60 research outputs found

    A note:gut bacteria produce components of a locust cohesion pheromone

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    Aims: Faecal pellets from germ-free locusts were used as culture media to determine the ability of locust gut bacteria to synthesize phenolic components of the locust cohesion pheromone. Methods and Results: Inoculation of germ-free faecal pellets with Pantoea agglomerans, a species commonly isolated from locusts, resulted in the release of large amounts of guaiacol and small amounts of phenol, both of which are components of the locust cohesion pheromone. Two other locust-derived species, Klebsiella pneumoniae pneumoniae and Enterobacter cloacae, also produced guaiacol from germ-free faecal pellets, but the opportunistic locust pathogen, Serratia marcescens, did not. The most likely precursor for guaiacol is the plant-derived vanillic acid, which is present in large amounts in the faeces of both conventional and germ-free locusts. Conclusions: These observations are consistent with previous ones, that locust gut bacteria are responsible for the production of components of the locust cohesion pheromone. Significance and Impact of the Study: These findings illustrate how an insect can adapt to make use of a common bacterial metabolite produced by one or more of its indigenous gut bacterial species. This observation has implications for our appreciation of insect gut microbiota interactions

    Effects of the juvenile hormone mimic pyriproxyfen on egg development, embryogenesis, larval development, and metamorphosis in the desert locust Schistocerca gregaria (Orthoptera : Acrididae)

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    The juvenile hormone mimic pyriproxyfen disrupted embryogenesis when applied topically to eggs of the desert locust Schistocerca gregaria Forskal. Eggs treated on days 3-6 were inhibited at various stages of development, depending on dose and age. In particular, 0.001-0.01 mu g blocked development of 3- and 4-d-old eggs at blastokinesis. Treatment of 7- to 11-d-old eggs was ineffective up to 10 mu g. Insects that hatched successfully failed to display any postembryonic defects. Topical application of the mimic to females had a small ovicidal effect. The metamorphic molt was disrupted when the mimic was applied topically to 5th-instar S. gregaria. Insects retained characteristics of the 5th instar and in extreme cases supernumerary 5th instars were formed. Additional defects included essentially normal adults that were malformed and could not fly. Oral doses were considerably less effective. Application to 4th-instar nymphs did not produce supernumerary characteristics in postecdysial insects, though a large proportion of insects showed abnormalities when they reached adult, which in some cases prevented night. Topical application of the mimic to 5th instar affected the length of the instar. The effects depended on dose and day of treatment

    Effect of Cavitation on Transverse Injection into Subsonic Crossflows

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