Entomology Commons^™

Mechanisms Of Differential Toxicity Between Honey Bee (Apis Mellifera L.) Castes With An Emphasis On Coumaphos, Lizette Dahlgren

Department of Entomology: Dissertations, Theses, and Student Research

Acaricides are used to treat honey bee (Apis mellifera L.) colonies to control the parasitic Varroa mite (Varroa destructor Anderson & Trueman), a worldwide threat to honey bee health. As such, these compounds act as drugs to mitigate bee losses but may also stress the bees. This dissertation quantifies differences between queen and worker tolerance of five acaricides and clarifies the honey bee mechanism of tolerance for coumaphos. Selected acaricides were topically applied to adult queen and worker bees to generate dose-response curves and LD₅₀s. Twenty-four hours after treatment, queens were 3-times more tolerant of tau-fluvalinate …

Population Occurrence And Pathogen Prevalence Of Lone Star Ticks (Acari: Ixodidae) Collected From Southeast Nebraska, Amanda C. Maegli

Department of Entomology: Dissertations, Theses, and Student Research

Lone star tick, Amblyomma americanum (L.), has recently become established in Nebraska; therefore, local biology, ecology, and tick-borne disease risk are not known. Research was conducted to determine monthly questing activity, establishment, and pathogenic microorganisms associated with the lone star tick in Nebraska.

Lone star tick populations were collected from May through August, 2012 in six sites in southeast Nebraska using carbon dioxide (CO₂) traps. A total of 747 adults, 3,076 nymphs, and 1,289 larvae were collected. Total ticks collected and monthly activity were significantly different for each site.

A semi-randomized sample of 251 adult ticks were selected …

Toxic And Repellent Effects Of Pyrethroids Used In Orchards On The Honey Bee, Apis Mellifera L. (Hymenoptera: Apidae), Erin M. Ingram

Department of Entomology: Dissertations, Theses, and Student Research

Managed honey bee colonies provide valuable pollination services and are rented by fruit orchards to improve fruit quality and yield. The placement of colonies in this agricultural setting increases the possibility of exposure to pyrethroids used for broad-spectrum pest control in orchards. Although highly toxic to bees, pyrethroids are believed to pose a relatively low hazard due to their low application rates in the field as well as their contact repellent properties. Previous studies have noted a decrease in foraging visits following pyrethroid application possibly preventing bees from acquiring a lethal dose in the field.

This research quantified behaviors associated …

Impact Of Wheat Streak Mosaic Virus And Triticum Mosaic Virus On Transmission By Aceria Tosichella Keifer (Eriophyidae) And Virus Epidemiology In Wheat, Camila F. De Oliveira

Department of Entomology: Dissertations, Theses, and Student Research

The wheat curl mite (WCM), Aceria tosichella Keifer, transmits a complex of viruses, Wheat streak mosaic virus (WSMV), Triticum mosaic virus (TriMV) and Wheat mosaic virus (WMoV), to wheat, Triticum aestivum, in the Great Plains. Co-infection of wheat by these viruses is frequently observed, increasing disease severity and yield loss.

Current genetic work classifies WCM populations into two genotypes, Type 1 and Type 2. It has been shown that different mite genotypes are able to transmit viruses at varying rates. WCM-virus relations are very specific and can impact vector biology. In this study, the primary objective was to determine …

Evaluation Of The Efficacy Of 1-Octen-3-Ol And Carbon Dioxide Chemoattractants With Mosquitoes And Bloodmeal Analysis Of Culex Mosquito Spp. In Lancaster County, Nebraska, Julianne N. Matczyszyn

Department of Entomology: Dissertations, Theses, and Student Research

The purpose of mosquito-borne disease surveillance is to assess the risk of pathogen transmission by assessing mosquito populations and the prevalence of disease pathogens in those populations. West Nile virus (WNV) is an important mosquito-borne virus in Nebraska, and can be transmitted by several mosquito species found in Lancaster County, Nebraska, including Culex pipiens L., Culex salinarius Coquillett, Culex restuans Theobald, Culex tarsalis Coquillett, Culex territans Walker, and Culex erraticus Dyar & Knab. These species are ornithophilic, yet many studies indicate a shift in host feeding to mammalian in late summer months. One-octen-3-ol (octenol) can be isolated …

Effects Of A Corn Root Defense Substance On Western Corn Rootworm Diabrotica Virgifera Virgifera Leconte Larvae, Zixiao Zhao

Department of Entomology: Dissertations, Theses, and Student Research

The objectives of this research were to evaluate the effects of hydroxamic acids, a group of corn root defense substances on western corn rootworm (Diabrotica virgifera virgifera LeConte) larvae and identify putative molecular mechanisms for hydroxamic acid detoxification. Corn line 428G carries a homozygous mutant bx1 gene, which makes it unable to synthesis hydroxamic acids. In contrast, H88 is the wild type parental line of 428G and is able to synthesize hydroxamic acids. Larvae were fed on 428G and H88 roots for 7 days for comparison. No significant difference was observed in growth, development, or survival rate. A RNA-Sequencing …

Characterization Of Resistance To The Cry1f Toxin From Bacillus Thuringiensis In Resistant Fall Armyworm, Spodoptera Frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) From Puerto Rico, Ana Maria Velez

Department of Entomology: Dissertations, Theses, and Student Research

Transgenic corn expressing Cry1F protein from Bacillus thuringiensis Berliner has been registered for Spodoptera frugiperda control since 2003. Unexpected damage to Cry1F corn was reported in 2006 in Puerto Rico and Cry1F resistance in S. frugiperda was documented. The inheritance of Cry1F resistance was characterized in a S. frugiperda resistant strain from Puerto Rico which displayed >387-fold resistance to Cry1F. Concentration-response bioassays of reciprocal crosses of resistant and susceptible parental populations indicated that resistance is recessive and autosomal. Bioassays of the backcross of the F₁ generation crossed with the resistant parental strain suggest that a single locus is responsible …

Investigations On Rangeland Grasshoppers: Ecoregion Level Distribution, Identification, Feeding Performance, And Vegetation Clipping, Muhammad Ullah

Department of Entomology: Dissertations, Theses, and Student Research

Short-horned grasshoppers (Orthoptera: Acrididae) were studied in the field as well as in laboratory for their distribution, identification, preferred food plants and feeding damage. These grasshoppers are important potential pests of rangelands where they compete for forage with cattle. Examination of the 20 most common grasshoppers by levels 3 and 4 of Nebraska ecoregions revealed specific habitat use and may be helpful in predicting hotspots. The relative abundance of all species analyzed showed at least some significant differences at ecoregion level 4 and two species showed single ecoregion that differed from all others at level 3.

Grasshoppers belonging to subfamilies …

Investigating The Tolerance Response Of Early Vegetative Stage Soybeans To Aphis Glycines Matsumura, Lia Da Silva Marchi

Department of Entomology: Dissertations, Theses, and Student Research

The objectives of this research were to evaluate the impact of soybean aphid (Aphis glycines Matsumura) feeding on the yield response of V1, V3, and R1 KS4202 soybean plants and examine the effect of soybean aphid feeding on peroxidase activity in V1 and V3 KS4202 plants. KS4202 plants infested during the early vegetative stages (VC, VE and V1) were identified as highly susceptible based upon plant damage and stunting of the plants. In contrast, V3, V4, and V5 stage KS4202 soybeans were classified as moderately resistant. In the yield response study, V1, V3 and R1 plants had aphid numbers …

Factors Affecting The Distribution And Survival Of Endangered American Burying Beetles, Nicrophorus Americanus Olivier, Jessica Jurzenski

Department of Entomology: Dissertations, Theses, and Student Research

The disappearance of the federally endangered American burying beetle (Nicrophorus americanus Olivier) over most of its range is poorly understood, which is why the identification and evaluation of conservation measures is important. The presence and distribution of all carrion beetles in Nebraska was first reported to help understand where American burying beetles (ABBs) occur to aid in creating a habitat suitability model for the Sandhills ecoregion and to locate suitable experiment areas. There are 18 Nebraska counties with records of ABB presence in the last 15 years. The final habitat suitability model performed well with an AUC value above …

Effects Of Thiamethoxam Seed Treatments On Bean Leaf Beetles, Chelsea L. Piitz

Department of Entomology: Dissertations, Theses, and Student Research

The increased use of thiamethoxam seed treatments for controlling target pests such as the bean leaf beetle, Cerotoma trifurcata (Forster), suggests the need for methods to measure and monitor the development of resistance to these insecticides. Overwintering and F1 bean leaf beetles were collected from alfalfa and soybean fields and used in early growth stage soybean studies to measure toxicity of thiamethoxam both in greenhouse experiments and laboratory bioassays involving exposure to treated foliage. Lethal and sub-lethal effects were detected in both greenhouse and lab bioassays. Lethal concentrations determined from laboratory assays were compared with residues determined from field grown …

Ecology And Integrated Pest Management Of Western Bean Cutworm Striacosta Albicosta (Smith) (Lepidoptera: Noctuidae) In Field Corn, Silvana L. Vieira De Paula Moraes

Department of Entomology: Dissertations, Theses, and Student Research

Western bean cutworm, Striacosta albicosta (Smith) (Lepidoptera: Noctuidae), is a native pest of dry beans (Phaseolus vulgaris L.) and corn (Zea mays L.), and historically distributed in the western United States. The insect’s recent expansion eastward is documented since 1999. The species is univoltine, the adults typically emerge in the middle of July, lay eggs on corn leaves, and the larvae feed on different corn tissues. In the fourth instar, larvae start colonization of the ear where they feed on kernels. There is a narrow window for management and early detection of the pest in the field is …

Transmission Of Triticum Mosaic Virus And Its Impact On The Biology Of The Wheat Curl Mite Aceria Tosichella Keifer (Eriophyidae), And An Evaluation Of Management Tactics For The Wheat Curl Mite And The Wheat–Mite–Virus Complex, Anthony J. Mcmechan

Department of Entomology: Dissertations, Theses, and Student Research

The wheat-mite-virus complex is an important production constraint to winter wheat production in the Great Plains, and consists of three viruses; wheat streak mosaic (WSMV), wheat mosaic (WMoV) and Triticum mosaic virus (TriMV). Synergistic interactions between these viruses have resulted in increased rates of replication and transmission of viruses, thus increasing the potential impact on wheat yields. The wheat curl mite (WCM), Aceria tosichella Keifer is the only known vector of the viruses within the wheat-mite-virus complex.

Currently, three colonies of WCM have been characterized by differential responses to mite resistant genes (biotypes) in wheat and differential transmission of WMoV. …

Sensory Morphology And Chemical Ecology Of The Stable Fly, Stomoxys Calcitrans: Host-Seeking And Ovipositional Selection, Khanobporn Tangtrakulwanich

Department of Entomology: Dissertations, Theses, and Student Research

Stable flies cause stress and discomfort to cattle, and other mammals, including humans and pets. Economic losses from stable flies to the U.S. cattle industry from loss of milk production and cattle weight gain exceed $2 billion annually.

Traditional stable fly management employing sanitation and insecticides is costly and often fails to provide acceptable levels of control. A novel method for managing stable flies involves the use of attractants and repellents. This approach could be used to enhance the current level of stable fly control and ultimately be incorporated into a sustainable stable fly management program.

Gravid females’ stable flies …

Characterization Of The Tolerance Response In The Soybean Ks4202 To Aphis Glycines Matsumura, Travis J. Prochaska

Department of Entomology: Dissertations, Theses, and Student Research

Since the introduction of the soybean aphid, Aphis glycines Matsumura, to the soybean growing regions of the United States, the soybean aphid has caused considerable economic damage and yield loss to soybean growers. The objectives of this research were to evaluate selected genotypes for resistance to the soybean aphid and characterize transcriptional changes in response to aphid feeding to better understand the underlying tolerant mechanism(s) in KS4202 and genes contributing to its tolerance response. A field study (2009) was conducted to evaluate selected soybean genotypes during their reproductive stages for resistance to A. glycines. The economic injury level (EIL) …

Ecology Of Ticks (Acari: Ixodidae) In Shelterbelts Of Southeastern Nebraska, Matthew W. Yans

Department of Entomology: Dissertations, Theses, and Student Research

Shelterbelts in the agricultural landscape provide valuable habitat to a variety of animals that in turn may be hosts to ixodid ticks. The purpose of this study is to determine if shelterbelt associated factors influence tick ecology. In 2010 and 2011, ticks were collected from several shelterbelts in southeast Nebraska in Lancaster and Saunders counties. Four tick species were identified.

Adjacent land use, shelterbelt composition, and time of day were all factors which did not influence the number of questing ticks collected. Differences in relation to aspect and distance from the shelterbelt were significant. The east side had continually higher …

Dung Beetle Ecology: Habitat And Food Preference, Hypoxia Tolerance, And Genetic Variation, Sean Doyle Whipple

Department of Entomology: Dissertations, Theses, and Student Research

Four studies were conducted on dung beetles (Coleoptera: Scarabaeidae), which are insects of great ecological and economic importance. Range management practices were found to impact dung beetle diversity and abundance. While sampling on organic and conventionally managed ranches in Nebraska, 93% (5,767) of total dung beetle capture was from the organically managed ranch. Only 480 dung beetles (7% of total) were collected from the conventionally managed ranch. Results indicated that organic ranching had increased numbers and diversity of dung beetles.

Comparison of the attractiveness of native and exotic herbivore, carnivore, and omnivore dung yielded 9,089 dung beetles from 15 species. …

Gravesoil Microbial Community Structure During Carcass Decomposition, Amy E. Maile

Department of Entomology: Dissertations, Theses, and Student Research

Dead bodies placed on soil represent unique challenges for investigators. Although processes in soils can be used to estimate postmortem interval, we know very little about how carcasses and insects affect gravesoil microbial communities.

To address this, the current project was composed of two experiments. Experiment one was conducted to investigate the effect of surface type on carcass decomposition and evaluate soil ecology methods. Experiment two was conducted to investigate the presence of an insect population (Lucilia sericata Meigen) on gravesoil microbial communities. Both experiments were conducted in a laboratory setting using freshly killed mouse carcasses. Mouse carcasses were …

Genetic Variability Of The Stable Fly, Stomoxys Calcitrans (L.) (Diptera: Muscidae) Assessed On A Global Scale Using Amplified Fragment Length Polymorphism, Kathleen M. Kneeland

Department of Entomology: Dissertations, Theses, and Student Research

The stable fly, Stomoxys calcitrans, is a cosmopolitan pest of livestock and humans. It is a major pest in livestock facilities, where exist excellent breeding sites such as spilled feed mixed with manure. The pestiferous nature and painful bite cause stress to cattle and other animals. Cattle perform avoidance behaviors such as bunching together, standing in water, tail swishing, ear flicking and leg stamping. The stress and avoidance behaviors result in reductions in weight gain or milk production, with an estimated annual economic loss of > $1billion. Therefore, the development of more efficient control methods would benefit the global economy, …

Frequency Of Extended Diapause In Nebraska Populations Of Diabrotica Barberi Smith And Lawrence, Ryan W. Geisert

Department of Entomology: Dissertations, Theses, and Student Research

This study was conducted to measure the frequency of extended diapause in populations of the northern corn rootworm, Diabrotica barberi Smith and Lawrence from eastern Nebraska. Adult D. barberi collections were made during late summer 2008 and 2009 from eight sites each year (seven sites were consistent over years). Eggs were obtained from 12-20 females per site and were held on moist soil under appropriate temperature profiles to facilitate egg survival, diapause development, and diapause termination within and among years. Percentage egg hatch was recorded after the first and second year for the 2008 collection and after the first year …

Population Genetics Of The Western Bean Cutworm (Striacosta Albicosta Smith) Across The United States, Erica Lindroth

Department of Entomology: Dissertations, Theses, and Student Research

The western bean cutworm, Striacosta albicosta (Smith), is a secondary pest of maize (Zea mays L.) and dry beans (Phaseolus vulgaris L.) in the western United States. Recently, this insect has undergone a major territory expansion into the eastern US and has become a pest throughout much of the Corn Belt. This study was instigated to examine the population genetics of this pest to facilitate control and resistance management, as well as to shed light on the current habitat expansion. To this end, western bean cutworm individuals were collected from 28 different locations across the traditional and expanded …

Genetic Variability And Gene Flow Of The Fall Armyworm Spodoptera Frugiperda (J.E. Smith) In The Western Hemisphere And Susceptibility To Insecticides, Difabachew B. Kondidie

Department of Entomology: Dissertations, Theses, and Student Research

The fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), is an economically important pest of maize, sorghum, cotton, and rice in the Western Hemisphere. Previous studies on genetic diversity of FAW focused on identification of the corn and rice host strains; there is limited information about geographic genetic variation. To bridge this gap, I investigated the genetic diversity of FAW using representative samples from the United States, Argentina, Panama, and Puerto Rico with amplified fragment length polymorphism (AFLP). This study also investigated the susceptibility of the Puerto Rico FAW population to ten different insecticides used by Dow AgroSciences …

The Role Of Peroxidase In The Defense Response Of Buffalograss To Chinch Bugs, Anh Hoang

Department of Entomology: Dissertations, Theses, and Student Research

In recent years, buffalograss, Buchloë dactyloides (Nuttall) Engelmann has gained popularity as a turfgrass because of its low maintenance requirement, drought tolerance, and limited pests and diseases. Within the last decade, however, the western chinch bug Blissus occiduus Barber has emerged as important pest of buffalograss. Considerable progress has been made toward identifying buffalograsses with resistance to the western chinch bug and understanding the mechanisms of the resistance. It has been hypothesized that chinch bug-resistant buffalograsses can effectively detoxify the elevated levels of Reactive Oxygen Species (ROS) through enhanced activity of ROS-scavenging enzymes, while ROS accumulates in the susceptible plants …

Morphological Characterization And Molecular Mediated Genetic Variation Of Thief Ant (Solenopsis Molesta Say, Hymenoptera: Formicidae), Ralph B. Narain

Department of Entomology: Dissertations, Theses, and Student Research

The thief ant, Solenopsis molesta (Say), a common nuisance ant species found throughout the United States is genetically related to other stinging ants. This research was undertaken to estimate genetic variation utilizing mitochondrial DNA sequences of cytochrome oxidase I in thief ant populations from various geographic locations. Thief ants were collected from nine states, identified to species using morphologic characteristics from available keys. DNA extractions were completed with Qiagen’s Gentra PUREGENE® DNA Isolation Kit using their solid tissue protocol. PCR reactions were run on the extracted DNA using primers Lep-F1 (forward) and Lep-R1 (reverse). The resulting DNA products were concentrated …

An Investigation Of Wild Bee Diversity And Abundance In Plots Managed By The Nature Conservancy In South-Central Nebraska And Of Beneficial Arthropods Associated With Native Nebraska Flora, Dori Ann Porter

Department of Entomology: Dissertations, Theses, and Student Research

Insect pollination is an essential ecosystem service, and bees are the principal pollinators of wild and cultivated plants. Habitat management and enhancement are a proven way to encourage wild bee populations, providing them with food and nesting resources. I examined bee diversity and abundance in plots managed by The Nature Conservancy near Wood River, NE. The plots were seeded with 2 seed mixes at 2 seeding rates: high diversity mix at the recommended rate, high diversity mix double the recommended rate, Natural Resources Conservation Service (NRCS) conservation planting (CP) 25 mix at one-half the recommended rate, and NRCS CP25 mix …

Niche Specialization And Conservation Biology Of Cicindela Nevadica Lincolniana, Tierney R. Brosius

Department of Entomology: Dissertations, Theses, and Student Research

As with many organisms across the globe, Cicindela nevadica lincolniana is threatened with extinction. Understanding ecological factors that contribute to extinction vulnerability and what methods aid in the recovery of those species is essential in developing successful conservation programs. Here we examine behavioral mechanisms for niche partitioning along with improving techniques for captive rearing protocol and increasing public awareness about the conservation of this local insect. Ovipositional selectivity was examined for Cicindela nevadica lincolniana, Cicindela circumpicta, Cicindela togata, Cicindela punctulata, and Cicindela fulgida. Models reflect that these species of co-occurring tiger beetles select different ranges of salinity in which to …

Remote Sensing To Detect The Movement Of Wheat Curl Mites Through The Spatial Spread Of Virus Symptoms, And Identification Of Thrips As Predators Of Wheat Curl Mites, Abby R. Stilwell

Department of Entomology: Dissertations, Theses, and Student Research

The wheat curl mite (WCM), Aceria tosichella Keifer, transmits three viruses to winter wheat: wheat streak mosaic virus, High Plains virus, and Triticum mosaic virus. This virus complex causes yellowing of the foliage and stunting of plants. WCMs disperse by wind, and an increased understanding of mite movement and subsequent virus spread is necessary in determining the risk of serious virus infections in winter wheat. These risk parameters will help growers make better decisions regarding WCM management. The objectives of this study were to evaluate the capabilities of remote sensing to identify virus infected plants and to establish the potential …

Hybridization In Diabrotica Barberi Smith And Lawrence And Diabrotica Longicornis (Say) (Coleoptera: Chrysomelidae): Biology, Behavior, Field Introgression, And A Reevaluation Of Taxonomic Status, Laura A. Campbell

Department of Entomology: Dissertations, Theses, and Student Research

Diabrotica barberi Smith and Lawrence and D. longicornis (Say) are currently recognized as closely related chrysomelid species. Morphological and genetic data support that the two species are sister taxa, and hybridization has been proposed to occur. The objectives of this work were to: 1) assess life history parameters of both taxa and hybrids, 2) compare mating behavior, pheromone response, and spermatophore transfer of both taxa and hybrids, and 3) examine genetic and morphological data for evidence of introgression. Using lab-reared individuals, fitness parameters and potential for population growth were assessed. D. barberi and D. longicornis differed in longevity and fecundity. …

The Chemistry Of Lipid Signal Molecules In Insects, Sean M. Putnam

Department of Entomology: Dissertations, Theses, and Student Research

I report on the chemical identification of lipid signaling molecules in three species of insects and describe the chemical isolation of a bacterial product that inhibits eicosanoid biosynthesis. Chapter 2 reports that eicosanoids mediate nodulation reactions to bacterial infection in newly-emerged, but not forager honeybees. Cyclooxygenase and lipoxygenase inhibitors attenuate nodulation, which is reversed in the presence of arachidonic acid. Older adult honeybees do not produce bacterial-induced nodules, and they have fewer circulating hemocytes, from which I infer that foraging honeybees express a physiological trade-off between maintaining a biologically expensive hemocytic immune system and flight activity associated with foraging. Chapters …

An Investigation Of Techniques For Using Oxalic Acid To Reduce Varroa Mite Populations In Honey Bee Colonies And Package Bees, Nicholas Aliano

Department of Entomology: Dissertations, Theses, and Student Research

I investigated strategies for reducing Varroa mite populations (Varroa destructor) in honey bee colonies (Apis mellifera) using oxalic acid (OA). I examined the efficacy of OA in both broodless colonies and colonies that contain brood. My data indicate that OA is most effective at reducing Varroa populations when colonies are broodless because repeated applications of OA did not significantly reduce mite populations in colonies when brood was present. Next, I quantified the contact toxicity of OA to Varroa mites and their honey bee hosts in laboratory bioassays. The results indicate that OA has a low acute …