Entomology Commons^™

Surveillance Of Culex And Aedes Mosquitoes In Lincoln, Lancaster County, Nebraska, William Noundou

Department of Entomology: Dissertations, Theses, and Student Research

In 2018, West Nile virus (WNV) was identified as the leading cause of mosquito-borne disease in the continental United States. In response to this very serious problem, the Lincoln-Lancaster County Public Health Department (LLCHD) reinforced their mosquito surveillance program, which constitutes one of the best available tools to fight against this serious threat to human health. The objectives of this study were to 1) expand knowledge of the activity and relative abundance of mosquito communities in understudied areas and 2) evaluate differences in mosquito communities by urban and rural location, especially focusing on known vector species. A total of 6 …

From Field To Film: Mosquito Surveillance And Survey Of Us Adults' Knowledge And Attitudes Towards Arthropod-Borne Disease Vectors, Justine Laviolette

Department of Entomology: Dissertations, Theses, and Student Research

Mosquito-borne disease is a public health challenge that warrants an active surveillance program for the identification of mosquito populations and the education of the public for prevention and protection against disease-transmitting arthropods. The communication of science to the public is necessary to prevent disease, change behavior, and promote a dialog between scientists and the public.

People are accustomed to high quality entertainment, which begs the question, “If we made science more entertaining, would the public be more interested?”

To address these issues, the objectives of this study are: 1) identify mosquito species and abundance at the US Meat Animal Research …

Using Adults To Monitor Rnai Susceptibility Of Western Corn Rootworm, Diabrotica Virgifera Virgifera Leconte, Field Populations, Matthew Welter

Department of Entomology: Dissertations, Theses, and Student Research

The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, is the most damaging corn pest in the U.S. Corn Belt, costing producers over $1 billion annually in control and damage costs. Currently, corn producers rely on three control strategies for WCR management: crop rotation, chemical insecticides, and transgenic corn expressing Bacillus thuringiensis Berliner (Bt) proteins. Populations of WCR have evolved resistance to all of these tactics, limiting effective control strategies for producers. RNA interference (RNAi), is the newest mode of action developed for WCR management. In July 2017, the first RNAi plant-incorporated protectant (PIP) corn product was approved for production …

A Mixed-Methods Study Of Entomology Incorporation In U.S. Secondary Science Instruction, Erin M. Ingram

Department of Entomology: Dissertations, Theses, and Student Research

To encourage understanding and appreciation of insects, entomology education advocates have supported and encouraged K-12 teachers to integrate insects and insect-related content into formal science instruction. However, research examining how and why science teachers incorporate entomology into secondary science courses is limited.

A sequential explanatory mixed-methods research study was conducted to address this gap. The study was conducted in two phases. During the first phase, quantitative survey research was conducted with a representative sample of 254 U.S. secondary life science teachers. During the subsequent qualitative phase, follow-up interviews were conducted with a purposeful sample of 18 survey participants and an …

Promoting Bee Communities Through Habitat Enhancements On Public And Private Lands In Nebraska, Kayla A. Mollet

Department of Entomology: Dissertations, Theses, and Student Research

Wild and managed bees are the most effective pollinators, accounting for about 80% of the pollination of flowering plants and 75% of fruits, nuts, and vegetables in the United States (USDA, 2019; USFWS, 2019). An estimated 4,000 species of bees reside in North America, the majority of which are wild and unmanaged. Wild bee communities are critical for maintaining healthy ecosystems, as they sustain native flora that provides soil stability and habitat for other wildlife. In a changing landscape, floral enhancements on privately and publicly-owned lands may have great impact for improving habitat for pollinators across the United States. Planting …

A Descriptive Study Of Wild Bees (Hymenoptera: Apoidea: Apiformes) And Angiosperms In A Tallgrass Prairie Corridor Of Southeastern Nebraska, Katie Lamke

Department of Entomology: Dissertations, Theses, and Student Research

The presence of diverse bee communities in an ecosystem is vital for maintaining healthy plant communities, promoting habitat resilience, and supporting sustainable agricultural production and urbanization. Approximately 20,000 known species of bees exist worldwide and assist with the successful reproduction of nearly 80% of Earth’s flowering plants by providing pollination services. In the US, wild bee declines have led to increased monitoring efforts for bees but there remain critical data gaps in prairies of the Great Plains ecoregion. Specific to the Tallgrass prairie where only 1-3% remains in native vegetation, the Nebraska Wildlife Action Plan has identified the loss of …

Characterization Of Pyrethroid Resistance In The Western Corn Rootworm Diabrotica Virgifera Virgifera Leconte, Dariane Sagaseta De Oliveira Souza

Department of Entomology: Dissertations, Theses, and Student Research

The western corn rootworm (WCR), Diabrotica virgifera virgifera Le Conte (Coleoptera: Chrysomelidae), is a major pest of maize (Zea mays L.) in the United States and has continuously challenged our ability to develop sustainable pest management solutions. Resistance to chemical insecticides, crop rotation, and most recently transgenic plants that express toxins derived from Bacillus thuringiensis Berliner (Bt) have been well documented among WCR populations. Furthermore, US regulatory insecticide prohibitions and the lack of new active ingredients have reduced the options for WCR control. Pyrethroid insecticides are one of the few remaining chemical options. Therefore, the recent confirmation …

Viral Prevalence Among Social Bees In Different Landscapes, Tugce Karacoban

Department of Entomology: Dissertations, Theses, and Student Research

Honey bees and wild bees provide important pollination services to numerous crops and native plants. In recent years, declines in bee populations have highlighted the importance of the ecological services they provide and the need for more research into the reasons for their decline. Currently, many conservation efforts to mitigate bee losses include increasing forage and habitat, however, there is growing concern over the role interspecific pathogen transmission plays in bee decline. Viruses commonly found in honey bees may be transmitted and pose a threat to other bee species when bees come together at foraging sites. To elucidate the impact …

Characterization Of The Natural Enemy Community, With Emphasis On Entomopathogens, For Management Of Western Corn Rootworm (Diabrotica Virgifera Virgifera) In West Central Nebraska, Camila Oliveira-Hofman

Department of Entomology: Dissertations, Theses, and Student Research

Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae),the western corn rootworm (WCR), is a major pest of corn (Zea mays L.) in the United States and Europe. WCR management options comprise mainly transgenic hybrids, insecticide applications and crop rotation. WCR is highly adaptable to management practices and field-evolved resistance to transgenic corn, insecticides and crop rotation in the United States Corn Belt has been reported. Therefore, the motivation for this project was to look into alternative options for WCR management. The goal of this dissertation is to characterize the natural enemies from irrigated commercial cornfields in Nebraska and examine their …

Gut Symbiont Viability In Honey Bees Exposed To Agrochemical Stressors, Bryant Justin Gabriel

Department of Entomology: Dissertations, Theses, and Student Research

The honey bee gut microbiome is essential for protecting this pollinator against abiotic and biotic stressors, including the prevention of harmful gut parasites and pathogens. Previous studies have not only demonstrated a linkage of bee gut dysbiosis to increased immunodeficiencies and pathogen sensitivities, but also report the maladaptation of the gut microbiome in bees exposed to agricultural and apicultural chemistries. There are few techniques available that allow for a simple and reliable analysis of the relative proportions of live and dead gut microbes in bees exposed to these chemistries. Previous techniques for measuring gut symbiont dysbiosis are temporally limited by …

Spatial Variation In Western Corn Rootworm (Coleoptera: Chrysomelidae) Susceptibility To Bacillus Thuringiensis Corn Events In Nebraska, Jordan D. Reinders

Department of Entomology: Dissertations, Theses, and Student Research

The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, is an economically important pest species of field corn (Zea mays L.) in the U.S. Corn Belt. Yield losses and control costs exceed greater than $1 billion annually. Over the past 10+ years, growers have adopted transgenic corn hybrids expressing rootworm-active Bacillus thuringiensis (Bt) proteins as a primary WCR management tactic. Field-evolved resistance to Cry3Bb1 and mCry3A proteins expressed in single-trait Bt hybrids has been confirmed in some areas of Nebraska. Growers have used different tactics as needed to prevent or mitigate resistance, resulting in a mosaic of selection pressure placed …

Conservation Biological Control Of Western Bean Cutworm: Molecular Gut Content Analysis Of Arthropod Predators, Feeding Trials For Key Predators And Agricultural Surveys For Integrated Pest Management, Westen Ray Archibald

Department of Entomology: Dissertations, Theses, and Student Research

Western bean cutworm (WBC), Striacosta albicosta, is a major pest of corn in western Nebraska. In 1999, its range expanded into much of North America causing damage from Nebraska to Canada and Mexico. WBC periodically causes kernel damage as severe as 15 bu/ac for one larva/plant. Control for WBC relies on Bt corn hybrids with Vip3A and Cry1F traits and insecticides. There has been a 5.2-fold decrease in efficacy of Cry1F for WBC. Concerns over management tactics may be creating space for conservation biological control to become part of a WBC integrated pest management (IPM) program. Objective 1, used …

Evaluation Of Host Plant Resistance Against Sunflower Moth, Homoeosoma Electellum(Hulst), In Cultivated Sunflower In Western Nebraska, Dawn M. Sikora

Department of Entomology: Dissertations, Theses, and Student Research

Sunflower moth, Homoeosoma electellum, is a serious pest of oilseed and confection sunflowers. In this study, we determine efficacy of resistance against this pest. Thirty commercial hybrids, inbreds, and varieties of sunflowers were tested in replicated field and laboratory studies. Trait efficacy is determined by pericarp strength by means of physical compression tests and damage to achenes. Initial sunflower entries were planted May 2014 and data collection began in early August 2014. A second season was planted June 2015, with sampling beginning late August the same year.

In 2014, oilseed varieties showed a strength average of 2.71 ± 0.11 N …

Analysis Of Cereal Aphid Feeding Behavior And Transcriptional Responses Underlying Switchgrass–Aphid Interactions, Kyle G. Koch

Department of Entomology: Dissertations, Theses, and Student Research

Switchgrass, Panicum virgatum L., is a perennial warm-season grass that is a model species for the development of bioenergy crops. However, the sustainability of switchgrass as a bioenergy feedstock will require efforts directed at improved biomass yield under a variety of stress factors. The objectives of this research were to: (1) elucidate greenbug and yellow sugarcane aphid feeding behavior on resistant and susceptible switchgrasses using electronic penetration graphs (EPG), (2) define transcriptional changes before and during insect feeding through RNA-seq to identify candidate resistance genes in a hybrid switchgrass cultivar, and (3) utilize methods in RNA sequencing of insects to …

Effects Of Temperature And Diet In Stable Fly (Diptera: Muscidae) Development, Melina Florez-Cuadros

Department of Entomology: Dissertations, Theses, and Student Research

Stable flies are among the most important blood feeding ectoparasites of cattle worldwide. The livestock industry is losing more than $2 billion dollar annually in the United States alone. Moist decaying vegetative material with bacteria supports larval development. Temperature and diet quality are important factors for stable fly development, affecting development rates, adult survival, and size, but how temperature affects adult size and interacts with nutrition is unknown. This study characterizes the relationship of temperature and diet quality in the development of stable flies. Two statistical models were used to analyze the effect of temperature alone (Lysyk, 1998) and temperature-diet …

Assessing The Risk Of Resistance Evolution, Adult And Larval Susceptibility, And Sublethal Effects After Exposure Of Corn Rootworms To Vacuolar Atpase-A And Snf7 Dsrnas, Adriano Elias Pereira

Department of Entomology: Dissertations, Theses, and Student Research

Corn rootworms are Diabroticite beetles from the genus Diabrotica and include the western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, and the northern corn rootworm, D. barberi Smith & Lawrence, as the most important pests in the U.S. Corn Belt. The southern corn rootworm (SCR), D. undecimpunctata howardi Barber, is considered a polyphagous plant pest and feeds in a wide variety of plants including peanuts, cucurbits, soybeans, and especially corn. Resistance to control methods including behavioral resistance to crop rotation and to corn hybrids expressing Bacillus thuringiensis Berliner toxins in WCR has frequently been reported. SCR has been considered a …

Characterization Of The Arthropod Communities And Aphid Feeding Behavior Associated With Perennial Warm-Season Grasses (Poaceae) Composition In Nebraska And Wisconsin, Kathryn M. Keller

Department of Entomology: Dissertations, Theses, and Student Research

Switchgrass, Panicum virgatum L., along with two other perennial warm-season grasses, big bluestem (Andropogon gerardii Vitman) and indiangrass, (Sorghastrum nutans L), compose a majority of the grasses found in North American tall grass prairies and have recently received attention as potential bioenergy feedstock. Limited research has been carried out on the relationship of arthropods on these three warm-season grasses in North America. Due to this limited research, the first objective of this research was to document the arthropods associated with switchgrass, big bluestem and indiangrass in Nebraska and Wisconsin over three sampling seasons. More than 10 arthropod orders …

Over-Summering Ecology Of The Wheat Curl Mite (Aceria Tosichella Keifer), Anthony J. Mcmechan

Department of Entomology: Dissertations, Theses, and Student Research

The wheat-mite-virus complex is a consistent and significant threat to winter wheat production in the western Great Plains. This complex consists of three viruses (Wheat streak mosaic virus, Triticum mosaic virus, and Wheat mosaic virus that are transmitted by the wheat curl mite (Aceria tosichella Keifer). Yield impacts from this complex are typically associated with the presence of volunteer wheat that emerges prior to harvest as a result of hail occurring during the heading stages of wheat in early summer. Historical literature on pre-harvest germination has been primarily focused on accelerating breeding programs; however, critical gaps in knowledge exist on …

Soybean Tolerance To Soybean Aphid (Aphis Glycines Matsumura) Herbivory, Lia Marchi Werle

Department of Entomology: Dissertations, Theses, and Student Research

This research examined the soybean aphid tolerant soybean KS4202 and its possible role in soybean aphid management. Studies documented the stage at which the tolerance response was initially expressed, quantified the relationship between cumulative aphid-days (CADs) and yield loss, and determined economic injury levels (EILs) for the soybean aphid tolerant KS4202 soybean. At high aphid infestation levels, aphids negatively impacted yield for KS4202 and K03-4686 (susceptible) plants that were infested at V1 stage; however, KS4202 expressed tolerance to the soybean aphid at low aphid infestation levels. No significant differences in the yield parameters were detected for KS4202 when infested at …

Ecological Risks Of The Conventional Insecticide/Fungicide Seed Treatment Mixture Of Thiamethoxam And Mefenoxam In Soybean On Beneficial Insects, Carolina Camargo

Department of Entomology: Dissertations, Theses, and Student Research

The impact of neonicotinoid seed treatments on beneficial insects has been a controversial topic during the last years. While neonicotinoids are usually used as mixtures with systemic fungicides, few studies have examined the impact of the mixtures on beneficial insects. Pesticide mixtures can have synergistic, additive, or antagonistic effects on the toxicity of neonicotinoids on non-target species.

Thiamethoxam with mefenoxam is the most used neonicotinoid insecticide/fungicide mixture applied to soybean. Based on the systemic nature of thiamethoxam and mefenoxam, residues of this insecticide/fungicide mixture can be present in soybean vegetative and floral tissue with potential impacts to beneficial insects. This …

Export Of Insect Ecosystem Services From Hayed Native Prairie, Wayne J. Ohnesorg

Department of Entomology: Dissertations, Theses, and Student Research

Natural areas, such as prairie, have the potential to provide the benefits of pest suppression and pollination for agricultural production. In Nebraska, prairie is often used for hay production. The impact of prairie hay production management practices on beneficial arthropods is not well understood. Four prairie hay meadows adjacent to row crop fields were selected in northeast Nebraska. The goal was to assess the impact of haying them on beneficial arthropods and the movement of natural enemies into adjacent crop fields. Three management practices were evaluated for hay harvested from prairie meadows one cut per growing season, two cuts per …

Dispersal And Sampling Of The Wheat Stem Sawfly, Cephus Cintus Norton, (Hymenoptera: Cephidae), Christopher Mccullough

Department of Entomology: Dissertations, Theses, and Student Research

The wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae), is a serious insect pest of wheat, Triticum aestivum L., in the northern central Great Plains. The sawfly has been a pest of wheat in Montana, North Dakota, and Canada since the early 20^th century. It was first detected in Nebraska winter wheat in the early 1990s, in Scotts Bluff County. The sawfly has since spread throughout the Nebraska Panhandle region and become a pest of serious concern. To gain a better understanding of the sawfly in Nebraska, investigations on the emergence, dispersal, and sampling of the sawfly were conducted. …

Investigation Of Reduced Agent And Area Treatments For Aphis Glycines Management And Its Effects On Key Predators, Jenny S. Enchayan

Department of Entomology: Dissertations, Theses, and Student Research

Soybeans are an abundant and valued agricultural crop in Nebraska and other parts of the world. Significant soybean aphid, Aphis glycines Matsumura, mortality has been observed in research plots adjacent to soybeans treated with chlorpyrifos in late July through August. The objectives of the study were to determine the efficacy of the chlorpyrifos vapor effect on A. glycines in adjacent untreated areas and assess the impact of the vapor effect on key biological control agents. Observation of A. glycines populations and sweep net samples for other arthropod species, including Oruis insidiosus, began weekly in mid to late July. When …

Biochemical, Physiological, And Anatomical Insights Into Aphid-Bioenergy Switchgrass Interactions, Travis J. Prochaska

Department of Entomology: Dissertations, Theses, and Student Research

Switchgrass, Panicum virgatum L., a perennial, warm-season grass native to North America, is a candidate for development as a bioenergy crop. Previously, warm-season grasses were considered to be relatively pest free in their native habitats. However, recent studies using the hemipteran family Aphididae have shown phloem-feeding insects can lead to significant injury in switchgrass. The objectives of this research were to: 1) gain physiological, biochemical, and anatomical insights into insect-bioenergy switchgrass interactions to determine potential insect resistance mechanisms among susceptible and resistant switchgrass genotypes; and 2) to generate and evaluate diverse segregating populations of switchgrass, both resistant and susceptible, to …

Assessment Of Variation In Susceptibility Of The Fall Armyworm, Spodoptera Frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), To Bacillus Thuringiensis Toxins, Karen Ferreira Da Silva

Department of Entomology: Dissertations, Theses, and Student Research

The fall armyworm, Spodoptera frugiperda, is a polyphagous insect pest affecting multiple crops. Fall armyworm is managed with insecticides and corn hybrids expressing insecticidal proteins derived from Bacillus thuringiensis. The early detection of insect resistance is important for making appropriate management decisions informs IPM and IRM recommendations.

The objective of the first study was to establish baseline susceptibility of fall armyworm populations to the Cry1F Bt insecticidal protein, emphasizing collections from locations where fall armyworm overwinters in the U.S. Fall armyworm neonates were exposed to artificial diet treated with increasing Cry1F concentrations, and mortality and growth inhibition were …

Monographic Revision Of The Genus Hoplopyga Thomson, 1880 (Coleoptera: Scarabaeidae: Cetoniinae: Gymnetini), Jennifer M. Shaughney

Department of Entomology: Dissertations, Theses, and Student Research

A comprehensive revision of the genus Hoplopyga Thomson, 1880 is presented. Eighteen species are redescribed and two new species are described. A key for identification, distribution maps, and images of the 20 species are provided. Hoplopyga ruteri Antoine is removed from the genus and placed in junior synonymy with Macrocranius similis Schürhoff. Lectotypes are designated for Hoplopyga brasiliensis (Gory and Percheron), Hoplopyga corumbana Schürhoff, and Hoplopyga multipunctata (Gory and Percheron). The following new synonyms are established: Hoplopyga lucidiventris (Thomson) is Hoplopyga foeda (Schaum); Hoplopyga spurca (Janson) is Hoplopyga liturata (Olivier); Hoplopyga monacha (Gory and Percheron) and Hoplopyga rubida …

Seasonal Activity And Sampling Methods For The Dectes Stem Borer, Dectes Texanus Leconte, In Nebraska Soybeans, Zachary D. Rystrom

Department of Entomology: Dissertations, Theses, and Student Research

The Dectes stem borer, Dectes texanus Leconte, has caused significant economic damage to soybean fields in south central Nebraska during recent years. Most economic injury occurs when soybean plants become susceptible to late season lodging due to larval girdling. Developing a comprehensive management plan for Dectes stem borer in Nebraska is limited by lack of knowledge of seasonal activity and effective sampling plans to monitor adult populations. Field studies were conducted in 2013 and 2014 to describe Dectes stem borer adult emergence patterns, female ovipositional period and adult densities in soybean fields. Calendar date predictions for adult emergence varied, while …

The Effect Of Agricultural Practices On Sugar Beet Root Aphid (Pemphigus Betae Doane) And Beneficial Epigeal Arthropods, Rudolph J. Pretorius

Department of Entomology: Dissertations, Theses, and Student Research

This study investigated the effect of several agricultural practices on the sugar beet root aphid (Pemphigus betae Doane) and beneficial epigeal natural enemies in western Nebraska sugar beet agroecosystems. Eight glyphosate-tolerant sugar beet varieties were evaluated under field conditions for their resistance to root aphids. High levels of aphid resistance were detected for some varieties. In conjunction to this, pitfall sampling was conducted to determine the beneficial epigeal natural enemy complex in the area, which could contribute to the management of both root aphids and glyphosate-resistant weeds. Ground beetles comprised an important and abundant component of this fauna, with …

Rna Interference As A Tool For The Functional Analysis Of Genes In The Colorado Potato Beetle, Leptinotarsa Decemlineata (Say), Ashley Danielle Yates

Department of Entomology: Dissertations, Theses, and Student Research

RNA interference (RNAi) is a naturally occurring phenomenon in eukaryotes in which a double-stranded RNA (dsRNA) suppresses the expression of a target gene. RNAi has markedly changed the way in which functional genetics studies are performed, especially in non-model organisms. In insects, the efficacy of RNAi is influenced by several factors, including the species and the methods of dsRNAs delivery.

The Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say), is a pest of the plant family Solanaceae. RNAi in the CPB is of interest for potential use in insect management and as a tool to study the interaction with host plants. …

Diversity And Ecology Of Host-Seeking Mosquitoes In Irrigated Agro-Ecosystems Of Clay County, Nebraska, Alister K. Bryson

Department of Entomology: Dissertations, Theses, and Student Research

In the United States, Nebraska has the third highest incidence of human West Nile virus (WNV). Since WNV was first detected in the state in 2002, 3,422 confirmed cases and 57 deaths have been reported. Irrigated agro-ecosystems, which have been associated with elevated WNV incidences in other states, are prevalent in Nebraska. The objectives of this investigation were to 1) characterize mosquito abundance and diversity in irrigated agro-ecosystems, and 2) evaluate associations of two primary vectors of WNV, Culex tarsalis and Culex pipiens, with irrigation methods (sprinkler vs. surface) and crop type (corn vs. soybean). Investigations were conducted …