The ability to isolate and generate a DNA profile from human DNA recovered from tropical bed bugs (Cimex hemipterus) for identifying individuals can be useful for public health, forensic, and medical entomology. In this study, genomic DNA was recovered from both male and female bed bugs at every time interval tested (0, 1, 3, 5, 7, 14, 30, and 45 days post blood meal). The total DNA concentrations recovered from male bed bugs ranged from 12.93 to 65.97 ng/µL, while the total DNA concentrations from female bed bugs ranged from 8.93 to 44.53 ng/µL. However, based on the results from the BLAST search and PCR products, human DNA could be detected from female bed bugs at 0, 3, 5, 14, and 30 days post blood meal using the D18S51 marker. Concentrations of PCR products of the D18S51 locus from male bed bugs ranged from 4.20 to 35.50 ng/µL, whereas, for female bed bugs, concentrations ranged from 4.31 to 22.47 ng/µL. These were generally higher compared to the PCR products of the first hypervariable part (HVR1) marker. The results indicate the HVR1 locus was less sensitive than the D18S51 locus.
The metagenomic datasets of the microbial DNA from tropical bed bugs (Cimex hemipterus) after feeding on human blood were presented. Next-generation sequencing of the community DNA was carried out on an Illumina Miseq platform and the raw fastq files were analyzed using QIIME (version 1.9.1). The metagenome of three samples comprised of 108,198 sequences representing 44,646,263 bps with a mean length of 412.63 bps. The sequence data is accessible at the NCBI SRA under the bioproject number PRJNA600667. Community analysis showed Proteobacteria was the most abundance (more than 99%) microbial community that present in the guts of fully fed tropical bed bugs.
With the development of new metagenomic techniques, the microbial community structure of common bed bugs, Cimex lectularius, is well-studied, while information regarding the constituents of the bacterial communities associated with tropical bed bugs, Cimex hemipterus, is lacking. In this study, the bacteria communities in the blood-fed and starved tropical bed bugs were analysed and characterized by amplifying the v3-v4 hypervariable region of the 16S rRNA gene region, followed by MiSeq Illumina sequencing. Across all samples, Proteobacteria made up more than 99% of the microbial community. An alpha-proteobacterium Wolbachia and gamma-proteobacterium, including Dickeya chrysanthemi and Pseudomonas, were the dominant OTUs at the genus level. Although the dominant OTUs of bacterial communities of blood-fed and starved bed bugs were the same, bacterial genera present in lower numbers were varied. The bacteria load in starved bed bugs was also higher than blood-fed bed bugs.
Tropical bed bugs, Cimex hemipterus, which commonly feeds on human blood, may be useful in forensic applications. However, unlike the common bed bug, Cimex lectularius, there is no information regarding tropical bed bug, C. hemipterus, being studied for its applications in forensics. Thus, in this study, lab-reared post-feeding tropical bed bugs were subjected to Short Tandem Repeat (STR) and Single Nucleotide Polymorphism (SNP) analyses to establish the usage of tropical bed bugs in forensics. Several post-feeding times (0, 5, 14, 30, and 45 days) were tested to determine when a complete human DNA profile could still be obtained after the bugs had taken the blood meal. The results showed that complete STR and SNP profiles could only be obtained from the D0 sample. The profile completeness decreased over time, and partial STR and SNP profiles could be obtained up to 45 days post-blood meal. The generated SNP profiles, complete or partial, were also viable for HIrisPlex-S phenotype prediction. In addition, field-collected bed bugs were also used to examine the viability of the tested STR markers, and the STR markers detected mixed profiles. The findings of this study established that the post-blood meal of tropical bed bugs is a suitable source of human DNA for forensic STR and SNP profiling. Human DNA recovered from bed bugs can be used to identify spatial and temporal relations of events.
The metagenomics dataset presented here is based on bacterial 16S rDNA gene amplicons of DNA extracted from tropical bed bugs (Cimex hemipterus). Amplicon-based sequencing was performed using the Illumina MiSeq platform, and the raw sequence data were analyzed using QIIME (version 2022.8.3). The metagenome sequence comprised ten samples that include C1 (133 511bps), C2 (108 920bps), CH1 (106 562bps), CH2 (101 778bps), P1 (103 618bps), P2 (133 258bps), T1 (113 558bps), T2 (133 952bps), TM1 (125 335bps), and TM2 (118 345bps). The sequence data is readily accessible at the NCBI SRA under bio project PRJNA918835. The most abundant microbial community present in the C. hemipterus is the Proteobacteria, with more than 99% of the abundance.
The draft genome data for Cimex hemipterus obtained through Illumina HiSeq sequencing were presented. The raw genomic data was deposited in GenBank under BioProject (PRJNA722579) with the BioSample accession number SAMN18780126. Software, including FLASH, SPADES, and QUAST, were used to merge, assemble, and qualify the raw dataset. The assembled genome was available in the Figshare repository. The assembled genomic data was compared to C. hemipterus data obtained using 454 Roche shotgun sequencing (BioProject, PRJNA308532), downloaded from NCBI. The draft genome data from this work demonstrated larger data volumes and an updated assembly of the C. hemipterus genome with better scaffolding compared to genome data obtained from 454 Roche shotgun sequencing.
As blood-feeding insects that feed on human hosts, bed bugs could be used in forensic investigations if they are present at a crime scene with no apparent evidence. This study describes how tropical bed bugs (Cimex hemipterus) can be used as forensic tools to collect valid human DNA samples. Short Tandem Repeat (STR) analysis was performed on collected bed bug samples, whereby the results indicate that the obtained quantities of human DNA are mostly substantial to facilitate a comprehensive genetic profiling process.
Tapinoma indicum is a household pest that is widely distributed in Asian countries. It is known as nuisance pest that causes annoyance and disturbance by constructing nests and foraging in building for food and water. This article documents the draft genome dataset of T. indicum collected in Penang Island, Malaysia using the next-generation sequencing known as the Illumina platform. This article presents the pair-end 150 bp genome dataset and the quality of the sequencing result. This dataset provides the information for further understanding of T. indicum in the molecular aspect and the opportunity to develop a novel method for pest control and regulation. The dataset is available under Sequence Read Archive (SRA) databases with the accession number SRR10848807.
Metagenomic datasets of the microbial DNA of workers of a Pheidole decarinata Santschi (Hymenoptera: Formicidae) around houses with three replicates were presented. Next-generation sequencing of the microbial DNA was performed on an Illumina Miseq platform. QIIME (version 1.9.1) was used to analyze the raw fastq files. Metagenome of the three (3) samples consist of 333,708 sequences representing 137,359,149 bps with an average length of 413.67 bps. The sequence data is available at the NCBI SRA with the bioproject number PRJNA632430. Community analysis revealed Proteobacteria was the predominant (84.77%) microbial community present in the microbial DNA of workers of the P. decarinata.
In this study, bifenthrin (Maxxthor SC, Ensystex Australasia Pty Ltd), imidacloprid (Prothor SC, Ensystex Australasia Pty Ltd) and fipronil (Regent(®)50SC, Bayer) were applied on the natural infest manures according to the manufacturer rate during a broiler breeding cycle. Solvent direct-immersion extraction (SDIE) was used in detecting the target compound and later, quantification of the insecticide residues in field condition was investigated. The samples were prior cleaned up by solid-phase extraction (SPE) and analysed by Ultra-Performance Liquid Chromatography (UPLC) - photodiode array (PDA) system. In the field trial, three insecticides were showed accumulation during the broiler breeding period and it is suggested that they acted as adulticides when applied on the poultry manures, this is supported by the significant correlation between the increment of insecticide residues to the reduction percentage of adult flies (<0.05). Fipronil showed significantly greater reduction on the adult fly compared to the other insecticides, in which the reduction rate compared to control population at the end of the broiler breeding period; fipronil, imidaclopril and bifenthrin reduced 51.51%, 28.30% and 30.84% of adult flies, respectively.
This study examined the tunneling activity and the behaviour of two subterranean termites, Globitermes sulphurues and Coptotermes gestroi treated with four plant extracts, namely Pyllanthus niruri, Azadirachta indica, Leucaena leucocephala and Andrographis paniculata. All plants were extracted with three different solvents (methanol, hexane and water) and were diluted into three concentrations (500, 5,000 and 10,000 ppm). A group of 50 workers and 2 soldiers were tested and observed daily during the exposure in order to determine their survivorship and behaviour. Both sections were scored to determine their tunneling activities after seven days. There was a significant difference of tunneling activities of C. gestroi on sand treated with plant extracts (X2(2) = 31.790, p < 0.0001) with a mean rank of 8.50 for methanolic extracts and 32.50 for both hexane and water extracts. Meanwhile, no significant difference was observed on tunneling activity of G. sulphureus on treated sand (X2(2) = 2.200, p = 0.333) with a mean rank of 20.72 for methanolic extracts, 26.31 for water extracts and 26.47 for hexane extracts. Results showed that plants extracted with methanol demonstrated strong repellent properties with 0 tunneling activity on the treated sand and low survivorship of both termites. Moreover, both termites did not survive (0%) when they were treated with methanolic extracts at 10,000 ppm. They also displayed a different behaviour post-exposure such as avoidance, gradually losing the ability to walk and low feeding consumption. These results indicate that there is a strong termiticidal activity of plants extracted with methanol against C. gestroi and G. sulphureus.
The tropical bed bug is scientifically recognized as a significant public health problem. While there is an increased awareness about their resurgence by medical and life science committees, efficient bed bug management still remains unresolved. The solution may soon arise, as information about bed bugs' infestation dynamics and systematics are becoming more distinguishable. Recent developments in studies about bed bugs are based on molecular intervention by determining their genetic variation and phylogeography. The aim of this study is to assess the phylogenetic relationships and genetic diversity among the populations of tropical bed bugs inhabiting Malaysia. A molecular genotyping study was conducted with 22 tropical bed bug populations composed of three individuals per population. The mitochondrial (COI) gene was used as a marker. The data obtained were analyzed using the T-Coffee, ClustalX, MEGA 6.0, and PAUP software. The results showed one main monophyletic clade that consisted of two groups: Ch01 and Ch02. Ch02 consists of samples from the Bandar Hilir population, differing from the other populations studied by one singleton base. However, as there were no changes in the amino acid, this singleton genetic variation was considered to have no effect on genetic differentiation. Ch01 shows similarity with some sequence of Cimex hemipterus (F.) from Thailand, suggesting an international diversity connection. The disparity index apparently suggests that all isolates are homogeneous populations and are supported by the low value of the mean pairwise distance between isolates. This study will increase the knowledge about phylogeographic diversity of tropical bed bug in Malaysia.
The subterranean termite Globitermus sulphureus is an important Southeast Asian pest with limited genomic resources that causes damages to agriculture crops and building structures. Therefore, the main goal of this study was to survey the G. sulphureus transcriptome composition. Here, we performed de novo transcriptome for G. sulphureus workers' heads using Illumina HiSeq paired-end sequencing technology. A total of 88, 639, 408 clean reads were collected and assembled into 243, 057 transcripts and 193, 344 putative genes. The transcripts were annotated with the Trinotate pipeline. In total, 27, 061 transcripts were successfully annotated using BLASTX against the SwissProt database and 17, 816 genes were assigned to 47, 598 GO terms. We classified 14, 223 transcripts into COG classification, resulting in 25 groups of functional annotations. Next, a total of 12, 194 genes were matched in the KEGG pathway and 392 metabolic pathways were predicted based on the annotation. Moreover, we detected two endogenous cellulases in the sequences. The RT-qPCR analysis showed that there were significant differences in the expression levels of two genes β-glucosidase and endo-β-1,4-glucanase between worker and soldier heads of G. sulphureus. This is the first study to characterize the complete head transcriptome of a higher termite G. sulphureus using a high-throughput sequencing. Our study may provide an overview and comprehensive molecular resource for comparative studies of the transcriptomics and genomics of termites.
The surge in tropical bed bug Cimex hemipterus (Fabricius) (Hemiptera: Cimicidae) infestations has led to an increase in genomic studies. In this study, the population genetics and breeding patterns of 22 Malaysian populations were analyzed, including genetic differentiation and genetic distance. For seven microsatellite loci, the number of alleles varied from 6 to 14. The allelels per loci contrasted sharply between the overall population and within the populations. The average observed and expected heterozygosity was 0.280 and 0.828 for the overall population and 0.281 and 0.657 among the populations, respectively. Based on polymorphic information criteria, the markers with a value >0.5 were highly polymorphic. In the Hardy-Weinberg equilibrium, the loci of Ch 09ttn, Ch 01dn, and Ch 13dn of the overall population showed signs of a null allele. The stutter peaks caused no scoring errors; large allele dropouts were not detected for any loci; and a correlation imbalance was not indicated. The genetic differentiation among populations was moderate, with a coefficient of genetic differentiation (FST) of 0.144. The bed bug populations showed strong inbreeding, with highly positive coefficients of inbreeding (FIS). The molecular variation attributed to inbreeding was 83% within the populations, compared with 17% among the populations. The admixture individuals in STRUCTURE and neighbor-joining phylogenetic trees also indicated weak genetic structure in the geographical populations, suggesting moderate gene flows between populations. Thus, moderately active dispersion and human-mediated transport shaped the genetic structure of C. hemipterus populations in Malaysia.
It is crucial to understand the degradation pattern of insecticides when designing a sustainable control program for the house fly, Musca domestica (L.), on poultry farms. The aim of this study was to determine the half-life and degradation rates of cyromazine, chlorpyrifos, and cypermethrin by spiking these insecticides into poultry manure, and then quantitatively analyzing the insecticide residue using ultra-performance liquid chromatography. The insecticides were later tested in the field in order to study the appropriate insecticidal treatment intervals. Bio-assays on manure samples were later tested at 3, 7, 10, and 15 d for bio-efficacy on susceptible house fly larvae. Degradation analysis demonstrated that cyromazine has the shortest half-life (3.01 d) compared with chlorpyrifos (4.36 d) and cypermethrin (3.75 d). Cyromazine also had a significantly greater degradation rate compared with chlorpyrifos and cypermethrin. For the field insecticidal treatment interval study, 10 d was the interval that had been determined for cyromazine due to its significantly lower residue; for ChCy (a mixture of chlorpyrifos and cypermethrin), the suggested interval was 7 d. Future work should focus on the effects of insecticide metabolites on targeted pests and the poultry manure environment.
Tapinoma indicum (Forel) (Hymenoptera: Formicidae) is a nuisance pest in Asia countries. However, studies on T. indicum are limited, especially in the field of molecular biology, to investigate the species characteristic at the molecular level. This paper aims to provide valuable genetic markers as tools with which to study the T. indicum population. In this study, a total of 143,998 microsatellite markers were developed based on the 2.61 × 106 microsatellites isolated from T. indicum genomic DNA sequences. Fifty selected microsatellite markers were amplified with varying numbers of alleles ranging from 0 to 19. Seven out of fifty microsatellite markers were characterized for polymorphism with the Hardy-Weinberg equilibrium (HWE) and linkage disequilibrium (LD) analysis. All seven microsatellite markers demonstrated a high polymorphic information content (PIC) value ranging from 0.87 to 0.93, with a mean value of 0.90. There is no evidence of scoring errors caused by stutter peaks, no large allele dropout, and no linkage disequilibrium among the seven loci; although loci Ti-Tr04, Ti-Tr09, Ti-Te04, Ti-Te13, and Ti-Pe5 showed signs of null alleles and deviation from the HWE due to excessive homozygosity. In conclusion, a significant amount of microsatellite markers was developed from the data set of next-generation sequencing, and seven of microsatellite markers were validated as informative genetic markers that can be utilized to study the T. indicum population.
The German cockroach, Blattella germanica (L.), a prominent pest that requires management due to its detrimental economic and medical consequences. Several research discovered that German cockroaches were insecticide resistant, mainly commercial pesticides. One-week-old nymphs from two strains in Penang, Malaysia (Georgetown strain: EL and Greenlane strain: IC strain) were tested in the laboratory against two commercial insecticides, Cislin® 25 (deltamethrin) and Sumithion 50 (fenitrothion). The concentration of solutions used in the residual test based on the manufacturer labeling. Cislin® was tested at 1.90 ppm, 1.60 ppm, 1.30 ppm, and 1.0 ppm; Sumithion 50 was tested at 25 and 27.00 ppm, 23.00 ppm, 18.00 ppm, 14.00 ppm using the residual method. Probit analysis and one-way analysis of variance (ANOVA) were used to compare the data. Cislin® 25 and Sumithion 50 were more effective and high toxicity against the IC strain compared with the EL strain. Sumithion 50 demonstrated a fast knockdown time on cockroaches, but Cislin® 25 showed no knockdown time. Sumithion 50 showed a significant mortality rate in cockroaches within a short period of time compared to Cislin® 25. Both insecticides were found to be effective against both strains, but Sumithion 50 is more effective at controlling cockroaches than Cislin® 25.
Due to the growing public health and tourism awareness, Cimex hemipterus Fabricius (Hemiptera: Cimicidae) has gained a great interest in increasing reported infestation cases in tropical regions of the world, including Malaysia. Since the information on the molecular ecology and population biology of this species are tremendously lacking, the isolation and development of molecular markers can be used to determine its genetic structure. In this study, novel microsatellite primers isolated from enriched genomic libraries of C. hemipterus were developed using 454 Roche shotgun sequencing. Seven validated polymorphic microsatellite primers were consistently amplified and characterized from 70 tropical bed bugs collected from seven locations throughout Malaysia. The number of alleles per locus identified ranged from 6 to 14. Comparison of loci for overall and between population were done with mean observed and expected heterozygosity were determined at 0.320 and 0.814, 0.320 and 0.727, respectively. Polymorphic information criteria (PIC) valued the markers as highly informative as PIC >0.5. Overall population, they are possibly in Hardy-Weinberg equilibrium with loci Ch_09ttn, Ch_01dn, and Ch_13dn showing signs of a null allele. There were no scoring errors caused by stutter peaks, no large allele dropout was detected for all loci and showed no evidence of linkage disequilibrium. In conclusion, all seven molecular microsatellite markers identified can be beneficially used to gain more information on the population genetic structure and breeding patterns of C. hemipterus as well as the relationship of dispersal and infestation.