Life Sciences Commons^™

Transcriptome Analysis Of Host-Associated Differentiation In Bemisia Tabaci (Hemiptera: Aleyrodidae), Wen Xie, Qingjun Wu, Shaoli Wang, Xiaoguo Jiao, Litao Guo, Xuguo Zhou, Youjun Zhang

Entomology Faculty Publications

Host-associated differentiation is one of the driving forces behind the diversification of phytophagous insects. In this study, host induced transcriptomic differences were investigated in the sweetpotato whitefly Bemisia tabaci, an invasive agricultural pest worldwide. Comparative transcriptomic analyses using coding sequence (CDS), 5′ and 3′ untranslated regions (UTR) showed that sequence divergences between the original host plant, cabbage, and the derived hosts, including cotton, cucumber and tomato, were 0.11–0.14%, 0.19–0.26%, and 0.15–0.21%, respectively. In comparison to the derived hosts, 418 female and 303 male transcripts, respectively, were up-regulated in the original cabbage strain. Among them, 17 transcripts were consistently up-regulated …

Selection Of Reference Genes For Expression Analysis Using Quantitative Real-Time Pcr In The Pea Aphid, Acyrthosiphon Pisum (Harris) (Hemiptera, Aphidiae), Chunxiao Yang, Huipeng Pan, Yong Liu, Xuguo Zhou

Entomology Faculty Publications

To facilitate gene expression study and obtain accurate qRT-PCR analysis, normalization relative to stable expressed housekeeping genes is required. In this study, expression profiles of 11 candidate reference genes, including actin (Actin), elongation factor 1 α (EF1A), TATA-box-binding protein (TATA), ribosomal protein L12 (RPL12), β-tubulin (Tubulin), NADH dehydrogenase (NADH), vacuolar-type H+-ATPase (v-ATPase), succinate dehydrogenase B (SDHB), 28S ribosomal RNA (28S), 16S ribosomal RNA (16S), and 18S ribosomal RNA (18S) from the pea aphid Acyrthosiphon pisum, …

Novel Mutations And Mutation Combinations Of Ryanodine Receptor In A Chlorantraniliprole Resistant Population Of Plutella Xylostella (L.), Lei Guo, Pei Liang, Xuguo Zhou, Xiwu Gao

Entomology Faculty Publications

A previous study documented a glycine to glutamic acid mutation (G4946E) in ryanodine receptor (RyR) was highly correlated to diamide insecticide resistance in field populations of Plutella xylostella (Lepidoptera: Plutellidae). In this study, a field population collected in Yunnan province, China, exhibited a 2128-fold resistance to chlorantraniliprole. Sequence comparison between resistant and susceptible P. xylostella revealed three novel mutations including a glutamic acid to valine substitution (E1338D), a glutamine to leucine substitution (Q4594L) and an isoleucine to methionine substitution (I4790M) in highly conserved regions of RyR. Frequency analysis of all four mutations in this field population showed that the three …

Validation Of Reference Housekeeping Genes For Gene Expression Studies In Western Corn Rootworm (Diabrotica Virgifera Virgifera), Thaís Barros Rodrigues, Chitvan Khajuria, Haichuan Wang, Natalie Matz, Danielle Cunha Cardoso, Fernando Hercos Valicente, Xuguo Zhou, Blair Siegfried

Entomology Faculty Publications

Quantitative Real-time PCR (qRT-PCR) is a powerful technique to investigate comparative gene expression. In general, normalization of results using a highly stable housekeeping gene (HKG) as an internal control is recommended and necessary. However, there are several reports suggesting that regulation of some HKGs is affected by different conditions. The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), is a serious pest of corn in the United States and Europe. The expression profile of target genes related to insecticide exposure, resistance, and RNA interference has become an important experimental technique for study of western corn rootworms; however, lack …

Factors Limiting The Spread Of The Protective Symbiont Hamiltonella Defensa In Aphis Craccivora Aphids, Hannah R. Dykstra, Stephanie R. Weldon, Adam J. Martinez, Jennifer A. White, Keith R. Hopper, George E. Heimpel, Mark K. Asplen, Kerry M. Oliver

Entomology Faculty Publications

Many insects are associated with heritable symbionts that mediate ecological interactions, including host protection against natural enemies. The cowpea aphid, Aphis craccivora, is a polyphagous pest that harbors Hamiltonella defensa, which defends against parasitic wasps. Despite this protective benefit, this symbiont occurs only at intermediate frequencies in field populations. To identify factors constraining H. defensa invasion in Ap. craccivora, we estimated symbiont transmission rates, performed fitness assays, and measured infection dynamics in population cages to evaluate effects of infection. Similar to results with the pea aphid, Acyrthosiphon pisum, we found no consistent costs to infection using …

Molecular Xenomonitoring Using Mosquitoes To Map Lymphatic Filariasis After Mass Drug Administration In American Samoa, Mark A. Schmaedick, Amanda L. Koppel, Nils Pilotte, Melissa Torres, Steven A. Williams, Stephen L. Dobson, Patrick J. Lammie, Kimberly Y. Won

Entomology Faculty Publications

BACKGROUND: Mass drug administration (MDA) programs have dramatically reduced lymphatic filariasis (LF) incidence in many areas around the globe, including American Samoa. As infection rates decline and MDA programs end, efficient and sensitive methods for detecting infections are needed to monitor for recrudescence. Molecular methods, collectively termed 'molecular xenomonitoring,' can identify parasite DNA or RNA in human blood-feeding mosquitoes. We tested mosquitoes trapped throughout the inhabited islands of American Samoa to identify areas of possible continuing LF transmission after completion of MDA.

METHODOLOGY/PRINCIPLE FINDINGS: Mosquitoes were collected using BG Sentinel traps from most of the villages on American Samoa's largest …

Effects Of Plant Virus And Its Insect Vector On Encarsia Formosa, A Biocontrol Agent Of Whiteflies, Xiaoyuan Liu, Wensheng Xiang, Xiaoguo Jiao, Youjun Zhang, Wen Xie, Qingjun Wu, Xuguo Zhou, Shaoli Wang

Entomology Faculty Publications

In this study, we investigated the tritrophic interactions among a persistently transmitted plant virus, Tomato yellow leaf curl virus (TYLCV), its insect vector, the sweetpotato whitefly Bemisia tabaci, and a parasitoid, Encarsia formosa Gahan, one of the most extensively used biological control agents. As an emerging invasive pest worldwide, the two most damaging whiteflies are B. tabaci B and Q cryptic species. On healthy tomato plants, parasitoid-induced mortality was significantly higher in B. tabaci B than in Q. In contrast, similar mortality levels of B and Q were observed on TYLCV-infected plants. A higher rate of parasitism was consistently observed …

Biomechanical Properties Of Hemlocks: A Novel Approach To Evaluating Physical Barriers Of The Plant-Insect Interface And Resistance To A Phloem-Feeding Herbivore, Paul Ayayee, Fuqian Yang, Lynne K. Rieske

Entomology Faculty Publications

Micromechanical properties that help mediate herbivore access may be particularly important when considering herbivorous insects that feed with piercing-sucking stylets. We used microindentation to quantify the micromechanical properties of hemlock, Tsuga spp., to quantify the hardness of the feeding site of the invasive hemlock woolly adelgid, Adelges tsugae. We measured hardness of the hemlock leaf cushion, the stylet insertion point of the adelgid, across four seasons in a 1 y period for four hemlock species growing in a common garden, including eastern, western, mountain, and northern Japanese hemlocks. Leaf cushion hardness was highest in the fall and winter and …

Bemisia Tabaci Q Carrying Tomato Yellow Leaf Curl Virus Strongly Suppresses Host Plant Defenses, Xiaobin Shi, Huipeng Pan, Hongyi Zhang, Xiaoguo Jiao, Wen Xie, Qingjun Wu, Shaoli Wang, Yong Fang, Gong Chen, Xuguo Zhou, Youjun Zhang

Entomology Faculty Publications

The concurrence of tomato yellow leaf curl virus (TYLCV) with the spread of its vector Bemisia tabaci Q rather than B in China suggests a more mutualistic relationship between TYLCV and Q. Here, we investigated the hypothesis that viruliferous B and Q have different effects on plant defenses. We found the fecundity of nonviruliferous B, nonviruliferous Q, viruliferous Q and viruliferous B was 11.080, 12.060, 10.760, and 11.220 respectively on plants previously attacked by the other biotype, however, on their respective noninfested control leaves fecundity was 12.000, 10.880, 9.760, and 8.020 respectively. Only viruliferous B had higher fecundity on viruliferous …

The Soldiers In Societies: Defense, Regulation, And Evolution, Li Tian, Xuguo Zhou

Entomology Faculty Publications

The presence of reproductively altruistic castes is one of the primary traits of the eusocial societies. Adaptation and regulation of the sterile caste, to a certain extent, drives the evolution of eusociality. Depending on adaptive functions of the first evolved sterile caste, eusocial societies can be categorized into the worker-first and soldier-first lineages, respectively. The former is marked by a worker caste as the first evolved altruistic caste, whose primary function is housekeeping, and the latter is highlighted by a sterile soldier caste as the first evolved altruistic caste, whose task is predominantly colony defense. The apparent functional differences between …

Gene Expression Profiling In Winged And Wingless Cotton Aphids, Aphis Gossypii (Hemiptera: Aphididae), Xiaowei Yang, Xiaoxia Liu, Xiangli Xu, Zhen Li, Yisong Li, Dongyan Song, Tian Yu, Fang Zhu, Qingwen Zhang, Xuguo Zhou

Entomology Faculty Publications

While trade-offs between flight capability and reproduction is a common phenomenon in wing dimorphic insects, the molecular basis is largely unknown. In this study, we examined the transcriptomic differences between winged and wingless morphs of cotton aphids, Aphis gossypii, using a tag-based digital gene expression (DGE) approach. Ultra high-throughput Illumina sequencing generated 5.30 and 5.39 million raw tags, respectively, from winged and wingless A. gossypii DGE libraries. We identified 1,663 differentially expressed transcripts, among which 58 were highly expressed in the winged A. gossypii, whereas 1,605 expressed significantly higher in the wingless morphs. Bioinformatics tools, including Gene Ontology, …

Transcriptomic Dissection Of Sexual Differences In Bemisia Tabaci, An Invasive Agricultural Pest Worldwide, Wen Xie, Litao Guo, Xiaoguo Jiao, Nina Yang, Xin Yang, Qingjun Wu, Shaoli Wang, Xuguo Zhou, Youjun Zhang

Entomology Faculty Publications

Sex difference involving chromosomes and gene expression has been extensively documented. In this study, the gender difference in the sweetpotato whitefly Bemisia tabaci was investigated using Illumina-based transcriptomic analysis. Gender-based RNAseq data produced 27 Gb reads, and subsequent de novo assembly generated 93,948 transcripts with a N50 of 1,853 bp. A total of 1,351 differentially expressed genes were identified between male and female B. tabaci, and majority of them were female-biased. Pathway and GO enrichment experiments exhibited a gender-specific expression, including enriched translation in females, and enhanced structural constituent of cuticle in male whiteflies. In addition, a putative transformer2 …

Revision Of The Genus Euagathis Szépligeti (Hymenoptera, Braconidae, Agathidinae) From Thailand, With Description Of Three New Species, Cornelis Van Achterberg, Michael J. Sharkey, Eric G. Chapman

Entomology Faculty Publications

The species of the genus Euagathis Szépligeti (Hymenoptera, Braconidae, Agathidinae) from Thailand are revised. Eight species are treated, three new species are described, i.e. Euagathis breviantennata sp.n., E. setosimaculata sp. n. and E. pallitarsis sp. n. Disophrys sogdiana Fahringer, 1937, D. chinensis Fahringer, 1937, and Euagathis sentosus Chen & Yang, 1995, are new junior synonyms of Euagathis chinensis (Holm‑gren, 1868). Euagathis guangxiensis (Chen & Yang, 2006) is a new combination. Lectotypes are designated for Disophrys sogdiana Fahringer, 1937, and D. chinensis Fahringer, 1937. A dichotomous illustrated key to species is presented; links to electronic interactive keys and to distribution …

Expression Profiling In Bemisia Tabaci Under Insecticide Treatment: Indicating The Necessity For Custom Reference Gene Selection, Pei Liang, Yajie Guo, Xuguo Zhou, Xiwu Gao

Entomology Faculty Publications

Finding a suitable reference gene is the key for qRT-PCR analysis. However, none of the reference gene discovered thus far can be utilized universally under various biotic and abiotic experimental conditions. In this study, we further examine the stability of candidate reference genes under a single abiotic factor, insecticide treatment. After being exposed to eight commercially available insecticides, which belong to five different classes, the expression profiles of eight housekeeping genes in the sweetpotato whitefly, Bemisia tabaci, one of the most invasive and destructive pests in the world, were investigated using qRT-PCR analysis. In summary, elongation factor 1α …

Population Variation In And Selection For Resistance To Pyrethroid-Neonicotinoid Insecticides In The Bed Bug, Jennifer R. Gordon, Mark H. Goodman, Michael F. Potter, Kenneth F. Haynes

Entomology Faculty Publications

Pyrethroid resistance in bed bugs, Cimex lectularius, has prompted a change to combination products that include a pyrethroid and a neonicotinoid. Ten populations of bed bugs were challenged with two combination products (Temprid SC and Transport GHP). Susceptibility of these populations varied, with the correlated response of the two products indicating cross resistance. We imposed selection on three populations using label rate Temprid, and then reared progeny from unselected and selected strains. All selected strains were significantly less susceptible to Temprid SC than unselected strains. Temprid selected strains were also less susceptible to Transport. The pyrethroid component of Temprid showed …

Assessing And Mitigating Lawn Insecticide Hazards To Bees And Other Beneficial Invertebrates, Jonathan Lane Larson

Theses and Dissertations--Entomology

Turfgrass settings, including lawns, golf courses, and sports fields, support many beneficial invertebrates that provide important ecosystem services. These non-target organisms and their associated predation, decomposition, and pollination services can be disrupted by the use of certain insecticides. I compared the ecotoxicity of representatives from three major turf insecticide groups, the neonicotinoids, premix formulations, and the anthranilic diamides, in lab and field realistic settings in order to inform industry initiatives towards environmental sustainability.

In lab and field bioassays clothianidin, a neonicotinoid, and a premix clothianidin/pyrethroid spray were acutely toxic to beneficial insects. Populations of predators, springtails, and earthworms, as well …

Changing Litter Resources Associated With Hemlock Woolly Adelgid Invasion Affect Benthic Communities In Headwater Streams, Christopher J. Strohm

Theses and Dissertations--Entomology

Hemlock woolly adelgid is an invasive herbivore causing extensive mortality of eastern hemlock, an important foundation species that provides stable conditions influencing biological communities. Hemlock is often found in riparian areas and following its decline, broadleaved species, including birch, beech, and rhododendron, will replace it. These plants differ from hemlock in patterns of canopy cover and leaf properties, which influence conditions and resources within streams.

My goal was to evaluate potential impacts of adelgid-induced alterations to riparian canopies and litter on benthic communities and litter breakdown in streams. I characterized benthic invertebrate communities, litter colonization and litter breakdown in streams …

The Role Of The Bacterial Endosymbiont, Arsenophonus, In The Soybean Aphid, Aphis Glycines, Jason A. Wulff

Theses and Dissertations--Entomology

Bacterial endosymbionts can have profound impacts on their host’s ecology. Notably, endosymbionts can protect their hosts against natural enemies and influence host plant interactions. The endosymbiont Candidatus Arsenophonus infects a wide taxonomic range of arthropod hosts, and is suspected of an uncharacterized mutualistic role in hemipterous insects. In the soybean aphid, Aphis glycines, an introduced pest of soybeans in the United States, Arsenophonus is the sole facultative endosymbiont. The focus of this dissertation is to characterize the role of Arsenophonus in the aphid, with an overall emphasis on its impact on aphid management strategies.

I first used diagnostic PCR …

Computational Identification And Molecular Verification Of Mirna In Eastern Subterranean Termites (Reticulitermes Flavipes), Tian Yu

Theses and Dissertations--Entomology

Reticulitermes flavipes is one of the most common termite species in the world, and has been an intriguing research model due to its ecological and biological and economic significance. The fundamental biological question addressed by this study is to elucidate the role of miRNAs in termite development and how miRNA can influence labor division. miRNAs are short non-coding RNAs that have an important role in gene regulation at post-transcriptional level, and can potentially be involved in the regulation of caste polyphenism. Using a computational approach, I identified 167 conserved and 33 novel miRNAs in the dataset. miR-iab-4 and 19 other …

Insecticide Resistance In The Bed Bug, Jennifer R. Gordon

Theses and Dissertations--Entomology

Populations of Cimex lectularius, the bed bug, have resurged around the world posing significant challenges for pest management professionals and causing physical, economic, and emotional strife. Pyrethroid resistance has been found in the vast majority of populations making pest management more difficult. The objectives of my dissertation research were to document the evolution of resistance to pyrethroid and neonicotinoid combination products (called combination products here) and to a neonicotinoid in the laboratory, to record potential fitness costs to resistance to the combination products, and to compare the efficacy of nine insecticides on six populations. In the laboratory, populations of …

Characterizing The Maternally Inherited Endosymbionts Of Solitary Bees, Abiya Saeed

Theses and Dissertations--Entomology

Solitary bees are important pollinators of crops, with species in the family Megachilidae (mason bees) being used for orchard pollination. Commercial movement of these bees also moves their microbiota, including bacterial endosymbionts capable of reproductive manipulation. To test for presence of these bacteria, I screened commercially available species of US orchard pollinators and locally captured solitary bees from Kentucky. I also set up mason bee boxes in five apple orchards to examine recruitment of local pollinators. I conducted 454-pyrosequencing to determine bacterial diversity within four species followed by diagnostic PCR of 30 collected species (184 individuals) to determine infection frequency …

Exploring The Links Between Seasonal Variation And Spider Foraging, Thomas Edward Dantas Whitney

Theses and Dissertations--Entomology

According to optimal foraging theory, generalist predators, such as spiders, are thought to feed indiscriminately on prey according to its availability, especially when food is scarce. In contrast, generalists can display selective feeding decisions under regimes of high prey abundance, but few studies have tracked changes in prey choice on a seasonal basis under open field conditions. Additionally, adaptations to surviving winter have been largely ignored in the research of foraging behavior. To elucidate this, I monitored prey availability and collected common forest-dwelling wolf spiders for molecular gut-content analysis, in parallel for 18 months, to assess the temporal changes occurring …

Grassland Sustainability In Kentucky: Case Studies Quantifying The Effects Of Climate Change On Slug Herbivory In Pastures And Different Home Lawn Systems On Turf Greenhouse Gas Emissions, Daniel Adam Weber

Theses and Dissertations--Plant and Soil Sciences

Grasslands comprise the greatest biome by land area, are sensitive to environmental factors affected by climate change, and can impact future climate change through their ability to store and release greenhouse gasses (GHGs). I performed two studies: 1) evaluated the effects of increased temperature and precipitation on slug herbivory/abundance and pasture forage production; 2) quantified different homeowner lawn system effects on soil-to-atmosphere GHG emissions. Climate change will likely affect pasture forage production, with implications for slug herbivory and abundance. I found little evidence that slugs have or will have significant effects on pasture production or plant community. Warming altered the …