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Bed bugs, Cimex lectularius (L.) (Hemiptera: Cimicidae) and Cimex hemipterus (F.), have become established worldwide in recent years largely due to the development of insecticide resistance. However, limited attention has been given to ongoing morphological and macroevolutionary changes within the species and their populations, which could have implications for their control. Here, we evaluated whether bed bugs of the species C. hemipterus inhabiting different communities in Cape Coast, Ghana are undergoing segregation, which could lead to possible speciation. We also aimed to provide a morphometric description of all nymphal stages. Nine-bed bug populations of C. hemipterus were field-collected in Cape Coast and were subjected to geometric morphometric analysis. The multivariate parameters applied distinguished various populations from each of the locations, indicating the presence of morphologically distinct subpopulations of C. hemipterus. Shape-based segregation and shape changes associated with the insect pronotum (which is an important taxonomic character in the Cimicidae) were evident across the populations. Through this comparative study of C. hemipterus, we showed that possible subpopulations of this bed bug are being spread from Ghana. The nymphal stages (first–fifth) of C. hemipterus were distinguished by the length of the last three antennal segment and pronota width; such information contributes to the taxonomic knowledge of the species.

Bed bugs are known to carry several microorganisms. The purpose of this study was to assess the prevalence of bed bug infestation in two rural areas of Senegal and determine the species present in the population. A screening was conducted to detect some arthropod associated pathogenic bacteria in bed bugs and to evaluate the prevalence of endosymbiont carriage. One survey took place in 17 villages in Niakhar and two surveys in Dielmo and Ndiop and surroundings area in the same 20 villages. Bed bugs collected were identified morphologically and by MALDI-TOF MS tools. Microorganisms screening was performed by qPCR and confirmed by sequencing. During the survey in the Niakhar region, only one household 1/255 (0.4%) in the village of Ngayokhem was found infested by bed bugs. In a monitoring survey of the surroundings of Dielmo and Ndiop area, high prevalence was found during the two rounds of surveys in 65/314 (21%) in 16/20 villages (January–March) and 93/351 (26%) in 19/20 villages (December). All bed bugs were morphologically identified as the species Cimex hemipterus, of which 285/1,637 (17%) were randomly selected for MALDI-TOF MS analysis and bacteria screening. Among the Bacteria tested only Wolbachia (Alphaproteobacteria, Rickettsiales, Rickettsiaceae) DNA was found in 248/276 (90%) of the bedbugs. We briefly describe a high level of non-generalized bed bug infestation in rural Senegal and the diversity of Wolbachia strains carried by C. hemipterus. This study opens perspectives for raising household awareness of bed bug infestations and possibilities for appropriate control.

The common bed bug (Cimex lectularius L.) is a hematophagous pest species that lives in close proximity to humans. Following a blood meal, bed bugs deposit fecal material indoors. The feces contain a variety of compounds, including histamine, which serves as a component of their aggregation pheromone. Histamine is a pivotal mammalian immune modulator, and recently it was shown to be present in high concentrations in household dust from homes infested with bed bugs. To better understand the dynamics of histamine excretion, we analyzed bed bug fecal material from different life stages and populations, along with fecal material collected at different post-feeding times and from bed bugs fed on different diets. Our analysis showed significant variation in histamine excretion among life stages, with mated females excreting the most histamine and first instar nymphs excreting the least histamine. However, when histamine excretion was normalized for blood consumption, males were found to excrete more histamine than the other life stages. There was no difference in histamine excretion among laboratory and recently home-collected bed bug populations. Further, we found histamine excretion continued for at least 14 d post-feeding, with the highest amount of histamine excreted 3–4 d after a bloodmeal. Overall, this work demonstrates that bed bugs excrete histamine across all feeding life stages, populations, and at various times after feeding, and that histamine excretion is directly related to blood feeding. These results will be used to better understand the health risks associated with histamine excretion and potential mitigation strategies of environmental histamine.

This study reports the first baseline information on tropical bed bug, Cimex hemipterus (F.) (Hemiptera: Cimicidae), infestations in Ghana. The purpose of this study was to assess bed bug infestation levels, and the efficacy of locally available insecticides and long-lasting insecticidal nets (LLINs) in controlling field bed bugs populations in the Cape Coast region. A survey was undertaken to assess bed bug infestation levels and current control practices by residents. In total, 205 bed bug affected households were identified in 20 communities and live bed bug infestations were associated with most of these premises. Many homeowners knew of other households (from 1 to 3) with a bed bug infestation. Residents reported itching and swelling of the skin from the bed bug bites and the bites were considered severe. The most common household bed bug control strategy was the application of insecticides. However, LLINs and commercially formulated insecticides commonly used by households (notably chloropyrifos and pyrethroid-based formulations) did not efficaciously suppress field collected strains of C. hemipterus. Using a dipping bioassay, mean mortality ranged from 0 to 60% for eggs, nymphs, and adults, and less than 40% mortality was observed in bed bugs placed on insecticide-treated filter paper. Each LLINs (all are pyrethroid based) produced a mean mortality of less than 20% in adult bed bugs. For a more effective response to the global bed bug resurgence in developing countries, government and supporting agencies need to render assistance to bed bug affected residents through the provision of improved pest management strategies.

The bed bug, Cimex lectularius L., is a common ectoparasite found to live among its vertebrate hosts. Antennal segments in bugs are critical for sensing multiple cues in the environment for survival. To determine whether the thermo receptors of bed bugs are located on their antennae; innovative bioassays were created to observe the choice between heated and unheated stimuli and to characterize the response of bugs to a heat source. Additionally, the effect of complete antenectomized segments on heat detection were evaluated. Heat, carbon dioxide, and moisture are cues that are found to activate bed bug behavior; a temperature at 38°C was used to assess the direction/degree at which the insect reacts to the change in distance from said stimulus. Using a lightweight spherical ball suspended by air through a vacuum tube, bed bugs and other insects are able to move in 360° while on a stationary point. Noldus EthoVision XT was used to capture video images and to track the bed bugs during 5-min bioassays. A bioassay was created using four Petri dish arenas to observe bed bug attraction to heat based on antennae segments at 40°C. The purpose of this study was to evaluate the effects of heat on complete antenectomized segments of the antennae. The results in this experiment suggest that bed bugs detect and are attracted to heat modulated by nutritional status. Learning the involvement of antennae segments in heat detection will help identify the location and role of thermoreceptors for bed bug host interaction.

The common bed bug, Cimex lectularius L., resurged as an important urban pest in the last 20 yr. Yet, there are no commercial repellent products labeled for bed bugs available in the United States. We evaluated the repellency of two catnip oils from newly developed cultivars, CR3 and CR9, and compared each to 10 and 25% N,N-diethyl-meta-toluamide (DEET). CR3 contains 63.4% E,Z-nepatalactone and 27.5% Z,E-nepatalactone, and CR9 contains 94.9% Z,E-nepatalactone. Arena studies showed that CR3 and CR9 oils were more effective than DEET within a 24-h period. At 10% concentration, both CR3 and CR9 oils exhibited a repellency of over 94% during the first 8 h. At 25% concentration, the repellency of CR3 and CR9 oils increased to 100%, and repellency of DEET was 92% during the first 24 h. Repellency of 25% CR3 and CR9 oils became lower than 25% DEET after being aged for 3 d. After 28-d aging, repellency of 25% CR3, CR9, and DEET reduced to 25, 64, and 92%, respectively. Soiled socks were placed above repellent treated bands to determine if the repellent can protect soiled socks from being infested. The 20% CR3 oil prevented 100% of bed bugs from infesting soiled socks showing that it was more effective than DEET. These results indicate that catnip oils from CR3 and CR9 cultivars are more repellent than DEET over a 24-h period following application, but their longevity is shorter than DEET after 72 h.

In the last two decades, bed bugs (Cimex lectularius L. and Cimex hemipterus F.) have become perennial and difficult to control indoor pests. Current pest control options are severely constrained by high prevalence of insecticide resistance and availability and relatively high costs of alternative interventions. Among various measures to counter the drawbacks of insecticide resistance include efforts to diversify the modes of action of insecticides with residual applications of combinations of insecticides, which include a juvenile hormone analog (JHA). JHAs, such as hydroprene and methoprene, have a desirable safety profile and are effective against a variety of indoor pests. We evaluated the potential of hydroprene and methoprene to be incorporated into an ingestible bait, with dose–response studies on fifth-instar male and female bed bugs. Females were more susceptible than males to both JHAs, and methoprene was more effective by ingestion than hydroprene at inducing both lethal and sublethal effects. Ingestion of ≥10 µg/ml blood of either JHA by last instar nymphs reduced oviposition; untreated females that mated with males exposed to high concentrations of either JHA also exhibited lower oviposition. We suggest that methoprene could be incorporated into integrated pest management programs in liquid baits and residual sprays in combination with other active ingredients.

Pests are frequently found in homes, especially in apartment buildings in low-income communities. We investigated the prevalence and patterns of pest infestations in low-income communities in four cities (Jersey City, Linden, Paterson, Trenton) in New Jersey, USA. Resident interviews, visual inspections, and the placement of monitors were used to identify pest infestations. A total of 1,753 apartments from 19 buildings or building complexes were accessed. The infestation rates of cockroaches, bed bugs (Cimex lectularius L.), and house mice (Mus musculus domesticus Schwarz and Schwarz) were 37, 9, and 20%, respectively. Among apartments with cockroaches, 97.8, 2.5, and 0.8% had German cockroach [Blattella germanica (L.)], American cockroach [Periplaneta americana (L.)], and Oriental cockroach (Blatta orientalis L.), respectively. The percentage of residents who were aware of the presence of cockroaches, bed bugs, and house mice was 70.8, 55.3, and 56.8%, respectively. The prevalence of pest infestation was associated with resident ethnicity and gender. Among 856 interview responses, 78% implemented methods themselves to control pests in their homes in the past six months. Chocolate spread detected 99% of house mouse infestations and was much more sensitive than three commercial blank baits. Significant differences were also observed in the feeding preference of the three commercial blank baits.

Bed bugs are hematophagous insects with a long history of presence in human communities. Over the last three decades, infestations by bed bugs in human dwellings have drastically increased, leading to a rise in bed bug concerns. This study was conducted in May 2019 in the Miarinarivo district of Madagascar. Eight locations with suspected infestations were inspected. Of these, five locations were found with active bed bug infestations. Overall, 23 (19 adults and four nymphs) specimens with numbers per apartment ranging from 2 to 6 were collected and analyzed using morphological and molecular approaches. Of 19 adults collected, 18 were morphologically identified as Cimex hemipterus (Hemiptera: Cimicidae), with the final adult identified as C. lectularius. Morphological identification of adults was confirmed by sequencing 450 bp fragment of COI gene. All four nymphs were also identified molecularly as C. hemipterus. Maximum likelihood phylogenetic tree of COI gene and sequence alignment of C. hemipterus specimens revealed the presence of two groups (first group clustered with previously reported haplotype from Asian and African countries and the second group encompassed a lesser known haplotype exclusively from Africa (Kenya and Senegal). This study presents low genetic diversity among C. hemipterus specimens and, for the first time, reports the occurrence of C. lectularius, known as temperate species, in Madagascar. These results can be helpful in control management strategies against these ectoparasites in this country.

Common bed bug Cimex lectularius (L.) (Hemiptera: Cimicidae) infestations are on the rise and due to the development of pesticide resistance they are becoming more difficult to control, affordably. We evaluated a naturally occurring compound methyl benzoate (MB) and related analogs, previously reported to have insecticidal activity on several agricultural pests, for its fumigant action on the common bed bug, C. lectularius L. A discriminating concentration was used to determine the effectiveness of MB, and several of its analogs as fumigants in a laboratory assay. It was found that MB provided >90% control of adult bed bugs in this laboratory fumigant assay. LC50 values were calculated for MB against both a pyrethroid-susceptible and a pyrethroid-resistant strain of common bed bugs. It was determined that both strains were susceptible in this laboratory assay. However, when MB was tested in a field-like assay and compared to a commercially available bed bug control product, it was found to be significantly less effective compared to the commercial product. Our study has found that while MB has the potential to be used as a bed bug control agent, refinements in the delivery system will be needed to increase efficacy under field-like conditions.

Bed bugs have become a common urban pest with consequences on human health and economic costs to the hotel and tourism sectors. Insecticide resistance is considered an important factor in the current bed bug resurgence, and multiple resistance mechanisms could be working in the resistant bed bug populations. In the present study, we determined the resistance profile to four insecticides with a different mode of action in Cimex lectularius L. (Heteroptera: Cimicidae) field-collected colonies from Argentina. Furthermore, the synergism effect of piperonyl butoxide (PBO) with deltamethrin was investigated to explore the contribution of detoxification metabolism to resistance. Our results showed that most of the field-collected colonies are extremely resistant to deltamethrin and propoxur, much more than to azametiphos and imidacloprid. The differences in resistance ratios among field-collected colonies could be associated with different modes of action of insecticides used in control pest and the mechanisms involved in the resistance. PBO pretreatment led to a significantly decreased RR in pyrethroid-resistant colonies, suggesting an upturn of monooxygenase activity for deltamethrin detoxification. However, the high RR detected could involve other mechanisms as part of the whole resistant phenotype in colonies of C. lectularius resistant to pyrethroids.

The common bed bug, Cimex lectularius (Linnaeus 1758), is a nocturnal blood-sucking ectoparasite of humans that is highly prevalent in the northeast of Iran. In recent years, the efficacy of those insecticides that have been frequently used to control bed bugs in Iran has not been studied. Due to frequent complaints about bed bug treatment failures in Mashhad city (northeastern Iran), this study assessed the susceptibility of C. lectularius collected from a student residence hall to Diazinon, Malathion, and λ-cyhalothrin. The desired concentrations of each insecticide were prepared in acetone, and bioassays were performed using insecticide-impregnated filter paper method. The concentration–response data were subjected to POLO-PC software and data were analyzed by the log-probit procedure. The LC50 values of Diazinon and λ-cyhalothrin for examined bed bugs were 1,337.40 and 2,022.36 ppm, respectively. Malathion at the highest concentration (10,000 ppm) did not exhibit any toxicity to examined C. lectularius. Comparing these results to the same previous studies showed that susceptibility of examined bed bugs to these insecticides has been highly decreased. This study revealed an occurrence of insecticide resistance in bed bug populations in northeastern Iran. It also suggests that Malathion, Diazinon, and λ-cyhalothrin are ineffective against bed bugs in this region.

Cimex lectularius L. populations have been documented worldwide to be resistant to pyrethroids and neonicotinoids, insecticides that have been widely used to control bed bugs. There is an urgent need to discover new active ingredients with different modes of action to control bed bug populations. Fipronil, a phenylpyrazole that targets the GABA receptor, has been shown to be highly effective on bed bugs. However, because fipronil shares the same target site with dieldrin, we investigated the potential of fipronil resistance in bed bugs. Resistance ratios in eight North American populations and one European population ranged from 1.4- to >985-fold, with highly resistant populations on both continents. We evaluated metabolic resistance mechanisms mediated by cytochrome P450s, esterases, carboxylesterases, and glutathione S-transferases using synergists and a combination of synergists. All four detoxification enzyme classes play significant but variable roles in bed bug resistance to fipronil. Suppression of P450s and esterases with synergists eliminated resistance to fipronil in highly resistant bed bugs. Target-site insensitivity was evaluated by sequencing a fragment of the Rdl gene to detect the A302S mutation, known to confer resistance to dieldrin and fipronil in other species. All nine populations were homozygous for the wild-type genotype (susceptible phenotype). Highly resistant populations were also highly resistant to deltamethrin, suggesting that metabolic enzymes that are responsible for pyrethroid detoxification might also metabolize fipronil. It is imperative to understand the origins of fipronil resistance in the development or adoption of new active ingredients and implementation of integrated pest management programs.

The common bed bug (Cimex lectularius L.) is a known pest and an obligate blood-feeding ectoparasite. Bed bugs can feed on warm-blooded animals including humans, bats, poultry, and rabbits, but no research has investigated the use of companion animals (canines and/or felines) as a blood source. This study investigates how long known host DNA could be detected in a bed bug and the prevalence of bed bugs feeding on companion animals. Laboratory-reared bed bugs were fed host blood to determine how long DNA of human, feline, canine, and rabbit blood could be detected up to 21 d postfeeding. Additionally, 228 bed bugs were collected from 12 apartments with pets (6: canine, 5: feline, and 1: canine and feline), characterized as engorged or unengorged, and then screened with host-specific primers to identify the bloodmeal. Host meals of human, rabbit, feline, and canine blood were detected up to 21 d after feeding laboratory strains. All bed bugs died after feeding on the canine blood, but DNA could be detected up to 21 d post feeding/death. Of the field-collected bed bugs analyzed, human DNA was amplified in 158 (69.3%) bed bugs, canine DNA amplified in 7 bed bugs (3.1%), and feline DNA amplified in 1 bed bug (0.4%). Results of this study suggest that bed bugs predominately feed on humans and rarely feed on companion animals when they cohabitate in low-income, high-rise apartments. Additionally, results from this study warrant future investigations into host use by bed bugs in different housing structures and socioeconomic environments.

From the 1960s to the 1980s, with the implementation of nationwide ‘Four-Pest Elimination’ campaigns (bed bugs, Cimex lectularius L. and Cimex hemipterus (F.) (Hemiptera: Cimicidae), were listed as one of the targeted pests), bed bug infestations were gradually eliminated in most provinces in China. However, during the last two decades, reports of bed bug infestations in the Pearl River Delta of China have shown an upward trend. Up to now, the bed bug species occurring in this area was much less frequently reported. In this study, we used both morphological and molecular methods to accurately identify the species of bed bugs collected from the cities of Guangzhou and Foshan, China. Results indicated that no significant difference was observed in the mean pronotum width-to-length ratio of Guangzhou (2.6) and Foshan (2.4) specimens; however, both were significantly lower than that of a laboratory strain C. lectularius (3.1). The genetic distances of our specimens with C. hemipterus and C. lectularius were 0–0.2% and 22.2–22.6%, respectively. On the basis of the morphological characteristics and mitochondrial DNA sequence data, it can be affirmed that bed bugs collected from Guangzhou and Foshan were C. hemipterus.

In recent years, bed bugs have experienced a remarkable resurgence on a near global scale. While reports have primarily focused on the common bed bug, Cimex lectularius (L.), which has resurged largely in temperate regions, in tropical regions the tropical bed bug, Cimex hemipterus (F.) (Hemiptera: Cimicidae), has reemerged as well. Recent reports of C. hemipterus introductions to subtropical and temperate regions, outside of the species natural distribution, suggest the potential for establishment and further spread. Establishment may be aided by insecticide resistance mechanisms, such as the presence of knockdown resistance (kdr)-associated mutations, which potentially confer resistance to pyrethroid, pyrethrin, and organochloride insecticides. Here, we present the first report of the detection and likely establishment of C. hemipterus in Honolulu, Hawaii, from samples collected in 2009 and 2019. Furthermore, through partial sequencing of the voltage-gated sodium channel, we report the presence of kdr-associated mutations in all samples. These findings have implications for the implementation of control strategies aimed at eradicating infestations.

DNA, the blue print of life, is densely wrapped around histone proteins to form chromatin. Chromatin remodeling ATPases unwind histone-DNA interactions to facilitate DNA transcription, modification, and repair. Four genes involved in chromatin remodeling, namely, imitation SWI (iswi), chromodomain-helicase-DNA-binding protein 1 (chd-1), DNA helicase INO80 (ino80) and mi-2 were silenced through the injection of dsRNA, and phenotypes were assessed in bed bugs. Bed bugs were injected with 0.2 µg dsRNA per insect between the last thoracic segment and first abdominal segment using a fine capillary tube fitted to a nanoinjector. We observed a significant reduction in reproductive potential with all the genes tested, suggesting the essential function of chromatin remodeling ATPases in many cellular processes including egg-laying and egg-hatching. Knockdown of mi-2 and iswi completely inhibited oviposition over time. Real-time quantitative polymerase chain reaction confirmed significant knockdown of targeted mRNAs for at least 30 d, which supports persistence of RNAi in bed bugs. In addition, we observed a significant depletion of targeted transcripts in eggs laid by bed bugs injected with dsRNAs specific to chromatin remodeling ATPases. This study demonstrates the importance of chromatin remodeling ATPase in bed bug reproduction.

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.

Bed bugs, Cimex lectularius L. (Hemiptera: Cimicidae), have become a major health nuisance in the past 20 ysin cities and elsewhere throughout many areas of the world. Few studies have reported on repellent compounds that could reduce their transport in luggage. We evaluated the repellency of six naturally occurring or related compounds used in flavor/fragrance applications or structurally related compounds, para-menthane-3,8-diol, and N,N-diethyl-meta-toluamide (DEET) to bed bugs in a 183 × 183-cm arena . Repellency was assessed using soft-sided polyester lunch bags serving as surrogates of luggage and barrier cloth towels upon which rested untreated lunch bags. We report for the first time repellency of delta dodecalactone, 2-(3, 7-dimethyl-2, 6-nonadien-1-yl)-cyclopentanone (a.k.a. 'methyl apritone'), gamma dodecalactone, and para-menthane-3,8-diol to bed bugs. Propyl dihydrojasmonate, 3-methyl-5-hexyl-2-cyclohexenone, gamma methyl tridecalactone, and DEET are also documented to be repellent to bed bugs. These compounds provided relatively long-term protection. Propyl dihydrojasmonate prevented bed bugs from seeking refuge in treated lunch bags 27 d after treatment, and when applied to cloth towels repelled harborage-seeking bed bugs for 146 d. Methyl apritone blended with 3-methyl-5-hexyl-2-cyclohexenone and delta dodecalactone as an individual compound applied to cloth towels repelled bed bugs for 190 and 276 d, respectively. The above-mentioned compounds, either individually or as blends, may reduce risk of bed bugs seeking harborage in treated suitcases or towels upon which untreated luggage is placed.

Bed bug populations are increasing around the world at an alarming rate and have become a major public health concern. The appearance of bed bug populations in areas where Chagas disease is endemic raises questions about the role of these insects in the transmission of Trypanosoma cruzi, the etiological agent of the disease. In a series of laboratory evaluations, bed bug adults and nymphs were experimentally fed with T. cruzi-infected blood to assess the ability of T. cruzi to survive inside the bed bug and throughout the insect's molting process. Live T. cruzi were observed in gut contents of experimentally infected bed bug adults via light microscopy and the identity of the parasite was confirmed via polymerase chain reaction analysis. T. cruzi persisted at least 97-d postinfection in adult bed bugs. Nymphal stage bed bugs that were infected with T. cruzi maintained the parasite after molting, indicating that transstadial passage of T. cruzi in bed bugs took place. This report provides further evidence of acquisition, maintenance, and for the first time, transstadial persistence of T. cruzi in bed bugs.

The subfossil remains of 14 cimicids (Hemiptera: Cimicidae) were recovered during archaeological investigations of the Paisley Five Mile Point Cave site (35LK3400), an exceptionally well-dated (n = 229 radiocarbon dates) late Pleistocene-early Holocene rock shelter site in south-central Oregon. Nine of the specimens have been assigned to three modern species of Nearctic Cimicidae-Cimex antennatus Usinger & Ueshima, Cimex latipennis Usinger & Ueshima, and Cimex pilosellus (Horvath)-whereas the remaining five individuals were too fragmentary to positively identify. The chronology of the insect assemblage puts one specimen at circa 5,100 calibrated years before present (cal. yr BP), and the remaining 13 range in age from 9,400 to almost 11,000 cal. yr BP. Although fossil and subfossil cimicid remains have been recovered at other archaeological sites, the fossil record for bed bugs is largely undocumented. The Paisley Caves specimens thus far represent the oldest remains of the genus in probable contact with humans on record.

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.

Cimex lectularius and Cimex hemipterus are the most common species of bedbugs that infest homes. Although case reports decreased substantially by the end of the 20th century, bed bugs, and especially C. lectularius, are currently suffering a resurgence mostly attributed to insecticide resistance, inadequate pest control, and increased travel. Here, we report, to the best of our knowledge, the first molecular confirmation of C. lectularius in Central America. Specimens were obtained from an apartment located in Heredia, Costa Rica. These specimens were identified morphologically as C. lectularius. The species identification was confirmed by amplifying and sequencing fragments of the cytochrome oxidase subunit I (COI) and the 16S rRNA (16S) genes. The phylogenetic analysis showed that the sequences obtained were more closely related to a C. lectularius mitochondrial complete genome sequence from China, with similarities of 98.84% (686/694) for COI and 98.97% (387/391) for 16S. The finding of C. lectularius in Costa Rica will require further investigation in order to determine the extent of current infestations and the susceptibility to insecticides, especially due to the impact that this species can have in human health, as well as the tourism industry in the region. Universidad de Costa Rica/[430-B5-735]/UCR/Costa Rica Universidad de Costa Rica/[ED-548]/UCR/Costa Rica UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Centro de Investigación en Enfermedades Tropicales (CIET) UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biología

Cimex hemipterus resistance to residual insecticides is a growing public health concern worldwide. Herein, we report the susceptibility status of C. hemipterus against pyrethroid (permethrin) and organophosphate (dichlorvos) insecticides in Dar es Salaam. The knockdown efficacy of dichlorvos (99%) was greater than that of permethrin (43%), and mortality at the end of 24 h was also greater for dichlorvos than for permethrin. Mortality in recommended concentration of permethrin was lower than manufacturer’s expectations. In contrast, similar concentrations in dichlorvos resulted into mortality of 100% at the end of 24 h. LC50 and LC95 values for permethrin were 3.36 (2.356–4.364) and 2,887.39 (2,886.37–2,888.39), respectively, whereas those of dichlorvos were 7.91 (3.85–11.97) and 44.39 (40.33–48.45). Dar es Salaam city has high coverage and usage of long-lasting insecticidal nets (LLINs) for prevent malaria. The resistance in bedbugs to permethrin may be related to the widespread use of the insecticide in LLINs. We recommend of the change from pyrethroids dichlorvos for the control of bedbugs.

Despite awareness of the mutations conferring insecticide resistance in the bed bug, Cimex lectularius L. (Hemiptera: Cimicidae), within the United States few studies address the distribution and frequency of these. Within the United States, studies have focused on collections made along the East Coast and Midwest, documenting the occurrence of two mutations (V419L and L925I) within the voltage-gated sodium channel α-subunit gene shown to be associated with knockdown resistance (kdr) to pyrethroids. Here, the distribution and frequency of the V419L and L925I site variants is reported from infestations sampled within Oklahoma and its immediately adjacent states. Additionally, the presence of a mutation previously undocumented in the United States (I935F) is noted. While novel in the United States, this mutation has previously been reported in Australian and Old World populations. No infestations were found to harbor wild-type individuals, and hence susceptible, at each of the three sites. Instead, ~21% were found to possess the resistant mutation at the L925I site (haplotype B), ~77% had mutations at both the V419L and L925I sites (haplotype C), and 2% possessed the mutation at the L936F site (haplotype Ab). The high frequency of haplotype C corresponds to previous studies in the United States, and contrasts dramatically with those of the Old World and Australia. The data presented here provide insight into the contemporary occurrence of kdr-associated insecticide resistance in the South Central United States, a region for which data have previously been absent. These data suggest that New World and Old World/Australian infestations are likely to have originated from different origins.

Steam application is an effective and environmentally friendly method for controlling bed bugs, Cimex lectularius L. (Hemiptera: Cimicidae). While a few studies documented the bed bug control efficacy of steam treatment, the sublethal effect of steam treatment on bed bug behavior and female fecundity is unknown. In this study, we evaluated the effect of steam treatment on the movement, feeding, mating behavior, and fecundity of female bed bugs in the laboratory. Bed bug adults received a calibrated steam treatment that caused approximately 28% mortality. The surviving bed bugs were observed for their feeding and mating behavior at 1 d posttreatment, female fecundity during a 7-d observation period, and offspring hatching. Steam-treated bed bugs were less active based on the percentage of bed bugs with movement, moving distance during a 10-min observation period, and feeding rate. However, steam treatment had no significant effect on blood intake (amount of blood taken per meal) among the fed bed bugs. After blood feeding, the steam-treated bed bugs had similar mating events and egg production as the control bed bugs. Furthermore, parental steam exposure had no significant effect on the offspring hatching. In conclusion, steam treatment could temporarily decrease bed bug activity levels and feeding rate, but had no significant impact on bed bug mating behavior and female fecundity.

Human bed bug infestations have dramatically increased worldwide since the mid-1990s. A similar phenomenon was also observed in Israel since 2005, when infestations were reported from all over the country. Two single nucleotide polymorphisms (V419L and L925I) in the bed bug voltage-sensitive sodium channel confer kdr-type resistance to pyrethroids. Using quantitative sequencing (QS), the resistance allele frequencies of Israeli bed bug populations from across the country were determined. Genomic DNA was extracted from samples of 12 populations of bed bugs collected from Israel and DNA fragments containing the V419L or L925I and I936F mutations sites were PCR amplified. The PCR products were analyzed by QS and the nucleotide signal ratios calculated and used to predict the resistance allele frequencies of the unknown populations. Results of the genetic analysis show that resistant nucleotide signals are highly correlated to resistance allele frequencies for both mutations. Ten of the 12 tested populations had 100% of the L925I mutation and 0% of the V419L mutation. One population was heterogeneous for the L925I mutation and had 0% of the V419L mutation and another population was heterogeneous for the V419L mutation and had 100% of the L925I mutation. I936F occurred only at low levels. These results indicate that bed bugs in Israel are genetically resistant to pyrethroids. Thus, pyrethroids should only be used for bed bug management with caution using effective application and careful monitoring procedures. Additionally, new and novel-acting insecticides and nonchemical means of controlling bed bugs should be explored.

With the recent global resurgence of the bed bugs (Cimex lectularius L.), there is a need to better understand its biology, ecology, and ability to establish populations. Bed bugs are domestic pests that feed mainly on mammalian blood. Although bed bugs have not been implicated as vectors of pathogens, their biting activity inflicts severe insomnia and allergic reactions. Moreover, they have recently developed resistance to various insecticides, which requires further molecular research to determine genetic variation and appropriate interventions. Population dynamics, including genetic differentiation and genetic distance of 10 populations from the Midwest were analyzed in this study. The bed bug samples collected by pest control companies were genotyped using eight species-specific microsatellite markers. Results showed all eight markers were polymorphic, with 8-16 alleles per locus, suggesting high genetic diversity. The FST values were >0.25, signifying pronounced genetic differentiation. The G-test results also indicated high genetic differentiation among populations. The frequency of the most common allele across all eight loci was 0.42. The coefficient of relatedness between each of the populations was >0.5, indicative of sibling or parent-offspring relationships, while the FIS and its confidence interval values were statistically insignificant within the populations tested. The populations departed from Hardy-Weinberg equilibrium, possibly because of high heterozygosity. The genetic distance analysis using a neighbor-joining tree showed that the populations from Kansas City, MO, were genetically separate from most of those from Nebraska, indicating a geographic pattern of genetic structure. Our study demonstrated the effectiveness of using microsatellite markers to study bed bugs population structure, thereby improving our understanding of bed bug population dynamics in the Midwest. Overall, this study showed a high genetic diversity and identified several new alleles in the bed bug populations in the Midwest.

Sublethal exposure to pesticides can alter insect behavior with potential for population-level consequences. We investigated sublethal effects of ActiveGuard, a permethrin-impregnated fabric, on feeding behavior and fecundity of bed bugs (Cimex lectularius L.) from five populations that ranged from susceptible to highly pyrethroid resistant. After exposure to ActiveGuard fabric or untreated fabric for 1 or 10 min, adult virgin female bed bugs were individually observed when offered a blood meal to determine feeding attempts and weight gain. Because bed bug feeding behavior is tightly coupled with its fecundity, all females were then mated, and the number of eggs laid and egg hatch rate were used as fecundity measures. We observed that pyrethroid-resistant and -susceptible bugs were not significantly different for all feeding and fecundity parameters. Bed bugs exposed to ActiveGuard for 10 min were significantly less likely to attempt to feed or successfully feed, and their average blood meal size was significantly smaller compared with individuals in all other groups. Independent of whether or not feeding occurred, females exposed to ActiveGuard for 10 min were significantly more likely to lay no eggs. Only a single female exposed to ActiveGuard for 10 min laid any eggs. Among the other fabric treatment-exposure time groups, there were no observable differences in egg numbers or hatch rates. Brief exposure of 10 min to ActiveGuard fabric appeared to decrease feeding and fecundity of pyrethroid-resistant and susceptible bed bugs, suggesting the potentially important role of sublethal exposure for the control of this ectoparasitic insect.

The brown dog tick, Rhipicephalus sanguineus (Latrielle), can be a serious residential pest due to its unique ability, among ticks, to complete its lifecycle indoors. A single engorged and fertilized female tick can oviposit around 4,000 eggs, allowing indoor establishment to be rapid and easy to miss in early-stage infestations. Acaricide treatment is currently the primary method of control, but can be costly and can lead to the development of acaricide resistance in tick populations. Traps of various designs can be used to help monitor and manage populations of indoor pests, such as cockroaches and bed bugs, but there are currently no commercially available traps for use with brown dog tick infestations. This study included a comparison of four commercially available bed bug traps (NightWatch [BioSensory Inc., Putnam, CT], Bed Bug Beacon [PackTite, Fort Collins, CO], ClimbUp [Susan McKnight Inc., Memphis, TN], and Verify [FMC Corporation, Philadelphia, PA]) with regard to their efficacy in capturing brown dog ticks, and also compared tick attraction to ClimbUp traps baited with several stimuli including CO2. Significantly more ticks were captured and attracted to the NightWatch and CO2-baited ClimbUp traps than the other two trap models. The results suggest that bed bug traps may be useful in brown dog tick monitoring, and CO2 will likely be an important component of a trapping system employed in the future.

The recent resurgence of bed bugs (Cimex spp.) in many developed countries has drawn increasing attention worldwide. The status of urban bed bug infestations were investigated in Shenzhen and Dongguan, two major cities in southern Guangdong Province of southern China, based on pest control service records from two different companies (one during 2012 and another during 2013). The results showed that Shenzhen and Dongguan have a severe problem with bed bug infestations: the control of bed bugs is a constant concern, except during the winter. In Shenzhen, a similar number of premises were treated for bed bugs in central business districts and suburban districts. However, in Dongguan, more premises were treated for bed bugs in suburban districts than in central business districts. The treatment rate for worker sleeping quarters, apartments, hotel, and private houses in Shenzhen was 53.8, 43.0, 1.9, and 1.3%, respectively. The percentage of treated rooms was 56.1% for worker sleeping quarters and 91.1% for apartments. In Dongguan, the treatment rate for worker sleeping quarters, apartments, hotel, and private houses was 90.0, 10.0, 0.0, and 0.0%, respectively.

For over two decades, the bed bug, Cimex lectularius L. (Hemiptera: Cimicidae) has been undergoing a dramatic global resurgence, likely in part to the evolution of mechanisms conferring resistance to insecticides. One such mechanism is knock-down resistance (kdr), resulting from nonsynonymous mutations within the voltage-gated sodium channel (VGSC) gene. To date, three mutations have been identified in C. lectularius, V419L, L925I, and I936F. Using Sanger sequencing, the frequency and distribution of these VGSC mutations across 131 populations collected from the bat-associated and human-associated lineages of C. lectularius found in Europe are documented. All populations from the bat-associated lineage lacked mutations at the three sites. In contrast, the majority of populations associated with humans (93.5%) possessed the mutation at the L925I site. The I936F mutation, previously only reported in Israel and Australia, was found in nine populations spread across several European countries, including the Czech Republic and Switzerland. The high frequency of kdr-associated resistance already reported in C. lectularius and the occurrence and broad geographic distribution of this additional VGSC mutation, questions the continued use of pyrethroids in the treatment of infestations.

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.

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.

Bat bugs (Cimex adjunctus Barber) (Hemiptera: Cimicidae) collected from big brown bats (Eptesicus fuscus Palisot de Beauvoir) in Colorado, United States were assessed for the presence of Bartonella, Brucella, and Yersinia spp. using molecular techniques. No evidence of Brucella or Yersinia infection was found in the 55 specimens collected; however, 4/55 (7.3%) of the specimens were positive for Bartonella DNA. Multi-locus characterization of Bartonella DNA shows that sequences in bat bugs are phylogenetically related to other Bartonella isolates and sequences from European bats.

Bed bugs (Cimex lectularius L.) are now endemic in most major cities, but information regarding their basic biology is still largely based on research done over four decades ago. We investigated the effects of starvation, mating, sperm storage, and female and male age on egg production and hatch. Egg production cycles varied with the number of bloodmeals that females received. Once-mated females fed every 5 d had constant egg production for ∼75 d followed by a monotonic decline to near zero. Percentage egg hatch was high and constant, but declined after ∼30 d to near zero. To determine whether the age of the female, male, or sperm affected these patterns, we mated newly eclosed females to 60-d-old virgin males, 60-d-old mated males, or newly eclosed males. Females produced the most eggs when mated to young males, followed by old mated males, and then old virgin males; percentage hatch followed a similar pattern, suggesting that sperm stored within males for long was deficient. To examine effects of sperm stored within females, we mated newly eclosed females, starved them for 30 or 60 d, then fed them every 5 d. The 60-d starved group produced fewer eggs than the 30-d starved group, and both produced fewer eggs than young females mated to old or young males. Longer periods of sperm storage within females caused lower corresponding percentage hatch. These findings indicate egg production and hatch are governed by complex interactions among female and male age, frequency of feeding and mating, and sperm condition.

Arthropods can be captured by two modes: a passive mode using traps or an active mode mainly based on the use of mouth or powered aspirators. These apparatuses are useful tools for collecting large numbers of crawling, flying, resting, or jumping arthropod specimens, particularly small specimens, such as mosquitoes or sandflies, for laboratory experiments or breeding. Different aspirator models are used to collect various arthropod specimens. However, to our knowledge, no specific system is currently available for the reliable sampling of live bed bugs in the field. Thus, we described a new system based on a classic autonomous house aspirator that requires few modifications for the collecting bed bugs. The low weight and size of this apparatus is advantageous, and it provides for rapid and secure bed bug sampling for medical entomology purposes.

The ability to mark individuals is a critical feature of many entomological investigations, including dispersal studies. Insect dispersal is generally investigated using mark-release-recapture techniques, whereby marked individuals are released at a known location and then captured at a measured distance. Ectoparasite dispersal has historically been challenging to study, in part because of the ethical concerns associated with releasing marked individuals. Here, we introduce the protein self-marking technique, whereby ectoparasites mark themselves in the field by feeding on the blood of an introduced host. We demonstrate the potential of this technique using laboratory-reared bed bugs (Cimex lectularius L.) that marked themselves by feeding on either rabbit or chicken blood. We then used enzyme-linked immunosorbent assays to detect host-specific blood serum proteins in bed bugs. We assessed these protein markers' ability to 1) distinctively identify marked individuals, 2) persist following multiple feedings on an alternate diet, 3) persist over time across a range of temperatures, and 4) transfer from marked to unmarked individuals. Protein markers were detectable in bed bugs before and after molting, remained detectible after multiple feedings on an alternate diet, persisted regardless of whether an individual was starved or fed on an alternate diet following original mark acquisition, and did not transfer between individuals. The duration of detectability depended on temperature. Our results suggest that protein self-marking is an effective technique for marking bed bugs and holds promise for use in dispersal studies of ectoparasitic insects.

We investigated the potential of carbon dioxide (CO2) fumigation as a method for controlling bed bugs, Cimex lectularius L. The effect of bed bug developmental stage, temperature, and CO2 concentration on the minimum time to kill 100% of bed bugs was determined. The minimum CO2 concentration lethal to all bed bug stages was approximately 30% with 24 h exposure time at 25 degrees C. The minimum fumigation time required to kill 100% of eggs using 100% CO2 at 20, 25, and 30 degrees C were 3, 7, and 8 h, respectively; the minimum fumigation time to kill 100% of adult males/nymphs were 8, 13, and 14 h, respectively. The minimum time to kill 100% of adult males/nymphs using 50 and 70% CO2 at 25 degrees C were 18 and 16 h, respectively. We found that eggs were not completely killed after 24 h fumigation when the CO2 concentration was lower than 80%. Thus, bed bug eggs were more susceptible to 100% CO2 fumigation than nymphs and adult males but more tolerant than nymphs and adult males with lower CO2 concentration (50-80%). There were no significant differences among nymphs, adult males, and adult females in their susceptibility to 100% CO2 fumigation. A 24 h fumigation in sealed 158 liter (42 gallon) heavy duty garbage bags filled 90% full with fabric materials and/or boxes and 1,350 g dry ice per bag was sufficient to kill all stages of bed bugs hidden in the materials at room temperature (23-24 degrees C). Sealed heavy duty garbage bags maintained > or = 94% CO2 for at least 24 h. Custom-made double zipper plastic bags (122 x 183 cm) were also used to evaluate the effectiveness of CO2 fumigation for controlling bed bugs. Each bag was filled with fabric and boxes to 50-90% full. Bed bugs were hidden in various locations of each bag. CO2 was introduced into the bags through a CO2 cylinder. CO2 fumigation lasting 24-48 h was sufficient to kill all stages of bed bugs at room temperature, depending on the quantity of materials placed in each bag and whether CO2 was introduced one or two times at the onset. CO2 is an effective alternative to conventional fumigants for eliminating bed bugs hiding in infested household items such as clothing, shoes, books, electronics, sofas, and so forth.

Although a variety of disease agents have been reported from bed bugs, the mechanical and biological disease transmission potential of bed bugs remains unelucidated. In this study we assayed survivability of the mildly pathogenic spotted fever group rickettsia, Rickettsia parkeri, in bed bugs after feeding on R. parkeri-infected chicken blood. Two groups of 15 adult bed bugs each were fed on infected or noninfected blood, and two groups of fourth-instar bed bugs also were fed on either infected or noninfected blood. One group of 15 adult bed bugs received no bloodmeal and was included as an additional control. Two weeks postfeeding, two pools of five live bed bugs from each group were surface sterilized, macerated, and placed in Vero cell cultures in an attempt to grow live organism. The remaining five individual bed bugs from each group were dissected, their salivary glands were removed for immunofluorescence assay (IFA) staining, and the remaining body parts were processed for polymerase chain reaction (PCR) analysis. Results indicated that no immature (now molted to fifth instar) bed bugs were positive for R. parkeri by IFA or PCR, indicating that organisms did not survive the molting process. After 4 wk of cell culture, no organisms were seen in cultures from any of the treatment or control groups, nor were any cultures PCR positive. However, two of the adult bed bugs were IFA positive for rickettsia-like organisms, and these two specimens were also PCR positive using R. parkeri-specific primers. These IFA and PCR results indicate that remnants of Rickettsia parkeri (possibly whole organisms) survived in the bugs for 2 wk, but the viability of the organisms in these two specimens could not be determined.

The effect of temperature and humidity on the survival and water loss of the tropical bed bug, Cimex hemipterus (F.), was studied using two field-collected strains. Insects were exposed to temperatures ranging from 20 to 45 degrees C and relative humidities (RHs) of 33, 75, and 100%. C. hemipterus survived longest under the interaction of low temperature (20 degrees C) and high RH (75-100%). Survival and water loss were significantly affected (P0.01) by temperature and RH (either singly, or in interaction). Strain and sex significantly (P0.01) influenced bed bug survival, but not on water loss. Eggs, first instars, and adults reached their upper thermal lethal limit within 1 h at 39 degrees C, 44 degrees C, and 46 degrees C, respectively. The survival and water loss profiles showed that starved C. hemipterus started to die after losing 35-45% of their body weights.

Hematophagous parasites such as leeches, ticks, mites, lice, bedbugs, mosquitoes, and myiasis-producing fly larvae are common health problems in Lao People's Democratic Republic. Several arthropod-borne infections, e.g., malaria, dengue fever, and Japanese encephalitis, are endemic there. Effective vector control methods including the use of pesticides, insecticide-treated bed nets, and synthetic and plant-based repellents are important means of control against such invertebrates and the pathogens they may transmit or directly cause. In this study, we documented traditional knowledge on plants that are used to repel or kill hematophagous arthropods, including mosquitoes, bedbugs, human lice, mites and ticks, fly larvae, and blood-sucking leeches. Structured interviews were carried out in 66 villages comprising 17 ethnic groups, covering a range of cultures, throughout Lao People's Democratic Republic. A total of 92 plant species was recorded as traditional repellents (including plants for pesticidal usages) in 123 different plant-ectoparasite combinations. The number and species of plants, and animal taxa repelled (or killed) per plant species differed per region, village, and ethnic group. Traditional use was confirmed in the scientific literature for 74 of these plant species, and for an additional 13 species using literature on closely related species. The use of botanical repellents and pesticides from many plant species is common and widespread in the Lao countryside. In the future, the identification of the active components in certain plants to develop more optimal, inexpensive repellents, insecticides, acaricides, or antileech compounds as alternatives to synthetic repellents/pesticides against blood-feeding insects, ticks, mites, and leeches is warranted.