incompatibility between nuclear and mitochondrial genomes between sister taxa. Short generation times, easy rearing in a lab setting, producing large amounts of progeny, and whole genome sequencing make Nasonia is an excellent candidate for studying incomplete reproductive isolation. Nasonia have five chromosomes and exhibit haplo-diploid sex determination in which fertilized eggs develop into diploid females and unfertilized eggs develop into haploid males. Recessive phenotypes are hidden in diploid females but are laid bare in haploid males as there is no interaction between …

Behavior And Chemical Signals As Markers Of Colony Identification In Argentine Ants (Linepithema Humile), Stephanie A. Rohrbach

Electronic Theses and Dissertations

Argentine ants, Linepithema humile, are a highly successful invasive species around the globe and are especially prominent in states such as California and the southeastern United States. L.humile have a unique form of unicoloniality, called “supercolonies”. L. humile can detect colonymates through scent markers in their outer cuticle. With these chemical markers, ants will exhibit high aggression if they smell different from one another. In our study, we performed aggression assays among ten different nest sites and analyzed their CHCs through gas chromatography mass spectrometry, or GC-MS, analysis. For our behavior results, while within-nest interactions displayed low aggression as …

Amblyomma Quadricavum (Schulze, 1941) (Acari:Ixodidae): First Description Of The Nymphal Stage And Phylogenetic Assessment Of Its Taxonomic Status, Ashleigh V. Riggs

Electronic Theses and Dissertations

The hard tick (Acari: Ixodidae) Amblyomma quadricavum (Schulze, 1941) is a parasite of snakes and is endemic to the Caribbean region. Morphological characters of this species, namely its rudimentary eye structures, have led to debate about its taxonomic status. The species was originally assigned to the genus Aponomma. However, with revisions of the genus Aponomma, and the recent creation of new genera created for some basal former-Aponomma, it has been suggested that perhaps Amblyomma quadricavum might be a close relative of Robertsicus elaphensis, the Trans-Pecos rat snake tick of the southwest United States and New Mexico, another eyeless former-Aponomma species …

Effects Of A Novel Dsrna-Based Insecticide On The Colorado Potato Beetle, Samuel J. Pallis

Electronic Theses and Dissertations

The Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae) is one of the most destructive pests of the cultivated potato, Solanum tuberosum. Colorado potato beetles have been devastating potato crops for the past 150 years and have expanded their range during that time, becoming a globally distributed agricultural pest. Potato beetles are well-suited to agricultural environments and have evolved some degree of resistance to virtually all chemical insecticides. As such, the development of novel control methods to both control potato beetle populations and manage the evolution of insecticide resistance are in constant demand

The knockdown of gene functioning through ribonucleic acid …

Adaptation Strategies For Wild Blueberry Growers In A Changing Climate: Mulching Effects On Crop Productivity And Fertility Effects On Blueberry Gall Midge, Rebecca Gumbrewicz

Electronic Theses and Dissertations

Wild blueberry (Vaccinium angustifolium Aiton.) cropping systems are considered resilient to environmental changes due to ecological and genetic diversity within each field. However, wild blueberries can be sensitive to weather fluctuations that cause extreme temperature or moisture regimes. Climate change in Maine is represented by increasing rates of warming temperatures, more intense precipitation events, and more frequent atmospheric “blocking” patterns. Warming temperatures result in the northward expansion of pest ranges and altered growing seasons. More extreme rainfall events lead to damaged plantings and soil erosion. Atmospheric blocking leads to an increased likelihood of heat waves and drought. Two experiments were …

Community Structure And Dynamics Of Benthic Macroinvertebrates In A Recreated Headwater Stream System On A Valley Fill In A Retrofitted Watershed Located In The Appalachian Coalfields Of Southeastern Kentucky (U.S.A.), Steven W. Bailey

Electronic Theses and Dissertations

The extraction of coal from steep-gradient surface mining sites such as in the Appalachian Coalfields of the U.S. produces excess debris that is often placed in adjacent valleys resulting in the creation of valley fills. Not only are headwater streams buried in the process, but watershed functions are either destroyed outright, or become fragmented and disconnected from adjacent ecosystems resulting in adverse effects to downstream biological communities. In this dissertation, the dynamics of stream macroinvertebrate community structure, composition, diversity, and biotic integrity are assessed at a “proof of concept” stream system recreated on a retrofitted valley fill. For comparison, two …

The Bees Of Two Sites In The Big Thicket National Preserve, Texas, With A Consideration Of The Effects Of A Rare Flooding Event, Archie Ray Sauls Jr.

Electronic Theses and Dissertations

Native bees are an important part of terrestrial ecosystems due to their coevolution with flowering plants. This study catalogued the bee fauna of two sandyland sites in the Big Thicket National Preserve and assessed whether a community was impacted by a historic hurricane-induced flooding event. It was hypothesized that a change in diversity metrics would be evident following the flood. Datasets were analyzed for differences in species richness, abundance, evenness, and Shannon’s diversity. Similarities between datasets were also assessed using the multivariate tests analysis of similarity (ANOSIM) and similarity of percentages (SIMPER). At two sites over two years of sampling …

Evaluation Of Biotype 4 Aphis Glycines (Hemiptera: Aphididae) Induced Susceptibility On Soybean And Soja, Jakob David Hicks

Electronic Theses and Dissertations

Soybean aphids have been a significant pest of soybeans in North America since 2000. Before 2000, soybeans did not face significant insect pest pressure from any arthropods with piercing-sucking mouthparts. It is estimated that economic damage from soybean aphids range from $1billion to $4.7 billion annually. Research efforts focused on the identification of host plant resistance genes in soybean and discovered many resistant to Aphis glycines genes (i.e., Rag genes) in soybean. However, the adoption of commercially released Rag soybean cultivars has been limited. The prospect of management with Rag genes was further complicated by the identification of three virulent …

Transcriptional Regulation Of Duox-Dependent Reactive Oxygen Species Production Against Bacterial Infection In The Gut Of Cat Fleas (Ctenocephalides Felis)., Ryne W. Maness

Electronic Theses and Dissertations

Fleas (Order Siphonaptera) are opportunistic blood feeders that parasitize a wide variety of mammals and birds. They also transmit bacterial pathogens that cause diseases in humans (e.g., murine typhus, flea-borne spotted fever, cat scratch disease, and plague). Because they acquire infectious pathogens while blood feeding, the flea gut is considered to be the initial site of infection. While immune responses have been well documented in other disease vectors, few studies have identified the immune mechanisms involved in defense of the flea gut. In other hematophagous insects, the synthesis of reactive oxygen species (ROS) is the immediate immune defense mechanism against …

Macroinvertebrate Responses To Hydrological Variation In Experimental Wetlands., Sergio A. Sabat-Bonilla

Electronic Theses and Dissertations

Predicted increases in the frequency of intense storms and periods of severe drought due to climate change represent a threat to wetland macroinvertebrate communities through alterations to the hydrological regime. I used experimental ponds to assess the effects of water permanence (i.e., duration of flooding) on the communities of aquatic macroinvertebrates. I predicted that permanent ponds would harbor higher diversity of longer-lived taxa whereas temporary ones will favor colonization by quick turnover, short-lived taxa and support lower consumer diversity. Results show differences in macroinvertebrate communities between permanent and temporary ponds can be mostly explained by hydrology and the amount of …

The Relative Abundance And Diversity Of Parasitoids Of The Browntail Moth (Euproctis Chrysorrhoea L.) And Factors That Influence Their Population Dynamics, Karla S. Boyd

Electronic Theses and Dissertations

The browntail moth (Euproctis chrysorrhea) is an invasive forest pest that has been present in the Northeast since it was first introduced from Europe in 1897. Originally, its range expanded very rapidly until it reached its peak invasion of 150,000 km², which included most of New England and parts of Southern Canada and Long Island, NY, in 1915. After this point, its range collapsed until only relic populations remained on islands in the Casco Bay Region of Maine and outer Cape Cod in Massachusetts. In 2016, a large population outbreak occurred that expanded its range into …

Role Of Plant Volatile Organic Compounds (Vocs) In Seed Priming And Plant-Herbivore Interactions., Abhinav Kumar Maurya

Electronic Theses and Dissertations

This dissertation explores and expands the existing knowledge on the role of plant volatiles in facilitating seed priming and providing direct defense against herbivore. Although the roles of plant volatiles in priming a plant’s defenses and providing direct defense against pests is well known, information regarding their effects on seed and the fitness of future plants and direct toxicity to herbivores is understudied. This dissertation does a thorough examination of these two understudied aspects of plant volatiles and provides novel insight into the role of plant volatiles in seed priming and direct defense (Chapter I). Seeds in the soil can …

The Status Of Dakota Skipper (Hesperia Dacotae Skinner) In Eastern South Dakota And The Effects Of Land Management, Kendal Annette Davis

Electronic Theses and Dissertations

Hesperia dacotae (Skinner, 1911) (Insecta: Lepidoptera), also known as Dakota skipper, is a northern Great Plains species of butterfly associated with tall or mixed grass prairies. Its range once extended from southern Manitoba, southeastern Saskatchewan, North Dakota, South Dakota, Minnesota, to Iowa and Illinois. Now H. dacotae is only found in small isolated pockets in southern Manitoba, southeastern Saskatchewan, North Dakota, South Dakota, and Minnesota. The species is often observed on alkaline prairies with poor soil not desirable for cultivation. Thus, many of the historical H. dacotae are used for pasturing cattle or as hay prairie. The loss of habitat …

The Potential For Dickeya Dianthicola To Be Vectored By Two Common Insect Pests Of Potatoes, Jonas K. Insinga

Electronic Theses and Dissertations

Dickeya dianthicola (Samson) causing blackleg and soft rot was first detected in potatoes grown in Maine in 2014. Previous work has suggested that insects, particularly aphids, may be able to vector bacteria in this genus between plants, but no conclusive work has been done to confirm this theory. In order to determine whether insect-mediated transmission is likely to occur in potato fields, two model potato pests common in Maine were used: the Colorado potato beetle (Leptinotarsa decimlineata Say) and the green peach aphids (Myzus persicae Sulzer). Olfactometry and recruitment experiments evaluated if either insect discriminates between infected and …

Spatial And Temporal Variation In The Aquatic Invertebrate Community Structure Of Rock Pools Along The Penobscot River, Maine, Chase R. Gagne

Electronic Theses and Dissertations

Pools of water that form in the fissures and depressions of rock outcrops, known as rock pools, are fairly common aquatic habitats that can easily be found along the rocky banks of many of Maine’s major rivers. In general, rock pools and the aquatic invertebrates inhabiting them have received little research attention and, though ubiquitous, have never been studied in Maine. My research addressed this knowledge gap by surveying 40 rock pools at four sites along the Penobscot River in Maine. The rock pools themselves had highly variable environmental characteristics and differed across sites and over time, especially in hydroperiod. …

Landscape Pattern And Wild Bee Communities In Maine, Brianne Du Clos

Electronic Theses and Dissertations

Commercial production of lowbush blueberry (Vaccinium angustifolium Aiton) in Maine relies primarily on managed honeybee hives; however, naturally occurring wild bees are more efficient pollinators of the crop. Wild bees have short foraging distances and must nest near crop fields to provide pollination services. After crop bloom, the surrounding landscape must provide sufficient forage to maintain wild bee populations for the remainder of the growing season. Lowbush blueberries in Maine are produced in a mixed-use landscape with two distinct landscape contexts. Here, we document bee communities and habitat resources (nesting and floral) in power line rights-of-way and eight land …

Blacklegged Tick (Ixodes Scapularis) Distribution In Maine, Usa, As Related To Climate Change, White-Tailed Deer, And The Landscape, Susan P. Elias

Electronic Theses and Dissertations

Lyme disease is caused by the bacterial spirochete Borrelia burgdorferi, which is transmitted through the bite of an infected blacklegged (deer) tick (Ixodes scapularis). Geographic invasion of I. scapularis in North America has been attributed to causes including 20th century reforestation and suburbanization, burgeoning populations of the white-tailed deer (Odocoileus virginianus) which is the primary reproductive host of I. scapularis, tick-associated non-native plant invasions, and climate change. Maine, USA, is a high Lyme disease incidence state, with a history of increasing I. scapularis abundance and northward range expansion. This thesis addresses the question: “To …