Morphological Characterization and Molecular Mediated Genetic Variation of Thief Ants (Hymenoptera: Formicidae)

The morphological characterization and molecular genetic variation were determined in populations of thief ants, Solenopsis molesta (Say). The genetic variations were elucidated using mitochondrial deoxyribonucleic acid (mDNA) sequences of cytochrome oxidase I. DNA from thief ants was extracted with Qiagen’s Gentra PUREGENE® DNA Isolation Kit using their solid tissue protocol. Polymerase chain reactions (PCR) were run on the extracted DNA using primers Lep-F1 (forward) and Lep-R1 (reverse). The DNA products were concentrated and purified by Microcon Centrifugal Filter Unit YM-100. Purified DNA samples were sequenced at the University of Arkansas Medical Sciences (UAMS) DNA Sequencing Core Facility. The sequences were edited and aligned using Codon Code Aligner. The contigs wee uploaded to www.Phylogeny.fr and phylogenetic trees were produced (Neighbor joining, Maximum likelihood and Bayesian). The trees displayed variation in genetic makeup of the thief ants from various geographic regions and genetic variation corresponded to the morphologic identification. The thief ants collected from different states were separated into three groups. Ants collected from New York, Indiana and one location in Nebraska formed one group identified as S. molesta validiuscula, a second group formed with ants from Louisiana identified as S. carolinensis and the third group consisted of ants from South Dakota, Washington, New Jersey Tennessee, Kansas and two other locations in Nebraska identified as S. molesta molesta

Knockdown of the Chromatin Remodeling Gene \u3ci\u3eBrahma\u3c/i\u3e by RNA Interference Reduces Reproductive Fitness and Lifespan in Common Bed Bug (Hemiptera: Cimicidae)

The common bed bug, Cimex lectularius L. (Hemiptera: Cimicidae) is a nuisance household pest causing significant medical and economic impacts. RNA interference (RNAi) of genes that are involved in vital physiological processes can serve as potential RNAi targets for insect control. Brahma is an ATPase subunit of a chromatin-remodeling complex involved in transcription of several genes for cellular processes, most importantly the homeotic genes. In this study, we used a microinjection technique to deliver double stranded RNA into female bed bugs. Delivery of 0.05 and 0.5 μg/insect of brahma dsRNA directly into hemocele resulted substantial reduction in oviposition. Eggs laid by bed bugs receiving both doses of brahma dsRNA exhibited significantly lower hatching percentage as compared to controls. In addition, brahma RNAi in female bed bugs caused significant mortality. Our results disclosed the potential of brahma RNAi to suppress bed bug population through injection of specific dsRNA, suggesting a critical function of this gene in bed bugs’ reproduction and survival. Based on our data, brahma can be a promising RNAi target for suppression of bed bug population

RNA Interference of the Muscle \u3ci\u3eActin\u3c/i\u3e Gene in Bed Bugs: Exploring Injection Versus Topical Application for dsRNA Delivery

Bed bugs are one the most troublesome household pests that feed primarily on human blood. RNA interference (RNAi) is currently being pursued as a potential tool for insect population management and has shown efficacy against some phytophagous insects. We evaluated the different techniques to deliver dsRNA specific to bed bug muscle actin (dsactin) into bed bugs. Initially, stability of dsRNA in human blood was studied to evaluate the feasibility of feeding method. Adult bed bugs were injected with dsRNA between last thoracic segment and first abdominal segment on the ventral side, with a dose of 0.2 μg dsactin per insect. In addition to injection, dsactin was mixed in acetone and treated topically in the abdomens of fifth stage nymphs. We found the quick degradation of dsRNA in blood. Injection of dsactin caused significant depletion of actin transcripts and substantial reduction in oviposition and lethality in female adults. Topically treated dsRNA in fifth stage nymphs had no effect on actin mRNA expression and survival. Our results demonstrated that injection is a reliable method of dsRNA delivery into bed bugs while topical treatment was not successful. This research provides an understanding on effective delivery methods of dsRNA into bed bugs for functional genomics research and feasibility of the RNAi based molecules for pest management purposes

RNAi-Mediated Knockdown of \u3ci\u3evATPase\u3c/i\u3e Subunits Affects Survival and Reproduction of Bed Bugs (Hemiptera: Cimicidae)

The common bed bug, Cimex lectularius L. (Hemiptera: Cimicidae) has resurged as one of the most troublesome household pests affecting people across the globe. Bed bug infestations have increased in recent years primarily due to the evolution of insecticide resistance and the insect’s ability to hitchhike with travelers. vATPases are one of the most evolutionarily conserved holoenzymes in eukaryotes, which are mainly involved in proton transport across the plasma membranes and intracellu­lar organelles. RNA interference (RNAi) has been developed as a promising tool for insect control. In this study, we used RNAi as an approach to knock down subunits A and E of the vATPase gene of bed bugs. Delivery of 0.2 μg/insect of dsRNA spe­cific to vATPase-A and vATPase-E into female bed bugs dramatically impaired the laying and viability of eggs over time. Injection of the vATPase-E dsRNA decreased survival of the bed bugs over 30 d. Our results also showed that the knockdown of mRNA is highly effective and persistent up to 30 d post injection. This research demonstrated that silencing of the two vATPase subunits A and E offers a potential strategy to suppress bed bug populations

Advances in Molecular Research on Bed Bugs (Hemiptera: Cimicidae)

With the resurgence and increase in infestations of the common bed bug, Cimex lectularius L. (Hemiptera: Cimicidae), across the world, there has been renewed interest in molecular research on this pest. In this paper, we present current information on the biology, medical importance, management practices, behavior and physiology, and molecular research conducted on bed bugs. The majority of molecular studies are focused towards understanding the molecular mechanism of insecticide resistance. Bed bugs are hematophagous insects with no prior record of vectoring any disease organisms. An improved understanding of how bed bugs lack vector competency may provide information to prevent disease transmission in other hematophagous insects. The genome of bed bugs has been sequenced, and genomic studies may provide a better understanding of bed bug behavior that might be utilized in developing effective management strategies. Recently, with the advancement of RNA interference (RNAi) as a tool to suppress insects, a few RNAi studies have been conducted in bed bugs. RNAi in bed bugs shows potential to suppress populations in laboratory conditions. However, delivery of double-stranded RNA (dsRNA) into bed bugs under field condition requires extensive research

Distribution and Inhibition of Esterases in Various Body Tissues of Susceptible and Resistant German Cockroaches (Dictyoptera: Blattellidae)

The distribution and inhibition of esterase activity among body of the resistant Crawford and susceptible CSMA strains of male German cockroach, Blattella germanica (L.), were evaluated with α- and β-naphthyl esters using a spectrophotometric assay and native polyacrylamide gel electrophoresis. The esterase activities in the Crawford strain were significantly higher than in the CSMA strain in most tissues except midgut and male genitalia, where the activities were similar. In both strains, isozyme a was dominant in the brain and fat body and isozymes c and d were more abundant in the midgut; but in addition to isozyme a, isozyme b was observed only in the Crawford strain. The α-naphthyl butyrate (α-NB) and β-naphthyl acetate (β-NA) esterase activities in the brain of both strains were completely inhibited by most inhibitors (DEF, 3,4-dichloroisocoumarine, paraoxon, pepstatin A, and propoxur). However, in the midgut tissue and contents, the activities and inhibition patterns of the α-NB and β-NA esterase were apparently different from the brain and between strains.The complete inhibition by paraoxon was observed regardless of the strain, substrate type, and body part for enzyme source. In esterase inhibition on native PAGE gels, paraoxon completely inhibited the activity of most esterases similar to the results from spectrophotometric assay. In addition, the esterase b was observed from the whole body homogenates of several German cockroach resistant strains on native PAGE analysis

Differential Gene Expression Profiling in Bed Bug (Cimex Lectularius L.) Fed on Ibuprofen and Caffeine in Reconstituted Human Blood

The recent resurgence of the common bed bug (Cimex lectularius L.) infestations worldwide has created a need for renewed research on biology, behavior, population genetics and management practices. Humans serve as exclusive hosts to bed bugs in urban environments. Since a majority of humans consume Ibuprofen (as pain medication) and caffeine (in coffee and other soft drinks) so bug bugs subsequently acquire Ibuprofen and caffeine through blood feeding. However, the effect of these chemicals at genetic level in bed bug is unknown. Therefore, this research was conducted to determine differential gene expression in bed bugs using RNA-Seq analysis at dosages of 200 ppm Ibuprofen and 40 ppm caffeine incorporated into reconstituted human blood and compared against the control. Total RNA was extracted from a single bed bug per replication per treatment and sequenced. Read counts obtained were analyzed using Bioconductor software programs to identify differentially expressed genes, which were then searched against the non-redundant (nr) protein database of National Center for Biotechnology Information (NCBI). Data on comparison of differentially expressed genes between control and Ibuprofen treatments revealed that 659 genes were significantly differentially regulated and 95% of them returned BLAST hits. Heat stress proteins were among the top significantly differentially down regulated genes. Comparison of the control vs caffeine treatments revealed that 2,161 genes were significantly differently regulated (Pad

NF96-269 Chiggers

This NebFact has information on chiggers

Efficacy of Transport Mikron Against Nuisance Ants When Applied Around Structures, 2015

Ants are nuisance pests around the homes and other structures. Insecticide baits and sprays are commonly used for controlling ants. The research was conducted to determine efficacy of Transport Mikron and Temprid SC against these nuisance ants. The trial was conducted around two buildings on East Campus, University of Nebraska-Lincoln, Lincoln, NE. A total of 20 experimental plots were established with 3 ft buffer zone between individual plots. The dimension of each experimental plot consists of 20 ft lengthx10 ft width + 3 ft high on foundation wall (260 ft2). Each treatment was replicated four times yielding 1040 ft2. Four plots were randomly assigned to one of the five treatments. The experimental design was a completely randomized design (CRD). Pretreatment ant population was monitored by placing four ant baittube traps made of cylindrical plastic tube (17x100mm (VWR, Chicago, IL)) in each experimental unit on 20 Aug. Peanut butter (0.5 inch diam) on paper was used as a bait in each. Foraging nuisance ant populations were pooled across species, counted, and used as a baseline for calculating the percent reduction in ant populations resulting from treatments. All insecticide treatments were applied using a 1-gallon B&G Compressed Air Sprayer (Jackson, GA) on 25 Aug. Ants were monitored at 1, 7, 14, and 31 days after insecticide treatment (DAT) using the same techniques used for pretreatment assessment. The percent reduction trends were evaluated using pre- and post-treatment nuisance ant population counts. Data were analyzed as repeated measures ANOVA (P\u3c0.05) using PROC GLIMMIX (SAS 9.4. SAS institute, NC). Means were analyzed/sorted by time with significant differences being collection interval specific

Efficacy of Transport Mikron Against Nuisance Ants When Applied Around Structures, 2015

Ants are nuisance pests around the homes and other structures. Insecticide baits and sprays are commonly used for controlling ants. The research was conducted to determine efficacy of Transport Mikron and Temprid SC against these nuisance ants. The trial was conducted around two buildings on East Campus, University of Nebraska-Lincoln, Lincoln, NE. A total of 20 experimental plots were established with 3 ft buffer zone between individual plots. The dimension of each experimental plot consists of 20 ft lengthx10 ft width + 3 ft high on foundation wall (260 ft2). Each treatment was replicated four times yielding 1040 ft2. Four plots were randomly assigned to one of the five treatments. The experimental design was a completely randomized design (CRD). Pretreatment ant population was monitored by placing four ant baittube traps made of cylindrical plastic tube (17x100mm (VWR, Chicago, IL)) in each experimental unit on 20 Aug. Peanut butter (0.5 inch diam) on paper was used as a bait in each. Foraging nuisance ant populations were pooled across species, counted, and used as a baseline for calculating the percent reduction in ant populations resulting from treatments. All insecticide treatments were applied using a 1-gallon B&G Compressed Air Sprayer (Jackson, GA) on 25 Aug. Ants were monitored at 1, 7, 14, and 31 days after insecticide treatment (DAT) using the same techniques used for pretreatment assessment. The percent reduction trends were evaluated using pre- and post-treatment nuisance ant population counts. Data were analyzed as repeated measures ANOVA (P\u3c0.05) using PROC GLIMMIX (SAS 9.4. SAS institute, NC). Means were analyzed/sorted by time with significant differences being collection interval specific