RESUMO
Lactones are cyclic esters of hydroxy carboxylic acids, present in several fruits and animals consumed by humans. There is evidence that some lactones modify insect behavior. The aim of the present study was to evaluate the repellent effect of four lactones (γ- and δ-nonalactone, and γ- and δ-dodecalactone) in first instar nymphs of the German cockroach, Blattella germanica (Linnaeus). To assess repellency, a nymph was placed on a circle of filter paper, half of which had been treated with lactone dissolved in acetone and the other half with acetone alone. The behavior of the nymph was recorded and the time the nymph spent in each half of the paper was quantified using Ethovision XT 10.1 software. Values of Distribution Coefficient (DC) were calculated: DC = (Tt - TA) / Tt, where Tt is the experimental time and TA is the time the nymph spent in the area treated with the repellent agent. DC can vary between 0 and 1. Values significantly higher than 0.5 indicate repellency. N,N-diethyl-meta-toluamide (DEET) was used as a positive control. DEET, δ- and γ-nonalactone caused repellency as from 77.9 µg/cm2, whereas γ- and δ-dodecalactone had a repellent effect starting at 779.0 µg/cm2. The values of DC for these concentrations were 0.89 (DEET), 0.86 (γ-nonalactone), 0.87 (δ-nonalactone), 0.83 (γ-dodecalactone), and 0.72 (δ-dodecalactone). To our knowledge, this is the first report of repellency produced by lactones in the German cockroach. This work allowed to identify two lactones that have a repellent effect similar to DEET.
Assuntos
Blattellidae , Repelentes de Insetos , Lactonas , Animais , Blattellidae/efeitos dos fármacosRESUMO
Although most of the diversity of true bugs (Hemiptera: Heteroptera) is terrestrial, over 550 species of water bugs (Heteroptera: Gerromorpha, Leptopodomorpha & Nepomorpha) have been recorded from Brazil alone. Southeastern Brazil, composed of the states of Esprito Santo, Minas Gerais, Rio de Janeiro and So Paulo, is the best studied region of the country, but there are still knowledge gaps in the area. Here, two new species are described from Esprito Santo: Hydrometra ruschii Cordeiro, Rodrigues & Moreira, sp. nov. and H. tuberculata Cordeiro, Rodrigues & Moreira, sp. nov. (Gerromorpha: Hydrometridae). Furthermore, new records from southeastern Brazil are provided for 78 species of water bugs, of which 19 are firstly recorded from Esprito Santo, four from Minas Gerais, eight from Rio de Janeiro, and seven from So Paulo.
Assuntos
Blattellidae , Hemípteros , Heterópteros , Animais , BrasilRESUMO
Many authors report biological differences among insecticide-resistant pest species, mainly associated with parameters of life history, but only a few studies approach differences at the behavioural level. Feeding behaviour in Blattella germanica (L.) is modulated by the detection of chemical volatiles emitted from food sources in order to be located a long-median distance, and also by the physicochemical properties of food. This work aimed to study the differences in the feeding behaviour of a susceptible and a pyrethroid-resistant strain of B. germanica, in the location and exploitation of a food source. Resistant males showed a lower performance in the feeding behaviour compared to susceptible males. Particularly, the time taken to locate the source was significantly higher in the resistant individuals, suggesting a lower capacity in the detection of food odours. In addition, although the Intake rate was negatively related to the stiffness of food for both strains, resistant individuals showed a lower intake rate compared to susceptible ones, when exploiting a food source of the same stiffness. In a control context, the phenotypic characteristics associated to feeding of pyrethroid-resistant individuals could induce a behavioural resistance mechanism caused by a reduction in the amount of toxic gel bait ingested. If that is the case, resistance of this strain would not be associated to physiological changes affecting the toxicity of the active principle of gel baits, but to a lower efficacy of these products against resistant individuals due to less amount of gel consumed, generating control problems of this pest.
Assuntos
Blattellidae , Baratas , Inseticidas , Piretrinas , Animais , Baratas/fisiologia , Comportamento Alimentar , Resistência a Inseticidas , Inseticidas/farmacologia , Masculino , Piretrinas/farmacologiaRESUMO
The use of chemical insecticides is the main control method for Blattella germanica worldwide. The prolonged and frequent use of insecticides produced the selection of insecticide-resistant individuals. The German cockroach is one of the most widespread urban pests in Argentina. In the last decades, resistance monitoring studies in this country demonstrated that there is a high prevalence of pyrethroid-resistant populations of B. germanica in the field. In this work, we studied the resistance mechanisms of a field-collected strain of B. germanica at toxicological, enzymatic, and molecular levels. A resistance ratio of 100 was obtained for the resistant strain when it was exposed to ß-cypermethrin. The pretreatment with specific synergists (piperonyl butoxide and triphenyl phosphate) led to a significant increase in the toxicity of the pyrethroid, suggesting an involvement of oxidases and esterases in the detoxification of this insecticide. Moreover, esterase and oxidase activities in the resistant strain were 1.5-fold and 2-fold higher respectively, compared to the susceptible individuals. On the other hand, the voltage-gated sodium channel gene of the resistant cockroaches did not show nucleotidic substitutions in the domain II which are associated to knockdown resistance in this species. These results suggest that the main mechanism of resistance of the studied cockroaches' strain is metabolic, mainly due to an increase in the activity of oxidase and esterase enzymes. The results of this work in addition to other reports found in literature show that the extended use of a single active principle for cockroach control promotes the development of resistance leading to control failure in the field. In contrast, integrated pest management strategies include the use of different control tools in addition to chemical insecticides, which delay the appearance of resistance increasing the efficacy of pest control.
Assuntos
Blattellidae , Inseticidas , Piretrinas , Animais , Argentina , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Piretrinas/farmacologiaRESUMO
The Neotropics harbors a tremendous diversity of cockroaches yet their evolutionary history is largely unknown. We reconstructed for the first time the phylogeny of the Neotropical genus Xestoblatta Hebard using mitochondrial and nuclear genes from 12 species distributed in Central America and northern South America. Additionally, we conducted a morphological analysis of external characters and male genitalia. In the phylogenetic analysis we recovered the genus Xestoblatta as non-monophyletic, resulting in three unrelated lineages. From the morphological variability described here, we identified three different morphological groups matching the phylogenetic results. The phylogenetic relationships of the three lineages within the Blattellidae were partially resolved. Lineage 1 was nested within a supported clade corresponding to the tribes Blattellini + Symplocini, while lineages 2 and 3 nested within the clade corresponding to the tribe Pseudomopini. Based on our results, we propose to divide Xestoblatta (sensu lato) into three monophyletic genera: Antroxestoblatta gen.n., Sinatablatta gen.n., and Xestoblatta (sensu stricto). We also describe a new species Sinatablatta magdalenensis sp.n. and propose a taxonomic rearrangement for Xestoblatta (sensu lato).
Assuntos
Blattellidae , Animais , Genitália , Masculino , Filogenia , Análise de Sequência de DNARESUMO
Juvenile hormone (JH) controls insect reproduction and development through an intracellular receptor complex comprising two bHLH-PAS proteins, the JH-binding Methoprene-tolerant (Met) and its partner Taiman (Tai). Many hemimetabolous insects including cockroaches strictly depend on JH for stimulation of vitellogenesis. In termites, the eusocial hemimetabolans, JH also regulates the development of caste polyphenism. Studies addressing the agonist ligand binding to recombinant JH receptors currently include three species belonging to two holometabolous insect orders, but none that would represent any of the hemimetabolous orders. Here, we examined JH receptors in two representatives of Blattodea, the cockroach Blattella germanica and the termite Prorhinotermes simplex. To test the JH-binding capacity of Met proteins from these species, we performed chemical synthesis and tritium labeling of the natural blattodean JH homolog, JH III. Our improved protocol increased the yield and specific activity of [10-3H]JH III relative to formerly available preparations. Met proteins from both species specifically bound [3H]JH III with high affinity, whereas Met variants mutated at a critical position within the ligand-binding domain were incapable of such binding. Furthermore, JH III and the synthetic JH mimic fenoxycarb stimulated dimerization between Met and Tai components of the respective JH receptors of both species. These data present primary evidence for agonist binding by JH receptors in any hemimetabolous species and provide a molecular basis for JH action in cockroaches and termites.
Assuntos
Blattellidae/metabolismo , Proteínas de Insetos/metabolismo , Isópteros/metabolismo , Sesquiterpenos/metabolismo , Animais , FemininoRESUMO
New diagnostic characters were used to study the genus Litoblatta Hebard: paraprocts, styles due to their shape and distribution of spines, and sclerites of the genitalia of the male with emphasis on the right complex. Male and female genitalia are described in detail. Four new species of cockroaches are described, Litoblatta elisae, Litoblatta lutea, Litoblatta misionerae, and Litoblatta tucumanae. The number of species recorded for Argentina rises to 7 and a key for male determination is provided. The geographic distribution of the studied species of cockroaches is extended.
Assuntos
Blattellidae , Distribuição Animal , Animais , Argentina , Feminino , Genitália , MasculinoRESUMO
The giant water bug fauna from tropical South America remains poorly known. Three species of Belostoma Latreille (Belostoma fittkaui De Carlo, B. sayagoi De Carlo and B. hirsutum Roback Nieser) have been cited only a few times in the literature. These three species are remarkable since they represent an extreme variation for the genus, with article II of the labium distinctly shorter than article III. Here, the synonymy of B. hirsutum with B. sayagoi is proposed based on examination of type material and additional specimens. Further, B. fittkaui and B. sayagoi are redescribed, including discussion about comparative morphology with congeners. A new species group is proposed for these species and a key to the Belostoma species groups is provided. Distribution records are also updated.
Assuntos
Blattellidae , Heterópteros , AnimaisRESUMO
The German cockroach, Blattella germanica L., is a hemimetabolous insect pest of economical and medical importance. N,N-diethyl-3-methylbenzamide (DEET) is an insect repellent whose effect on this species has received very little attention. The objective of this work was to determine whether the behavioral response of B. germanica to DEET varies along its life cycle. DEET repellence was assessed in small, medium, and large nymphs, and in adults of both sexes, all originated from the same laboratory colony (CIPEIN). The experimental arena consisted in a piece of filter paper treated with repellent on one half (195 µg/cm2) and solvent alone on the other half. A cockroach was placed on the filter paper, and its behavior was filmed. An image analyzer was used to quantify how long the insect spent on each side of the paper. As a control, a cockroach was exposed to a piece of filter paper treated with solvent (acetone) alone. Each assay was repeated independently six times. Distribution coefficient (DC) values were calculated, a parameter that ranges between 0 (attraction) and 1 (repellence). Small nymphs were more sensitive to DEET (mean DCâ =â 0.93). The mean DC values of the other groups varied between 0.62 (medium nymphs) and 0.71 (male adults). The group of medium nymphs was the only one whose behavior was not significantly altered by exposure to DEET. The results show the importance of assessing insect repellents at different stages of the insect's life cycle in order to obtain a complete panorama of its effect.
Assuntos
Blattellidae , Repelentes de Insetos , Acetona , Animais , DEET , Masculino , NinfaRESUMO
Essential oils (EO) from peppermint, palmarosa, geranium, lavender and rosemary were tested against the German cockroach, Blatella germanica L. (Blattaria: Blatellidae). Peppermint and palmarosa oils were the most effective and were included in a polyethylene glycol 6000 matrix to obtain EO loaded polymeric nanoparticles (EOPN). The physicochemical analyses indicated that, at 7 days postformulation, peppermint EOPN had sizes of 380 nm, the loading efficiency (LE) was 72.25% and the polydispersity index (PDI) was >0.4 (polydisperse sample). Palmarosa EOPN had sizes of 191 nm; LE was 89.75% and PDI was <0.25 (monodisperse sample). Peppermint and palmarosa EOPN enhanced the lethal and sublethal effects of the EO on B. germanica. These results suggest that the newly developed nanoinsecticides could be successfully used to control German cockroach.
Assuntos
Blattellidae/efeitos dos fármacos , Inseticidas/farmacologia , Nanopartículas/química , Óleos Voláteis/farmacologia , Óleos de Plantas/farmacologia , Polietilenoglicóis/farmacologia , Animais , Feminino , Inseticidas/química , Masculino , Óleos Voláteis/química , Óleos de Plantas/química , Projetos de Pesquisa , Análise de SobrevidaRESUMO
Three new species of Chromatonotus Hebard (C. bahiaensis, C. dextrodigitatus, C. diminutivus) are described from Mato Grosso, Bahia and Pernambuco states, Brazil, and Chromatonotus elegantula R.S. Albuquerque, 1974 is transferred to Ischnoptera Burmeister, 1838 as I. elegantula (R.S. Albuquerque, 1974) comb. nov. The material studied in this paper were stored in the Entomological Collection of Department of the Entomology, Museu Nacional, but was lost in the fire that took place in the Museu Nacional on September 2, 2018.
Assuntos
Blattellidae , AnimaisRESUMO
We describe a new genus and species of Chilean Blattodea (Ectobiidae), collected on Isla Grande de Chiloé and associated with Fascicularia bicolor (Bromeliaceae). We study the morphology of both sexes with SEM. The new taxon is brachypterous, with tiny ellipsoid tegmina and hind wings absent. The female presents strongly sclerotized genital sclerites and spermathecal plate developed. The male without tergal specializationsand asymmetrical styles. Medium phallomere with modified sclerites, compose a sclerotized complex that includes a long ejaculatory duct.
Assuntos
Blattellidae , Insetos , Animais , Bromeliaceae , Chile , Feminino , Genitália , MasculinoRESUMO
Introduction: Mites are an important source of allergens in the tropics. Other potential sources of allergens prevalent in the region such as insects have been poorly studied. Objective: To determine the relationship between exposure and allergic sensitization to cockroaches, mosquitos, ants and the interaction with mite sensitization. Materials and methods: We included patients with allergy tests for Blatella germanica, Aedes aegypti, Solenopsis invicta, Blomia tropicalis, Dermatophagoides farinae and D. pteronyssinus. IgE sensitization was evaluated by intraepidermal tests. Exposure to insects in houses was evaluated using traps for crawling and flying insects. Results: A total amount of 186 patients were included; 73 (39.2%) of them were sensitized to an insect (cockroaches: 21%, mosquitoes: 29%, ants: 26,3%), 71 (97.2%) also had sensitization to mites. Of the 148 patients sensitized to mites, only 47.9% were sensitized to an insect. In total, 104 houses were evaluated: 74% had cockroaches, 22% ants, and 52% mosquitoes. Among insect-sensitized patients, the number of insects at home was directly related to the size of the weal generated during the skin test: Cockroaches, r=0.781, p<0.001; mosquitoes, r=0.811, p<0.001, and ants, r=0.840, p<0.001. Conclusion: Sensitization to insects is frequent in allergic populations of the tropics and is strongly associated with sensitization to mites.
Assuntos
Exposição Ambiental , Hipersensibilidade Imediata/epidemiologia , Insetos/imunologia , Adolescente , Adulto , Idoso , Alérgenos/imunologia , Animais , Formigas/imunologia , Blattellidae/imunologia , Criança , Pré-Escolar , Colômbia , Culicidae/imunologia , Feminino , Habitação , Humanos , Hipersensibilidade Imediata/etiologia , Hipersensibilidade Imediata/imunologia , Imunoglobulina E/imunologia , Lactente , Masculino , Pessoa de Meia-Idade , Ácaros/imunologia , Testes Cutâneos , Adulto JovemRESUMO
Our species have altered their surroundings since its early dispersion on Earth. Unfortunately, thanks to human-modified habitats, several pest organisms such as domiciliary insects have expanded their distributions. Moreover, pest-related microorganisms may also be aided by anthropization. Pest cockroaches are globally distributed and capable of carrying several diseases. We explored if urbanization may buffer environmental conditions allowing pest insects to expand their distribution. Specifically, we suggest that human settlements may generate suitable microhabitats for synanthropic cockroaches, helping them to survive and establish with disregard to overall climatic restrictions. To test this idea we studied the distribution of pest cockroaches spanning the length of Chilean territory. Chile, along its 4270 km length north to south extent, is a country offering a formidable sampling of Earth's climatic diversity accompanied by dense urbanizations. We studied entomological collections and spatially analyzed pest cockroach distribution found in Chile and discovered that synanthropic cockroach populations are consistently concentrated near most urban developed zones of the country and not limited by overall temperature. Furthermore, health-concern pest cockroach species were widely distributed in Chilean territory, found even in its most southern urban centers as well as Easter Island. Therefore, these disease vectors could exist even in isolated and extreme climatic zones as long as urbanization provides the adequate microhabitat. We discuss the need for further research in order to assess if these distributions can be extrapolated to the pathogenic strains these pest insects may be carrying as reported in other regions of the planet.
Assuntos
Distribuição Animal , Blattellidae , Periplaneta , Urbanização , Animais , Chile , Insetos VetoresRESUMO
The present study assessed the capacity of Blattella germanica and Periplaneta americana to disseminate and transmit infective phases of T. canis to rats, which were used as a model paratenic host. P. americana and B. germanica inoculated orally with T. canis larvated eggs shed eggs and larvae in their fecal matter during the first 6days post-inoculation. Larvae were recovered from the brain, lungs, kidneys and liver of rats that had been inoculated with either infected cockroaches or their feces. ELISAs of serum detected an increase of antibodies anti-T. canis excretion-secretion antigens, whereas Western Blot (WB) showed 4 bands (120, 50, 35 and 28kDa) that were similar to those found in positive control rats. Macroscopically, the liver and kidneys of infected rats had hemorrhagic areas with milk-spot-like lesions. The lungs showed diffuse grey protuberances. Histologically, hemorrhagic areas with leucocytic infiltrate were observed in the liver, lungs and kidneys. Some larvae were found within a granuloma that was surrounded by eosinophils and other leucocytic infiltrates. Larvae were found in the brain, but without inflammatory infiltrate. Both cockroach species that ingested larvated eggs of T. canis may shed viable larvae or eggs in their fecal matter. The induction of specific serum antibodies, presence of larvae in tissues and characteristic lesions associated with larval migration in the organs of rats that had ingested either whole adults or feces of B. germanica or P. americana demonstrate the capacity of these cockroaches to transmit toxocariosis to paratenic hosts.
Assuntos
Blattellidae/parasitologia , Periplaneta/parasitologia , Toxocara canis/fisiologia , Toxocaríase/parasitologia , Animais , Fezes/parasitologia , Larva , Masculino , Ratos , Ratos Wistar , Toxocaríase/transmissãoRESUMO
The importance of juvenile hormone regulating insect oogenesis suggests looking for genes whose expression is regulated by this hormone. SPARC is a calcium-binding glycoprotein that forms part of the extracellular membranes, which in vertebrates participates in bones mineralization or regulating cell proliferation in some cancer types. This large number of functions described for SPARC in different species might be related to the significant differences in its structure observed when comparing different species-groups. Indeed, these structural differences allow characterizing the different clades. In the cockroach Blattella germanica, a SPARC homolog emerged from ovarian transcriptomes that were constructed to find genes responding to juvenile hormone. In insects, SPARC functions have been studied in oogenesis and in embryo development of Drosophila melanogaster. In the present work, using RNAi approaches, novel functions for SPARC in the B. germanica panoistic ovaries are described. We found that depletion of SPARC does not allow to the follicular cells to complete mitosis, resulting in giant follicular cells nuclei and in a great alteration of the ovarian follicle cytoskeleton. The SPARC contribution to B. germanica oogenesis occurs stabilizing the follicular cell program and helping to maintain the nuclear divisions. Moreover, SPARC is necessary to maintain the cytoskeleton of the follicular cells. Any modification of these key processes disables females for oviposition.
Assuntos
Blattellidae/embriologia , Citoesqueleto/metabolismo , Epitélio/fisiologia , Oogênese/fisiologia , Osteonectina/metabolismo , Folículo Ovariano/embriologia , Animais , Proliferação de Células , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Hormônios Juvenis/metabolismo , Mitose/fisiologia , Oogênese/genética , Osteonectina/genética , Folículo Ovariano/citologia , Folículo Ovariano/metabolismo , Interferência de RNA , RNA Interferente Pequeno/genética , Vitelogeninas/biossínteseRESUMO
The genus Lanta Hebard 1921 includes three species found in the Neotropical region. Two species are known from Argentina, L. peniculiger (province of Santa Fe), and L. scotia (provinces of Córdoba and Santiago del Estero) (see Crespo et al. 2010), and one from Brazil, L. borgesae, (Araras, São Paulo) (Rocha e Silva & Vasconcellos, 1984). All species have been described on the basis of male external characters, such as wing veins, leg spines, hypandrium, shape and position of the styli, in addition to coloration and size. Except for a partial representation of the male genitalia of L. borgesae (Rocha e Silva & Vasconcellos 1984), this structure went untreated in morphological and phylogenetic investigations of the Blattaria (Snodgrass 1937; McKittrick 1964; Grandcolas 1996; Klass 1997; Roth 2003;). Females remain unknown.
Assuntos
Blattellidae/classificação , Genitália Masculina/anatomia & histologia , Distribuição Animal , Estruturas Animais/anatomia & histologia , Estruturas Animais/crescimento & desenvolvimento , Animais , Blattellidae/anatomia & histologia , Blattellidae/crescimento & desenvolvimento , Tamanho Corporal , Brasil , Feminino , Genitália Masculina/crescimento & desenvolvimento , Masculino , Tamanho do ÓrgãoRESUMO
A wild, forest-dwelling cockroach from the subfamily Ectobiidae (order Blattodea) in a nature reserve in Cavalcante, in the state of Goiás, Brazil, was found to be infected by a new, genetically distinct species in the Metarhizium flavoviride species complex that we describe here as Metarhizium blattodeae. The status of this fungus as a new species is supported by both multigenic sequence comparisons and protein profiles generated by MALDI-TOF (matrix-assisted laser desorption/ionization time-of-flight) mass spectrometry. This is one of the first reports of a naturally occurring fungal pathogen affecting any sylvatic (forest-dwelling) cockroach from any part of the world. M. blattodeae caused up to 96 % mortality of Periplaneta americana nymphs (a serious peridomestic cockroach species) after 10 d.
Assuntos
Blattellidae/microbiologia , Metarhizium/classificação , Metarhizium/isolamento & purificação , Micoses/microbiologia , Animais , Brasil , Análise por Conglomerados , DNA Fúngico/química , DNA Fúngico/genética , DNA Ribossômico/química , DNA Ribossômico/genética , DNA Espaçador Ribossômico/química , DNA Espaçador Ribossômico/genética , Proteínas Fúngicas/análise , Genes de RNAr , Metarhizium/química , Metarhizium/genética , Microscopia , Fator 1 de Elongação de Peptídeos/genética , Filogenia , RNA Polimerase II/genética , RNA Fúngico/genética , RNA Ribossômico 5,8S/genética , Análise de Sequência de DNA , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por MatrizRESUMO
N,N-diethyl-3-methylbenzamide (DEET) is the active principle of most insect repellents used worldwide. However, its toxicity on insects has not been widely studied. The aim of this work is to study the effects of DEET on the locomotor activity of Blattella germanica. DEET has a dose-dependent repellent activity on B. germanica. Locomotor activity was significantly lower when insects were pre-exposed to 700 µg/cm(2) of DEET for 20 or 30 minutes, but it did not change when pre-exposure was shorter. Locomotor activity of insects that were pre-exposed to 2.000 µg/cm(2) of DEET for 10 minutes was significantly lower than the movement registered in controls. No differences were observed when insects were pre-exposed to lower concentrations of DEET. A 30-minute pre-exposure to 700 µg/cm(2) of DEET caused a significant decrease in locomotor activity. Movement was totally recovered 24 h later. The locomotor activity measured during the exposure to different concentrations of DEET remained unchanged. Insects with decreased locomotor activity were repelled to the same extent than control insects by the same concentration of DEET. We demonstrated that the repellency and modification of locomotor activity elicited by DEET are non-associated phenomena. We also suggested that the reduction in locomotor activity indicates toxicity of DEET, probably to insect nervous system.