The composition of the bacterial community in the foam produced by Mahanarva fimbriolata is distinct from those at gut and soil.

The development of insects is strongly influenced by their resident microorganisms. Symbionts play key roles in insect nutrition, reproduction, and defense. Bacteria are important partners due to the wide diversity of their biochemical pathways that aid in the host development. We present evidence that the foam produced by nymphs of the spittlebug Mahanarva fimbriolata harbors a diversity of bacteria, including some that were previously reported as defensive symbionts of insects. Analysis of the microbiomes in the nymph gut and the soil close to the foam showed that the microorganisms in the foam were more closely related to those in the gut than in the soil, suggesting that the bacteria are actively introduced into the foam by the insect. Proteobacteria, Actinobacteria, and Acidobacteria were the predominant groups found in the foam. Since members of Actinobacteria have been found to protect different species of insects by producing secondary metabolites with antibiotic properties, we speculate that the froth produced by M. fimbriolata may aid in defending the nymphs against entomopathogenic microorganisms.

Ação antimicrobiana de óleos essenciais de sucupira branca (Pterodon emarginatus); folhas de pêssego (Prunus persica); bagas de junipero (Juniperus communis); rosa de damasco (Rosa damascena) e petitgrain mandarina (Citrus deliciosa) / Antimicrobial action of white sucupira essential oils (Pterodon emarginatus); peach leaves (Prunus persica); juniper berries (Juniperus communis); pink apricot (Rosa damascena) and petitgrain mandarin (Citrus deliciosa)

Os óleos essenciais são complexos naturais formados por cerca de 20 ­ 60 componentes em distintas concentrações, sendo caracterizados por dois ou três componentes presentes em maiores concentrações (20 ­ 70%) quando comparados aos demais. A atividade antibacteriana de muitas plantas deve-se aos compostos sintetizados no metabolismo secundário. Tais produtos são conhecidos por suas substâncias ativas. Este trabalho apresentou como objetivo verificar a ação antibacteriana dos óleos essenciais: bagas de junípero (Junipeus communis), folhas de pêssego (Prunus pérsica), petitgrain mandarina (Citrus deliciosa), rosa de damasco 10% (Rosa damascena) e sucupira branca (Pterodon emarginatus). Os testes foram realizados com os óleos essenciais individualmente e combinados. Os óleos essenciais foram impregnados em discos de papel filtro de 6 mm de diâmetro, próprios para antibiograma, colocados em placas de Petri com meio de cultura apropriado, semeado previamente com os seguintes micro-organismos: Bacillus cereus, Bacillus subtilis, Escherichia coli, Salmonella Typhimurium, Salmonella Enteritidis e Staphylococcus aureus, posteriormente incubadas a 35 °C/ 24 ­ 48 horas. Considerou-se de ação antimicrobiana eficaz aqueles que apresentaram halos iguais ou superiores a 10 mm. Resultados eficazes foram observados para o óleo essencial de folhas de pêssego sobre S. aureus (halo de 60 mm) e S. Typhimurium (halo de 62 mm); óleo essencial de folhas de pêssego e petitgrain mandarina sobre B. subtilis (halo de 62 mm). E. coli foi inibida eficientemente por todos os óleos essenciais testados. A atividade inibitória mais eficaz foi observada para o óleo essencial de folhas de pêssego.

Essential oils are natural complexes formed by 20 to 60 components in varying amounts; being characterized by two or three components present in higher concentrations (20-70%) when compared to the others. The antibacterial activity of many plants is due to the compounds synthesized in the secondary metabolism. Such products are known for their active substances. This research aimed to verify the antibacterial action of essential oils: juniper berries (Junipeus communis), peach leaves (Prunus persica), petitgrain mandarin (Citrus deliciosa), apricot rose 10% (Rosa damascena) and sucupira branca (Pterodon emarginatus). The tests were performed with the essential oils individually and in combination. The essential oils were impregnated into 6 mm diameter filter paper disks, suitable for antibiogram, placed in Petri dishes with appropriate culture medium, previously seeded with the following microorganisms: Bacillus cereus, Bacillus subtilis, Escherichia coli, Salmonella Typhimurium, Salmonella Enteritidis and Staphylococcus aureus, subsequently incubated at 35 °C/24 - 48 hours. Efficient antimicrobial action was considered in those essential oils with halos equal to or greater than 10 mm. Efficient results were observed for the essential oil of peach leaves on S. aureus (60 mm halo) and S. Typhimurium (62 mm halo); for essential oil of peach leaves and petitgrain mandarin on B. subtilis (62 mm halo). E. coli was efficiently inhibited for all essential oils tested. The most effective inhibitory activity observed for the essential oil of peach leaves.

Spittlebugs produce foam as a thermoregulatory adaptation.

Insects have evolved multiple mechanisms to adapt to variations in environmental temperatures, including postural control of solar input, variations in diurnal activity, external morphological structures and selecting/generating microhabitats. Foam produced by Mahanarva fimbriolata nymphs (also known as root spittlebugs) was found to aid in creating a constant thermal microhabitat despite environmental temperature fluctuations. The temperature within the foam was found to be similar to that of soil during the day and remained constant despite fluctuating external temperatures. In chemically analysing the composition of the foam, palmitic and stearic acids, carbohydrates and proteins were detected. These substances have previously been shown to act as a surfactant to stabilize and modulate foams. Since the immature ancestor of the spittlebug developed below ground, it is speculated that the foam may function as an 'extension' of the soil and, thus, may have enabled the spittlebug to emerge from the soil and adopt an epigean lifestyle.

Interspecific Cross-Attraction between the South American Cerambycid Beetles Cotyclytus curvatus and Megacyllene acuta is Averted by Minor Pheromone Components.

During field screening trials conducted in Brazil in 2015, adults of both sexes of the cerambycid beetles Cotyclytus curvatus (Germar) and Megacyllene acuta (Germar) (subfamily Cerambycinae, tribe Clytini) were significantly attracted to racemic 3-hydroxyhexan-2-one and racemic 2-methylbutan-1-ol, chemicals which previously have been identified as male-produced aggregation-sex pheromones of a number of cerambycid species endemic to other continents. Subsequent analyses of samples of beetle-produced volatiles revealed that males of C. curvatus sex-specifically produce only (R)-3-hydroxyhexan-2-one, whereas males of M. acuta produce the same compound along with lesser amounts of (2S,3S)-2,3-hexanediol and (S)-2-methylbutan-1-ol. Follow-up field trials showed that both sexes of both species were attracted to synthetic reconstructions of their respective pheromones, confirming that males produce aggregation-sex pheromones. The minor pheromone components of M. acuta, (S)-2-methylbutan-1-ol and (2S,3S)-2,3-hexanediol, synergized attraction of that species, but antagonized attraction of C. curvatus to (R)-3-hydroxyhexan-2-one. Beetles of other cerambycine species also were attracted in significant numbers, including Chrysoprasis linearis Bates, Cotyclytus dorsalis (Laporte & Gory), and Megacyllene falsa (Chevrolat). Our results provide further evidence that 3-hydroxyhexan-2-one is a major component of attractant pheromones of numerous cerambycine species world-wide. Our results also highlight our increasing understanding of the crucial role of minor pheromone components in imparting species specificity to cerambycid pheromone blends, as is known to occur in numerous species in other insect families.

A novel interaction between plant-beneficial rhizobacteria and roots: colonization induces corn resistance against the root herbivore Diabrotica speciosa.

A number of soil-borne microorganisms, such as mycorrhizal fungi and rhizobacteria, establish mutualistic interactions with plants, which can indirectly affect other organisms. Knowledge of the plant-mediated effects of mutualistic microorganisms is limited to aboveground insects, whereas there is little understanding of what role beneficial soil bacteria may play in plant defense against root herbivory. Here, we establish that colonization by the beneficial rhizobacterium Azospirillum brasilense affects the host selection and performance of the insect Diabrotica speciosa. Root larvae preferentially orient toward the roots of non-inoculated plants versus inoculated roots and gain less weight when feeding on inoculated plants. As inoculation by A. brasilense induces higher emissions of (E)-ß-caryophyllene compared with non-inoculated plants, it is plausible that the non-preference of D. speciosa for inoculated plants is related to this sesquiterpene, which is well known to mediate belowground insect-plant interactions. To the best of our knowledge, this is the first study showing that a beneficial rhizobacterium inoculant indirectly alters belowground plant-insect interactions. The role of A. brasilense as part of an integrative pest management (IPM) program for the protection of corn against the South American corn rootworm, D. speciosa, is considered.