Blattella Germanica Research Articles

Analysis of lethal and sublethal doses: Comparative toxicity of three commonly used pesticides on Blattella germanica, an important allergen and vector of pathogens

The study investigates the comparative toxicity of three widely used insecticides-fenitrothion, malathion, and deltamethrin-on Blattella germanica, a major urban pest.Using bioassay tests based on World Health Organization (WHO) protocols, we determined the lethal doses 50 (LD50) for each insecticide. 2.5 mL of each insecticide in acetone was placed in glass jars. Ten adult male cockroaches were tested per dilution, with three to four replicates. Acetone alone served as the control. After 1 h of exposure, the cockroaches were moved to containers with food and water, and mortality was recorded after 72 h. Probit regression analysis was employed to analyze the mortality rates at various doses, and statistical significance was confirmed for all tested insecticides.Results showed that malathion had the lowest lethal dose, with an LD50 of 4.29 ppm, making it more potent at lower concentrations. Fenitrothion followed with an LD50 of 5.11 ppm, while deltamethrin exhibited the highest LD50 of 8.56 ppm, indicating lower toxicity at standard concentrations.The study also emphasized the importance of understanding sublethal doses, which, though not immediately fatal, could induce behavioral and physiological changes leading to pesticide resistance. The findings provide critical insights for pest management strategies, highlighting the need for appropriate dosing to balance efficacy with safety concerns. This research establishes baseline data for future studies on B. germanica and its resistance mechanisms, contributing to improved pest control measures with minimal environmental impact.

Investigation and Analysis of Inhalant Allergens in Patients with Allergic Rhinitis in Yinchuan, China

Introduction: This study aimed to analyze the types and distribution characteristics of major inhalant allergens in patients with allergic rhinitis (AR) in Yinchuan, China. Methods: In this cross-sectional study, 2,000 outpatients suspected of having AR were included from 2022 to 2023 at the Department of Otolaryngology-Head and Neck Surgery, General Hospital of Ningxia Medical University. Skin prick tests were performed on the included individuals using 13 common inhalant allergens: house dust mites, dust mites, tropical mites, Artemisia, dog hair, ragweed, cat hair, grass pollen, tree pollen, mold group I, mold group IV, German cockroach (Blattella germanica), and American cockroach (Periplaneta americana). The results of the skin prick tests were summarized, and patients with positive results were grouped by ethnicity, gender, and age to compare the differences in the positive rates of various inhalant allergens between the groups. The number of patients visiting each month was recorded to analyze the temporal variation in the incidence rate and compare the differences in the main inhalant sensitizers among patients in each quarter. Results: Among the 2,000 included patients, there were 1,060 males and 940 females, with an average age of 18.7 years. Among the 2,000 outpatients who underwent allergen skin prick tests, 1,346 cases (67.30%) had positive results. The inhalant allergens were ranked in descending order of positive rates as follows: Artemisia (53.25%), dust mites (51.10%), house dust mites (49.10%), ragweed (45.70%), tropical mites (43.15%), dog hair (19.20%), cat hair (16.05%), American cockroach (12.10%), German cockroach (11.25%), grass pollen (9.15%), tree pollen (7.10%), mold group I (6.10%), and mold group IV (5.05%). There were no statistically significant differences in positive rates between different ethnicities or genders (all p > 0.05). Compared to patients aged 18 years and above, patients under 18 years old had statistically significant differences in positive rates for dust mites, Artemisia, ragweed, mold group I, and German cockroach (all p < 0.05). The seasonal distribution indicated that autumn had the highest number of patient visits in a year (579 cases, 58.95%). Conclusion: Artemisia and dust mites were the major inhalant allergens in patients with suspected AR in Yinchuan, China. The positive rate of inhalant allergen skin prick tests was not correlated with the ethnicity or gender of the local population. Autumn was the season with the highest frequency of visits by patients with suspected AR.

Efficacy and utility of isocycloseram a novel isoxazoline insecticide against urban pests and public health disease vectors.

Isoxazolines inhibit γ-aminobutyric acid chloride channels in insects and acarids by binding to postsynaptic receptors. This prevents chloride influx, leading to depolarization/hyperexcitation, paralysis, and death. Here, we evaluated the potential utility of a novel isoxazoline, isocycloseram, against several urban insect pests. Isocycloseram was active at low doses against the German cockroach, Blattella germanica (L.)[median lethal dose (LD50) 5-15 ng per insect at 72 h, topical assays]; Argentine ant (Linepithema humile Mayr), Pharaoh ant (Monomorium pharaonis (L.), common bed bug (Cimex lectularius (L.) (approximately 40 mg m-2, residual surface spray); Eastern subterranean termite (Reticulitermes flavipes (Kollar)and Formosan subterranean termite (Coptotermes formosanus Shiraki) (5 μg g-1 w/w, tunneling assays); and mosquito, Anopheles stephensi Liston (120 and 150 mg m-2 treated surfaces, aged indoors for 9 months). Additionally, cockroach gel bait at 1% isocycloseram (w/w) caused 95-100% mortality in German, American (Periplaneta americana (L.), and oriental (Blatta orientalis (L.) cockroaches within 5-14 days. Isocycloseram proved to be active against both laboratory and field populations of German cockroaches at doses lower or equal to those of other chemicals. Ants, bed bugs, and mosquitoes readily acquired lethal doses of isocycloseram from different surfaces treated with formulated products. Given its non-repellent nature, delayed effects, and activity at low rates, isocycloseram can be a very effective compound against subsocial, social, and other human disease vector insect pests. © 2024 Society of Chemical Industry.

Female contact sex pheromone recognition in the German cockroach (Blattella germanica) is mediated by two male antennae-enriched sensory neuron membrane proteins.

The German cockroach Blattella germanica is a notorious urban health pest that has developed resistance to multiple pesticides. Thus, novel non-lethal pest control agents are urgently needed. Olfaction interference via disruption of sex pheromone recognition-related genes offers a promising approach. The German cockroach has a unique courtship behavior in which female adults emit contact sex pheromones (CSPs) in response to antennal touching, which subsequently triggers distinctive male sex behavioral responses. Due to the limited volatility of CSPs, the molecular mechanisms underlying their recognition and the specific olfactory pathways activated remain poorly defined. Although the odorant receptor coreceptor (Orco) is critical for most insect olfaction, sensory neuron membrane proteins (SNMPs), in particular SNMP1, also play crucial roles in sex pheromone recognition in moths and flies. While multiple SNMP1 homologs have been identified in multiple insect species, they have yet to be fully functionally characterized in cockroaches. In this study, RNA-interference (RNAi)-mediated knockdown of BgerOrco reduced both the electrophysiology responses and courtship behaviors of males, indicating CSP perception proceeds via an olfaction pathway. Similar RNAi knockdown of BgerSNMP1e and BgerSNMP1d, which are predominantly expressed in male antennae, revealed critical roles in perceiving the major component of the Blattella germanica CSP blend. Unlike BgerSNMP1e, BgerSNMP1d was also found to function in the perception of the minor CSP component. Molecular docking analyses revealed no differences in the binding affinities of BgerSNMP1d for the major and minor CSP components, whereas the binding affinities of BgerSNMP1e displayed clear selectivity for the major component. Our results show that the olfactory pathway is critical for CSP recognition and that two male-enriched SNMP genes, BgerSNMP1e and BgerSNMP1d, are crucial factors mediating the male response to CSP stimulation in German cockroaches. This study lays a foundation for studying the mechanisms of CSP recognition and provides novel molecular targets with potential to be exploited as disruptors of courtship behavior. © 2024 Society of Chemical Industry.

Prevalence of inhaled allergen sensitization among patients with suspected allergic diseases in Sichuan province: 3-year data from a single center.

Allergic diseases are becoming increasingly common, and they are a threat to people's health. Exploring the distribution characteristics of allergen-specific immunoglobulin E (sIgE) in people from Sichuan province, southwest China, can provide clinical epidemiological data. This study enrolled 12,204 consecutive patients with suspected allergies from May 2018 to May 2021. Among the patients, 4206 were diagnosed with allergic rhinitis or asthma. The Rayto Lumiray 1600 detection system and sIgE and total IgE (tIgE) detection kits were used to measure the levels of nine common sIgE and tIgE. sIgE ≥ 0.35 IU/mL was considered positive. The sensitization rate of D1 (Dermatophagoides pteronyssinus) is the highest (22.97%), followed by D2 (Dermatophagoides farinae) (23.33%); M3 (Aspergillus fumigatus) has the lowest positive rate (1.5%). E5 (Canis familiaris) and I6 (Blatella germanica) exhibited relatively high sensitization rates (8.64% and 12.35%, respectively). Allergen sensitization was significantly higher in men than in women. Moreover, 90.3% of sensitization samples from D1 were combined with at least one of the other eight allergens. Similarly, a positive correlation was demonstrated between D1, D2, and E1 (Felis domesticus). In addition, patients with allergic rhinitis (91.88% and 91.54%, respectively), allergic asthma (72.44% and 74.01%, respectively), and allergic rhinitis with asthma (92.12% and 93.22%, respectively) were mainly sensitized to D1 and D2. D1, D2, I6, and E5 are the main allergens. Moreover, D1 and D2 are the main allergens in patients with respiratory allergic diseases. Research focusing on the distribution of allergens and the characteristics of hypersensitivity in different people helps prevent, diagnose, and treat allergic diseases.

Characterization of insecticide resistance and their mechanisms in field populations of the German cockroach (Blattodea: Ectobiidae) in Taiwan under different treatment regimes.

This study investigated how management strategies influence resistance profiles in German cockroach (Blattella germanica (L.)) populations and their impact on the performance of commercial gel baits containing fipronil, imidacloprid, and indoxacarb. Field populations from premises managed under 3 different strategies: Baiting, random insecticide (RI) used, and insecticide rotation (IR) were tested. Almost all populations under RI and IR were resistant to deltamethrin, but low to moderate resistance was observed under the Baiting approach. Cytochrome P450 monooxygenases (P450) were involved in deltamethrin resistance in these resistant populations. All individuals under Baiting and RI were homozygous for the L993F mutation, but the populations under IR lacked homozygous-resistant individuals. Eighty-three percent of field populations with complete homozygosity for the Rdl mutation displayed low mortality upon exposure to 3× LD95 fipronil. The effect of P450 and the Rdl mutation conferred high fipronil resistance in populations under the Baiting approach, recording moderate performance indices (PI) of 44-67 in fipronil bait. By contrast, those populations under RI and IR, in which involve glutathione S-transferases in fipronil resistance, had high PIs of 78-93. Almost 80% of populations exhibited over 90% mortality at 3× LD95 indoxacarb treatment, accompanied by high PIs of 90-100 in indoxacarb bait. Partial mortality from 1× LD95 imidacloprid occurred across all field populations due to the involvement of P450. PIs of imidacloprid bait ranged 5-57 and 20-94 in populations under RI and IR, respectively. Field populations demonstrate different resistance profiles depending on the treatment regimes, and the resistance mechanisms involved influenced gel bait's effectiveness.

Do commercial dog extracts cross-react with Felis domesticus allergen 1.

Background: Half of U.S. households own a dog despite 10% of individuals being sensitized to dog. Assessment and treatment options for dog allergy include the use of commercial dog extracts which have inconsistent performance, making diagnosing and managing dog allergy challenging. Contamination of dog extracts with other allergens has previously been reported. Objective: We sought to determine whether commercial dog extracts contain other aeroallergens. Methods: An extract purity and quantification study on acetone precipitated dog hair and dander extract (AP dog) was performed, 6 aeroallergens; Alternaria (Alt a 1), Ragweed (Amb a 1), German Cockroach (Bla g 2), Dust Mite (Der p t), Cat (Fel d 1), and Rye Grass (Lol p 1). Following, conventional dog hair and dander extract (CV dog) and the new ultrafiltered dog hair and dander extract (UF dog) were also assessed based on the initial results of AP dog. SDS-PAGE was performed on all three dog extracts to compare allergen content. Lastly, serology results and aeroallergen immunotherapy prescriptions were compared. Results: The ELISA trays with Alt a 1, Amb a 1, Bla g 2, Der p 1, and Lol p 1 antibodies did not capture AP dog, while the ELISA tray with Fel d 1 antibody captured AP dog, CV dog, and UF dog. SDS-PAGE results of the 3 dog extracts did not reveal a band at the molecular weight for Fel d 1. Conculsion: Contamination of commercial dog extracts was not found. However, our findings are supportive of commercial dog extracts containing a Fel d 1-like dog allergen that is cross-reactive to Fel d 1. Cross-reactivity between commercial dog extracts and Fel d 1 could be responsible for double positivity to cat and dog in serology. Additional studies are needed to better illustrate this Fel d 1-like dog allergen.

Early embryonic development of the German cockroach Blattella germanica

BackgroundEarly embryogenesis is characterized by dramatic cell proliferation and movement. In most insects, early embryogenesis includes a phase called the uniform blastoderm, during which cells evenly cover the entirety of the egg. However, the embryo of the German cockroach, Blattella germanica, like those of many insects within the super order Polyneoptera, does not have a uniform blastoderm; instead, its first cells condense rapidly at the site of a future germband. We investigated early development in this species in order to understand how early gene expression is or is not conserved in these insect embryos with distinct early cell behaviors.ResultsWe present a detailed time series of nuclear division and distribution from fertilization through germband formation and report patterns of expression for the early patterning genes hunchback, caudal, and twist in order to understand early polarization and mesoderm formation. We show a detailed time course of the spatial expression of two genes involved in the segmentation cascade, hedgehog and even-skipped, and demonstrate two distinct dynamics of the segmentation process.ConclusionsDespite dramatic differences in cell distribution between the blastoderms of many Polyneopteran insects and those of more well-studied developmental models, expression patterns of early patterning genes are mostly similar. Genes associated with axis determination in other insects are activated relatively late and are probably not maternally deposited. The two phases of segmentation—simultaneous and sequential—might indicate a broadly conserved mode of morphological differentiation. The developmental time course we present here should be of value for further investigation into the causes of this distinct blastoderm type.

Insecticidal effect of Quinolizidine and phenolic compounds extracted from lupines luteus against American cockroach (Periplaneta Americana) and German cockroach (Blattella germanica)

Insecticidal effect of Quinolizidine and phenolic compounds extracted from lupines luteus against American cockroach (Periplaneta Americana) and German cockroach (Blattella germanica)

Classification, identification, and DNA barcoding study for common cockroach species (Dictyoptera: Blattaria) from China

Cockroaches are well-known pests and quarantined organisms worldwide. Due to morphological diversity and a lack of molecular data, their classification and identification are facing challenges. This study performed classification, identification, and DNA barcoding for cockroaches collected from China. Seventy-six samples were morphologically identified as seven species of two superfamilies that included Blattella germanica, Eublaberus posticus and Blaptica dubia belonging to the superfamily Blaberoidea, and Periplaneta americana, Periplaneta lateralis, Periplaneta fuliginosa and Periplaneta australasiae belonging to the superfamily Blattoidea. Based on sequence alignments of nine ribosomal and mitochondrial genes across the order Blattaria retrieved from GenBank, rDNA ITS2-517 bp and mtDNA 16S-327 bp were screened as candidates for molecular identification. Universal primers were designed for PCR amplification, cloning, and sequencing of the 37 representative samples. Sequence alignments and phylogeny analysis showed that both ITS2 and 16S confirmed samples 1–9, 20–24, and 25–29 as B. germanica, P. americana, and P. lateralis, respectively; only 16S (not ITS2) confirmed samples 10–14, 15–19, 30–34, and 35–37 as E. posticus, Blap. dubia, P. fuliginosa, and P. australasiae, respectively, indicating that 16S was a better target than ITS2 for molecular identification of cockroaches. Conservative motif and divergence analysis further revealed that ITS2 sequences vary significantly among different taxa, whereas 16S sequences are relatively conserved. There is an obvious barcoding gap between maximum intraspecific divergence and minimum interspecific divergence (2.57 % vs. 5.62 %) for ITS2, but not for 16S (6.15 % vs. 2.63 %). Therefore, it was confirmed that ITS2 is an ideal DNA barcode for molecular identification of cockroaches at lower category.

Frequent and asymmetric cell division in endosymbiotic bacteria of cockroaches.

Many insects are obligatorily associated with and dependent on specific microbial species as essential mutualistic partners. In the host insects, such microbial mutualists are usually maintained in specialized cells or organs, called bacteriocytes or symbiotic organs. Hence, potentially exponential microbial growth cannot be realized but must be strongly constrained by spatial and resource limitations within the host cells or tissues. How such endosymbiotic bacteria grow, divide, and proliferate is important for understanding the interactions and dynamics underpinning intimate host-microbe symbiotic associations. Here we report that Blattabacterium, the ancient and essential endosymbiont of cockroaches, exhibits unexpectedly high rates of cell division (20%-58%) and, in addition, the cell division is asymmetric (average asymmetry index >1.5) when isolated from the German cockroach Blattella germanica. The asymmetric division of endosymbiont cells at high frequencies was observed irrespective of host tissues (fat bodies vs ovaries) or developmental stages (adults vs nymphs vs embryos) of B. germanica, and also observed in several different cockroach species. By contrast, such asymmetric and frequent cell division was observed neither in Buchnera, the obligatory bacterial endosymbiont of aphids, nor in Pantoea, the obligatory bacterial gut symbiont of stinkbugs. Comparative genomics of cell division-related genes uncovered that the Blattabacterium genome lacks the Min system genes that determine the cell division plane, which may be relevant to asymmetric cell division. These observations combined with comparative symbiont genomics provide insight into what processes and regulations may underpin the growth, division, and proliferation of such bacterial mutualists continuously constrained under within-host conditions.IMPORTANCEDiverse insects are dependent on specific bacterial mutualists for their survival and reproduction. Due to the long-lasting coevolutionary history, such symbiotic bacteria tend to exhibit degenerative genomes and suffer uncultivability. Because of their microbiological fastidiousness, the cell division patterns of such uncultivable symbiotic bacteria have been poorly described. Here, using fine microscopic and quantitative morphometric approaches, we report that, although bacterial cell division usually proceeds through symmetric binary fission, Blattabacterium, the ancient and essential endosymbiont of cockroaches, exhibits frequent and asymmetric cell division. Such peculiar cell division patterns were not observed with other uncultivable essential symbiotic bacteria of aphids and stinkbugs. Gene repertoire analysis revealed that the molecular machinery for regulating the bacterial cell division plane are lost in the Blattabacterium genome, suggesting the possibility that the general trend toward the reductive genome evolution of symbiotic bacteria may underpin their bizarre cytological/morphological traits.

Changes in Prevalence of IgE Sensitization and Allergenic Exposition over a 10-Year Period in a Tropical Region.

Multiple antigen environmental sources have been identified as possible causes of allergies, but few studies have evaluated changes in the sensitization profiles over time. The aim of this study was to evaluate the changes in IgE sensitization and exposure to dust mites, cats, dogs, and cockroaches over a 10-year period. During a period of 10 years among patients with asthma, rhinitis and/or atopic dermatitis, we evaluated the annual frequency of atopy to Dermatophagoides farinae, Dermatophagoides pteronyssinus, Blomia tropicalis, Canis familiaris, Felis domesticus and cockroaches (Periplaneta americana and Blatella germanica). Exposure to sources was also assessed using questionnaires (Pets) or direct counts (House dust mites and cockroaches). The association between some risk factors and the prevalence of atopy was explored. A total of 6,000 records were included. Among the patients, 82% had IgE sensitization to at least one of the six allergenic sources. Sensitization to Dermatophagoides spp. was the most frequent (&gt;78%). Exposure and sensitization in the first decade of life to Dermatophagoides spp. seem to determine the molecular spreading to other allergenic sources. Exposure to Blomia tropical increases significantly over time (year 2015; 38% vs. year 2022; 51%, p 0.03). Exposure to dogs was higher than with cats but association between atopy and exposure was stronger with cats (OR 27.4, 95% CI: 22.3-33.6, p &lt; 0.01). Exposure and sensitization in the first decade of life to Dermatophagoides spp. determine the molecular spreading of IgE antibodies to other allergenic sources. Household exposure to dogs and cats seems to be important for the subsequent development of atopy. Sensitization to B. tropicalis and cockroach appears to be mostly from cross-reactivity rather than direct exposure.

Энтомопатогенные грибы как средство подавления численности рыжего таракана

The use of mycoinsecticides can be an alternative to reduce chemical pollution in human dwellings. The use of Beauveria bassiana and Metarhizium anisopliae is gradually increasing, reaching commercial scale in such countries as Brazil, China, and Mexico. At the same time, significant progress has been made in understanding the molecular aspects of pathogenesis, allowing the selection of highly effective fungal strains. Differences in the susceptibility of adults and nymphs of the German cockroach Blattella germanica L. to entomopathogenic fungi was shown. The possibility of enhancing the pathogenicity of various types of fungi when integrated with insecticides in sublethal doses is considered. The German cockroach has evolved many physical barriers, behavioral traits, and physiological mechanisms that prevent infection by various entomopathogens. These barriers include the outer cuticle, inner cuticle, digestive tract and peritrophic membrane, and immunological barriers. Fungal conidia entering the cockroach’s digestive tract was inactivated by a combination of antimicrobial compounds produced by the cockroach and commensal microorganisms, intestinal pH and digestive enzymes. The microbiota of Bl.?germanica may play a critical role in protecting cockroaches from fungal invasion and colonization. Keywords: insecticide resistance, Blattella germanica, Beauveria bassiana, Metarhizium anisopliae, mycoinsecticides, entomopathogenic fungi.

Common consumer residual insecticides lack efficacy against insecticide-susceptible and resistant populations of the German cockroach (Blattodea: Ectobiidae).

The German cockroach, Blattella germanica (L.) (Blattodea: Ectobiidae), is a ubiquitous pest in affordable housing. They represent a major threat to human health due to their contribution of asthma-exacerbating allergens and the potential to transfer pathogenic microorganisms indoors. Despite well-documented pyrethroid resistance, pyrethroid-based broadcast residual insecticide products are often used by residents to control cockroaches in their homes. Additionally, there is little empirical independent testing of these products. Thus, it remains unclear how effective these commonly used do-it-yourself products are at controlling German cockroaches. This study represents a comprehensive examination of the efficacy of these products with direct, limited, and continuous exposure assays on a variety of common household surfaces on field populations of cockroaches with varying levels of pyrethroid resistance. While most products performed well when applied directly to test insects, mortality was substantially lower across all surfaces with limited exposure (30min). In continuous exposure assays on a nonporous surface, products took at least 24hr to cause 100% mortality in a field population, with some products taking up to 5d to achieve 100% mortality. The findings of this study demonstrate a lack of residual efficacy from common pyrethroid-based consumer-use pesticides products. Given that it is not feasible to find and treat every cockroach in a home directly, the residuality of spray-based formulations is critical for products designed to control German cockroaches. Without residual efficacy, as shown in the consumer aerosol and spray products tested, we expect these products to add little to no value to cockroach control.

Adaptability of the gut microbiota of the German cockroach Blattella germanica to a periodic antibiotic treatment

High-throughput sequencing studies have shown that diet or antimicrobial treatments impact animal gut microbiota equilibrium. However, properties related to the gut microbial ecosystem stability, such as resilience, resistance, or functional redundancy, must be better understood. To shed light on these ecological processes, we combined advanced statistical methods with 16 S rRNA gene sequencing, functional prediction, and fitness analyses in the gut microbiota of the cockroach Blattella germanica subject to three periodic pulses of the antibiotic (AB) kanamycin (n=512). We first confirmed that AB did not significantly affect cockroaches' biological fitness, and gut microbiota changes were not caused by insect physiology alterations. The sex variable was examined for the first time in this species, and no statistical differences in the gut microbiota diversity or composition were found. The comparison of the gut microbiota dynamics in control and treated populations revealed that (1) AB treatment decreases diversity and completely disrupts the co-occurrence networks between bacteria, significantly altering the gut community structure. (2) Although AB also affected the genetic composition, functional redundancy would explain a smaller effect on the functional potential than on the taxonomic composition. (3) As predicted by Taylor's law, AB generally affected the most abundant taxa to a lesser extent than the less abundant taxa. (4) Taxa follow different trends in response to ABs, highlighting "resistant taxa," which could be critical for community restoration. (5) The gut microbiota recovered faster after the three AB pulses, suggesting that gut microbiota adapts to repeated treatments.

A comparative analysis of beta-cypermethrin nanoemulsion and traditional emulsion dosages on enzyme activities in Blattella germanica

ObjectiveTo compare the impact of two pesticide dose forms on Blattella germanica (B. germanica)resistance enzymes.The micro-drop technique was utilized on subcultured B. germanica, and the metabolic enzyme activity was assessed.Using spectrophotometry, the relative enzyme activities of B.germanica were determined.Profile analysis was used to compare the enzyme activities of beta-cypermethrin in both nanoemulsion and traditional emulsion forms.Findings: The suppression percentages of the acetylcholinesterase enzyme (AchE), GST, and P450–O demethylases across different pesticide formulations were analyzed using regression equations, yielding F = 31.18, P < 0.001; F = 9.18, P < 0.001; and F = 4.58, P < 0.02.Conclusion: The suppression of AchE, GST, and P450–O demethylase by beta-cypermethrin nanoemulsion was more significant compared to the beta-cypermethrin emulsifiable concentrate.The study concluded that beta-cypermethrin nanoemulsion had a significant impact on insect detoxifying enzymes compared to beta-cypermethrin emulsifiable concentrate due to their numerous advantages.

Functional redundancy of the three insulin receptors of cockroaches

Gene duplication is a fundamental evolutionary process which provides opportunities to acquire new gene functions. In the case of the insulin receptors (InRs) in cockroaches and close-related insects, two successive duplications determined the occurrence of three InR genes: InR2, InR1 and InR3, the last two forming a sister cluster to InR2. The biological role of each of the gene duplicates and whether they resulted from neofunctionalization or subfunctionalization is still unclear. The analysis of the sequences from different lineages did not detect positive selection as driving the divergence of InR1 and InR3, discarding neofunctionalization, and suggesting that there is no functional divergence between both gene copies. Using the cockroach Blattella germanica as a model, we have determined that BgInR2 is the gene with the highest expression levels in all the tissues analyzed, both in adult females and males, as well as in nymphs and embryos. BgInR3 is second in expression levels while BgInR1 is expressed at lower levels and only in some tissues. The selective depletion by RNAi of each of the three InRs, analyzed in terms of phenotype and fat body transcriptomic profiles, resulted in essentially redundant effects, with a magnitude approximately proportional to the level of expression of the respective InR. Therefore, the results indicate that the InR duplicates likely experienced a subfunctionalization process, by which the three InRs maintained similar functions but contributing to those functions proportionally to their expression levels.

First record of the lobster cockroach Nauphoeta cinerea (Olivier, 1789) (Insecta: Blattodea) in Europe with remarks on synanthropic cockroaches of the Iberian Peninsula

AbstractGlobalization has facilitated the introduction and establishment of organisms beyond their natural ranges, leading to significant ecological and economic consequences. While many non‐native species are well documented, others remain understudied, either due to their unknown impact or morphological similarities with native species. This study addresses such a case, focusing on synanthropic cockroaches within the order Blattodea. Despite the order's diversity, less than 1% of known species are recorded in urban environments. While certain species like Periplaneta americana, Blatta orientalis and Blattella germanica are well distributed and studied, others remain largely unknown. This research unveils the first established population of Nauphoeta cinerea in Europe, specifically in Spain (Asturias, northern Iberian Peninsula), with specific genetic and morphological confirmation. This study also explores potential pathways of introduction for N. cinerea. Long‐distance transport by ships or escape/release from captivity are proposed as potential pathways for the newly established populations in Asturias. The species' high fecundity and parthenogenetic reproduction raise concerns about its potential invasiveness. Additionally, this study includes unpublished data on various synanthropic cockroaches in Asturias (with the first records of P. lateralis and Supella longipalpa for this area), drawn from specimens deposited in biological collections and some extra collections. An identification key for all Spanish non‐native synanthropic cockroach species is provided to assist in future detections. This research emphasizes the imperative need for robust monitoring systems, highlights the scarcity of scientific information regarding synanthropic cockroach distribution and underscores the pivotal role of biological collections in advancing our understanding of invasive species.

Composition and abundance of cockroaches in traditional markets of Purwokerto City, Indonesia

Abstract. Ambarningrum TB, Widhiono I, Kusmintarsih ES, Pratiknyo H, Haryanto T, Hasyifah FN. 2024. Composition and abundance of cockroaches in traditional markets of Purwokerto City, Indonesia. Biodiversitas 25: 2773-2779. Markets with high human activity and abundant food are ideal conditions for cockroaches. This study aimed to investigate the composition and abundance of cockroaches infesting three markets in Purwokerto City, Central Java, Indonesia. To achieve this objective a survey method with random sampling used baiting traps and hand collection. The analysis used the Shannon-Wiener index (H'), Evenness index, relative abundance, and density index. The results showed that three cockroach families were identified, namely Blattellidae, Blattidae, and Blaberidae. The cockroaches found in markets 1 and 3 consisted of five species, namely Blattella germanica (Linnaeus, 1767), Periplaneta americana (Linnaeus, 1758), Blatta lateralis (Serville, 1838), Nauphoeta cinerea (Olivier, 1789), and Pycnoscelus surinamensis (Linnaeus, 1758), while in Market 2 there were only three species, namely B. germanica, P. americana, and N. cinerea. The total population were 2467, 81, and 3627 individuals in Market 1, 2, and 3 respectively. The B. germanica predominated in Markets 1 and 2, while N. cinerea dominated in Market 3. Furthermore, density levels varied across markets, showing differing infestation intensities. The study explained the importance of integrated pest management strategies and regular monitoring to control cockroaches population effectively. These results provide valuable insights for local pest control efforts aimed at maintaining hygiene and health standards in market environments.

Comparative study on biochemical responses to imidacloprid and clothianidin in cockroaches (Blattella germanica)

AbstractCockroaches, ubiquitous pests known for significant reproduction and as potential vectors of diseases, are notorious for their adoptability to a variety of insecticides that cause substantial challenges in pest control. The present research evaluated the LC50 concentrations of imidacloprid (0.65 mg/L) and clothianidin (2.5 μg/L) for Blattella germanica using topical and bait methods. The cockroaches were exposed to one‐third concentration of LC50 at a regular interval of 1, 2, 4, 8, 12, 16 and 20 days. During exposure, the activity of P450 monooxygenase increased, whereas the activity of brain acetylcholinesterase decreased. Lactate dehydrogenase, alkaline and acid phosphatase activity were highest on day 4, with a slight recovery on day 20. The elevated activities for superoxide dismutase and catalase, as well as increased lipid peroxidation levels on day 4, followed by a significant recovery in activity on day 20. The glutathione‐S‐transferase activity was elevated while the glutathione content was reduced, and a significant restoration was observed at the end of the experiment. The biochemical mechanisms of the organisms such as P450, esterase enzymes and oxidative systems, are actively involved in the detoxification mechanism. The study elucidated that the insecticide defence mechanism triggers detoxification pathways that encompass the metabolism of endogenous insecticidal compounds, with clothianidin showing greater efficacy and lower detoxification compared with imidacloprid.