Life Sciences Commons^™

Molecular Gut Content Analysis Of Different Spider Body Parts, Nuria Macías-Hernández, Kacie J. Athey, Vanina Tonzo, Owen S. Wangensteen, Miquel Arnedo, James D Harwood

Entomology Faculty Publications

Molecular gut-content analysis has revolutionized the study of food webs and feeding interactions, allowing the detection of prey DNA within the gut of many organisms. However, successful prey detection is a challenging procedure in which many factors affect every step, starting from the DNA extraction process. Spiders are liquid feeders with branched gut diverticula extending into their legs and throughout the prosoma, thus digestion takes places in different parts of the body and simple gut dissection is not possible. In this study, we investigated differences in prey detectability in DNA extracts from different parts of the spider´s body: legs, prosoma …

Impact Of Sublethal Exposure To A Pyrethroid-Neonicotinoid Insecticide On Mating, Fecundity And Development In The Bed Bug Cimex Lectularius L. (Hemiptera: Cimicidae), Sydney E. Crawley, Jennifer R. Gordon, Katelyn A. Kowles, Michael F. Potter, Kenneth F. Haynes

Entomology Faculty Publications

Sublethal exposure to an insecticide may alter insect feeding, mating, oviposition, fecundity, development, and many other life history parameters. Such effects may have population-level consequences that are not apparent in traditional dose-mortality evaluations. Earlier, we found that a routinely used combination insecticide that includes a pyrethroid and a neonicotinoid (Temprid^® SC) had deleterious effects on multiple bed bug (Cimex lectularius, L.) behaviors. Here, we demonstrate that sublethal exposure impacts physiology and reproduction as well. We report that sublethal exposure to Temprid SC has variable aberrant effects on bed bugs depending on the strain, including: a reduction in …

Genome Sequencing Of The Sweetpotato Whitefly Bemisia Tabaci Med/Q, Wen Xie, Chunhai Chen, Zezhong Yang, Litao Guo, Xin Yang, Dan Wang, Ming Chen, Jinqun Huang, Yanan Wen, Yang Zeng, Yating Liu, Jixing Xia, Lixia Tian, Hongying Cui, Qingjun Wu, Shaoli Wang, Baoyun Xu, Xianchun Li, Xinqiu Tan, Murad Ghanim, Baoli Qiu, Huipeng Pan, Dong Chu, Helene Delatte, M. N. Maruthi, Feng Ge, Xueping Zhou, Xiaowei Wang, Fanghao Wan, Yuzhou Du, Xuguo Joe Zhou

Entomology Faculty Publications

The sweetpotato whitefly Bemisia tabaci is a highly destructive agricultural and ornamental crop pest. It damages host plants through both phloem feeding and vectoring plant pathogens. Introductions of B. tabaci are difficult to quarantine and eradicate because of its high reproductive rates, broad host plant range, and insecticide resistance. A total of 791 Gb of raw DNA sequence from whole genome shotgun sequencing, and 13 BAC pooling libraries were generated by Illumina sequencing using different combinations of mate-pair and pair-end libraries. Assembly gave a final genome with a scaffold N50 of 437 kb, and a total length of 658 Mb. …

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 …

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 …

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 …

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 …

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 …

Wolbachia Infections That Reduce Immature Insect Survival: Predicted Impacts On Population Replacement, Philip R. Crain, James W. Mains, Eunho Suh, Yunxin Huang, Philip H. Crowley, Stephen L. Dobson

Entomology Faculty Publications

BACKGROUND: The evolutionary success of Wolbachia bacteria, infections of which are widespread in invertebrates, is largely attributed to an ability to manipulate host reproduction without imposing substantial fitness costs. Here, we describe a stage-structured model with deterministic immature lifestages and a stochastic adult female lifestage. Simulations were conducted to better understand Wolbachia invasions into uninfected host populations. The model includes conventional Wolbachia parameters (the level of cytoplasmic incompatibility, maternal inheritance, the relative fecundity of infected females, and the initial Wolbachia infection frequency) and a new parameter termed relative larval viability (RLV), which is the survival of infected larvae relative to …

Male Mating Competitiveness Of A Wolbachia-Introgressed Aedes Polynesiensis Strain Under Semi-Field Conditions, Eric W. Chambers, Limb Hapairai, Bethany A. Peel, Hervé Bossin, Stephen L. Dobson

Entomology Faculty Publications

BACKGROUND: Lymphatic filariasis (LF), a global public health problem affecting approximately 120 million people worldwide, is a leading cause of disability in the developing world including the South Pacific. Despite decades of ongoing mass drug administration (MDA) in the region, some island nations have not yet achieved the threshold levels of microfilaremia established by the World Health Organization for eliminating transmission. Previously, the generation of a novel Aedes polynesiensis strain (CP) infected with an exogenous type of Wolbachia has been described. The CP mosquito is cytoplasmically incompatible (i.e., effectively sterile) when mated with wildtype mosquitoes, and a strategy was proposed …

Molecular Evidence For A Functional Ecdysone Signaling System In Brugia Malayi, George Tzertzinis, Ana L. Egaña, Subba Reddy Palli, Marc Robinson-Rechavi, Chris R. Gissendanner, Canhui Liu, Thomas R. Unnasch, Claude V. Maina

Entomology Faculty Publications

BACKGROUND: Filarial nematodes, including Brugia malayi, the causative agent of lymphatic filariasis, undergo molting in both arthropod and mammalian hosts to complete their life cycles. An understanding of how these parasites cross developmental checkpoints may reveal potential targets for intervention. Pharmacological evidence suggests that ecdysteroids play a role in parasitic nematode molting and fertility although their specific function remains unknown. In insects, ecdysone triggers molting through the activation of the ecdysone receptor: a heterodimer of EcR (ecdysone receptor) and USP (Ultraspiracle).

METHODS AND FINDINGS: We report the cloning and characterization of a B. malayi EcR homologue (Bma-EcR). Bma-EcR dimerizes with …

Co-Up-Regulation Of Three P450 Genes In Response To Permethrin Exposure In Permethrin Resistant House Flies, Musca Domestica, Fang Zhu, Ting Li, Lee Zhang, Nannan Liu

Entomology Faculty Publications

BACKGROUND: Insects may use various biochemical pathways to enable them to tolerate the lethal action of insecticides. For example, increased cytochrome P450 detoxification is known to play an important role in many insect species. Both constitutively increased expression (overexpression) and induction of P450s are thought to be responsible for increased levels of detoxification of insecticides. However, unlike constitutively overexpressed P450 genes, whose expression association with insecticide resistance has been extensively studied, the induction of P450s is less well characterized in insecticide resistance. The current study focuses on the characterization of individual P450 genes that are induced in response to permethrin …

Interspecific Hybridization Yields Strategy For South Pacific Filariasis Vector Elimination, Corey L. Brelsfoard, Yves Séchan, Stephen L. Dobson

Entomology Faculty Publications

BACKGROUND: Lymphatic filariasis (LF) is a leading cause of disability in South Pacific regions, where >96% of the 1.7 million population are at risk of LF infection. As part of current global campaign, mass drug administration (MDA) has effectively reduced lymphatic filiariasis prevalence, but mosquito vector biology can complicate the MDA strategy. In some regions, there is evidence that the goal of LF elimination cannot be attained via MDA alone. Obligate vector mosquitoes provide additional targets for breaking the LF transmission cycle, but existing methods are ineffective for controlling the primary vector throughout much of the South Pacific, Aedes polynesiensis. …

Genome-Wide Analysis Of The Interaction Between The Endosymbiotic Bacterium Wolbachia And Its Drosophila Host, Zhiyong Xi, Laurent Gavotte, Yan Xie, Stephen L. Dobson

Entomology Faculty Publications

BACKGROUND: Intracellular Wolbachia bacteria are obligate, maternally-inherited, endosymbionts found frequently in insects and other invertebrates. The success of Wolbachia can be attributed in part to an ability to alter host reproduction via mechanisms including cytoplasmic incompatibility (CI), parthenogenesis, feminization and male killing. Despite substantial scientific effort, the molecular mechanisms underlying the Wolbachia/host interaction are unknown.

RESULTS: Here, an in vitro Wolbachia infection was generated in the Drosophila S2 cell line, and transcription profiles of infected and uninfected cells were compared by microarray. Differentially-expressed patterns related to reproduction, immune response and heat stress response are observed, including multiple genes that have …