External Bacterial Flora and Antimicrobial Susceptibility Patterns of Staphylococcus spp. and Pseudomonas spp. Isolated from Two Household Cockroaches, Blattella germanica and Blatta orientalis

A study was performed to estimate the prevalence of the external bacterial flora of two domestic cockroaches （Blattella germanica and Blatta orientalis） collected from households in Tebessa （northeast AIgeria）.Three major bacterial groups were cultured （total aerobic, enterobacteria, and staphylococci） from 14 specimens of cockroaches, and antibiotic susceptibility was tested for both Staphylococcus and Pseudomonas isolates. Culturing showed that the total bacterial load of cockroaches from different households were comparable （P〈0.001） and enterobacteria were the predominant colonizers of the insect surface, with a bacterial load of （2.1×10^5 CFU/insect）, whereas the staphylococci group was the minority. Twenty-eight bacterial species were isolated, and susceptibility patterns showed that most of the staphylococci isolates were highly susceptible to chloramphenicol, gentamycin, pristinamycin, ofloxacin, clindamycin, and vancomycin; however, Pseudomonas strains exhibited resistance to amoxicillin/clavulanic acid, imipenem, and the second-generation antibiotic cephalosporin cefuroxime.

Book review:Cockroaches of Southeastern China

The book, Cockroaches of Southeastern China, wrote by Xianwei Liu, Weibing Zhu, Li Dai and Hanqiang Wang, was published in 2017.In this book,the cockroachs fauna of the Southern China was observed,occupied Shandong, Anhui,Jiangsu, Shanghai, Zhejiang, Fujian, Jiangxi, Taiwan, Guangdong and Hainan Provinces.

First molecular genetic evidenee for automictic parthenogenesis in cockroaches

Parthenogenesis is an asexual mode of reproduction that plays an important role in the evolution of sex, sociality, and reproduction strategies in insects. Some species of cockroach exhibit thelytoky, a type of parthenogenesis in which female offspring are produced without fertilization. However, the cytological and genetic mecha? nisms of parthenogenesis in cockroaches are not well understood. Here we provide the first molecular genetic evidence that cockroaches can reproduce through automixis. Using the American cockroach Periplaneta aniericana, we performed microsatellite analysis to investigate the genetic relationship between parthenogenetically produced nymphs and the parent virgin females, and found that all parthenogenetic offspring were homozygous for autosomal microsatellite markers, whereas the female parents were heterozygous. In addition, flow cytometry analysis revealed that the parthenogenetic offspring were diploid. Taken together, our results demonstrate that P. americana exhibits automixis-type thelytoky, in which diploidy is restored by gamete duplication or terminal fusion. These findings highlight the unique reproduction strategies of cockroaches, which are more varied than was previously recognized.

Habitat influences on diversity of bacteria found on German cockroach in Beijing

Cockroaches are worldwide indoor pests carrying microorganisms of medical importance. German cockroaches （Blattella germanica） were sampled in five habitats （hospital, restaurant, office home, and market） in Beijing, and the bacteria were isolated from their external surface and alimentary tract and identified using a Biolog identification system. Cockroach densities significantly differed among habitats （market 〉 home 〉 office 〉 restaurant 〉 hospital）. However, no significant differences in bacterial abundance carried by individual German cockroaches （of either sex） were found among habitats. The bacterial abundance in the gut was significantly higher than that on the surface. There were no significant differences in bacterial species richness observed among habitats, sex, carrying position or their interaction. Cluster analysis showed that cockroach densities and bacterial abundance found in the market differed significantly from the other four habitats. The bacterial diversity was not significantly reduced in sensitive facilities such as hospital and restaurant, even though pesticide and bactericide were more frequently applied there. The implications of these findings were discussed in this article.

Efficient Protein-based Bait Formulation for Attraction and Feeding Response of Fruit Flies (Diptera: Tephritidae) in Myanmar

Protein baitsprays were produced from many different sources for the controlling fruit flies in the integrated pest management program around the world.Here,fruit fly baits were formulated based on cost-effective bait mixtures such as local jaggery,brewers spent grain(BSG),apple cider vinegar,wheat bran powder and local red wine with the fresh enzyme from papaya and pineapple.Fruit fly Baits were prepared by mixing the small amount of local detergent as insecticide.Our results indicated that the best efficient fruit fly bait for area wide integrated pest management(AW-IPM)is the BSG-based bait whereas the second efficient bait is local red wine-based bait.The highest fruit fly per trap per day(FTD)value by BSG-based bait traps was discovered.The highest female captured percentage is BSG-based bait with papaya solution.The field analysis of one week and one month old protein-based bait showed that FTD values decreased slightly while only one month old wheat bran-based bait dropped to the base.The BSG-based baits analysis is effective not only female fruit flies but also cockroaches male in Myanmar’s tropical region.Thus our results reveal that the efficient protein-based bait is the fresh BSG-based bait with papaya solution.

New aspects about Supella longipalpa(Blattaria:Blattellidae)

The brown-banded cockroach,Supella longipalpa(Blattaria:Blattellidae)(S.longipalpa),recently has infested the buildings and hospitals in wide areas of Iran,and this review was prepared to identify current knowledge and knowledge gaps about the brown-banded cockroach.Scientific reports and peer-reviewed papers concerning S.longipalpa and relevant topics were collected and synthesized with the objective of learning more about health-related impacts and possible management of S.longipalpa in Iran.Like the German cockroach,the brown-banded cockroach is a known vector for food-borne diseases and drug resistant bacteria,contaminated by infectious disease agents,involved in human intestinal parasites and is the intermediate host of Tnchospirura leptostoma and Moniliformis moniliformis.Because its habitat is widespread,distributed throughout different areas of homes and buildings,it is difficult to control.Considering its possible resistance to insecticides,the control situation may be far more complex.For improved control of S.longipalpa an integrated pest management program is needed.Sanitation,indoor insecticide spraying in the initial cockroach control phase and insecticide formulation baits are recommended simultaneously.

Effects of Organic Substrates on Development and Survival of Blattela germanica for Food and Feed in Kenya

Entomophagy has gained popularity as a novel approach to addressing food and nutrition insecurity, particularly in sub-tropical and tropical countries. Cockroaches, for example, have the potential to alleviate nutritional deficiencies, as well as the erratic supply of protein in feeds. They can also be reared on locally available organic substrates. This study investigated growth performance and survival of german cockroach (Blattella germanica) reared on locally available organic matter substrates as treatments;spent brewers’ grain (Treatment A), Treatment B consisting of (40%: wheat bran: 40% spent brewers’ grain: 20% Caridina nilotica), wheat bran (Treatment C), and C. nilotica (Treatment D) and in a completely randomised design (CRD). Each treatment was replicated four times, while in each replicate 20 - 30 nymphs were reared for forty-two days. Feed intake for all the treatments was not significantly different. There was a significant difference (P 0.05) in mature weight, average daily weight gain, live weight, and survival during rearing period. Cockroach performed well on treatment B and recorded highest mature weight, overall performance index, survival was 90.25 mg, 197.35, 96%. The least perfomance was reported in Treatment C;1.78, 83, 143.17 and 72.5 for average growth rate, survival, overall perfomance and mature weight respectively. B. Based on these findings, a single feed as used in this study was inferior to the composite (Treatment B) in all parameters of growth performance and survival. The composite diet (Treatment B) could be suitable substrate for mass production of B. germanica for feed and food.

Two sex pheromone receptors for sexual communication in the American cockroach

Volatile sex pheromones are vital for sexual communication between males and females.Females of the American cockroach,Periplaneta americana,produce and emit two sex pheromone components,periplanone-A(PA)and periplanone-B(PB).Although PB is the major sex attractant and can attract males,how it interacts with PA in regulating sexual behaviors is still unknown.In this study,we found that in male cockroaches,PA counteracted PB attraction.We identified two odorant receptors(ORs),OR53 and OR100,as PB/PA and PA receptors,respectively.OR53 and OR100 were predominantly expressed in the antennae of sexually mature males,and their expression levels were regulated by the sex differentiation pathway and nutrition-responsive signals.Cellular localization of OR53 and OR100 in male antennae further revealed that two types of sensilla coordinate a complex two-pheromone-two-receptor pathway in regulating cockroach sexual behaviors.These findings indicate distinct functions of the two sex pheromone components,identify their receptors and possible regulatory mechanisms underlying the male-specific and age-dependent sexual behaviors,and can guide novel strategies for pest management.

Acetyl coenzyme A carboxylase modulates lipogenesis and sugar homeostasis in Blattella germanica

Lipid and sugar homeostasis is critical for insect development and survival.In this study,we characterized an acetyl coenzyme A carboxylase gene in Blattella germanica(BgACC)that is involved in both lipogenesis and sugar homeostasis.We found that BgACC was dominantly expressed in the fat body and integument,and was significantly upregulated after molting.Knockdown of BgACC in 5th-instar nymphs did not affect their normal molting to the next nymphal stage,but it caused a lethal phenotype during adult emergence.BgACC-RNA interference(RNAi)significantly downregulated total free fatty acid(FFA)and triacylglycerol(TAG)levels,and also caused a significant decrease of cuticular hydrocarbons(CHCs).Repression of BgACC in adult females affected the development of oocytes and resulted in sterile females,but BgACC-RNAi did not affect the reproductive ability of males.Interestingly,knockdown of BgACC also changed the expression of insulin-like peptide genes(BglLPs),which mimicked a physiological state of high sugar uptake.In addition,BgACC was upregulated when B.germanica were fed on a high sucrose diet,and repression of BgACC upregulated the expression of the glycogen synthase gene(BgGlyS).Moreover,BgACC-RNAi increased the circulating sugar levels and glycogen storage,and a longevity assay suggested that BgACC was important for the survival of B.germanica under conditions of high sucrose uptake.Our results confirm that BgACC is involved in multiple lipid biogenesis and sugar homeostasis processes,which further modulates insect reproduction and sugar tolerance.This study benefits our understanding of the crosstalk between lipid and sugar metabolism.

Prevalence of sensitivity to cockroach allergens and IgE crossreactivity between cockroach and house dust mite allergens in Chinese patients with allergic rhinitis and asthma

Background Cockroaches are an important indoor allergen source causing allergic rhinitis and asthma. The aim of this study was to investigate the cockroach prevalence in mainland of China and the cross-reactivity of IgE between cockroach and house dust mite allergen in Chinese patients.Methods The cockroach sensitization pattern was based on a skin prick test （SPT） obtained from a national multicenter prevalence study, in which 6304 patients from 25 allergy centers across China participated. Factors, including different regions of China, age, gender and the correlations between the American and German cockroaches and house dust mite Der p were investigated. Eighteen out of 1236 clinical sera from south China were selected to perform the cross-inhibition assay between house dust mites and cockroaches.Results Totally 25.7% of patients were SPT positive to the American cockroach （Periplaneta Americana, Per a） and 18.7% SPT positive to the German cockroach （Blattella germanica, Bla g）. The prevalence of positive cockroach SPT was higher in southern than in northern China, higher in adults than in children, and higher in males than in females.Patients had relatively low levels of cockroach SPT reactions, mainly class 1 or 2. Of the SPT positive cockroach patients,88% were also SPT positive to house dust mite （Dermatophagoides pteronyssinus, Der p）. An IgE cross-inhibition study confirmed that Der P sensitization could cause false positive SPT reactions against cockroach.Conclusions A relatively high prevalence of cockroach sensitivity was found in mainland of China. However, a cross-inhibition study showed that only a small number of patients appear to have Bla g and/or Per a as primary sensitizing source. The importance of cockroaches as a risk factor for sensitization and triggers of allergic symptoms in mainland of China needs to be further investigated.

Morphometrics confirms the conspecific between Blaptica dubia(Serville) and B. interior Hebard(Blattodea:Blaberidae)

Blaptica dubia(Serville, 1838) and B. interior Hebard, 1921 were considered to be cryptic species. The characteristics originally proposed for their identification are not reliable.Thus the relationship between the two species should be re-considered. As a comparative approach and to analyze intraspecific variability, morphological and morphometric methods were performed. Traditional and new characters such as wing shape and pronotum contour were utilized. We found significant differences between both species(p <0.05) in the shape of the wing, but there was an overlap of values. We did not find differences in the body measurements or in the shape and size of the pronotum between the species. The variability gradient does not allow an accurate identification of species neither with the male genitalia or the pronotal macula.Based on the obtained results, B. interior Hebard 1921 is considered to be a junior synonym of B. dubia(Serville, 1838).

Derived, still living cockroach genus Cariblattoides （Blattida： Blattellidae） from the Eocene sediments of Green River in Colorado, USA

Cariblattoides labandeirai sp.n. from the Eocene sediments of Green River in Colorado, USA bear only two plesiomorphies, but also several significant autapomorphies within the advanced and highly derived living cockroach genus. Thus, Cariblattoides with extant occurrence in the Caribbean and South America was historically common in the Nearctic, and represents important evidence for the occurrence of derived living genera of cockroaches -50 Ma ago. Generally, the vast majority of living genera were absent during the Palaeocene, thus the diversification of most living cockroach lineages near the Palaeocene/Eocene boundary must have been extremely rapid. Females of living C. suave, the type species, have identical （sophisticated） coloration ofpronotum, but the most related living taxa are C. piraiensis and C.fontesi from Brazil （supported by phylogenetical analysis）.

Molecular Characteristics of Cockroach Allergens

Cockroaches, commonly found in urban dwellings worldwide, have long been considered vectors of various infectious diseases and cockroach allergens are one of the major etiologic risk factors for IgE-mediated allergic respiratory illness throughout the world. A high prevalence of cockroach hypersensitivity in atopic （20-55 %） and asthmatic （49-60 %） populations has been documented. Cockroach allergens with molecular weights ranging from 6 to 120 kD have been identified by various standard immunochemical techniques. This article covers the characteristics of major cockroach allergens that have been purified, sequenced, cloned, and produced as recombinant proteins. Cellular ＆ Molecular Immunology. 2005;2（3）： 177-180.

Grainy head signaling regulates epithelium development and ecdysis in Blattella germanica

The transcription factor grainy head(Grh)functions in the protection of the epithelium against the external environment by generating strongly adhesive layers,and this function is conserved in vertebrates and invertebrates.In Drosophila,the top model for holometabolous insects,Grh is necessary during embryonic development,epidermal differentiation,central nervous system specification and epithelial repair.However,the function of this gene in hemimetabolous insect epithelia remains unknown.To examine the function of Grh signaling in regulating epithelium development in Hemimetabola,we focused on the Blattella germanica epidermal layer using a gene knockdown strategy.The spatiotemporal expression pattern of BgGrh was detected,and knockdown of Bg-Grh and BgCad96ca,which provide positive feedback to BgGrh,caused severe defects in new epithelium development and impeded the molting process required to discard the old integument.Knockdown of the expression of BgGrh and BgCad96ca caused increased expression of chitin synthase gene{BgCHSl)and chitinase gene{BgCht5),the upregulations of which should be mediated by the higher level of hormone receptor 3{BgHr3)gene.In conclusion,epithelium development is regulated by Grh signaling,which might represent a potential target for the control of urban pest cockroaches.

Effect of exposure to chlorpyrifos on the cuticular and internal lipid composition of Blattella germanica males

The results of our research on the cuticular and internal lipids of Blattella germanica males provide new information on variation in the composition of the cuticular and internal lipids ofB. germanica males after exposure to the presence of the insecticide. gas chromatography and gas chromatography-mass spectrometry analyses were used to identify and quantify the cuticular and internal lipid composition in males and males exposed to insecticide. There were significantly more acids having an even number of carbon atoms in the molecule, and these were also generally in higher concentrations. The following acids were in a higher concentration： C16：0 and C18：1, C18：2, C18：0. In both males and males exposed to insecticide, 24 fatty acids ranging from C6 to C22 were determined. However, there was a significantly higher content of fatty acids in the surface lipids of B. germanica males after exposure to insecticide. Our results indicate a higher content of n-alkanes, sterols, particularly cholesterol, fatty acids, and fatty acid methyl esters in the B. germanica surface after exposure to chlorpyrifos than in males that were not exposed.

Two putative fatty acid synthetic genes of BgFas3 and BgElo1 are responsible for respiratory waterproofing in Blattella germanica

Water retention is critical for physiological homeostasis and survival in terrestrial insects. While deposition of hydrocarbons on insect cuticles as a key measure for water conservation has been extensively investigated, we know little about other mechanisms for preventing water loss in insects. Here, we report two fatty acid synthetic genes that are independent of hydrocarbon production but crucial for water retention in the German cockroach Blattella germanica (L.). First, an integument enriched fatty acid elongase gene (BgElo1) was identified as a critical gene for desiccation resistance in B. germanica;however, knockdown of BgElo1 surprisingly failed to cause a decline in cuticular lipids. In addition, RNA interference (RNAi)-knockdown of an upstream fatty acid synthase gene (BgFas3) showed a similar phenotype, and transmission electron microscopy analysis revealed that BgFas3- or BgElo1-RNAi did not affect cuticle architecture. Bodyweight loss test showed that repression of BgFas3 and BgElo1 significantly increased the weight loss rate, but the difference disappeared when the respiration was closed by freeze killing the cockroaches. A water immersion test was performed, and we found that BgFas3- and BgElo1-RNAi made it difficult for cockroaches to recover from drowning, which was supported by the upregulation of hypoxia-related genes after a 10-h recovery from drowning. Moreover, a dyeing assay with water-soluble Eosin Y showed that this was caused by the entry of water into the respiratory system. Our research suggests that BgFas3 and BgElo1 are required for both inward and outward waterproofing of the respiratory system. This study benefits the understanding of water retention mechanisms in insects.

Systemic RNAi of V-ATPase subunit B causes molting defect and developmental abnormalities in Periplaneta fuliginosa

The vacuolar (H+)-ATPases (V-ATPases) are ATP-driven proton pumps with multiple functions in many organisms. In this study, we performed structural and functional analysis of vha55 gene that encodes V-ATPase subunit B in the smokybrown cockroach Periplaneta fuliginosa (Blattodea). We observed a high homology score of the deduced amino acid sequences between 10 species in seven orders. RNAi of the vha55 gene in R fuliginosa caused nymphal/nymphal molting defects with incomplete shedding of old cuticles, growth inhibition, as well as bent and wrinkled cuticles of thoraxes and abdominal segments. Since growth inhibition caused by vha55 RNAi did not interfere in the commencement of cockroach molting, molting timing and body growth might be controlled by independent mechanism. Our study suggested V-ATPases might be a good candidate molecule for evolutionary and developmental studies of insect molting.

Testing decreasing variabililty of cockroach forewings through time using four Recent species： Blattella germanica, Polyphaga aegyptiaca, Shelfordella lateralis and Blaberus craniifer, with implications for the study of fossil cockroach forewings

Vrsansky, （2000） considered there is decreasing variability in the forewings of cockroaches through time, based on a study of fossil and Recent species. This study tests his theory, based on a study of four Recent species of cockroaches： Blattella germanica （Blattellidae）, Polyphaga aegyptiaca （Polyphagidae）, Shelfordella lateralis （Blattidae） and Blaberus craniifer （Blaberidae）. The new results, based on the coefficient of variation （CV） of the number of veins, indicate that Recent species can be more variable than fossil species and therefore do not support the theory. The results also show that at least 30 complete wings of the same species are required for a reliable CV value that is compa- rable between species.

Primal structure and activity studies of allatostatin 4 (AST 4)

The juvenile hormones (JH) are critical to the contro1 of insect development andreproduction. The production of JH by the corpora allata (CA) is regulatd in part bypeptides originating from brain. One group of these peptides termed allatostatins (AST)reversibly inhibits the biosynthesis of JH invitro. The correlation of these events suggeststhat AST, i.e. their biosynthesis, are important in the regulation of JH biosynthesis.

Melanin synthesis genes BgTH and BgDdc affect body color and cuticle permeability in Blattella germanica

Melanin is involved in cuticle pigmentation and sclerotization of insects,which is critical for maintaining structural integrity and functional completeness of insect cuti-cle.The 2 key enzymes of tyrosine hydroxylase(TH)and dopa decarboxylase(DDC)predicted in melanin biosynthesis are usually conserved in insects.However,it is unclear whether their function is related to epidermal permeability.In this study,we identified and cloned the gene sequences of BgTH and BgDdc from Blattella germanica,and revealed that they both showed a high expression at the molting,and BgTH was abundant in the head and integument while BgDdc was expressed highest in the fat body.Using RNA in-terference(RNAi),we found that knockdown of BgTH caused molting obstacles in some cockroaches,with the survivors showing pale color and softer integuments,while knock-down of BgDdc was viable and generated an abnormal light brown body color.Desiccation assay showed that the dsBgTH-injected adults died earlier than control groups under a dry atmosphere,but dsBgDdc-injected cockroaches did not.In contrast,when dsRNA-treated cockroaches were reared under a high humidity condition,almost no cockroaches died in all treatments.Furthermore,with eosin Y staining assay,we found that BgTH-RNAi resulted in a higher cuticular permeability,and BgDdc-RNAi also caused slight dye pen-etration.These results demonstrate that BgTH and BgDdc function in body pigmentation and affect the waterproofing ability of the cuticle,and the reduction of cuticular perme-ability may be achieved through cuticle melanization.