Life Sciences Commons^™

Molecular Cloning And Characterization Of A P-Glycoprotein From The Diamondback Moth, Plutella Xylostella (Lepidoptera: Plutellidae), Lixia Tian, Jiaqiang Yang, Wenjie Hou, Baoyun Xu, Wen Xie, Shaoli Wang, Youjun Zhang, Xuguo Zhou, Qingjun Wu

Entomology Faculty Publications

Macrocyclic lactones such as abamectin and ivermectin constitute an important class of broad-spectrum insecticides. Widespread resistance to synthetic insecticides, including abamectin and ivermectin, poses a serious threat to the management of diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), a major pest of cruciferous plants worldwide. P-glycoprotein (Pgp), a member of the ABC transporter superfamily, plays a crucial role in the removal of amphiphilic xenobiotics, suggesting a mechanism for drug resistance in target organisms. In this study, PxPgp1, a putative Pgp gene from P. xylostella, was cloned and characterized. The open reading frame (ORF) of PxPgp1 consists of 3774 …

Identification And Developmental Profiling Of Micrornas In Diamondback Moth, Plutellaxylostella (L.), Pei Liang, Bing Feng, Xuguo Zhou, Xiwu Gao

Entomology Faculty Publications

MicroRNAs (miRNAs) are a group of small RNAs involved in various biological processes through negative regulation of mRNAs at the post-transcriptional level. Although miRNA profiles have been documented in over two dozen insect species, few are agricultural pests. In this study, both conserved and novel miRNAs in the diamondback moth, Plutella xylostella L., a devastating insect pest of cruciferous crops worldwide, were documented. High-throughput sequencing of a small RNA library constructed from a mixed life stages of P. xylostella, including eggs, 1st to 4th (last) instar larvae, pupae and adults, identified 384 miRNAs, of which 174 were P. xylostella specific. …

The Hymenopteran Tree Of Life: Evidence From Protein-Coding Genes And Objectively Aligned Ribosomal Data, Seraina Klopfstein, Lars Vilhelmsen, John M. Heraty, Michael J. Sharkey, Fredrik Ronquist

Entomology Faculty Publications

Previous molecular analyses of higher hymenopteran relationships have largely been based on subjectively aligned ribosomal sequences (18S and 28S). Here, we reanalyze the 18S and 28S data (unaligned about 4.4 kb) using an objective and a semi-objective alignment approach, based on MAFFT and BAli-Phy, respectively. Furthermore, we present the first analyses of a substantial protein-coding data set (4.6 kb from one mitochondrial and four nuclear genes). Our results indicate that previous studies may have suffered from inflated support values due to subjective alignment of the ribosomal sequences, but apparently not from significant biases. The protein data provide independent confirmation of …

Exploring Valid Reference Genes For Quantitative Real-Time Pcr Analysis In Plutella Xylostella (Lepidoptera: Plutellidae), Wei Fu, Wen Xie, Zhuo Zhang, Shaoli Wang, Qingjun Wu, Yong Liu, Xiaomao Zhou, Xuguo Zhou, Youjun Zhang

Entomology Faculty Publications

Quantitative real-time PCR (qRT-PCR), a primary tool in gene expression analysis, requires an appropriate normalization strategy to control for variation among samples. The best option is to compare the mRNA level of a target gene with that of reference gene(s) whose expression level is stable across various experimental conditions. In this study, expression profiles of eight candidate reference genes from the diamondback moth, Plutella xylostella, were evaluated under diverse experimental conditions. RefFinder, a web-based analysis tool, integrates four major computational programs including geNorm, Normfinder, BestKeeper, and the comparative ΔCt method to comprehensively rank the tested candidate …

Assessing Insecticide Hazard To Bumble Bees Foraging On Flowering Weeds In Treated Lawns, Jonathan L. Larson, Carl T. Redmond, Daniel A. Potter

Entomology Faculty Publications

Maintaining bee-friendly habitats in cities and suburbs can help conserve the vital pollination services of declining bee populations. Despite label precautions not to apply them to blooming plants, neonicotinoids and other residual systemic insecticides may be applied for preventive control of lawn insect pests when spring-flowering weeds are present. Dietary exposure to neonicotinoids adversely affects bees, but the extent of hazard from field usage is controversial. We exposed colonies of the bumble bee Bombus impatiens to turf with blooming white clover that had been treated with clothianidin, a neonicotinoid, or with chlorantraniliprole, the first anthranilic diamide labeled for use on …

Juvenile Hormone And Insulin Regulate Trehalose Homeostasis In The Red Flour Beetle, Tribolium Castaneum, Jingjing Xu, Zhentao Sheng, Subba R. Palli

Entomology Faculty Publications

Insulin/IGF-1 signaling (IIS) has been well studied for its role in the control of life span extension and resistance to a variety of stresses. The Drosophila melanogaster insulin-like receptor (InR) mutant showed extended life span due to reduced juvenile hormone (JH) levels. However, little is known about the mechanism of cross talk between IIS and JH in regulation of life span extension and resistance to starvation. In the current study, we investigated the role of IIS and JH signaling in regulation of resistance to starvation. Reduction in JH biosynthesis, JH action, or insulin-like peptide 2 (ILP2) syntheses by RNA interference …

Transcriptomic And Proteomic Responses Of Sweetpotato Whitefly, Bemisia Tabaci, To Thiamethoxam, Nina Yang, Wen Xie, Xin Yang, Shaoli Wang, Qingjun Wu, Rumei Li, Huipeng Pan, Baiming Liu, Xiaobin Shi, Yong Fang, Baoyun Xu, Xuguo Zhou, Youjun Zhang

Entomology Faculty Publications

BACKGROUND: The sweetpotato whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae), is one of the most widely distributed agricultural pests. Although it has developed resistance to many registered insecticides including the neonicotinoid insecticide thiamethoxam, the mechanisms that regulate the resistance are poorly understood. To understand the molecular basis of thiamethoxam resistance, "omics" analyses were carried out to examine differences between resistant and susceptible B. tabaci at both transcriptional and translational levels.

RESULTS: A total of 1,338 mRNAs and 52 proteins were differentially expressed between resistant and susceptible B. tabaci. Among them, 11 transcripts had concurrent transcription and translation profiles. KEGG analysis mapped 318 …

Mitochondrial Genomes Of Two Barklice, Psococerastis Albimaculata And Longivalvus Hyalospilus (Psocoptera: Psocomorpha): Contrasting Rates In Mitochondrial Gene Rearrangement Between Major Lineages Of Psocodea, Hu Li, Renfu Shao, Fan Song, Xuguo Zhou, Qianqian Yang, Zhihong Li, Wanzhi Cai

Entomology Faculty Publications

The superorder Psocodea has ∼10,000 described species in two orders: Psocoptera (barklice and booklice) and Phthiraptera (parasitic lice). One booklouse, Liposcelis bostrychophila and six species of parasitic lice have been sequenced for complete mitochondrial (mt) genomes; these seven species have the most rearranged mt genomes seen in insects. The mt genome of a barklouse, lepidopsocid sp., has also been sequenced and is much less rearranged than those of the booklouse and the parasitic lice. To further understand mt gene rearrangements in the Psocodea, we sequenced the mt genomes of two barklice, Psococerastis albimaculata and Longivalvus hyalospilus, the first representatives from …

Differential Undertaking Response Of A Lower Termite To Congeneric And Conspecific Corpses, Qian Sun, Kenneth F. Haynes, Xuguo Zhou

Entomology Faculty Publications

Undertaking behaviour is an essential activity in social insects. Corpses are often recognized by a postmortem change in a chemical signature. Reticulitermes flavipes responded to corpses within minutes of death. This undertaking behaviour did not change with longer postmortem time (24 h); however, R. flavipes exhibited distinctively different behaviours toward dead termites from various origins. Corpses of the congeneric species, Reticulitermes virginicus, were buried onsite by workers with a large group of soldiers guarding the burial site due to the risk of interspecific competition; while dead conspecifics, regardless of colony origin, were pulled back into the holding chamber for nutrient …

The Endosymbiont Arsenophonus Is Widespread In Soybean Aphid, Aphis Glycines, But Does Not Provide Protection From Parasitoids Or A Fungal Pathogen, Jason A. Wulff, Karrie A. Buckman, Kongming Wu, George E. Heimpel, Jennifer A. White

Entomology Faculty Publications

Aphids commonly harbor bacterial facultative symbionts that have a variety of effects upon their aphid hosts, including defense against hymenopteran parasitoids and fungal pathogens. The soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is infected with the symbiont Arsenophonus sp., which has an unknown role in its aphid host. Our research goals were to document the infection frequency and diversity of the symbiont in field-collected soybean aphids, and to determine whether Arsenophonus is defending soybean aphid against natural enemies. We performed diagnostic PCR and sequenced four Arsenophonus genes in soybean aphids from their native and introduced range to estimate infection frequency …

Corpse Management In Social Insects, Qian Sun, Xuguo Zhou

Entomology Faculty Publications

Undertaking behavior is an essential adaptation to social life that is critical for colony hygiene in enclosed nests. Social insects dispose of dead individuals in various fashions to prevent further contact between corpses and living members in a colony. Focusing on three groups of eusocial insects (bees, ants, and termites) in two phylogenetically distant orders (Hymenoptera and Isoptera), we review mechanisms of death recognition, convergent and divergent behavioral responses toward dead individuals, and undertaking task allocation from the perspective of division of labor. Distinctly different solutions (e.g., corpse removal, burial and cannibalism) have evolved, independently, in the holometabolous hymenopterans and …

Bed Bugs Evolved Unique Adaptive Strategy To Resist Pyrethroid Insecticides, Fang Zhu, Hemant Gujar, Jennifer R. Gordon, Kenneth F. Haynes, Michael F. Potter, Subba R. Palli

Entomology Faculty Publications

Recent advances in genomic and post-genomic technologies have facilitated a genome-wide analysis of the insecticide resistance-associated genes in insects. Through bed bug, Cimex lectularius transcriptome analysis, we identified 14 molecular markers associated with pyrethroid resistance. Our studies revealed that most of the resistance-associated genes functioning in diverse mechanisms are expressed in the epidermal layer of the integument, which could prevent or slow down the toxin from reaching the target sites on nerve cells, where an additional layer of resistance (kdr) is possible. This strategy evolved in bed bugs is based on their unique morphological, physiological and behavioral characteristics …

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 …

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 …

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 …

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 …

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 …