Entomology Commons^™

Effects Of Acorns On Populations Of Aedes Mosquitoes, Rachel Rogers

Honors Theses

Aedes albopictus (Asian tiger mosquito) and Aedes aegypti (yellow fever mosquito) are two mosquito species that are non-native to North America and are of medical importance. Both species can be found in aquatic container habitats, such as discarded tires and tree holes. In container habitats, the influx of detritus from the outside environment is essential to mosquito production and can include a variety of plant and animal material. Seeds from oak trees (acorns) can seasonally contribute to the detritus of these container habitats. This study examined the effect of acorns from the southern live oak (Quercus virginiana) on the performance …

Expression Of Glycine-Rich Proteins Found In Salivary Glands Of The Lone Star Tick (Amblyomma Americanum) Using A Mammalian Cell Line, Annabelle Clark

Honors Theses

Ticks play an important ecological role as well as a growing role in human health and veterinary care. Ticks are hosts to a plethora of microbial pathogens that can be transferred during feeding to cause tick-borne diseases in humans and many animals. Ticks may in large part owe the success of the transfer of these pathogens between hosts to their complex saliva. The saliva secreted upon a tick’s attachment to a host serves the following, among other, functions: anti-hemostasis of the blood pool, preventing an inflammatory response at the bite site, and serving as a natural anti-microbial substance. An important …

Investigating The Functional Role Of Tick Antioxidants In Hematophagy And Vector Competence, Deepak Kumar

Dissertations

Ticks are obligate hematophagous arthropods and harbor several pathogens which transmit various diseases to humans and their domesticated animals. Host blood- digestion in a tick midgut (MG) generates several reactive oxygen species (ROS), which are extremely toxic to essential macromolecules (e.g. DNA, proteins, and lipids) within the cell, resulting in high oxidative stress. Thus, this dissertation focuses on the questions of how tick homeostasis responds to high oxidative stress, and how ticks and their harbored pathogens survive the high surge of oxidative stress during blood digestion. We are specifically interested in the tick-pathogen, Rickettsia parkeri (R. parkeri, Rp), harbored by …

Characterization Of Glycine Rich Proteins From The Salivary Glands Of The Lone Star Tick Amblyomma Americanum, Rebekah Lynn Bullard

Dissertations

Ticks are blood sucking arthropods that feed on living hosts for up to three weeks. The ticks secrete a multitude of pharmacologically active proteins into the host during feeding which allow the tick to avoid the host immune response, establish a blood pool, and form a firm attachment. The firm attachment is facilitated by the formation of a cement cone which surrounds the tick mouthparts and intertwine between the host skin layers. In this study, gene expression of 44 A. americanum genes was measured throughout the bloodmeal to reveal the differential expression of these genes. Each of the genes tested …

The Uas-Gal4 System In D. Melanogaster: An Insight Into The Influence Of Micrornas On The Developmental Pathways Of The Wing, Emily R. Wilson

Honors Theses

By examining genetic pathways in D. melanogaster, a better understanding of the homologous regulatory mechanisms in humans can be utilized to further enhance knowledge of the roles of microRNA within development. This study utilizes the UAS-Gal4 system in order to produce a mutant phenotype capable of being visually studied and analyzed, focusing on the developmental pathway of the wing in D. melanogaster. Dissections of the wandering third instar larvae yielded wing disc tissue expressing the downregulation of loquacious and CG17386.

Environmental Impacts And Carry-Over Effects In Complex Life Cycles: The Role Of Different Life History Stages, Nnaemeka F. Ezeakacha

Dissertations

A challenge faced by organisms with complex life cycles is how environmental factors experienced at an earlier life stage affect the fitness at that stage or are carried over to subsequent life stages. I used container-inhabiting mosquitoes: Aedes albopictus, Aedes aegypti, Aedes triseriatus and Culex quinquefasciatus to study the interactions and performance of life history stages under specific environmental factors. I investigated the effects of egg-desiccation tolerance on egg viability and larval performance in the Aedes mosquitoes. I found increase in egg hatch rate with relative humidity and interaction between relative humidity and egg storage period. Larval performance …

Elucidating The Molecular Function Of Reprolysin Metalloproteases In Tick-Host-Pathogen Interaction, Jaclyn Bo Williams

Master's Theses

Ticks are ectoparasites that attach to their host for many days to weeks, feeding to engorgement and continuing their species life cycle. The mechanisms behind the successful feeding and manipulation of host immune responses have been associated with the secretion of their specialized saliva. Tick saliva includes a variety of modulatory molecules that must disrupt and counteract defense mechanisms, including a variety of proteases. Reprolysin Metalloproteases, in the Zn²⁺ dependent family, is secreted as a proenzyme and is shown to have proteolytic activity, degrading fibrinogen and gelatinase activity, as well as disturbing homeostasis¹². Previous work with …

First Record Of A Spotted Fever Group Rickettsia Sp. And Theileria Annulata In Hyalomma Dromedarii (Acari: Ixodidae) Ticks In The United Arab Emirates, Mohammad Ali Al-Deeb, Sabir Bin Muzaffar, Yousif Ali Abu-Zeid, Mohamed Rizk Enan, Shahid Karim

Faculty Publications

Rickettsiosis and theileriosis can cause mortalities in camel populations. This study was conducted to achieve 2 objectives: (1) to detect the presence of SFG Rickettsia sp. and Theileria sp. in Hyalomma dromedarii Koch, 1844 (Acari: Ixodidae) ticks and (2) to determine their prevalence in the tick population on the sampled camel farms in Al-Ain, United Arab Emirates (UAE). Camel ticks (H. dromedarii) were collected from a total of 625 one-humped camels (Camelus dromedarius) in 22 sampling locations in Al-Ain, UAE. Tick samples were analyzed by Polymerase Chain Reaction (PCR). An SFG Rickettsia sp., which was 99% …

Influence Of Resource Levels, Organic Compounds And Laboratory Colonization On Interspecific Competition Between The Asian Tiger Mosquito Aedes Albopictus (Stegomyia Albopicta) And The Southern House Mosquito Culex Quinquefasciatus, D.W. Allgood, Donald A. Yee

Faculty Publications

The mosquitoes Aedes albopictus (Stegomyia albopicta) (Skuse) and Culex quinquefasciatus (Say) (Diptera: Culicidae) are common inhabitants of tyres and other artificial containers, which constitute important peridomestic mosquito breeding habitats. We tested the hypotheses that interspecific resource competition between the larvae of these species is asymmetrical, that the concentration of chemicals associated with decomposing detritus affects the competitive outcomes of these species, and that wild and colonized strains of Cx. quinquefasciatus are affected differently by competition with Ae. albopictus. We conducted two laboratory competition experiments wherein we measured survivorship and estimated population growth (λ′) in both species under …

Transcriptional Activation Of Antioxidants May Compensate For Selenoprotein Deficiences In Amblyomma Maculatum (Acari: Ixodidae) Injected With Selk- Or Selm- Dsrna, S. Adamson, R. Browning, P. Singh, S. Nobles, A. Villareal, Shahid Karim

Faculty Publications

The Gulf‐Coast tick, Amblyomma maculatum, possesses an elaborate set of selenoproteins, which prevent the deleterious effects from oxidative stress that would otherwise occur during feeding. In the current work, we examined the role of selenoprotein K (SelK) and selenoprotein M (SelM) in feeding A. maculatum by bioinformatics, transcriptional gene expression, RNA interference and antioxidant assays. The transcriptional expression of SelK did not vary significantly in salivary glands or midguts throughout the bloodmeal. However, there was a 58‐fold increase in transcript levels of SelM in tick midguts. Ticks injected with selK‐dsRNA or selM‐dsRNA did not reveal any observable …

An Insight Into The Microbiome Of The Amblyomma Maculatum(Acari: Ixodidae), Khemraj Budachetri, Rebecca E. Browning, Steven W. Adamson, Scot E. Dowd, Chien-Chung Chao, Wei-Mei Ching, Shahid Karim

Faculty Publications

The aim of this study was to survey the bacterial diversity of Amblyomma maculatum Koch, 1844, and characterize its infection with Rickettsia parkeri. Pyrosequencing of the bacterial 16S rRNA was used to determine the total bacterial population in A. maculatum. Pyrosequencing analysis identified Rickettsia in A. maculatum midguts, salivary glands, and saliva, which indicates successful trafficking in the arthropod vector. The identity of Rickettsia spp. was determined based on sequencing the rickettsial outer membrane protein A (rompA) gene. The sequence homology search revealed the presence of R. parkeri, Rickettsia amblyommii, and Rickettsia endosymbiont of …

Interspecific Competition Of A New Invasive Mosquito, Culex Coronator, And Two Container Mosquitoes, Aedes Albopictus And Cx. Quinquefasciatus (Diptera: Culicidae), Across Different Detritus Environments, D. A. Yee, J. F. Skiff

Faculty Publications

The mosquito Culex coronator (Dyar and Knab) (Diptera: Culicidae) has undergone rapid range expansion in the United States since 2003, with its historical distribution in the southwest expanding eastward to the Atlantic coast. Although Cx. coronator nominally use small natural aquatic habitats for development, the use of containers (e.g., tires) makes it potentially important as container invasive. To determine the potential ecological effects of Cx. coronator on resident container species, we conducted a laboratory experiment to assess its competitive ability with two common tire-inhabiting species, Aedes albopictus (Skuse) and Culex quinquefasciatus (Say) (Diptera: Culicidae). Larvae were reared under a factorial …

Knockdown Of Selenocysteine-Specific Elongation Factor In Amblyomma Maculatum Alters The Pathogen Burden Of Rickettsia Parkeri With Epigenetic Control By The Sin3 Histone Deacetylase Corepressor Complex, Steven W. Adamson, Rebecca E. Browning, Khemraj Budachetri, José M.C. Ribeiro, Shahid Karim

Faculty Publications

Selenocysteine is the 21st naturally-occurring amino acid. Selenoproteins have diverse functions and many remain uncharacterized, but they are typically associated with antioxidant activity. The incorporation of selenocysteine into the nascent polypeptide chain recodes the TGA stop codon and this process depends upon a number of essential factors including the selenocysteine elongation factor (SEF). The transcriptional expression of SEF did not change significantly in tick midguts throughout the blood meal, but decreased in salivary glands to 20% at the end of the fast feeding phase. Since selenoprotein translation requires this specialized elongation factor, we targeted this gene for knockdown by RNAi …

A Deep Insight Into The Sialotranscriptome Of The Gulf Coast Tick, Amblyomma Maculatum, Shahid Karim, Parul Singh, José M.C. Ribeiro

Faculty Publications

Background

Saliva of blood sucking arthropods contains compounds that antagonize their hosts' hemostasis, which include platelet aggregation, vasoconstriction and blood clotting; saliva of these organisms also has anti-inflammatory and immunomodullatory properties. Perhaps because hosts mount an active immune response against these compounds, the diversity of these compounds is large even among related blood sucking species. Because of these properties, saliva helps blood feeding as well as help the establishment of pathogens that can be transmitted during blood feeding.

Methodology/Principal Findings

We have obtained 1,626,969 reads by pyrosequencing a salivary gland cDNA library from adult females Amblyomma maculatum ticks at different …

Influence Of Detritus Levels And Organic Pollution On Interspecific Resource Competition, Oviposition Behavior, And Larval Survival Of Two Tire-Inhabiting Mosquito Species (Diptera: Culicidae), David Wayne Allgood

Master's Theses

Mosquitoes (Diptera: Culicidae) are vectors of disease in the adult stage, but understanding the factors affecting distributions of the immature stages is important to the understanding and control of adult populations. Discarded automobile tires comprise important larval mosquito habitats. The Asian tiger mosquito (Aedes albopictus) and the southern house mosquito (Culex quinquefasciatus) are two medically important species commonly found in tires, but factors affecting their larval distributions in tires have not been studied, nor have their interspecific interactions. I investigated the effects of chemicals associated with organic pollution on oviposition preferences and larval survival of both …

Investigating Mechanisms Of Co-Occurrence Between Two Similar Specis Of Predaceous Diving Beetles (Coleoptera: Dytiscidae) In Temporary Aquatic Habitats, Kristopher Alexander Pitcher

Master's Theses

Predaceous diving beetles (Coleoptera: Dytiscidae) are a model group of organisms for testing coexistence and exclusion mechanisms because numerous species of the family interact in isolated, aquatic habitats, and are ubiquitous throughout landscapes. Two morphologically similar species, laccophilus fasciatus rufus and Laccophilus proximus, co-occur in numerous habitats in South Mississippi, but are hypothesized to have strong interspecific interactions. I investigated several possible mechanisms that may promote such coexistence, including segregation in habitat domain, differences in behavior, and differences in dispersal that may allow co-occurrence between these two species of beetle. Habitat domain and behaviors such as activity and prey consumption …

Stable Isotope Analysis Reveals Detrital Resource Base Sources Of The Tree Hole Mosquito, Aedes Triseriatus, Michael G. Kaufman, Kirsten S. Pelz-Stelinski, Donald A. Yee, Steven A. Juliano, Peggy H. Ostrom, Edward D. Walker

Faculty Publications

1. Detritus that forms the basis for mosquito production in tree hole ecosystems can vary in type and timing of input. We investigated the contributions of plant‐ and animal‐derived detritus to the biomass of Aedes triseriatus (Say) pupae and adults by using stable isotope (¹⁵N and ¹³C) techniques in laboratory experiments and field collections.
2. Laboratory‐reared mosquito isotope values reflected their detrital resource base, providing a clear distinction between mosquitoes reared on plant or animal detritus.
3. Isotope values from field‐collected pupae were intermediate between what would be expected if a single (either plant or animal) detrital source dominated the …

Functional Genomics Tool: Gene Silencing In Ixodes Scapularis Eggs And Nymphs By Electroporated Dsrna, Shahid Karim, Emily Troiano, Thomas N. Mather

Faculty Publications

Background

Ticks are blood-sucking arthropods responsible for transmitting a wide variety of disease-causing agents, and constitute important public health threats globally. Ixodes scapularis is the primary vector of the Lyme disease agent in the eastern and central U.S. RNAi is a mechanism by which gene-specific double-stranded RNA (dsRNA) triggers degradation of homologous mRNA transcripts. Here, we describe an optimized protocol for effectively suppressing gene expression in the egg and nymphal stages of I. scapularis by electroporation.

Results

The genes encoding the putative Phospholipase A₂ (PLA₂), cytoplasmic Cystatin, Syntaxin-5, β-Actin and Calreticulin were targeted by delivering the dsRNA …

Environmental Correlates Of Abundances Of Mosquito Species And Stages In Discarded Vehicle Tires, Donald A. Yee, Jamie M. Kneitel, Steven A. Juliano

Faculty Publications

Discarded vehicle tires are a common habitat for container mosquito larvae, although the environmental factors that may control their presence or abundance within a tire are largely unknown. We sampled discarded vehicle tires in six sites located within four counties of central Illinois during the spring and summer of 2006 to determine associations between a suite of environmental factors and community composition of container mosquitoes. Our goal was to find patterns of association between environmental factors and abundances of early and late instars. We hypothesized that environmental factors correlated with early instars would be indicative of oviposition cues, whereas environmental …