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R.h.c. Strang - One of the best experts on this subject based on the ideXlab platform.
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Biosynthesis of taurine in tissues of the locust (Schistocerca Americana gregaria) and the effect of physiological and toxicological stresses on biosynthetic rate of this amino acid
Insect Biochemistry and Molecular Biology, 1995Co-Authors: Peter S. Whitton, Russell A. Nicholson, Michael F. Bell, R.h.c. StrangAbstract:Abstract The biosynthesis of the amino acid taurine has been studied in the locust Schistocerca Americana gregaria . Tissue concentrations of putative precursors of taurine, and taurine itself were estimated in haemolymph, nervous tissue and muscle. Following this locusts were injected with 20 μCi of [ 35 S]cysteine and tissue samples were taken at times thereafter, and taurine and its precursors were extracted and separated by thin-layer chromatography (TLC). Taurine, cysteine sulphinic acid (CSA) were quantified by scintillation counting. Cysteic acid and hypotaurine were qualitatively detected by autoradiography of TLC plates. Results indicate that in haemolymph and muscle the biosynthetic pathway for taurine is cysteine then CSA, cysteic acid and thereafter taurine. In nervous tissue both cysteic acid and hypotaurine were detected suggesting two possible pathways for taurine since both are immediate precursors of this amino acid. Taurine biosynthesis was markedly greater in juvenile compared with mature adult locusts. It was also observed that picrotoxin treatment and prolonged flying, which have both previously been found to cause a redistribution of taurine in the locust, increased the biosynthesis of this amino acid.
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Uptake of [14C]taurine into tissues of Schistocerca gregaria in vivo
Insect Biochemistry and Molecular Biology, 1992Co-Authors: Peter S. Whitton, Russell A. Nicholson, R.h.c. StrangAbstract:Abstract Locusts ( Schistocerca Americana gregaria ) were injected with a tracer dose of 0.25 μCi of [ 14 C]taurine into the haemolymph and its clearance from haemolymph and uptake into flight muscle, thoracic ganglia and eye were studied at times thereafter. Clearance of labelled taurine from haemolymph suggested that the amino acid was rapidly taken up by some tissues and more slowly by others. Thus uptake of [ 14 C]taurine was rapid into nervous tissues and eye, but was much more gradual into flight muscle. Uptake was inhibited by cold and the structural analogues of taurine, s-alanine, γ-aminobutyric acid and hypotaurine. Taurine was retained in all tissues over a long period, indicating a very slow rate of catabolism for this amino acid in the locust.
Peter S. Whitton - One of the best experts on this subject based on the ideXlab platform.
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Biosynthesis of taurine in tissues of the locust (Schistocerca Americana gregaria) and the effect of physiological and toxicological stresses on biosynthetic rate of this amino acid
Insect Biochemistry and Molecular Biology, 1995Co-Authors: Peter S. Whitton, Russell A. Nicholson, Michael F. Bell, R.h.c. StrangAbstract:Abstract The biosynthesis of the amino acid taurine has been studied in the locust Schistocerca Americana gregaria . Tissue concentrations of putative precursors of taurine, and taurine itself were estimated in haemolymph, nervous tissue and muscle. Following this locusts were injected with 20 μCi of [ 35 S]cysteine and tissue samples were taken at times thereafter, and taurine and its precursors were extracted and separated by thin-layer chromatography (TLC). Taurine, cysteine sulphinic acid (CSA) were quantified by scintillation counting. Cysteic acid and hypotaurine were qualitatively detected by autoradiography of TLC plates. Results indicate that in haemolymph and muscle the biosynthetic pathway for taurine is cysteine then CSA, cysteic acid and thereafter taurine. In nervous tissue both cysteic acid and hypotaurine were detected suggesting two possible pathways for taurine since both are immediate precursors of this amino acid. Taurine biosynthesis was markedly greater in juvenile compared with mature adult locusts. It was also observed that picrotoxin treatment and prolonged flying, which have both previously been found to cause a redistribution of taurine in the locust, increased the biosynthesis of this amino acid.
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Uptake of [14C]taurine into tissues of Schistocerca gregaria in vivo
Insect Biochemistry and Molecular Biology, 1992Co-Authors: Peter S. Whitton, Russell A. Nicholson, R.h.c. StrangAbstract:Abstract Locusts ( Schistocerca Americana gregaria ) were injected with a tracer dose of 0.25 μCi of [ 14 C]taurine into the haemolymph and its clearance from haemolymph and uptake into flight muscle, thoracic ganglia and eye were studied at times thereafter. Clearance of labelled taurine from haemolymph suggested that the amino acid was rapidly taken up by some tissues and more slowly by others. Thus uptake of [ 14 C]taurine was rapid into nervous tissues and eye, but was much more gradual into flight muscle. Uptake was inhibited by cold and the structural analogues of taurine, s-alanine, γ-aminobutyric acid and hypotaurine. Taurine was retained in all tissues over a long period, indicating a very slow rate of catabolism for this amino acid in the locust.
John L. Capinera - One of the best experts on this subject based on the ideXlab platform.
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antifeedant effect of commercial chemicals and plant extracts against Schistocerca Americana orthoptera acrididae and diaprepes abbreviatus coleoptera curculionidae
Pest Management Science, 2011Co-Authors: Andres F Sandovalmojica, John L. CapineraAbstract:BACKGROUND: The deterrent effect of seven commercial compounds against Schistocerca Americana (Drury) nymphs and Diaprepes abbreviatus L. adults, two important citrus pests, was investigated. Extracts of three Florida local plants were also tested as deterrents. Antifeedant activity was assayed using a leaf-disk bioassay in choice and no-choice tests. The residual activity of the commercial compounds that significantly deterred the insects was assayed by applying them to foliage of citrus plants exposed to three time intervals of sunlight. RESULTS: Sabadilla, azadirachtin and ryanodine effectively deterred S. Americana, whereas rotenone, sabadilla and ryanodine reduced the feeding activity of D. abbreviatus. Methanol and methylene chloride extracts of Ceratiola ericoides Michaux deterred D. abbreviatus, but only methylene chloride extract dissuaded S. Americana. Methanol extract of Ardisia crenata Sims functioned as a feeding deterrent against both S. Americana and D. abbreviatus, but only the latter species was deterred by methylene chloride extract of A. crenata. Extracts of Illicium parviflorum Michaux ex Ventetat only dissuaded the insects in choice bioassays. Rapid loss of effectiveness was observed under field conditions. Sabadilla was the only compound that maintained its antifeedant properties in the field, but only against S. Americana. CONCLUSION: Based on their deterrency, some of the commercial products and plant extracts have potential for use as substitute crop protectants against the pest species tested. Copyright © 2011 Society of Chemical Industry
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Behavioral responses of Schistocerca Americana (Orthoptera: Acrididae) to Azadirex (neem)-treated host plants.
Journal of economic entomology, 2007Co-Authors: John L. Capinera, Jason G. FroebaAbstract:Azadirex (azadirachtin and other biologically active extracts from neem trees) has been shown to have considerable potential to be used in integrated pest management systems based on its growth regulator/insecticide properties. Less well known are the antifeedant properties. The feeding-deterrent properties of a commercial azadirex formulation (Azatrol EC) were evaluated using both no-choice and choice tests, the American grasshopper, Schistocerca Americana (Drury), and four host plants [savoy cabbage, Brassica oleracea variety capitata L.; cos (romaine) lettuce, Lactuca sativa variety longifolia Lam.; sweet orange, Citrus sinensis variety Hamlin L.; and peregrina, Jatropha integerrima Jacq.]. These studies demonstrated that azadirex application can significantly affect the feeding behavior of grasshoppers. Some degree of protection can be afforded to plants that differ markedly in their innate attractiveness to the insect, although the level of protection varies among hosts. The tendency of grasshoppers to sometimes feed on azadirex-treated foliage suggests that it will be difficult to prevent damage from occurring at all times, on all hosts. No evidence of rapid habituation to azadirex was detected. Rapid loss of efficacy was observed under field conditions, suggesting that daily retreatment might be necessary to maintain protection of plants from feeding.
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Arsenic hyperaccumulation in the Chinese brake fern (Pteris vittata) deters grasshopper (Schistocerca Americana) herbivory.
The New phytologist, 2007Co-Authors: Bala Rathinasabapathi, John L. Capinera, Jason G. Froeba, Murugesan Rangasamy, Ron Cherry, Heather J. Mcauslane, Mrittunjai Srivastava, Lena Q.Abstract:Summary • Brake fern, Pteris vittata , not only tolerates arsenic but also hyperaccumulates it in the frond. The hypothesis that arsenic hyperaccumulation in this fern could function as a defense against insect herbivory was tested. •F ronds from control and arsenic-treated ferns were presented to nymphs of the grasshopper Schistocerca Americana . Feeding damage was recorded by visual observation and quantification of the fresh weight of frond left uneaten and number of fecal pellets produced over a 2-d period. Grasshopper weight was determined before and after 5 d of feeding. • Grasshoppers consumed significantly greater amounts of the frond tissue, produced more fecal pellets and had increased body weight on control plants compared with grasshoppers fed arsenic-treated ferns. Very little or none of the arsenic-treated ferns were consumed indicating feeding deterrence. In a feeding deterrent experiment with lettuce, sodium arsenite at 1.0 m M deterred grasshoppers from feeding whereas 0.1 m M did not. In a choice experiment, grasshoppers preferred to feed on lettuce dipped in water compared with lettuce dipped in 1.0 m M sodium arsenite. • Our results show that arsenic hyperaccumulation in brake fern is an elemental defense against grasshopper herbivory.
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Microbial Control of Schistocerca Americana (Orthoptera: Acrididae) by Metarhizium flavoviride (Deuteromycotina): Instar Dependent Mortality and Efficacy of Ultra Low Volume Application Under Greenhouse Conditions
Journal of Economic Entomology, 1998Co-Authors: D. H. Sieglaff, Roberto M. Pereira, John L. CapineraAbstract:The entomopathogenic fungus Metarhizium flavoviride Gams & Rozsypal has been widely tested for the suppression of African grasshoppers, but there has been no research on Nearctic species. We examined the potential of M. flavoviride for the control of the American grasshopper, Schistocerca Americana (Drury). When tested under conidial dosages of 1.2 x 10 3 , 1.2 x 10 4 , and 1.2 x 10 5 , 4th-instar S. Americana were significantly more susceptible to M. flavoviride than 6th-instar and adult S. Americana. At the conidial dosage of 1.2 x 10 5 , M. flavoviride produced 89.7, 12.8, and 17.6% mean mortality 7 d after treatment in 4th-instar, 6th-instar, and adult S. Americana, respectively. By the 14th d after treatment, the M. flavoviride conidial dosage of 1.2 x 10 5 produced 99.4, 86.1, and 80.8% mean mortality in 4th-instar, 6th-instar, and adult S. Americana, respectively. The LD 50 estimates for M. flavoviride of 1.7 x 10 4 conidia for the 4th-instar, 1.3 x 10 4 conidia for the 6th-instar, and 3.1 x 10 4 conidia for the adult S. Americana are generally greater than those used for other acridids. Furthermore, mortality in M. flavoviride-treated S. Americana was positively dosage dependent, as described by mean percentage of cumulative mortality and LT 50 estimates. Greenhouse trials evaluating ultra low volume application to grasshoppers, foliage, or grasshoppers and foliage produced from 78.1 to 92.0% mean mortality 14 d after treatment. In this simulated field trial, grasshoppers and M. flavoviride were exposed to temperatures ranging from 10 to 40°C, which demonstrated the potential of M. flavoviride to be effective under large temperature fluctuations, as may occur in the field.
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Pathogenicity of Beauveria bassiana and Metarhizium flavoviride (Deuteromycotina) to Schistocerca Americana (Orthoptera: Acrididae)
Journal of Economic Entomology, 1997Co-Authors: D. H. Sieglaff, Roberto M. Pereira, John L. CapineraAbstract:The entomopathogenic fungi Beauveria bassiana (Balsamo) Vuillemin and Metarhizium flavoviride Gams and Rozspal have been widely tested for the suppression of grasshoppers. However, with the exception of Melanoplus sanguinipes (F.), there has been little research on Nearctic species. We examined the potential of these 2 microbial agents for control of the American grasshopper, Schistocerca Americana (Drury), and the migratory grasshopper, M. sanguinipes. M. flavoviride was much more virulent than B. bassiana to both grasshopper species. At the conidial dosage of 1.2 x 105, M. flavoviride produced 69.2 and 74.2% mean mortality 7 d after treatment in S. Americana and M. sanguinipes , respectively. In contrast, B. bassiana produced 1.7 and 11.7% mean mortality 7 d after treatment in S. Americana and M. sanguinipes , respectively. Treatment with M. flavoviride also caused a significant reduction in feeding beginning 48 h after treatment of 6th-instar S. Americana . Furthermore, M. flavoviride -treated S. Americana showed an average reduction of 36.6% mean cumulative consumption, 5-8 d after treatment, when compared with untreated grasshoppers.
Daniel A. Hahn - One of the best experts on this subject based on the ideXlab platform.
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Larval nutrition affects lipid storage and growth,but not protein or carbohydrate storage in newly eclosed adults of the grasshopper Schistocerca Americana
Journal of insect physiology, 2005Co-Authors: Daniel A. HahnAbstract:Nitrogen availability from dietary protein can have profound effects on the physiology and evolutionary ecology of insect herbivores. While many studies consider the effects of nutrition on consumption and gross body composition of protein and other important nutrients, few consider partitioning to storage for future use. I used chemically defined artificial diets to quantitatively manipulate the amount of dietary carbohydrates and proteins available to growing larvae of the grasshopper Schistocerca Americana to determine how larval nutrient availability affects growth and all three classes of stored nutrients (proteins, lipids, and carbohydrates) carried over from larval feeding into adulthood. Larvae on poor diets increased consumption, but could not compensate for diet quality, eclosing small and containing no significant nutrient stores at adulthood. Individuals fed intermediate to high nutrient content diets as larvae were significantly larger and contained a significantly greater proportion of lipid stores at adult eclosion, but not protein or carbohydrate stores than individuals fed low nutrient content diets. This suggests that larvally derived lipid stores may be more important to adult fitness than carbohydrate or protein stores. This result is contrary to previous studies performed on the role of larval nutrition and allocation to protein stores, and this difference is likely due to variation in the relative availability of protein in adult diets across species.
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Presence of a single abundant storage hexamerin in both larvae and adults of the grasshopper, Schistocerca Americana
Journal of insect physiology, 2003Co-Authors: Daniel A. Hahn, Diana E. WheelerAbstract:We identified a single hexameric storage protein in the grasshopper, Schistocerca Americana, and monitored its abundance through the last larval instar and up until reproductive competence in adults of both sexes. This storage hexamerin, termed Schistocerca Americana Persistent Storage Protein (saPSP) was the most abundant soluble protein in both larvae and adults. In both sexes, saPSP abundance started out low at the onset of the last larval instar and accumulated during feeding, peaking just prior to molting. Adults of both sexes contained significant amounts of saPSP after eclosion. In adult males, saPSP content dropped continuously after eclosion and was lowest once individuals reached reproductive maturity. In contrast, adult females depleted saPSP reserves during the first days of adulthood, but subsequently accumulated significant saPSP stores. In adult females, saPSP stores peaked just prior to the completion of egg provisioning. Given the overall patterns of abundance, saPSP has functions in both larvae and adults. In addition, the observed pattern of storage hexamerin accumulation differs from patterns of accumulation in the other known grasshoppers, Locusta migratoria and Romalea microptera, suggesting that significant functional diversity has evolved in storage hexamerins among the grasshoppers.
R. F. Chapman - One of the best experts on this subject based on the ideXlab platform.
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Development of phenotypic differences in sensillum populations on the antennae of a grasshopper, Schistocerca Americana.
Journal of morphology, 2002Co-Authors: R. F. ChapmanAbstract:The development of diet-induced phenotypic differences in numbers of sensilla on the antennae of the grasshopper Schistocerca Americana was studied using the exuviae produced at each molt. This made it possible to follow changes within an individual insect. In the first instar, insects had similar numbers of four sensillum types: uniporous trichoid sensilla, coeloconic sensilla, and large and small multiporous basiconic sensilla. Rearing on lettuce resulted in sixth instars with greater numbers of three sensillum types than siblings reared on an artificial diet. The first statistically significant differences between treatments in numbers of trichoid sensilla and large basiconic sensilla occurred in the third and fourth instars, respectively. No major reductions in sensillum numbers occurred at any time and the phenotypic differences resulted from differences in the numbers added at each molt.
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The relationship between plant acceptability and suitability for survival and development of the polyphagous grasshopper,Schistocerca Americana (Orthoptera: Acrididae)
Journal of Insect Behavior, 1994Co-Authors: R. F. Chapman, G. A. SwordAbstract:The feeding behavior of final-instar nymphs of Schistocerca Americana was observed when they first encountered plants that ranged in acceptability from being eaten in large amounts to not being eaten at all. Growth and survival on the same plants through the last stadium were also studied and the results combined as a suitability index to facilitate comparison with the behavior. Although the plants that were eaten most gave the highest suitability index and those that were not eaten permitted no survival, there was no simple relationship between the amounts eaten and the suitability for growth and survival. The possibility that the insects might become habituated to plants that were initially unacceptable was investigated, but no habituation was found over a 3-day period. It is suggested that food intake is largely determined by the presence of deterrent compounds in the less acceptable foods and that nutritional differences between the plants are likely to have been of minor importance. The behavior on some foods suggests that food aversion learning may be involved. It is concluded that the variability of the insects' behavior makes it impossible to predict the suitability of a plant from their immediate behavioral responses. In the field, insects may sometimes reject foods that would be suitable for survival and development, and feed on plants that are nutritionally deficient or even toxic.
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Variation in the surface lipids of the grasshopper, Schistocerca Americana (Drury)
Biochemical Systematics and Ecology, 1994Co-Authors: Karl E. Espelie, R. F. Chapman, Gregory A. SwordAbstract:Abstract Cuticular lipids of adult Schistocerca Americana from a number of different localities were analysed. The most abundant n -alkanes had chain lengths of C 25 , C 27 , C 29 and C 3 . The principal methyl-branched alkanes had 33, 35 and 37 carbon atoms in the backbone. There was greater variation in the overall patterns of components between populations than within populations. Insects reared in the laboratory on three different species of plant exhibited the same ranges of components, but the pattern differed according to the food plant. No differences were observed in the cuticular hydrocarbons of the two sexes. The variation in the hydrocarbon patterns of laboratory-reared insects was generally within the range of that observed in the field-collected insects, but the effects of food plant show that for taxonomic studies the use of laboratory-reared insects must be viewed with caution.
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The importance of palpation in food selection by a polyphagous grasshopper (Orthoptera: Acrididae)
Journal of Insect Behavior, 1993Co-Authors: R. F. Chapman, G. SwordAbstract:The behavioral responses of final-instar nymphs of Schistocerca Americana to a variety of acceptable and unacceptable plants were recorded. Palpation occurred on all plants and the palps are involved in both acceptance and rejection. On most unacceptable plants, rejection was at first dependent on biting the leaf, but subsequently on Lantana, Machaeranthera, Moms, and Physalis, rejection often occurred after palpation of the surface alone. This is consistent with the suggestion that associative learning occurs. This response did not wane even when the insects had been without food for over 2 h. There was also some evidence of an innate response to the surface characteristics of Physalis. The features of the surfaces that produced these responses were not determined .
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SENSORY CODING FOR FEEDING DETERRENCE IN THE GRASSHOPPER Schistocerca Americana
The Journal of Experimental Biology, 1991Co-Authors: R. F. Chapman, A. Ascoli-christensen, P. R. WhiteAbstract:The electrophysiological responses of sensilla on the tibia of Schistocerca Americana (Drury) to six compounds were examined. All the compounds were shown to cause feeding deterrence at high concentrations. Nicotine hydrogen tartrate, quinine, hordenine (all alkaloids) and salicin (a phenolic glycoside) all stimulated one cell in each sensillum. This was shown by differential adaptation experiments to be the same cell. In some sensilla this cell also responded to linamarin (a cyanogenic glycoside). Earlier work had shown that the activity of this cell was correlated with feeding deterrence. However, canavanine (a nonprotein amino acid) did not stimulate this cell, although it caused feeding deterrence. All the compounds, except salicin, produced a marked depression in the activity of cells responding to sucrose, and at higher concentrations of the compounds this inhibition was almost complete. The activity of the deterrent cell and inhibition of the activity of sucrose-sensitive cells appear to act together to produce the behavioural effects of most chemicals, but canavanine appears to act only by suppressing the activity of other cells and salicin primarily through activity of the deterrent cell. In addition, quinine disrupts the activity of all the cells and in its presence the deterrent cell adapts very slowly so that the message signalling deterrence is sustained. At low concentrations, salicin, and probably hordenine, increased the duration of feeding. In the case of hordenine this was due to an increase in the firing rate of sucrose-sensitive neurones; with salicin the increase was associated with a high threshold of response and a rapid rate of adaptation of the deterrent cell. Thus, similar behavioural effects are produced by a variety of sensory phenomena with each compound acting in a slightly different manner from the others.
