Entomology Commons^™

Integrated Analysis Of Cytochrome P450 Gene Superfamily In The Red Flour Beetle, Tribolium Castaneum, Fang Zhu, Timothy W. Moural, Kapil Shah, Subba Reddy Palli

Entomology Faculty Publications

BACKGROUND: The functional and evolutionary diversification of insect cytochrome P450s (CYPs) shaped the success of insects. CYPs constitute one of the largest and oldest gene superfamilies that are found in virtually all aerobic organisms. Because of the availability of whole genome sequence and well functioning RNA interference (RNAi), the red flour beetle, Tribolium castaneum serves as an ideal insect model for conducting functional genomics studies. Although several T. castaneum CYPs had been functionally investigated in our previous studies, the roles of the majority of CYPs remain largely unknown. Here, we comprehensively analyzed the phylogenetic relationship of all T. castaneum CYPs …

Population Impacts Of Wolbachia On Aedes Albopictus, James W. Mains, Corey L. Brelsfoard, Philip R. Crain, Yunxin Huang, Stephen L. Dobson

Entomology Faculty Publications

Prior studies have demonstrated that Wolbachia, a commonly occurring bacterium capable of manipulating host reproduction, can affect life history traits in insect hosts, which in turn can have population-level effects. Effects on hosts at the individual level are predicted to impact population dynamics, but the latter has not been examined empirically. Here, we describe a biological model system based on Aedes albopictus (Asian tiger mosquito) that allows for measurement of population dynamics, which has not been accomplished in prior field trials or laboratory designs. The results demonstrate the studied populations to be robust and allow for persistent, closed populations with …

Wolbachia Association With The Tsetse Fly, Glossina Fuscipes Fuscipes, Reveals High Levels Of Genetic Diversity And Complex Evolutionary Dynamics, Rebecca E. Symula, Uzma Alam, Corey L. Brelsfoard, Yineng Wu, Richard Echodu, Loyce M. Okedi, Serap Aksoy, Adalgisa Caccone

Entomology Faculty Publications

BACKGROUND: Wolbachia pipientis, a diverse group of α-proteobacteria, can alter arthropod host reproduction and confer a reproductive advantage to Wolbachia-infected females (cytoplasmic incompatibility (CI)). This advantage can alter host population genetics because Wolbachia-infected females produce more offspring with their own mitochondrial DNA (mtDNA) haplotypes than uninfected females. Thus, these host haplotypes become common or fixed (selective sweep). Although simulations suggest that for a CI-mediated sweep to occur, there must be a transient phase with repeated initial infections of multiple individual hosts by different Wolbachia strains, this has not been observed empirically. Wolbachia has been found in the tsetse fly, Glossina …

Reference Gene Selection For Qrt-Pcr Analysis In The Sweetpotato Whitefly, Bemisia Tabaci (Hemiptera: Aleyrodidae), Rumei Li, Wen Xie, Shaoli Wang, Qingjun Wu, Nina Yang, Xin Yang, Huipeng Pan, Xiaomao Zhou, Lianyang Bai, Baoyun Xu, Xuguo Zhou, Youjun Zhang

Entomology Faculty Publications

BACKGROUND: Accurate evaluation of gene expression requires normalization relative to the expression of reliable reference genes. Expression levels of "classical" reference genes can differ, however, across experimental conditions. Although quantitative real-time PCR (qRT-PCR) has been used extensively to decipher gene function in the sweetpotato whitefly Bemisia tabaci, a world-wide pest in many agricultural systems, the stability of its reference genes has rarely been validated.

RESULTS: In this study, 15 candidate reference genes from B. tabaci were evaluated using two Excel-based algorithms geNorm and Normfinder under a diverse set of biotic and abiotic conditions. At least two reference genes were …

Putting Theory Into Practice: Predicting The Invasion And Stability Of Wolbachia Using Simulation Models And Empirical Studies, Philip R. Crain

Theses and Dissertations--Entomology

A new strategy to fight mosquito-borne disease is based on infections of the maternally-transmitted, intracellular bacterium Wolbachia pipientis. Estimates predict that Wolbachia infects nearly half of all insect species, as well as other arthropods and some nematodes. Wolbachia manipulates the reproduction of its host to promote infection, most commonly causing a form of conditional sterility known as cytoplasmic incompatibility. Generally, Wolbachia infections are benign and do not inflict significant costs upon its host. However, studies demonstrate that some infections are associated with substantial costs to its host. These same infections can also induce pathogen interference and decrease vector competency …

Selective Utilization Of Microhabitats By Web-Building Spiders, Kelton D. Welch

Theses and Dissertations--Entomology

Natural enemies are members of complex ecological communities, and their ability to contribute to the biological control of pest organisms is strongly influenced by a convoluted network of ecological interactions with many other organisms within these communities. Researchers must develop an understanding of the mechanisms that shape trophic webs to predict and promote top-down effects of predators. The behavior of predators can have a strong influence on their potential as biological control agents.

Web-building spiders are a useful example organism for the study of natural enemy behavior because of the experimentally tractable nature of their foraging behavior. Specifically, patterns in …

An Assessment Of The Invasive Poison Hemlock And Its Insect Associates In Kentucky, Christine D. Allen

Theses and Dissertations--Entomology

Poison hemlock, Conium maculatum (Apiaceae), is an invasive plant in North America with a unique toxic chemistry. Previous research on this plant has focused on identifying herbivores as potential biological control agents or describing the toxic plant alkaloids. However, none have examined the role of higher trophic levels in the food web surrounding poison hemlock. Generalist predators and food web interactions are an important component of studies investigating invasion effects, as plant or animal introductions can alter ecosystem functioning. In this study, predators in poison hemlock were sampled at the foliar and epigeal levels, resulting in 956 Carabidae and 321 …

Enhancing Beneficial Insect Biodiversity And Biological Control In Turf: Mowing Height, Naturalized Roughs, And Operation Pollinator, Emily Dobbs

Theses and Dissertations--Entomology

The goal of this study was to evaluate several sustainable turf maintenance techniques for their potential to increase beneficial insect populations, which could then provide ecosystem services including pest suppression and pollination. The three techniques in question were 1) raising mowing height in commercial and residential lawns, 2) establishing naturalized roughs on golf courses, and 3) creating pollinator refuges on golf courses through the program Operation Pollinator. We found that raising mowing heights did increase populations of some predators such as spiders and staphylinids, but did not increase predation, which was ubiquitously high because ant populations were unaffected by mowing …

Endosymbiotic Prevalence And Reproductive Manipulation Of The Spider Mermessus Fradeorum, Meghan M. Curry

Theses and Dissertations--Entomology

Spiders are host to a plethora of heritable endosymbiotic bacteria. Broad-taxa screening studies indicate that endosymbionts are particularly common among spiders, however, little is known about how these bacteria affect their spider hosts. In insects these bacteria ensure vertical transmission by either conveying a benefit to the host or manipulating host reproduction to eliminate males that serve as evolutionary dead-ends for maternally-inherited bacteria. Common modes of reproductive manipulation include parthenogenesis, male killing, feminization, and cytoplasmic incompatibility. Screening an assemblage of Mermessus genus spiders, I detected a high frequency and diversity of endosymbiont infection. Within a single species, M. fradeorum …

Doublesex Target Genes In The Red Flour Beetle, Tribolium Castaneum, Jayendra Nath Shukla, Subba Reddy Palli

Entomology Faculty Publications

Sex determination cascade in insects terminates with the production of sex-specific protein, Doublesex (Dsx). We identified the dsx homolog (Tcdsx) in Tribolium castaneum. The pre-mRNA of Tcdsx is sex-specifically spliced into three female (Tcdsxf1, Tcdsxf2 and Tcdsxf3) and one male-specific (Tcdsxm) isoforms. Cis-regulatory elements potentially involved in sex-specific splicing of the Tcdsx pre-mRNA were identified in the female-specific exon and the adjoining intronic sequences. All the three female-specific TcDsx proteins share common OD1 and OD2 domains and differ in their C-terminal sequences. Knockdown of Tcdsx resulted in a reduction in the oocyte development, egg production and hatching of eggs laid. …

Reactive Oxygen Species Production And Brugia Pahangi Survivorship In Aedes Polynesiensis With Artificial Wolbachia Infection Types, Elizabeth S. Andrews, Philip R. Crain, Yuqing Fu, Daniel K. Howe, Stephen L. Dobson

Entomology Faculty Publications

Heterologous transinfection with the endosymbiotic bacterium Wolbachia has been shown previously to induce pathogen interference phenotypes in mosquito hosts. Here we examine an artificially infected strain of Aedes polynesiensis, the primary vector of Wuchereria bancrofti, which is the causative agent of Lymphatic filariasis (LF) throughout much of the South Pacific. Embryonic microinjection was used to transfer the wAlbB infection from Aedes albopictus into an aposymbiotic strain of Ae. polynesiensis. The resulting strain (designated "MTB") experiences a stable artificial infection with high maternal inheritance. Reciprocal crosses of MTB with naturally infected wild-type Ae. polynesiensis demonstrate strong bidirectional incompatibility. Levels of reactive …

Characterization Of Head Transcriptome And Analysis Of Gene Expression Involved In Caste Differentiation And Aggression In Odontotermes Formosanus (Shiraki), Qiuying Huang, Pengdong Sun, Xuguo Zhou, Chaoliang Lei

Entomology Faculty Publications

Background

The subterranean termite Odontotermes formosanus (Shiraki) is a serious insect pest of trees and dams in China. To date, very little is known about genomic or transcriptomic data for caste differentiation and aggression in O. formosanus. Hence, studies on transcriptome and gene expression profiling are helpful to better understand molecular basis underlying caste differentiation and aggressive behavior in O. formosanus.

Methodology and Principal Findings

Using the Illumina sequencing, we obtained more than 57 million sequencing reads derived from the heads of O. formosanus. These reads were assembled into 116,885 unique sequences (mean size = 536 bp). …

Open Release Of Male Mosquitoes Infected With A Wolbachia Biopesticide: Field Performance And Infection Containment, Linda O'Connor, Catherine Plichart, Ayo Cheong Sang, Corey L. Brelsfoard, Hervé C. Bossin, Stephen L. Dobson

Entomology Faculty Publications

BACKGROUND: Lymphatic filariasis (LF) is a globally significant disease, with 1.3 billion persons in 83 countries at risk. A coordinated effort of administering annual macrofilaricidal prophylactics to the entire at-risk population has succeeded in impacting and eliminating LF transmission in multiple regions. However, some areas in the South Pacific are predicted to persist as transmission sites, due in part to the biology of the mosquito vector, which has led to a call for additional tools to augment drug treatments. Autocidal strategies against mosquitoes are resurging in the effort against invasive mosquitoes and vector borne disease, with examples that include field …

Wolbachia Strain Wpip Yields A Pattern Of Cytoplasmic Incompatibility Enhancing A Wolbachia-Based Suppression Strategy Against The Disease Vector Aedes Albopictus, Maurizio Calvitti, Riccardo Moretti, Amanda R. Skidmore, Stephen L. Dobson

Entomology Faculty Publications

BACKGROUND: Cytoplasmic incompatibility (CI) is induced in nature by Wolbachia bacteria, resulting in conditional male sterility. Previous research demonstrated that the two Wolbachia strains (wAlbA and wAlbB) that naturally co-infect the disease vector mosquito Aedes albopictus (Asian tiger mosquito) can be replaced with the wPip Wolbachia strain from Culex pipiens. Since Wolbachia-based vector control strategies depend upon the strength and consistency of CI, a greater understanding is needed on the CI relationships between wPip, wAlbA and wAlbB Wolbachia in Ae. albopictus.

METHODS: This work consisted of a collaborative series of crosses carried out in Italy and in US to study …

Cloning, Ligand-Binding, And Temporal Expression Of Ecdysteroid Receptors In The Diamondback Moth, Plutella Xylostella, Baozhen Tang, Wei Dong, Pei Liang, Xuguo Zhou, Xiwu Gao

Entomology Faculty Publications

BACKGROUND: The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), is a devastating pest of cruciferous crops worldwide, and has developed resistance to a wide range of insecticides, including diacylhydrazine-based ecdysone agonists, a highly selective group of molt-accelerating biopesticides targeting the ecdysone receptors.

RESULT: In this study, we cloned and characterized the ecdysone receptors from P. xylostella, including the two isoforms of EcR and a USP. Sequence comparison and phylogenetic analysis showed striking conservations among insect ecdysone receptors, especially between P. xylostella and other lepidopterans. The binding affinity of ecdysteroids to in vitro-translated receptor proteins indicated that PxEcRB isoform bound specifically …

Comparative Mitogenomic Analysis Of Damsel Bugs Representing Three Tribes In The Family Nabidae (Insecta: Hemiptera), Hu Li, Haiyu Liu, Fan Song, Aimin Shi, Xuguo Zhou, Wanzhi Cai

Entomology Faculty Publications

BACKGROUND: Nabidae, a family of predatory heteropterans, includes two subfamilies and five tribes. We previously reported the complete mitogenome of Alloeorhynchus bakeri, a representative of the tribe Prostemmatini in the subfamily Prostemmatinae. To gain a better understanding of architecture and evolution of mitogenome in Nabidae, mitogenomes of five species representing two tribes (Gorpini and Nabini) in the subfamily Nabinae were sequenced, and a comparative mitogenomic analysis of three nabid tribes in two subfamilies was carried out.

METHODOLOGY/PRINCIPAL FINDINGS: Nabid mitogenomes share a similar nucleotide composition and base bias, except for the control region, where differences are observed at the …

Widespread And Persistent Invasions Of Terrestrial Habitats Coincident With Larval Feeding Behavior Transitions During Snail-Killing Fly Evolution (Diptera: Sciomyzidae), Eric G. Chapman, Andrey A. Przhiboro, James D. Harwood, Benjamin A. Foote, Walter R. Hoeh

Entomology Faculty Publications

BACKGROUND: Transitions in habitats and feeding behaviors were fundamental to the diversification of life on Earth. There is ongoing debate regarding the typical directionality of transitions between aquatic and terrestrial habitats and the mechanisms responsible for the preponderance of terrestrial to aquatic transitions. Snail-killing flies (Diptera: Sciomyzidae) represent an excellent model system to study such transitions because their larvae display a range of feeding behaviors, being predators, parasitoids or saprophages of a variety of mollusks in freshwater, shoreline and dry terrestrial habitats. The remarkable genus Tetanocera (Tetanocerini) occupies five larval feeding groups and all of the habitat types mentioned above. …

Novel Role Of A Cypovirus In Polydnavirus-Parasitoid-Host Relationship, Philip Houtz

Kaleidoscope

No abstract provided.

Three New Species Of Sesioctonus Viereck (Hymenoptera, Braconidae, Agathidinae) From Peru, Lidia Sulca, Michael J. Sharkey

Entomology Faculty Publications

Three new species of Sesioctonus (Braconidae: Agathidinae) are described and illustrated, i.e., Sesioctonus huggerti, Sesioctonus wayquecha, and Sesioctonus bina. Two new Peruvian species records for Sesioctonus are reported: Sesioctonus longinoi and Sesioctonus diazi. A revised key to all known species of Sesioctonus is presented.

Pyrosequencing The Bemisia Tabaci Transcriptome Reveals A Highly Diverse Bacterial Community And A Robust System For Insecticide Resistance, Wen Xie, Qing-Shu Meng, Qing-Jun Wu, Shao-Li Wang, Xin Yang, Ni-Na Yang, Ru-Mei Li, Xiao-Guo Jiao, Hui-Peng Pan, Bai-Ming Liu, Qi Su, Bao-Yun Xu, Song-Nian Hu, Xuguo Zhou, You-Jun Zhang

Entomology Faculty Publications

BACKGROUND: Bemisia tabaci (Gennadius) is a phloem-feeding insect poised to become one of the major insect pests in open field and greenhouse production systems throughout the world. The high level of resistance to insecticides is a main factor that hinders continued use of insecticides for suppression of B. tabaci. Despite its prevalence, little is known about B. tabaci at the genome level. To fill this gap, an invasive B. tabaci B biotype was subjected to pyrosequencing-based transcriptome analysis to identify genes and gene networks putatively involved in various physiological and toxicological processes.

METHODOLOGY AND PRINCIPAL FINDINGS: Using Roche 454 pyrosequencing, …

Population Genetic Structure Of Aedes Polynesiensis In The Society Islands Of French Polynesia: Implications For Control Using A Wolbachia-Based Autocidal Strategy, Corey L. Brelsfoard, Stephen L. Dobson

Entomology Faculty Publications

BACKGROUND: Aedes polynesiensis is the primary vector of Wuchereria bancrofti in the South Pacific and an important vector of dengue virus. An improved understanding of the mosquito population genetics is needed for insight into the population dynamics and dispersal, which can aid in understanding the epidemiology of disease transmission and control of the vector. In light of the potential release of a Wolbachia infected strain for vector control, our objectives were to investigate the microgeographical and temporal population genetic structure of A. polynesiensis within the Society Islands of French Polynesia, and to compare the genetic background of a laboratory strain …

Rapid Spread Of Tomato Yellow Leaf Curl Virus In China Is Aided Differentially By Two Invasive Whiteflies, Huipeng Pan, Dong Chu, Wenqian Yan, Qi Su, Baiming Liu, Shaoli Wang, Qingjun Wu, Wen Xie, Xiaoguo Jiao, Rumei Li, Nina Yang, Xin Yang, Baoyun Xu, Judith K. Brown, Xuguo Zhou, Youjun Zhang

Entomology Faculty Publications

BACKGROUND: Tomato yellow leaf curl virus (TYLCV) was introduced into China in 2006, approximately 10 years after the introduction of an invasive whitefly, Bemisia tabaci (Genn.) B biotype. Even so the distribution and prevalence of TYLCV remained limited, and the economic damage was minimal. Following the introduction of Q biotype into China in 2003, the prevalence and spread of TYLCV started to accelerate. This has lead to the hypothesis that the two biotypes might not be equally competent vectors of TYLCV.

METHODOLOGY/PRINCIPAL FINDINGS: The infection frequency of TYLCV in the field-collected B. tabaci populations was investigated, the acquisition and transmission …

Gene Expression Modulation System For Use In Plants And Method For Modulating Gene Expression In Plants, Subba Reddy Palli, Ajay Kumar Singh

Entomology Faculty Patents

An EcR-based gene expression modulation system for use in plants includes an EcR gene expression cassette, a modified RXR gene expression cassette, and a gene-of-interest expression cassette, which can be expressed in a host plant cell.

Rna Interference Of Nadph-Cytochrome P450 Reductase Results In Reduced Insecticide Resistance In The Bed Bug, Cimex Lectularius, Fang Zhu, Sarah Sams, Tim Moural, Kenneth F. Haynes, Michael F. Potter, Subba R. Palli

Entomology Faculty Publications

BACKGROUND: NADPH-cytochrome P450 reductase (CPR) plays a central role in cytochrome P450 action. The genes coding for P450s are not yet fully identified in the bed bug, Cimex lectularius. Hence, we decided to clone cDNA and knockdown the expression of the gene coding for CPR which is suggested to be required for the function of all P450s to determine whether or not P450s are involved in resistance of bed bugs to insecticides.

METHODOLOGY/PRINCIPAL FINDINGS: The full length Cimex lectularius CPR (ClCPR) cDNA was isolated from a deltamethrin resistant bed bug population (CIN-1) using a combined PCR strategy. Bioinformatics and in …

The Complete Mitochondrial Genome And Novel Gene Arrangement Of The Unique-Headed Bug Stenopirates Sp. (Hemiptera: Enicocephalidae), Hu Li, Hui Liu, Aimin Shi, Pavel Stys, Xuguo Zhou, Wanzhi Cai

Entomology Faculty Publications

Many of true bugs are important insect pests to cultivated crops and some are important vectors of human diseases, but few cladistic analyses have addressed relationships among the seven infraorders of Heteroptera. The Enicocephalomorpha and Nepomorpha are consider the basal groups of Heteroptera, but the basal-most lineage remains unresolved. Here we report the mitochondrial genome of the unique-headed bug Stenopirates sp., the first mitochondrial genome sequenced from Enicocephalomorpha. The Stenopirates sp. mitochondrial genome is a typical circular DNA molecule of 15, 384 bp in length, and contains 37 genes and a large non-coding fragment. The gene order differs substantially from …

Effects Of Methoprene On The Survivorship Of Adult Aedes Mosquitoes: A Strategy Or Inactivating Released Mosquitoes, Peter J. Brabant Iii

Theses and Dissertations--Entomology

Methoprene is a Juvenile Hormone (JH) analogue commonly used for the control of mosquito larvae. When applied to a mosquito breeding site, methoprene enters the haemolymph, where it mimics the function of JH and interferes with normal metamorphosis, resulting in larval mortality. Methoprene is commonly used for the control of larvae and has not been used as an adulticide, due to an absence of acute effects. This study evaluated possible chronic effects caused by the exposure of adult Aedes mosquitoes to methoprene. Methoprene was applied, in both technical grade and the commercially available Altosid®, topically to adults through droplet application …

Gene Expression Profiling In The Thiamethoxam Resistant And Susceptible B-Biotype Sweetpotato Whitefly, Bemisia Tabaci, Wen Xie, Xin Yang, Shao-Ii Wang, Qing-Jun Wu, Ni-Na Yang, Ru-Mei Li, Xiao-Guo Jiao, Hui-Peng Pan, Bai-Ming Liu, Yun-Tao Feng, Bao-Yun Xu, Xuguo Zhou, You-Jun Zhang

Entomology Faculty Publications

Thiamethoxam has been used as a major insecticide to control the B-biotype sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae). Due to its excessive use, a high level of resistance to thiamethoxam has developed worldwide over the past several years. To better understand the molecular mechanisms underlying this resistance in B. tabaci, gene profiles between the thiamethoxam-resistant and thiamethoxam-susceptible strains were investigated using the suppression subtractive hybridization (SSH) library approach. A total of 72 and 52 upand down-regulated genes were obtained from the forward and reverse SSH libraries, respectively. These expressed sequence tags (ESTs) belong to several functional categories based …

Empirical And Conceptual Approaches To Life-History Trade-Offs: The Size And Number Of Offspring In Broods Of A Parasitoid Wasp, Yoriko Saeki

Theses and Dissertations--Biology

Trade-offs in resource allocation underlie key life history traits of organisms. My dissertation focuses on the size-number trade-off in clonal broods of offspring using the polyembryonic wasp, Copidosoma bakeri parasitizing immature stages of the moth Agrotis ipsilon. I aim to characterize responses of wasp brood size and individual body mass by manipulating the environments in order to understand the allocation pattern in the size number trade-off. In reviewing the functional forms of trade-off relationships in relation to resource constraints, I distinguish among three main trade-off types based on graphical representations of the relationship between the trade-off variables: linear, convex …

Juvenile Hormone Regulates Vitellogenin Gene Expression Through Insulin-Like Peptide Signaling Pathway In The Red Flour Beetle, Tribolium Castaneum, Zhentao Sheng, Jingjing Xu, Hua Bai, Fang Zhu, Subba R. Palli

Entomology Faculty Publications

Our recent studies identified juvenile hormone (JH) and nutrition as the two key signals that regulate vitellogenin (Vg) gene expression in the red flour beetle, Tribolium castaneum. Juvenile hormone regulation of Vg synthesis has been known for a long time in several insects, but the mechanism of JH action is not known. Experiments were conducted to determine the mechanism of action of these two signals in regulation of Vg gene expression. Injection of bovine insulin or FOXO double-stranded RNA into the previtellogenic, starved, or JH-deficient female adults increased Vg mRNA and protein levels, thereby implicating the pivotal role for …

Revision Of The New World Genus Crassomicrodus Ashmead (Hymenoptera, Braconidae, Agathidinae), With An Identification Key To Species, José Isaac Figueroa, Michael J. Sharkey, Jesus Romero Nápoles, José Antonio Sánchez García, Ana Mabel Martínez, Victor López-Martínez, Samuel Pineda

Entomology Faculty Publications

A key to species and descriptions are presented for 14 species of the New World genus Crassomicrodus Ashmead. Seven new species, Crassomicrodus azteca, Crassomicrodus clypealis, Crassomicrodus costaricensis, Crassomicrodus jalisciensis, Crassomicrodus mariae, Crassomicrodus oaxaquensis,and Crassomicrodus olgae are described. Crassomicrodus fenestratus (Viereck) is synonymized with Crassomicrodus nigriceps (Cresson). Crassomicrodus melanopleurus (Ashmead) is recognized as a valid species.