WorldWideScience

Sample records for controlling insect metamorphosis

  1. A phosphoproteomics approach to elucidate neuropeptide signal transduction controlling insect metamorphosis

    DEFF Research Database (Denmark)

    Rewitz, Kim F; Larsen, Martin R; Lobner-Olesen, Anders

    2009-01-01

    In insects, the neuropeptide prothoracicotropic hormone (PTTH) stimulates production of ecdysone (E) in the prothoracic glands (PGs). E is the precursor of the principal steroid hormone, 20-hydroxyecdysone (20E), that is responsible for eliciting molting and metamorphosis. In this study, we used ...

  2. A role for Taiman in insect metamorphosis.

    Directory of Open Access Journals (Sweden)

    Jesus Lozano

    2014-10-01

    Full Text Available Recent studies in vitro have reported that the Methoprene-tolerant (Met and Taiman (Tai complex is the functional receptor of juvenile hormone (JH. Experiments in vivo of Met depletion have confirmed this factor's role in JH signal transduction, however, there is no equivalent data regarding Tai because its depletion in larval or nymphal stages of the beetle Tribolium castaneum and the bug Pyrrhocoris apterus results in 100% mortality. We have discovered that the cockroach Blattella germanica possesses four Tai isoforms resulting from the combination of two indels in the C-terminal region of the sequence. The presence of one equivalent indel-1 in Tai sequences in T. castaneum and other species suggests that Tai isoforms may be common in insects. Concomitant depletion of all four Tai isoforms in B. germanica resulted in 100% mortality, but when only the insertion 1 (IN-1 isoforms were depleted, mortality was significantly reduced and about half of the specimens experienced precocious adult development. This shows that Tai isoforms containing IN-1 are involved in transducing the JH signal that represses metamorphosis. Reporter assays indicated that both T. castaneum Tai isoforms, one that contains the IN-1 and another that does not (DEL-1 activated a JH response element (kJHRE in Krüppel homolog 1 in conjunction with Met and JH. The results indicate that Tai is involved in the molecular mechanisms that repress metamorphosis, at least in B. germanica, and highlight the importance of distinguishing Tai isoforms when studying the functions of this transcription factor in development and other processes.

  3. Adaptive significance of critical weight for metamorphosis in holometabolous insects.

    Science.gov (United States)

    Hironaka, Ken-Ichi; Morishita, Yoshihiro

    2017-03-21

    Holometabolous insect larvae become committed to metamorphosis when they reach a critical weight. Although the physiological mechanisms involved in this process have been well-studied, the adaptive significance of the critical weight remains unclear. Here, we developed a life history model for holometabolous insects and evaluated it from the viewpoint of optimal energy allocation. We found that, without a priori assumptions about critical weight, the optimal growth schedule is always biphasic: larval tissues grow predominately until they reach a certain threshold, after which the imaginal tissues begin rapid growth, suggesting that the emergence of a critical weight as a phase-transition point is a natural consequence of optimal growth scheduling. Our model predicts the optimal timing of critical-weight attainment, in agreement with observations in phylogenetically-distinct species. Furthermore, it also predicts the scaling of growth scheduling against environmental change, i.e., the relative value and timing of the critical weight should be constant, thus providing a general interpretation of observed phenotypic plasticity. This scaling relationship allows the classification of adaptive responses in critical weight into five possible types that reflect the ecological features of focal insects. In this manner, our theory and its consistency with experimental observations demonstrate the adaptive significance of critical weight.

  4. TGF-β signaling in insects regulates metamorphosis via juvenile hormone biosynthesis.

    Science.gov (United States)

    Ishimaru, Yoshiyasu; Tomonari, Sayuri; Matsuoka, Yuji; Watanabe, Takahito; Miyawaki, Katsuyuki; Bando, Tetsuya; Tomioka, Kenji; Ohuchi, Hideyo; Noji, Sumihare; Mito, Taro

    2016-05-17

    Although butterflies undergo a dramatic morphological transformation from larva to adult via a pupal stage (holometamorphosis), crickets undergo a metamorphosis from nymph to adult without formation of a pupa (hemimetamorphosis). Despite these differences, both processes are regulated by common mechanisms that involve 20-hydroxyecdysone (20E) and juvenile hormone (JH). JH regulates many aspects of insect physiology, such as development, reproduction, diapause, and metamorphosis. Consequently, strict regulation of JH levels is crucial throughout an insect's life cycle. However, it remains unclear how JH synthesis is regulated. Here, we report that in the corpora allata of the cricket, Gryllus bimaculatus, Myoglianin (Gb'Myo), a homolog of Drosophila Myoglianin/vertebrate GDF8/11, is involved in the down-regulation of JH production by suppressing the expression of a gene encoding JH acid O-methyltransferase, Gb'jhamt In contrast, JH production is up-regulated by Decapentaplegic (Gb'Dpp) and Glass-bottom boat/60A (Gb'Gbb) signaling that occurs as part of the transcriptional activation of Gb'jhamt Gb'Myo defines the nature of each developmental transition by regulating JH titer and the interactions between JH and 20E. When Gb'myo expression is suppressed, the activation of Gb'jhamt expression and secretion of 20E induce molting, thereby leading to the next instar before the last nymphal instar. Conversely, high Gb'myo expression induces metamorphosis during the last nymphal instar through the cessation of JH synthesis. Gb'myo also regulates final insect size. Because Myo/GDF8/11 and Dpp/bone morphogenetic protein (BMP)2/4-Gbb/BMP5-8 are conserved in both invertebrates and vertebrates, the present findings provide common regulatory mechanisms for endocrine control of animal development.

  5. Metamorphosis alters contaminants and chemical tracers in insects: implications for food webs.

    Science.gov (United States)

    Kraus, Johanna M; Walters, David M; Wesner, Jeff S; Stricker, Craig A; Schmidt, Travis S; Zuellig, Robert E

    2014-09-16

    Insects are integral to most freshwater and terrestrial food webs, but due to their accumulation of environmental pollutants they are also contaminant vectors that threaten reproduction, development, and survival of consumers. Metamorphosis from larvae to adult can cause large chemical changes in insects, altering contaminant concentrations and fractionation of chemical tracers used to establish contaminant biomagnification in food webs, but no framework exists for predicting and managing these effects. We analyzed data from 39 studies of 68 analytes (stable isotopes and contaminants), and found that metamorphosis effects varied greatly. δ(15)N, widely used to estimate relative trophic position in biomagnification studies, was enriched by ∼ 1‰ during metamorphosis, while δ(13)C used to estimate diet, was similar in larvae and adults. Metals and polycyclic aromatic hydrocarbons (PAHs) were predominantly lost during metamorphosis leading to ∼ 2 to 125-fold higher larval concentrations and higher exposure risks for predators of larvae compared to predators of adults. In contrast, manufactured organic contaminants (such as polychlorinated biphenyls) were retained and concentrated in adults, causing up to ∼ 3-fold higher adult concentrations and higher exposure risks to predators of adult insects. Both food web studies and contaminant management and mitigation strategies need to consider how metamorphosis affects the movement of materials between habitats and ecosystems, with special regard for aquatic-terrestrial linkages.

  6. Metamorphosis alters contaminants and chemical tracers in insects: implications for food webs

    Science.gov (United States)

    Kraus, Johanna M.; Walters, David M.; Wesner, Jeff S.; Stricker, Craig A.; Schmidt, Travis S.; Zuellig, Robert E.

    2014-01-01

    Insects are integral to most freshwater and terrestrial food webs, but due to their accumulation of environmental pollutants they are also contaminant vectors that threaten reproduction, development, and survival of consumers. Metamorphosis from larvae to adult can cause large chemical changes in insects, altering contaminant concentrations and fractionation of chemical tracers used to establish contaminant biomagnification in food webs, but no framework exists for predicting and managing these effects. We analyzed data from 39 studies of 68 analytes (stable isotopes and contaminants), and found that metamorphosis effects varied greatly. δ15N, widely used to estimate relative trophic position in biomagnification studies, was enriched by 1‰ during metamorphosis, while δ13C used to estimate diet, was similar in larvae and adults. Metals and polycyclic aromatic hydrocarbons (PAHs) were predominantly lost during metamorphosis leading to 2 to 125-fold higher larval concentrations and higher exposure risks for predators of larvae compared to predators of adults. In contrast, manufactured organic contaminants (such as polychlorinated biphenyls) were retained and concentrated in adults, causing up to 3-fold higher adult concentrations and higher exposure risks to predators of adult insects. Both food web studies and contaminant management and mitigation strategies need to consider how metamorphosis affects the movement of materials between habitats and ecosystems, with special regard for aquatic-terrestrial linkages.

  7. The insect neuropeptide PTTH activates receptor tyrosine kinase torso to initiate metamorphosis.

    Science.gov (United States)

    Rewitz, Kim F; Yamanaka, Naoki; Gilbert, Lawrence I; O'Connor, Michael B

    2009-12-04

    Holometabolous insects undergo complete metamorphosis to become sexually mature adults. Metamorphosis is initiated by brain-derived prothoracicotropic hormone (PTTH), which stimulates the production of the molting hormone ecdysone via an incompletely defined signaling pathway. Here we demonstrate that Torso, a receptor tyrosine kinase that regulates embryonic terminal cell fate in Drosophila, is the PTTH receptor. Trunk, the embryonic Torso ligand, is related to PTTH, and ectopic expression of PTTH in the embryo partially rescues trunk mutants. In larvae, torso is expressed specifically in the prothoracic gland (PG), and its loss phenocopies the removal of PTTH. The activation of Torso by PTTH stimulates extracellular signal-regulated kinase (ERK) phosphorylation, and the loss of ERK in the PG phenocopies the loss of PTTH and Torso. We conclude that PTTH initiates metamorphosis by activation of the Torso/ERK pathway.

  8. Transcription factor E93 specifies adult metamorphosis in hemimetabolous and holometabolous insects.

    Science.gov (United States)

    Ureña, Enric; Manjón, Cristina; Franch-Marro, Xavier; Martín, David

    2014-05-13

    All immature animals undergo remarkable morphological and physiological changes to become mature adults. In winged insects, metamorphic changes either are limited to a few tissues (hemimetaboly) or involve a complete reorganization of most tissues and organs (holometaboly). Despite the differences, the genetic switch between immature and adult forms in both types of insects relies on the disappearance of the antimetamorphic juvenile hormone (JH) and the transcription factors Krüppel-homolog 1 (Kr-h1) and Broad-Complex (BR-C) during the last juvenile instar. Here, we show that the transcription factor E93 is the key determinant that promotes adult metamorphosis in both hemimetabolous and holometabolous insects, thus acting as the universal adult specifier. In the hemimetabolous insect Blattella germanica, BgE93 is highly expressed in metamorphic tissues, and RNA interference (RNAi)-mediated knockdown of BgE93 in the nymphal stage prevented the nymphal-adult transition, inducing endless reiteration of nymphal development, even in the absence of JH. We also find that BgE93 down-regulated BgKr-h1 and BgBR-C expression during the last nymphal instar of B. germanica, a key step necessary for proper adult differentiation. This essential role of E93 is conserved in holometabolous insects as TcE93 RNAi in Tribolium castaneum prevented pupal-adult transition and produced a supernumerary second pupa. In this beetle, TcE93 also represses expression of TcKr-h1 and TcBR-C during the pupal stage. Similar results were obtained in the more derived holometabolous insect Drosophila melanogaster, suggesting that winged insects use the same regulatory mechanism to promote adult metamorphosis. This study provides an important insight into the understanding of the molecular basis of adult metamorphosis.

  9. Common and distinct roles of juvenile hormone signaling genes in metamorphosis of holometabolous and hemimetabolous insects.

    Directory of Open Access Journals (Sweden)

    Barbora Konopova

    Full Text Available Insect larvae metamorphose to winged and reproductive adults either directly (hemimetaboly or through an intermediary pupal stage (holometaboly. In either case juvenile hormone (JH prevents metamorphosis until a larva has attained an appropriate phase of development. In holometabolous insects, JH acts through its putative receptor Methoprene-tolerant (Met to regulate Krüppel-homolog 1 (Kr-h1 and Broad-Complex (BR-C genes. While Met and Kr-h1 prevent precocious metamorphosis in pre-final larval instars, BR-C specifies the pupal stage. How JH signaling operates in hemimetabolous insects is poorly understood. Here, we compare the function of Met, Kr-h1 and BR-C genes in the two types of insects. Using systemic RNAi in the hemimetabolous true bug, Pyrrhocoris apterus, we show that Met conveys the JH signal to prevent premature metamorphosis by maintaining high expression of Kr-h1. Knockdown of either Met or Kr-h1 (but not of BR-C in penultimate-instar Pyrrhocoris larvae causes precocious development of adult color pattern, wings and genitalia. A natural fall of Kr-h1 expression in the last larval instar normally permits adult development, and treatment with an exogenous JH mimic methoprene at this time requires both Met and Kr-h1 to block the adult program and induce an extra larval instar. Met and Kr-h1 therefore serve as JH-dependent repressors of deleterious precocious metamorphic changes in both hemimetabolous and holometabolous juveniles, whereas BR-C has been recruited for a new role in specifying the holometabolous pupa. These results show that despite considerable evolutionary distance, insects with diverse developmental strategies employ a common-core JH signaling pathway to commit to adult morphogenesis.

  10. Common and distinct roles of juvenile hormone signaling genes in metamorphosis of holometabolous and hemimetabolous insects.

    Science.gov (United States)

    Konopova, Barbora; Smykal, Vlastimil; Jindra, Marek

    2011-01-01

    Insect larvae metamorphose to winged and reproductive adults either directly (hemimetaboly) or through an intermediary pupal stage (holometaboly). In either case juvenile hormone (JH) prevents metamorphosis until a larva has attained an appropriate phase of development. In holometabolous insects, JH acts through its putative receptor Methoprene-tolerant (Met) to regulate Krüppel-homolog 1 (Kr-h1) and Broad-Complex (BR-C) genes. While Met and Kr-h1 prevent precocious metamorphosis in pre-final larval instars, BR-C specifies the pupal stage. How JH signaling operates in hemimetabolous insects is poorly understood. Here, we compare the function of Met, Kr-h1 and BR-C genes in the two types of insects. Using systemic RNAi in the hemimetabolous true bug, Pyrrhocoris apterus, we show that Met conveys the JH signal to prevent premature metamorphosis by maintaining high expression of Kr-h1. Knockdown of either Met or Kr-h1 (but not of BR-C) in penultimate-instar Pyrrhocoris larvae causes precocious development of adult color pattern, wings and genitalia. A natural fall of Kr-h1 expression in the last larval instar normally permits adult development, and treatment with an exogenous JH mimic methoprene at this time requires both Met and Kr-h1 to block the adult program and induce an extra larval instar. Met and Kr-h1 therefore serve as JH-dependent repressors of deleterious precocious metamorphic changes in both hemimetabolous and holometabolous juveniles, whereas BR-C has been recruited for a new role in specifying the holometabolous pupa. These results show that despite considerable evolutionary distance, insects with diverse developmental strategies employ a common-core JH signaling pathway to commit to adult morphogenesis.

  11. Control of target gene specificity during metamorphosis by the steroid response gene E93

    OpenAIRE

    Mou, Xiaochun; Duncan, Dianne M.; Baehrecke, Eric H; Duncan, Ian

    2012-01-01

    Hormonal control of sexual maturation is a common feature in animal development. A particularly dramatic example is the metamorphosis of insects, in which pulses of the steroid hormone ecdysone drive the wholesale transformation of the larva into an adult. The mechanisms responsible for this transformation are not well understood. Work in Drosophila indicates that the larval and adult forms are patterned by the same underlying sets of developmental regulators, but it is not understood how the...

  12. Phylogenetic distribution of extant richness suggests metamorphosis is a key innovation driving diversification in insects.

    Science.gov (United States)

    Rainford, James L; Hofreiter, Michael; Nicholson, David B; Mayhew, Peter J

    2014-01-01

    Insects and their six-legged relatives (Hexapoda) comprise more than half of all described species and dominate terrestrial and freshwater ecosystems. Understanding the macroevolutionary processes generating this richness requires a historical perspective, but the fossil record of hexapods is patchy and incomplete. Dated molecular phylogenies provide an alternative perspective on divergence times and have been combined with birth-death models to infer patterns of diversification across a range of taxonomic groups. Here we generate a dated phylogeny of hexapod families, based on previously published sequence data and literature derived constraints, in order to identify the broad pattern of macroevolutionary changes responsible for the composition of the extant hexapod fauna. The most prominent increase in diversification identified is associated with the origin of complete metamorphosis, confirming this as a key innovation in promoting insect diversity. Subsequent reductions are recovered for several groups previously identified as having a higher fossil diversity during the Mesozoic. In addition, a number of recently derived taxa are found to have radiated following the development of flowering plant (angiosperm) floras during the mid-Cretaceous. These results reveal that the composition of the modern hexapod fauna is a product of a key developmental innovation, combined with multiple and varied evolutionary responses to environmental changes from the mid Cretaceous floral transition onward.

  13. Control of target gene specificity during metamorphosis by the steroid response gene E93.

    Science.gov (United States)

    Mou, Xiaochun; Duncan, Dianne M; Baehrecke, Eric H; Duncan, Ian

    2012-02-21

    Hormonal control of sexual maturation is a common feature in animal development. A particularly dramatic example is the metamorphosis of insects, in which pulses of the steroid hormone ecdysone drive the wholesale transformation of the larva into an adult. The mechanisms responsible for this transformation are not well understood. Work in Drosophila indicates that the larval and adult forms are patterned by the same underlying sets of developmental regulators, but it is not understood how the same regulators pattern two distinct forms. Recent studies indicate that this ability is facilitated by a global change in the responsiveness of target genes during metamorphosis. Here we show that this shift is controlled in part by the ecdysone-induced transcription factor E93. Although long considered a dedicated regulator of larval cell death, we find that E93 is expressed widely in adult cells at the pupal stage and is required for many patterning processes at this time. To understand the role of E93 in adult patterning, we focused on a simple E93-dependent process, the induction of the Dll gene within bract cells of the pupal leg by EGF receptor signaling. In this system, we show that E93 functions to cause Dll to become responsive to EGF receptor signaling. We demonstrate that E93 is both necessary and sufficient for directing this switch. E93 likely controls the responsiveness of many other target genes because it is required broadly for patterning during metamorphosis. The wide conservation of E93 orthologs suggests that similar mechanisms control life-cycle transitions in other organisms, including vertebrates.

  14. Progress on Regulatory Role of miRNA in Complete Metamorphosis Insects Development%miRNA对完全变态昆虫发育的调控作用研究进展

    Institute of Scientific and Technical Information of China (English)

    柴连琴; 王乐; 苗迎春

    2015-01-01

    昆虫尤其是完全变态昆虫的发育过程是一个复杂的网络调控过程,仍有很多问题尚待解决。miRNA是近年来发现的在真核生物中普遍存在的一类19~25 nt微小RNA分子,在转录后水平上发挥重要作用,广泛参与多种重要生物学过程。综述了近年来miRNA在调控完全变态昆虫(果蝇、家蚕、伊蚊、按蚊等)胚胎发育、组织分化以及变态发育等方面的研究进展,以期为深化理解昆虫变态发育机制、发现新的生物防控靶标分子奠定基础。%There are still many issues to be studied about the development of insects,especially complete metamorphosis insects,which is a complex network of regulatory processes. miRNA is present in eukaryotic cells and is a class of natural small regulatory RNA. Its size is 19—25 nucleotides. miRNAs play an important role in post-transcriptional gene regulation,and they can control hundreds of gene targets and regulate diverse biological processes. Here, we review recent developments of the roles of miRNAs in embryogenesis, tissue differentiation and metamorphosis of complete metamorphosis insects, such as drosophila,silkworm,aedes and anopheles,etc,in order to lay the foundation for profoundly reveal the metamorphosis developmental mechanism of insects and discover new molecular targets for prevention and control of insect pests.

  15. 1977 Kansas Field Crop Insect Control Recommendations.

    Science.gov (United States)

    Brooks, Leroy; Gates, Dell E.

    This publication is prepared to aid producers in selecting methods of insect population management that have proved effective under Kansas conditions. Topics covered include insect control on alfalfa, soil insects attacking corn, insects attacking above-ground parts of corn, and sorghum, wheat, and soybean insect control. The insecticides…

  16. 21 CFR 1250.95 - Insect control.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Insect control. 1250.95 Section 1250.95 Food and... SANITATION Sanitation Facilities and Conditions on Vessels § 1250.95 Insect control. Vessels shall be... generally accepted methods of insect control....

  17. Insect Control (1): Use of Pheromones

    Science.gov (United States)

    Marx, Jean L.

    1973-01-01

    Discusses current research relating to the use of pheromones as a means of controlling insect pests. These chemicals, which are secreted by insects to affect the behavior of other individuals of the same species, may be used to eliminate pests without destroying their predators and other beneficial insects. (JR)

  18. Insect Control (1): Use of Pheromones

    Science.gov (United States)

    Marx, Jean L.

    1973-01-01

    Discusses current research relating to the use of pheromones as a means of controlling insect pests. These chemicals, which are secreted by insects to affect the behavior of other individuals of the same species, may be used to eliminate pests without destroying their predators and other beneficial insects. (JR)

  19. Modeling resistance to genetic control of insects.

    Science.gov (United States)

    Alphey, Nina; Bonsall, Michael B; Alphey, Luke

    2011-02-07

    The sterile insect technique is an area-wide pest control method that reduces pest populations by releasing mass-reared sterile insects which compete for mates with wild insects. Modern molecular tools have created possibilities for improving and extending the sterile insect technique. As with any new insect control method, questions arise about potential resistance. Genetic RIDL(®)(1) (Release of Insects carrying a Dominant Lethal) technology is a proposed modification of the technique, releasing insects that are homozygous for a repressible dominant lethal genetic construct rather than being sterilized by irradiation. Hypothetical resistance to the lethal mechanism is a potential threat to RIDL strategies' effectiveness. Using population genetic and population dynamic models, we assess the circumstances under which monogenic biochemically based resistance could have a significant impact on the effectiveness of releases for population control. We assume that released insects would be homozygous susceptible to the lethal genetic construct and therefore releases would have a built-in element of resistance dilution. We find that this effect could prevent or limit the spread of resistance to RIDL constructs; the outcomes are subject to competing selective forces deriving from the fitness properties of resistance and the release ratio. Resistance that is spreading and capable of having a significant detrimental impact on population reduction is identifiable, signaling in advance a need for mitigating action.

  20. Mechanics and aerodynamics of insect flight control.

    Science.gov (United States)

    Taylor, G K

    2001-11-01

    Insects have evolved sophisticated fight control mechanisms permitting a remarkable range of manoeuvres. Here, I present a qualitative analysis of insect flight control from the perspective of flight mechanics, drawing upon both the neurophysiology and biomechanics literatures. The current literature does not permit a formal, quantitative analysis of flight control, because the aerodynamic force systems that biologists have measured have rarely been complete and the position of the centre of gravity has only been recorded in a few studies. Treating the two best-known insect orders (Diptera and Orthoptera) separately from other insects, I discuss the control mechanisms of different insects in detail. Recent experimental studies suggest that the helicopter model of flight control proposed for Drosophila spp. may be better thought of as a facultative strategy for flight control, rather than the fixed (albeit selected) constraint that it is usually interpreted to be. On the other hand, the so-called 'constant-lift reaction' of locusts appears not to be a reflex for maintaining constant lift at varying angles of attack, as is usually assumed, but rather a mechanism to restore the insect to pitch equilibrium following a disturbance. Differences in the kinematic control mechanisms used by the various insect orders are related to differences in the arrangement of the wings, the construction of the flight motor and the unsteady mechanisms of lift production that are used. Since the evolution of insect flight control is likely to have paralleled the evolutionary refinement of these unsteady aerodynamic mechanisms, taxonomic differences in the kinematics of control could provide an assay of the relative importance of different unsteady mechanisms. Although the control kinematics vary widely between orders, the number of degrees of freedom that different insects can control will always be limited by the number of independent control inputs that they use. Control of the moments

  1. Skeletomuscular development of genital segments in the dragonfly Anax imperator (Odonata, Aeshnidae) during metamorphosis and its implications for the evolutionary morphology of the insect ovipositor.

    Science.gov (United States)

    Matushkina, Natalia A

    2008-07-01

    The skeleton-muscular organisation of abdominal segments 7-9 in female Anax imperator L. (Anisoptera, Aeshnidae) was examined in the stages of ultimate larva, teneral imago, and mature imago, with special emphasis on the transformation of the muscle arrangement. The absence of certain muscles in the genital segments compared to the 7th pre-genital segment was noted on all studied stages. Reductions of certain muscles in adults compared to those in larvae are reported. Some of ovipositor's muscles appear already in larvae. Attachment sites of larval muscles are retained in freshly emerged females concurrently with integument transformations. This situation allows for precise determination of the borders of newly differentiated genital sclerites and, therefore, of the possible origin of certain ovipositor elements in odonates. All changes in the segmental sets of studied abdominal muscles during metamorphosis are tabulated, and displacements of muscles are documented and illustrated. Schematic figures illustrating homologies between the parts of larval and imaginal abdominal sclerites are provided. The origins of the components of the endophytic ovipositor in Odonata as well as their implications for the evolutionary morphology of the insect ovipositor are discussed.

  2. Chemosterilants for Control of Insects and Insect Vectors of Disease.

    Science.gov (United States)

    Baxter, Richard H G

    2016-10-01

    Both historically and at present, vector control is the most generally effective means of controlling malaria transmission. Insecticides are the predominant method of vector control, but the sterile insect technique (SIT) is a complementary strategy with a successful track record in both agricultural and public health sectors. Strategies of genetic and radiation-induced sterilization of Anopheles have to date been limited by logistical and/or regulatory hurdles. A safe and effective mosquito chemosterilant would therefore be of major utility to future deployment of SIT for malaria control. Here we review the prior and current use of chemosterilants in SIT, and assess the potential for future research. Recent genomic and proteomic studies reveal opportunities for specific targeting of seminal fluid proteins, and the capacity to interfere with sperm motility and storage in the female.

  3. Remote radio control of insect flight.

    Science.gov (United States)

    Sato, Hirotaka; Berry, Christopher W; Peeri, Yoav; Baghoomian, Emen; Casey, Brendan E; Lavella, Gabriel; Vandenbrooks, John M; Harrison, Jon F; Maharbiz, Michel M

    2009-01-01

    We demonstrated the remote control of insects in free flight via an implantable radio-equipped miniature neural stimulating system. The pronotum mounted system consisted of neural stimulators, muscular stimulators, a radio transceiver-equipped microcontroller and a microbattery. Flight initiation, cessation and elevation control were accomplished through neural stimulus of the brain which elicited, suppressed or modulated wing oscillation. Turns were triggered through the direct muscular stimulus of either of the basalar muscles. We characterized the response times, success rates, and free-flight trajectories elicited by our neural control systems in remotely controlled beetles. We believe this type of technology will open the door to in-flight perturbation and recording of insect flight responses.

  4. Remote radio control of insect flight

    Directory of Open Access Journals (Sweden)

    Hirotaka Sato

    2009-10-01

    Full Text Available We demonstrated the remote control of insects in free flight via an implantable radio-equipped miniature neural stimulating system. The pronotum mounted system consisted of neural stimulators, muscular stimulators, a radio transceiver-equipped microcontroller and a microbattery. Flight initiation, cessation and elevation control were accomplished through neural stimulus of the brain which elicited, suppressed or modulated wing oscillation. Turns were triggered through the direct muscular stimulus of either of the basalar muscles. We characterized the response times, success rates, and free-flight trajectories elicited by our neural control systems in remotely-controlled beetles. We believe this type of technology will open the door to in-flight perturbation and recording of insect flight responses.

  5. 7 CFR 58.147 - Insect and rodent control program.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Insect and rodent control program. 58.147 Section 58... Service 1 Operations and Operating Procedures § 58.147 Insect and rodent control program. In addition to... made responsible for the performance of a regularly scheduled insect and rodent control...

  6. 7 CFR 58.247 - Insect and rodent control program.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Insect and rodent control program. 58.247 Section 58... Service 1 Operations and Operating Procedures § 58.247 Insect and rodent control program. In addition to... made responsible for the performance of a regularly scheduled insect and rodent control program...

  7. Control of vectors through interference with normal processes of insect physiology, reproduction and behavior. Final report 1968-1976

    Energy Technology Data Exchange (ETDEWEB)

    Schermeister, L.J.; Sandal, P.C.; Frye, R.D.

    1978-04-01

    Over 3000 crude water, alcohol and pet-ether plant part extracts were bioassayed with mosquitoes and Drosophila in an effort to identify agents which specifically interfere with insect metamorphosis, and which could provide environmentally safe insect control. About 10% of the extracts modified metamorphosis. Juvenile hormone type activity was noted in some extracts. Preliminary fractionation of promising extracts revealed fractions-bioassay results similar to that of the crude extracts. Exact nature of active fractions was not fully determined; however, flavanoids, alkaloids, and glycosides were suggested. Other agents including teratogens, hormones, and chemosterilant apholate, and gamma-radiation showed promise as potential vector control agents. Wing movements, sound patterns, and population dynamics of mosquitoes were studied as a step toward developing insect behavior and confusion and surveillance techniques. Transmission electron microscopy revealed the morphological nature of the cuticle layer of mosquito but additional studies are needed to understand chemical penetration of the cuticle. The septum of mosquito testes was found to be layered and surrounded by mitochondria. Ovaries were cultured on artificial media and a stain for neurosecretory activity was developed. Synthesis of Difluroperazine dihydro chloride and position labeling was achieved.

  8. 25 CFR 163.31 - Insect and disease control.

    Science.gov (United States)

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Insect and disease control. 163.31 Section 163.31 Indians... Management and Operations § 163.31 Insect and disease control. (a) The Secretary is authorized to protect and preserve Indian forest land from disease or insects (Sept. 20, 1922, Ch. 349, 42 Stat. 857). The...

  9. 20 CFR 654.415 - Insect and rodent control.

    Science.gov (United States)

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Insect and rodent control. 654.415 Section 654.415 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR SPECIAL... Insect and rodent control. Housing and facilities shall be free of insects, rodents, and other vermin....

  10. New pheromones and insect control strategies.

    Science.gov (United States)

    Reddy, Gadi V P; Guerrero, Angel

    2010-01-01

    A survey of the new environmentally safe strategies used for insect control is presented. The survey includes mating disruption, pheromone antagonists as chemical communication inhibitors, pheromones and plant-based volatiles, attractant-and-kill, and push-pull strategies. Important successes have been obtained, particularly in mating disruption with significant reduction in pesticide use in low to moderate pest infestations. One important factor of concern is the high cost of semiochemicals and formulations containing them in comparison to the conventional insecticide treatments, and a combined effort by scientists, producers, and farmers should be made to reduce the cost of application of these semiochemicals. Copyright © 2010 Elsevier Inc. All rights reserved.

  11. RNAi for insect control: current perspective and future challenges.

    Science.gov (United States)

    Katoch, Rajan; Sethi, Amit; Thakur, Neelam; Murdock, Larry L

    2013-10-01

    The research on the RNA interference (RNAi) for the control of insect pests has made significant growth in recent years. The availability of the genomic sequences of insects has further widened the horizons for the testing of this technology to various insect groups. Different modes of application of double-stranded RNA (dsRNA) have been tested; however, the practicability of delivery of dsRNA in insects still remains the biggest challenge. Till date, the oral delivery of dsRNA in insects is one of the efficient approaches for the practical application of this technique. The uptake of dsRNA from the insect gut is mediated either by SID-1/SID-2 transmembrane proteins or by endocytosis; however, the systemic RNAi machinery still remains to be revealed in insect species. The RNAi-mediated gene knockdown has shown striking results in different insect groups, pointing it to be the upcoming technique for insect control. However, before the successful application of this technique for insect control, some potential issues need to be resolved. This review presents the account of prospects and challenges for the use of this technology for insect control.

  12. The FOXO transcription factor controls insect growth and development by regulating juvenile hormone degradation in the silkworm, Bombyx mori.

    Science.gov (United States)

    Zeng, Baosheng; Huang, Yuping; Xu, Jun; Shiotsuki, Takahiro; Bai, Hua; Palli, Subba Reddy; Huang, Yongping; Tan, Anjiang

    2017-07-14

    Forkhead box O (FOXO) functions as the terminal transcription factor of the insulin signaling pathway and regulates multiple physiological processes in many organisms, including lifespan in insects. However, how FOXO interacts with hormone signaling to modulate insect growth and development is largely unknown. Here, using the transgene-based CRISPR/Cas9 system, we generated and characterized mutants of the silkworm Bombyx mori FOXO (BmFOXO) to elucidate its physiological functions during development of this lepidopteran insect. The BmFOXO mutant (FOXO-M) exhibited growth delays from the first larval stage and showed precocious metamorphosis, pupating at the end of the fourth instar (trimolter) rather than at the end of the fifth instar as in the wild-type (WT) animals. However, different from previous reports on precocious metamorphosis caused by juvenile hormone (JH) deficiency in silkworm mutants, the total developmental time of the larval period in the FOXO-M was comparable with that of the WT. Exogenous application of 20-hydroxyecdysone (20E) or of the JH analog rescued the trimolter phenotype. RNA-seq and gene expression analyses indicated that genes involved in JH degradation but not in JH biosynthesis were up-regulated in the FOXO-M compared with the WT animals. Moreover, we identified several FOXO-binding sites in the promoter of genes coding for JH-degradation enzymes. These results suggest that FOXO regulates JH degradation rather than its biosynthesis, which further modulates hormone homeostasis to control growth and development in B. mori In conclusion, we have uncovered a pivotal role for FOXO in regulating JH signaling to control insect development. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  13. Insect vision: controlling actions through optic flow.

    Science.gov (United States)

    Collett, Thomas S

    2002-09-17

    Insects depend upon optic flow to supply much of their information about the three-dimensional structure of the world. Many insects use translational flow to measure the distance of objects from themselves. A recent study has provided new insights into the way Drosophila use optic flow to pick out a close target to approach.

  14. Precocious metamorphosis in the juvenile hormone-deficient mutant of the silkworm, Bombyx mori.

    Directory of Open Access Journals (Sweden)

    Takaaki Daimon

    Full Text Available Insect molting and metamorphosis are intricately governed by two hormones, ecdysteroids and juvenile hormones (JHs. JHs prevent precocious metamorphosis and allow the larva to undergo multiple rounds of molting until it attains the proper size for metamorphosis. In the silkworm, Bombyx mori, several "moltinism" mutations have been identified that exhibit variations in the number of larval molts; however, none of them have been characterized molecularly. Here we report the identification and characterization of the gene responsible for the dimolting (mod mutant that undergoes precocious metamorphosis with fewer larval-larval molts. We show that the mod mutation results in complete loss of JHs in the larval hemolymph and that the mutant phenotype can be rescued by topical application of a JH analog. We performed positional cloning of mod and found a null mutation in the cytochrome P450 gene CYP15C1 in the mod allele. We also demonstrated that CYP15C1 is specifically expressed in the corpus allatum, an endocrine organ that synthesizes and secretes JHs. Furthermore, a biochemical experiment showed that CYP15C1 epoxidizes farnesoic acid to JH acid in a highly stereospecific manner. Precocious metamorphosis of mod larvae was rescued when the wild-type allele of CYP15C1 was expressed in transgenic mod larvae using the GAL4/UAS system. Our data therefore reveal that CYP15C1 is the gene responsible for the mod mutation and is essential for JH biosynthesis. Remarkably, precocious larval-pupal transition in mod larvae does not occur in the first or second instar, suggesting that authentic epoxidized JHs are not essential in very young larvae of B. mori. Our identification of a JH-deficient mutant in this model insect will lead to a greater understanding of the molecular basis of the hormonal control of development and metamorphosis.

  15. Evolutionary biology and genetic techniques for insect control

    OpenAIRE

    Leftwich, Philip; Bolton, Michael; Chapman, Tracey

    2015-01-01

    Abstract The requirement to develop new techniques for insect control that minimize negative environmental impacts has never been more pressing. Here we discuss population suppression and population replacement technologies. These include sterile insect technique, genetic elimination methods such as the release of insects carrying a dominant lethal (RIDL), and gene driving mechanisms offered by intracellular bacteria and homing endonucleases. We also review the potential of newer or underutil...

  16. Advances in microbial insect control in horticultural ecosystems

    Science.gov (United States)

    The use of microbial organisms as biological control agents has progressed significantly since Metschnikoff launched the first attempt at microbial insect control with Metarhizium anisopliae in 1879. Following the lead of Metschnikoff, entomopathogenic nematodes, fungi, bacteria and viruses have b...

  17. Discover for Yourself: An Optimal Control Model in Insect Colonies

    Science.gov (United States)

    Winkel, Brian

    2013-01-01

    We describe the enlightening path of self-discovery afforded to the teacher of undergraduate mathematics. This is demonstrated as we find and develop background material on an application of optimal control theory to model the evolutionary strategy of an insect colony to produce the maximum number of queen or reproducer insects in the colony at…

  18. Discover for Yourself: An Optimal Control Model in Insect Colonies

    Science.gov (United States)

    Winkel, Brian

    2013-01-01

    We describe the enlightening path of self-discovery afforded to the teacher of undergraduate mathematics. This is demonstrated as we find and develop background material on an application of optimal control theory to model the evolutionary strategy of an insect colony to produce the maximum number of queen or reproducer insects in the colony at…

  19. Recent developments in the remote radio control of insect flight.

    Science.gov (United States)

    Sato, Hirotaka; Maharbiz, Michel M

    2010-01-01

    The continuing miniaturization of digital circuits and the development of low power radio systems coupled with continuing studies into the neurophysiology and dynamics of insect flight are enabling a new class of implantable interfaces capable of controlling insects in free flight for extended periods. We provide context for these developments, review the state-of-the-art and discuss future directions in this field.

  20. Corticosteroid signaling in frog metamorphosis.

    Science.gov (United States)

    Kulkarni, Saurabh S; Buchholz, Daniel R

    2014-07-01

    Stress in fetal and larval life can impact later health and fitness in humans and wildlife. Long-term effects of early life stress are mediated by altered stress physiology induced during the process of relaying environmental effects on development. Amphibian metamorphosis has been an important model system to study the role of hormones in development in an environmental context. Thyroid hormone (TH) is necessary and sufficient to initiate the dramatic morphological and physiological changes of metamorphosis, but TH alone is insufficient to complete metamorphosis. Other hormones, importantly corticosteroid hormones (CSs), influence the timing and nature of post-embryonic development. Stressors or treatments with CSs delay or accelerate metamorphic change, depending on the developmental stage of treatment. Also, TH and CSs have synergistic, antagonistic, and independent effects on gene regulation. Importantly, the identity of the endogenous corticosteroid hormone or receptor underlying any gene induction or remodeling event has not been determined. Levels of both CSs, corticosterone and aldosterone, peak at metamorphic climax, and the corticosteroid receptors, glucocorticoid and mineralocorticoid receptors, have wide expression distribution among tadpole tissues. Conclusive experiments to identify the endogenous players have been elusive due to difficulties in experimental control of corticosteroid production and signaling. Current data are consistent with the hypothesis that the two CSs and their receptors serve largely overlapping functions in regulating metamorphosis and synergy with TH. Knowledge of the endogenous players is critical to understanding the basic mechanisms and significance of corticosteroid action in regulating post-embryonic development in environmental contexts.

  1. Eicosanoids: Exploiting Insect Immunity to Improve Biological Control Programs

    Science.gov (United States)

    Stanley, David; Haas, Eric; Miller, Jon

    2012-01-01

    Insects, like all invertebrates, express robust innate, but not adaptive, immune reactions to infection and invasion. Insect immunity is usually resolved into three major components. The integument serves as a physical barrier to infections. Within the hemocoel, the circulating hemocytes are the temporal first line of defense, responsible for clearing the majority of infecting bacterial cells from circulation. Specific cellular defenses include phagocytosis, microaggregation of hemocytes with adhering bacteria, nodulation and encapsulation. Infections also stimulate the humoral component of immunity, which involves the induced expression of genes encoding antimicrobial peptides and activation of prophenoloxidase. These peptides appear in the hemolymph of challenged insects 6–12 hours after the challenge. Prostaglandins and other eicosanoids are crucial mediators of innate immune responses. Eicosanoid biosynthesis is stimulated by infection in insects. Inhibition of eicosanoid biosynthesis lethally renders experimental insects unable to clear bacterial infection from hemolymph. Eicosanoids mediate specific cell actions, including phagocytosis, microaggregation, nodulation, hemocyte migration, hemocyte spreading and the release of prophenoloxidase from oenocytoids. Some invaders have evolved mechanisms to suppress insect immunity; a few of them suppress immunity by targeting the first step in the eicosanoid biosynthesis pathways, the enzyme phospholipase A2. We proposed research designed to cripple insect immunity as a technology to improve biological control of insects. We used dsRNA to silence insect genes encoding phospholipase A2, and thereby inhibited the nodulation reaction to infection. The purpose of this article is to place our view of applying dsRNA technologies into the context of eicosanoid actions in insect immunity. The long-term significance of research in this area lies in developing new pest management technologies to contribute to food security in

  2. Eicosanoids: Exploiting Insect Immunity to Improve Biological Control Programs

    Directory of Open Access Journals (Sweden)

    David Stanley

    2012-05-01

    Full Text Available Insects, like all invertebrates, express robust innate, but not adaptive, immune reactions to infection and invasion. Insect immunity is usually resolved into three major components. The integument serves as a physical barrier to infections. Within the hemocoel, the circulating hemocytes are the temporal first line of defense, responsible for clearing the majority of infecting bacterial cells from circulation. Specific cellular defenses include phagocytosis, microaggregation of hemocytes with adhering bacteria, nodulation and encapsulation. Infections also stimulate the humoral component of immunity, which involves the induced expression of genes encoding antimicrobial peptides and activation of prophenoloxidase. These peptides appear in the hemolymph of challenged insects 6–12 hours after the challenge. Prostaglandins and other eicosanoids are crucial mediators of innate immune responses. Eicosanoid biosynthesis is stimulated by infection in insects. Inhibition of eicosanoid biosynthesis lethally renders experimental insects unable to clear bacterial infection from hemolymph. Eicosanoids mediate specific cell actions, including phagocytosis, microaggregation, nodulation, hemocyte migration, hemocyte spreading and the release of prophenoloxidase from oenocytoids. Some invaders have evolved mechanisms to suppress insect immunity; a few of them suppress immunity by targeting the first step in the eicosanoid biosynthesis pathways, the enzyme phospholipase A2. We proposed research designed to cripple insect immunity as a technology to improve biological control of insects. We used dsRNA to silence insect genes encoding phospholipase A2, and thereby inhibited the nodulation reaction to infection. The purpose of this article is to place our view of applying dsRNA technologies into the context of eicosanoid actions in insect immunity. The long-term significance of research in this area lies in developing new pest management

  3. Laser system for identification, tracking, and control of flying insects.

    Science.gov (United States)

    Mullen, Emma R; Rutschman, Phillip; Pegram, Nathan; Patt, Joseph M; Adamczyk, John J; Johanson, 3ric

    2016-05-30

    Flying insects are common vectors for transmission of pathogens and inflict significant harm to humans and agricultural production in many parts of the world. We present proof of principle for an optical system capable of highly specific vector control. This system utilizes a combination of optical sources, detectors, and sophisticated software to search, detect, and identify flying insects in real-time, with the capability of eradication using a lethal laser pulse. We present data on two insect species to show species distinction; Diaphorina citri, a vector of the causal agent of citrus greening disease, and Anopheles stephensi, a malaria vector.

  4. The use of insecticides to control insect pests

    Directory of Open Access Journals (Sweden)

    M Wojciechowska

    2016-07-01

    Full Text Available Pesticides are used as plants protection products. Among those, insecticides serve as agents to control insects. When incorrectly applied, however these substances may negatively affect people's health and natural environment. Administration routes of insecticides depend on many factors and vary from spraying to fertilizers. These different methods influence how insects prey and how pests develop. Additionally, too frequent use of the same chemicals can lead to development of resistance of insects to these insecticides. In order to prevent occurrence of negative effects of insecticides on surroundings, the effects of these compounds should be studied

  5. Application of Genomics for Understanding Plant Virus-Insect Vector Interactions and Insect Vector Control.

    Science.gov (United States)

    Kaur, Navneet; Hasegawa, Daniel K; Ling, Kai-Shu; Wintermantel, William M

    2016-10-01

    The relationships between plant viruses and their vectors have evolved over the millennia, and yet, studies on viruses began virus and vector interactions even more recently. The advent of next generation sequencing, including rapid genome and transcriptome analysis, methods for evaluation of small RNAs, and the related disciplines of proteomics and metabolomics offer a significant shift in the ability to elucidate molecular mechanisms involved in virus infection and transmission by insect vectors. Genomic technologies offer an unprecedented opportunity to examine the response of insect vectors to the presence of ingested viruses through gene expression changes and altered biochemical pathways. This review focuses on the interactions between viruses and their whitefly or thrips vectors and on potential applications of genomics-driven control of the insect vectors. Recent studies have evaluated gene expression in vectors during feeding on plants infected with begomoviruses, criniviruses, and tospoviruses, which exhibit very different types of virus-vector interactions. These studies demonstrate the advantages of genomics and the potential complementary studies that rapidly advance our understanding of the biology of virus transmission by insect vectors and offer additional opportunities to design novel genetic strategies to manage insect vectors and the viruses they transmit.

  6. Recent Developments in the Remote Radio Control of Insect Flight

    Directory of Open Access Journals (Sweden)

    Hirotaka eSato

    2010-12-01

    Full Text Available The continuing miniaturization of digital circuits and the development of low power radio systems coupled with continuing studies into the neurophysiology and dynamics of insect flight are enabling a new class of implantable interfaces capable of controlling insects in free flight for extended periods. We provide context for these developments, review the state-of-the-art and discuss future directions in this field.

  7. UVB Radiation Delays Tribolium castaneum Metamorphosis by Influencing Ecdysteroid Metabolism.

    Science.gov (United States)

    Sang, Wen; Yu, Lin; He, Li; Ma, Wei-Hua; Zhu, Zhi-Hui; Zhu, Fen; Wang, Xiao-Ping; Lei, Chao-Liang

    2016-01-01

    Ultraviolet B (UVB) radiation is an important environmental factor. It is generally known that UVB exhibits high genotoxicity due to causing DNA damage, potentially leading to skin carcinogenesis and aging in mammals. However, little is known about the effects of UVB on the development and metamorphosis of insects, which are the most abundant terrestrial animals. In the present study, we performed dose-response analyses of the effects UVB irradiation on Tribolium castaneum metamorphosis, assessed the function of the T. castaneum prothoracicotropic hormone gene (Trcptth), and analyzed ecdysteroid pathway gene expression profile and ecdysterone titers post-UVB irradiation. The results showed that UVB not only caused death of T. castaneum larvae, but also delayed larval-pupal metamorphosis and reduced the size and emergence rate of pupae. In addition, we verified the function of Trcptth, which is responsible for regulating metamorphosis. It was also found that the expression profiles of Trcptth as well as ecdysteroidogenesis and response genes were influenced by UVB radiation. Therefore, a disturbance pulse of ecdysteroid may be involved in delaying development under exposure to irradiation. To our knowledge, this is the first report indicating that UVB can influence the metamorphosis of insects. This study will contribute to a better understanding of the impact of UVB on signaling mechanisms in insect metamorphosis.

  8. UVB Radiation Delays Tribolium castaneum Metamorphosis by Influencing Ecdysteroid Metabolism.

    Directory of Open Access Journals (Sweden)

    Wen Sang

    Full Text Available Ultraviolet B (UVB radiation is an important environmental factor. It is generally known that UVB exhibits high genotoxicity due to causing DNA damage, potentially leading to skin carcinogenesis and aging in mammals. However, little is known about the effects of UVB on the development and metamorphosis of insects, which are the most abundant terrestrial animals. In the present study, we performed dose-response analyses of the effects UVB irradiation on Tribolium castaneum metamorphosis, assessed the function of the T. castaneum prothoracicotropic hormone gene (Trcptth, and analyzed ecdysteroid pathway gene expression profile and ecdysterone titers post-UVB irradiation. The results showed that UVB not only caused death of T. castaneum larvae, but also delayed larval-pupal metamorphosis and reduced the size and emergence rate of pupae. In addition, we verified the function of Trcptth, which is responsible for regulating metamorphosis. It was also found that the expression profiles of Trcptth as well as ecdysteroidogenesis and response genes were influenced by UVB radiation. Therefore, a disturbance pulse of ecdysteroid may be involved in delaying development under exposure to irradiation. To our knowledge, this is the first report indicating that UVB can influence the metamorphosis of insects. This study will contribute to a better understanding of the impact of UVB on signaling mechanisms in insect metamorphosis.

  9. Companion and refuge plants to control insect pests

    Science.gov (United States)

    Introduction: The sweetpotato whitefly, Bemisia tabaci and aphids are major pests of crops in the southeast USA. An environmentally-friendly management strategy is “push-pull” technology which combines the use of repellent (“push”) and trap crops (“pull”) for insect pest control. The repellent crop,...

  10. Nocturnal insects use optic flow for flight control.

    Science.gov (United States)

    Baird, Emily; Kreiss, Eva; Wcislo, William; Warrant, Eric; Dacke, Marie

    2011-08-23

    To avoid collisions when navigating through cluttered environments, flying insects must control their flight so that their sensory systems have time to detect obstacles and avoid them. To do this, day-active insects rely primarily on the pattern of apparent motion generated on the retina during flight (optic flow). However, many flying insects are active at night, when obtaining reliable visual information for flight control presents much more of a challenge. To assess whether nocturnal flying insects also rely on optic flow cues to control flight in dim light, we recorded flights of the nocturnal neotropical sweat bee, Megalopta genalis, flying along an experimental tunnel when: (i) the visual texture on each wall generated strong horizontal (front-to-back) optic flow cues, (ii) the texture on only one wall generated these cues, and (iii) horizontal optic flow cues were removed from both walls. We find that Megalopta increase their groundspeed when horizontal motion cues in the tunnel are reduced (conditions (ii) and (iii)). However, differences in the amount of horizontal optic flow on each wall of the tunnel (condition (ii)) do not affect the centred position of the bee within the flight tunnel. To better understand the behavioural response of Megalopta, we repeated the experiments on day-active bumble-bees (Bombus terrestris). Overall, our findings demonstrate that despite the limitations imposed by dim light, Megalopta-like their day-active relatives-rely heavily on vision to control flight, but that they use visual cues in a different manner from diurnal insects.

  11. Evolutionary biology and genetic techniques for insect control.

    Science.gov (United States)

    Leftwich, Philip T; Bolton, Michael; Chapman, Tracey

    2016-01-01

    The requirement to develop new techniques for insect control that minimize negative environmental impacts has never been more pressing. Here we discuss population suppression and population replacement technologies. These include sterile insect technique, genetic elimination methods such as the release of insects carrying a dominant lethal (RIDL), and gene driving mechanisms offered by intracellular bacteria and homing endonucleases. We also review the potential of newer or underutilized methods such as reproductive interference, CRISPR technology, RNA interference (RNAi), and genetic underdominance. We focus on understanding principles and potential effectiveness from the perspective of evolutionary biology. This offers useful insights into mechanisms through which potential problems may be minimized, in much the same way that an understanding of how resistance evolves is key to slowing the spread of antibiotic and insecticide resistance. We conclude that there is much to gain from applying principles from the study of resistance in these other scenarios - specifically, the adoption of combinatorial approaches to minimize the spread of resistance evolution. We conclude by discussing the focused use of GM for insect pest control in the context of modern conservation planning under land-sparing scenarios.

  12. 50 CFR 35.7 - Control of wildfires, insects, pest plants, and disease.

    Science.gov (United States)

    2010-10-01

    ... MANAGEMENT General Rules § 35.7 Control of wildfires, insects, pest plants, and disease. To the extent necessary, the Director shall prescribe measures to control wildfires, insects, pest plants, and disease to... 50 Wildlife and Fisheries 6 2010-10-01 2010-10-01 false Control of wildfires, insects, pest plants...

  13. Cathepsins of lepidopteran insects: Aspects and prospects.

    Science.gov (United States)

    Saikhedkar, Nidhi; Summanwar, Aarohi; Joshi, Rakesh; Giri, Ashok

    2015-09-01

    Molecular understanding of lepidopteran physiology has revealed that proteases consist of one of the central regulatory/reacting system for insect growth and survival. Among the various proteases, cathepsins are the most crucial cellular proteases, which play vital roles during insect development. In the present review, we have discussed various aspects of the lepidopteran insect cathepsins, emphasizing their roles in processes like development, growth, metamorphosis, apoptosis and immunity. Cathepsins are categorized into different types on the basis of their sequence diversification, leading to variation in structure and catalytic function. Cathepsins exhibit tissue and stage specific expression pattern which is fine-tuned by a delicate balance of expression, compartmentalization, zymogen activation, inhibition by protein inhibitors and degradation. The indispensability of cathepsins as cellular proteases in the above mentioned processes proposes them as novel targets for designing effective and specific insect controlling strategies.

  14. Gamma radiation in the control of insects in animal feed

    Energy Technology Data Exchange (ETDEWEB)

    Arthur, Paula B.; Arthur, Valter; Silva, Lucia C.A.S.; Franco, Suely S.H., E-mail: paula.arthur@hotmail.com, E-mail: arthur@cena.usp.br [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil); Franco, Jose G.; Villavicencio, Anna Lucia, E-mail: gilmita@uol.com.br, E-mail: villavic@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Harder, Marcia N.C., E-mail: marcia.harder@fatec.sp.gov.br [Centro Paula Souza, Curso Superior de Tecnologia em Biocombustiveis (FATEC), Piracicaba, SP (Brazil)

    2015-07-01

    The pests as beetles, acarids, moths and mushrooms among other, usually infest products stored as: grains, crumbs, flours, coffee, tobacco, dried fruits, animal feeds, spices and dehydrated plants, causing the visual depreciation and promoting the deterioration of the products. The objective of this study was to use gamma radiation of Cobalt-60 in the disinfestation of some types of commercial feeds used for animals of small size. In the experiment, packages measuring 10 cm x 15 cm, with capacity of 30 grams of substrate with 4 types of trademarks were irradiated with doses of: 0 (control) 0.5; 1.0 and 2.0 kGy. Each treatment had 10 repetitions, infested with 10 insects for each package with the following species: Lasioderma serricorne, Plodia interpuctella, Sitophilus zeamais and S. oryzae. After the irradiation, all the packages were maintained at acclimatized room with 27 ± 2ºC and relative humidity of 70 ± 5%. The number of insects and holes in all packages were assessed after 60 days. The results showed that the dose of 0.5 kGy was sufficient to control all the species of insects in the tested feeds. (author)

  15. Neural and Hormonal Control of Postecdysial Behaviors in Insects

    Science.gov (United States)

    White, Benjamin H.; Ewer, John

    2016-01-01

    The shedding of the old exoskeleton that occurs in insects at the end of a molt (a process called ecdysis) is typically followed by the expansion and tanning of a new one. At the adult molt, these postecdysial processes include expanding and hardening the wings. Here we describe recent advances in understanding the neural and hormonal control of wing expansion and hardening, focusing on work done in Drosophila where genetic manipulations have permitted a detailed investigation of postecdysial processes and their modulation by sensory input. To place this work in context, we briefly review recent progress in understanding the neuroendocrine regulation of ecdysis, which appears to be largely conserved across insect species. Investigations into the neuroendocrine networks that regulate ecdysial and postecdysial behaviors, will provide insights into how stereotyped, yet environmentally-responsive, sequences are generated, as well as into how they develop and evolve. PMID:24160420

  16. Elemental concentration in mealworm beetle (Tenebrio molitor L.) during metamorphosis.

    Science.gov (United States)

    Simon, Edina; Baranyai, Edina; Braun, Mihály; Fábián, István; Tóthmérész, Béla

    2013-07-01

    Mealworm beetles have been used in numerous experiments as bioindicators. The aim of our experiment was to study the elemental composition in three larvae, pupae and first and second generation adult stages during their life cycle. We selected 180 larvae from a genetically similar population and put them in three groups, in two boxes (60 larvae in each box). Larvae were fed with mashed potato made of the same quality and quantity of potato powder. Then, we selected 10 individuals from each stage to the elemental analysis, using the ICP-OES method. The following elements were analysed in the studied stages: Ca, Cu, Fe, K, Mg, Mn, Na, P, S, Sr and Zn. The results of principal component analysis demonstrated that based on elemental composition, different stages were separated with each other, but in the cases of the three larvae stages, high overlap was found. The results of the GLM ANOVA showed significant differences between the different stages of metamorphosis-based elemental composition. Our results show that the calcium and magnesium were found in a relatively high concentration, while the iron and zinc may be essential elements during the metamorphosis. Our results also show that in insect, the concentration of sodium was higher than in the pupa which may cause by hemolymph. We also demonstrated that the metamorphosis has an effect on the concentration of elements. Our study shows that in the different stages of insects, there are significant changes in the elemental composition of different stages of insects during their metamorphosis.

  17. Insect pathogens as biological control agents: Back to the future.

    Science.gov (United States)

    Lacey, L A; Grzywacz, D; Shapiro-Ilan, D I; Frutos, R; Brownbridge, M; Goettel, M S

    2015-11-01

    The development and use of entomopathogens as classical, conservation and augmentative biological control agents have included a number of successes and some setbacks in the past 1years. In this forum paper we present current information on development, use and future directions of insect-specific viruses, bacteria, fungi and nematodes as components of integrated pest management strategies for control of arthropod pests of crops, forests, urban habitats, and insects of medical and veterinary importance. Insect pathogenic viruses are a fruitful source of microbial control agents (MCAs), particularly for the control of lepidopteran pests. Most research is focused on the baculoviruses, important pathogens of some globally important pests for which control has become difficult due to either pesticide resistance or pressure to reduce pesticide residues. Baculoviruses are accepted as safe, readily mass produced, highly pathogenic and easily formulated and applied control agents. New baculovirus products are appearing in many countries and gaining an increased market share. However, the absence of a practical in vitro mass production system, generally higher production costs, limited post application persistence, slow rate of kill and high host specificity currently contribute to restricted use in pest control. Overcoming these limitations are key research areas for which progress could open up use of insect viruses to much larger markets. A small number of entomopathogenic bacteria have been commercially developed for control of insect pests. These include several Bacillus thuringiensis sub-species, Lysinibacillus (Bacillus) sphaericus, Paenibacillus spp. and Serratia entomophila. B. thuringiensis sub-species kurstaki is the most widely used for control of pest insects of crops and forests, and B. thuringiensis sub-species israelensis and L. sphaericus are the primary pathogens used for control of medically important pests including dipteran vectors. These pathogens

  18. Identification and Control of Common Insect Pests of Ornamental Shrubs and Trees.

    Science.gov (United States)

    Gesell, Stanley G.

    This agriculture extension service publication from Pennsylvania State University introduces the identification and control of common ornamental insect pests. For each of the insects or insect groups (i.e. aphids) identified in this publication, information on host plants, pest description, and damage caused by the pest is given. Also a calendar…

  19. Entomopathogenic Nematodes for the Biological Control of Pest Insects

    OpenAIRE

    Ljerka Oštrec

    2001-01-01

    Entomopathogenic nematodes are part of 9 families, but only some species of these families: Heterorhabditidae, Mermithidae and Steinernematidae kill insects. Infective juveniles enter the insect host through the cuticle, or through the mouth, anus, etc., to reach the haemocel. The infective juveniles also enter the insect by the foot. After that the nematodes leave the insect who usually dies. The infective juveniles are associated with symbiotic bacterium (Xenorhabdus, Photorhabdus) which h...

  20. Entomopathogenic Nematodes for the Biological Control of Pest Insects

    OpenAIRE

    Ljerka Oštrec

    2001-01-01

    Entomopathogenic nematodes are part of 9 families, but only some species of these families: Heterorhabditidae, Mermithidae and Steinernematidae kill insects. Infective juveniles enter the insect host through the cuticle, or through the mouth, anus, etc., to reach the haemocel. The infective juveniles also enter the insect by the foot. After that the nematodes leave the insect who usually dies. The infective juveniles are associated with symbiotic bacterium (Xenorhabdus, Photorhabdus) which h...

  1. Insect-controlled Robot: A Mobile Robot Platform to Evaluate the Odor-tracking Capability of an Insect.

    Science.gov (United States)

    Ando, Noriyasu; Emoto, Shuhei; Kanzaki, Ryohei

    2016-12-19

    Robotic odor source localization has been a challenging area and one to which biological knowledge has been expected to contribute, as finding odor sources is an essential task for organism survival. Insects are well-studied organisms with regard to odor tracking, and their behavioral strategies have been applied to mobile robots for evaluation. This "bottom-up" approach is a fundamental way to develop biomimetic robots; however, the biological analyses and the modeling of behavioral mechanisms are still ongoing. Therefore, it is still unknown how such a biological system actually works as the controller of a robotic platform. To answer this question, we have developed an insect-controlled robot in which a male adult silkmoth (Bombyx mori) drives a robot car in response to odor stimuli; this can be regarded as a prototype of a future insect-mimetic robot. In the cockpit of the robot, a tethered silkmoth walked on an air-supported ball and an optical sensor measured the ball rotations. These rotations were translated into the movement of the two-wheeled robot. The advantage of this "hybrid" approach is that experimenters can manipulate any parameter of the robot, which enables the evaluation of the odor-tracking capability of insects and provides useful suggestions for robotic odor-tracking. Furthermore, these manipulations are non-invasive ways to alter the sensory-motor relationship of a pilot insect and will be a useful technique for understanding adaptive behaviors.

  2. Controls on fluvial metamorphosis during global warming at the Paleocene-Eocene boundary (56 Ma) in Spain: extreme droughts, extreme floods or both?

    Science.gov (United States)

    Castelltort, Sebastien; Chen, Chen; Guerit, Laure; Foreman, Brady; Paola, Chris; Adatte, Thierry

    2017-04-01

    How does global warming change the frequency and intensity of extreme weather events? The response to this question is partly preserved in the geological record. 56 Ma ago, global temperatures increased during the Paleocene-Eocene Thermal Maximum (PETM), leading to a major biotic turnover, but how this event affected the nature of extreme events remains unknown. On several continents, fluvial systems with sinuous channels within fine-grained floodplains suddenly transformed at the P-E boundary into apparently coarser-grained braid plains with frequent lateral migrations, washing their muddy floodplains to the seas. This landscape transformation has been related to aridification and intensification of precipitation allowing transport of coarser material as a result of P-E global warming, with important implications for predicting the consequences of current global change. Here we test this hypothesis by quantifying the magnitude of grain size change and flow depth at a representative P-E locality in Northern Spain. We find that the size of pebbles in transport and flow depth remained similar to, or even smaller than, pre-PETM conditions. This suggests that, if more seasonal and extreme precipitation occurred, they are not necessarily borne out in the predicted deeper flow depths and coarser grain sizes, but rather trigger a shift to multiple active channels. However, an alternative or complementary explanation may rest in pollen data found in coeval marine records and which document a dramatic vegetation shift from permanent conifer forests prior to the crisis into periodic vegetation in brief periods of rain during the hyperthermal episode. Such change induced by long periods of intense droughts, could have enhanced erodibility of channel banks by decreasing root-controlled cohesion of fine-grained floodplains and interfluves, promoting their lateral mobility and the observed fluvial metamorphosis. Thus, although water is regarded as the main agent sculpting

  3. Recent Advances in Biological Control of Pest Insects by Using Viruses in China

    Institute of Scientific and Technical Information of China (English)

    Xiu-lian SUN; Hui-yin PENG

    2007-01-01

    Insect viruses are attractive as biological control agents and could be a feasible alternative to chemical insecticides in the management of insect infestations. This review describes recent advances in the development of wild-type and genetically modified viruses as insecticides. A new strategy of application of insect viruses in China is reviewed. Also, the assessment of biosafety of genetically modified Helicoverpa armigera Nucleopolyhedovirus (HearNPV) is emphasized as a case-study.

  4. Pest control of ligniperdous insects by means of ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Baer, M. (Akademie der Wissenschaften der DDR, Leipzig. Zentralinstitut fuer Isotopen- und Strahlenforschung); Kerner, G.; Unger, W. (Amt fuer Standardisierung, Messwesen und Warenpruefung, Berlin (German Democratic Republic)); Koehler, W. (Staatliche Schloesser und Gaerten, Potsdam-Sanssouci (German Democratic Republic). Abt. Restaurierung)

    1983-01-01

    Wooden objects of art and monuments are endangered by wood-destroying insects. The treatment of these objects with ionizing radiation is one way to control these pests. For this purpose the portable HWK-3 high-dose irradiation device was developed. In July 1979, a radiation experiment was made under field conditions in Potsdam-Sanssouci in order to gain experience in the operation and effectiveness of the new device. During the following 18 months the results of this experiment were evaluated by means of the SM 231 vibration measuring instrument. It became evident that a total dose of over 3 kGy would kill all of the death-watch beetles (Anobium punctatum de Geer) and doses down to 0.55 kGy would largely diminish the population, with future damages caused by death-watch beetles being highly unlikely. Delayed damages in the larvae caused by low total doses still add to the effectiveness of the pest control.

  5. The Mechanisms of the Ecdysone Pulses that Cause Metamorphosis

    DEFF Research Database (Denmark)

    Møller, Morten Erik

    Maturation in both mammals and insects is caused by pulses of steroid hormones released from glands in response to a brain-derived signal. The timing of this developmental transition is secured by the integration of many developmental cues, such as size, external environment and nutritional...... condition, with hardwired genetic programs. In holometabolous insects, pulses of the steroid hormone ecdysone cause the transition between the larval stages and the initiation of the metamorphosis, which transforms the juvenile larva to a sexually mature adult. Ecdysone is produced in the prothoracic gland...

  6. Factors determining the use of botanical insect pest control methods ...

    African Journals Online (AJOL)

    user

    2009-05-16

    May 16, 2009 ... production and protection challenges such as diseases, insect pests ... Pest management innovations are ... The botanicals and other indigenous products locally used by small ..... Credit Constraints as a Barrier to Technology.

  7. Metabolism of a Glycosaminoglycan during Metamorphosis in the Japanese Conger eel, Conger myriaster

    Directory of Open Access Journals (Sweden)

    Yutaka Kawakami

    2009-01-01

    Full Text Available Hyaluronan (HA is a linear polysaccharide of high molecular weight that exists as a component of the extracellular matrix. The larvae (leptocephali of the Japanese conger eel (Anguilliformes: Conger myriaster have high levels of hyaluronan (HA which is thought to help control body water content. We isolated glycosaminoglycans (GAGs from Japanese conger eel leptocephali and measured the changes in tissue HA content during metamorphosis. HA content decreased during metamorphosis. In contrast, neutral sugar content increased during metamorphosis. We hypothesize that the leptocephali utilize a metabolic pathway that converts HA to glucose during metamorphosis. Glucose may then be metabolized to glycogen and stored in the juvenile life-history stage.

  8. Biology and Control of Insect and Related Pests of Livestock in Wyoming. MP-23.

    Science.gov (United States)

    Lloyd, John E.

    This document provides information that a potential insecticide applicator can utilize to safely and effectively control insects and related pests of livestock. The first section of the manual discusses the general methods of preparation and application of insecticides. The second section concerns itself with the recognition of insect problems,…

  9. Midgut morphological changes and autophagy during metamorphosis in sand flies.

    Science.gov (United States)

    Malta, Juliana; Heerman, Matthew; Weng, Ju Lin; Fernandes, Kenner M; Martins, Gustavo Ferreira; Ramalho-Ortigão, Marcelo

    2017-03-11

    During metamorphosis, holometabolous insects undergo significant remodeling of their midgut and become able to cope with changes in dietary requirements between larval and adult stages. At this stage, insects must be able to manage and recycle available food resources in order to develop fully into adults, especially when no nutrients are acquired from the environment. Autophagy has been previously suggested to play a crucial role during metamorphosis of the mosquito. Here, we investigate the overall morphological changes of the midgut of the sand fly during metamorphosis and assess the expression profiles of the autophagy-related genes ATG1, ATG6, and ATG8, which are associated with various steps of the autophagic process. Morphological changes in the midgut start during the fourth larval instar, with epithelial degeneration followed by remodeling via the differentiation of regenerative cells in pre-pupal and pupal stages. The changes in the midgut epithelium are paired with the up-regulation of ATG1, ATG6 and ATG8 during the larva-adult transition. Vein, a putative epidermal growth factor involved in regulating epithelial midgut regeneration, is also up-regulated. Autophagy has further been confirmed in sand flies via the presence of autophagosomes residing within the cytoplasmic compartment of the pupal stages. An understanding of the underlying mechanisms of this process should aid the future management of this neglected tropical vector.

  10. Towards Biological Control of Kudzu Through an Improved Understanding of Insect-Kudzu Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Orr, D.; Barber, G.; DeBarr, G.; Thornton, M.

    2001-08-03

    The authors evaluated various approaches to the biological control of kudzu and exotic weed that infests the SRS. A large number of native pollinators were found to be attracted to kudzu. The viability of seed was found to be low, between 2% and 11%. This is the result of native Hemiptera. The results suggest that seed feeding insects should not be targeted for importation. Both kudzu and soybeans had the same level of abundance and diversity of herbivore insects and the same levels of defoliation. No vine or root damaging species were found. Efforts should be targeted to the latter insects to control kudzu.

  11. Use of a regulatory mechanism of sex determination in pest insect control

    Indian Academy of Sciences (India)

    Tarig Dafa'alla; Gouliang Fu; Luke Alphey

    2010-09-01

    The sexual development of an insect is defined through a hierarchical control of several sex determining genes. Of these genes, transformer (tra) and doublesex (dsx) are well characterized and functionally conserved, especially dsx. Both genes are regulated at the transcriptional level through sex-specific alternative splicing. Incorporation of a genetically engineered sex-specific splicing module derived from these genes in transgenic systems, such as RIDL (release of insects carrying a dominant lethal), would allow the production of male-only insects for control programmes without any physical intervention.

  12. Laser system for identification, tracking, and control of flying insects

    Science.gov (United States)

    Flying insects are common vectors for transmission of pathogens and inflict significant harm on humans in large parts of the developing world. Besides the direct impact to humans, these pathogens also cause harm to crops and result in agricultural losses. Here, we present a laser-based system that c...

  13. Biological control of pests and insects. (Latest citations from the NTIS bibliographic database). Published Search

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-04-01

    The bibliography contains citations concerning the use of biological agents to control insects and pests. Radiation, genetic breeding, bacteria, fungi, viruses, and pheromones are discussed as alternatives to pesticidal management. Methods for monitoring the effectiveness and environmental impact of these agents are reviewed. Population control of fruit flies, spruce sawflies, flies, mosquitoes, cockroaches, gypsy moths, and other agriculturally-important insects is also discussed. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  14. Biological control of pests and insects. (Latest citations from the NTIS bibliographic database). Published Search

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-02-01

    The bibliography contains citations concerning the use of biological agents to control insects and pests. Radiation, genetic breeding, bacteria, fungi, viruses, and pheromones are discussed as alternatives to pesticidal management. Methods for monitoring the effectiveness and environmental impact of these agents are reviewed. Population control of fruit flies, spruce sawflies, flies, mosquitoes, cockroaches, gypsy moths, and other agriculturally-important insects is also discussed. (Contains a minimum of 190 citations and includes a subject term index and title list.)

  15. The use of phytochemicals as fumigants for the control of stored product insect pests

    Directory of Open Access Journals (Sweden)

    Eli Shaaya

    2011-08-01

    Full Text Available The current study is aimed to evaluate the potential use of the known isothyiocyanates, as compared to a new isothyiocyanate (ITC isolated from Eruca sativa (salad rocket as fumigants for the control of stored product insects. The biological activity of methyl iodide (CH3I, carbon disulphide (CS2, benzaldehyde (C7H6O and essential oils were also evaluated. The toxicity of the various fumigants was assessed against adults and larvae of a number of major stored product insects. ITCs are known to have high toxicity and only very low concentrations are needed for the control of stored product insects. Eruca sativa is used worldwide as a food supplement. Methylthio butyl ITC, the main bioactive component in this plant has high toxicity against insects, but lower mammalian toxicity as compared to other active ITCs. This makes this compound a potential candidate for insect control. Comparative studies with CH3I, CS2 and C7H6O showed that the first was the most active compound against stored product insects followed by the second and third. C7H6O was found active, but very sorptive; therefore it was less effective against insects. The activity of a large number of essential oils (EOs isolated from aromatic plants was also evaluated.

  16. Environmental and genetic control of insect abundance and herbivory along a forest elevational gradient.

    Science.gov (United States)

    Garibaldi, Lucas A; Kitzberger, Thomas; Chaneton, Enrique J

    2011-09-01

    Environmental conditions and plant genotype may influence insect herbivory along elevational gradients. Plant damage would decrease with elevation as temperature declines to suboptimal levels for insects. However, host plants at higher elevations may exhibit traits that either reduce or enhance leaf quality to insects, with uncertain net effects on herbivory. We examined folivory, insect abundance and leaf traits along six replicated elevational ranges in Nothofagus pumilio forests of the northern Patagonian Andes, Argentina. We also conducted a reciprocal transplant experiment between low- and high-elevation sites to test the extent of environmental and plant genetic control on insect abundance and folivory. We found that insect abundance, leaf size and specific leaf area decreased, whereas foliar phosphorous content increased, from low-, through mid- to high-elevation sites. Path analysis indicated that changes in both insect abundance and leaf traits were important in reducing folivory with increasing elevation and decreasing mean temperature. At both planting sites, plants from a low-elevation origin experienced higher damage and supported greater insect loads than plants from a high-elevation origin. The differences in leaf damage between sites were twofold larger than those between plant origins, suggesting that local environment was more important than host genotype in explaining folivory patterns. Different folivore guilds exhibited qualitatively similar responses to elevation. Our results suggest an increase in insect folivory on high-elevation N. pumilio forests under future climate warming scenarios. However, in the short-term, folivory increases might be smaller than expected from insect abundance only because at high elevations herbivores would encounter more resistant tree genotypes.

  17. Salt controls feeding decisions in a blood-sucking insect.

    Science.gov (United States)

    Pontes, Gina; Pereira, Marcos H; Barrozo, Romina B

    2016-12-15

    Salts are necessary for maintaining homeostatic conditions within the body of all living organisms. Like with all essential nutrients, deficient or excessive ingestion of salts can result in adverse health effects. The taste system is a primary sensory modality that helps animals to make adequate feeding decisions in terms of salt consumption. In this work we show that sodium and potassium chloride salts modulate the feeding behavior of Rhodnius prolixus in a concentration-dependent manner. Feeding is only triggered by an optimal concentration of any of these salts (0.1-0.15M) and in presence of the phagostimulant ATP. Conversely, feeding solutions that do not contain salts or have a high-salt concentration (>0.3M) are not ingested by insects. Notably, we show that feeding decisions of insects cannot be explained as an osmotic effect, because they still feed over hyperosmotic solutions bearing the optimal salt concentration. Insects perceive optimal-salt, no-salt and high-salt solutions as different gustatory information, as revealed the electromyogram recordings of the cibarial pump. Moreover, because insects do a continuous gustatory monitoring of the incoming food during feeding, sudden changes beyond the optimal sodium concentration decrease and even inhibit feeding. The administration of amiloride, a sodium channel blocker, noticeably reduces the ingestion of the optimal sodium solution but not of the optimal potassium solution. Salt detection seems to occur at least through two salt receptors, one amiloride-sensitive and another amiloride-insensitive. Our results confirm the importance of the gustatory system in R. prolixus, showing the relevant role that salts play on their feeding decisions.

  18. Combination of Methoprene and Controlled Aeration to Manage Insects in Stored Wheat.

    Science.gov (United States)

    Liu, Samuel S; Arthur, Frank H; VanGundy, Douglas; Phillips, Thomas W

    2016-06-17

    A commercial formulation of the insect growth regulator methoprene was applied to wheat stored in small bins either alone or in combination with controlled aeration of the bins, to lower grain temperature for insect pest management of stored wheat. Grain temperatures were monitored and modified by a computer-controlled thermocouple system that also activated the aeration system at programmed set-points to move cool ambient air through the grain mass to lower grain temperature. Results from sampling insect populations in experimental storage bins along with laboratory mortality bioassays of insects placed on wheat taken from the bins over the course of the storage period showed that methoprene was very effective in controlling infestation by the externally-feeding stored grain insects Plodia interpunctella (Hübner), the Indian meal moth Tribolium castaneum (Herbst), the red flour beetle, Cryptolestes ferrugineus (Stephens), the rusty grain beetle, and also for the internal-feeding pest Rhyzopertha dominica( Fauvel), the lesser grain borer. Methoprene did not give good control of the internal-feeding pest Sitophilus oryzae (L.), the rice weevil. Aeration alone was somewhat effective in suppressing insect population development, while methoprene alone or when combined with aeration greatly enhanced insect control. Commercial grain grading for industry quality standards at the end of the storage period confirmed the impact of insect suppression on maintaining high quality of the stored wheat. This field experiment shows that methoprene combined with aeration to cool grain can be effective for pest management of stored wheat in the southern plains of the United States of America.

  19. Combination of Methoprene and Controlled Aeration to Manage Insects in Stored Wheat

    Directory of Open Access Journals (Sweden)

    Samuel S. Liu

    2016-06-01

    Full Text Available A commercial formulation of the insect growth regulator methoprene was applied to wheat stored in small bins either alone or in combination with controlled aeration of the bins, to lower grain temperature for insect pest management of stored wheat. Grain temperatures were monitored and modified by a computer-controlled thermocouple system that also activated the aeration system at programmed set-points to move cool ambient air through the grain mass to lower grain temperature. Results from sampling insect populations in experimental storage bins along with laboratory mortality bioassays of insects placed on wheat taken from the bins over the course of the storage period showed that methoprene was very effective in controlling infestation by the externally-feeding stored grain insects Plodia interpunctella (Hübner, the Indian meal moth Tribolium castaneum (Herbst, the red flour beetle, Cryptolestes ferrugineus (Stephens, the rusty grain beetle, and also for the internal-feeding pest Rhyzopertha dominica( Fauvel, the lesser grain borer. Methoprene did not give good control of the internal-feeding pest Sitophilus oryzae (L., the rice weevil. Aeration alone was somewhat effective in suppressing insect population development, while methoprene alone or when combined with aeration greatly enhanced insect control. Commercial grain grading for industry quality standards at the end of the storage period confirmed the impact of insect suppression on maintaining high quality of the stored wheat. This field experiment shows that methoprene combined with aeration to cool grain can be effective for pest management of stored wheat in the southern plains of the United States of America.

  20. Recent advances of rearing cabinet instrumentation and control system for insect stock culture

    Science.gov (United States)

    Hermawan, Wawan; Kasmara, Hikmat; Melanie, Panatarani, Camellia; Joni, I. Made

    2017-01-01

    Helicoverpa armigera (Hubner) is one of a serious pest of horticulture in Indonesia. Helicoverpa armigera Nuclear Polyhedrovirus (HaNPV) has attracted interest for many researchers as a pest control for larvae of this species. Currently, we investigating the agrochemical formulations of HaNPV by introducing nanotechnology. Thus it is required an acceptable efficiency of insect stock cultures equipped with advance instruments to resolve the difficulties on insect stock seasons dependency. In addition, it is important to improve the insect survival with the aid of artificial natural environment and gain high insect production. This paper reports the rearing cabinet used as preparation of stock culture includes air-conditioning system, lighting, i.e. day and night control, and the main principles on recent technical and procedural advances apparatus of the system. The rearing system was moveable, designed and build by allowing air-conditioned cabinet for rearing insects, air motion and distribution as well as temperature and humidity being precisely controlled. The air was heated, humidified, and dehumidified respectively using a heater and ultrasonic nebulizer as actuators. Temperature and humidity can be controlled at any desired levels from room temperature (20°C) to 40 ± 1°C and from 0 to 80% RH with an accuracy of ±3% R.H. It is concluded that the recent design has acceptable performance based on the defined requirement for insect rearing and storage.

  1. Modelling Aedes aegypti mosquito control via transgenic and sterile insect techniques: endemics and emerging outbreaks.

    Science.gov (United States)

    Seirin Lee, S; Baker, R E; Gaffney, E A; White, S M

    2013-08-21

    The invasion of pest insects often changes or destroys a native ecosystem, and can result in food shortages and disease endemics. Issues such as the environmental effects of chemical control methods, the economic burden of maintaining control strategies and the risk of pest resistance still remain, and mosquito-borne diseases such as malaria and dengue fever prevail in many countries, infecting over 100 million worldwide in 2010. One environmentally friendly method for mosquito control is the Sterile Insect Technique (SIT). This species-specific method of insect control relies on the mass rearing, sterilization and release of large numbers of sterile insects. An alternative transgenic method is the Release of Insects carrying a Dominant Lethal (RIDL). Our objective is to consider contrasting control strategies for two invasive scenarios via SIT and RIDL: an endemic case and an emerging outbreak. We investigate how the release rate and size of release region influence both the potential for control success and the resources needed to achieve it, under a range of conditions and control strategies, and we discuss advantageous strategies with respect to reducing the release resources and strategy costs (in terms of control mosquito numbers) required to achieve complete eradication of wild-type mosquitoes.

  2. Modelling Aedes aegypti mosquito control via transgenic and sterile insect techniques: Endemics and emerging outbreaks

    KAUST Repository

    Seirin Lee, S.

    2013-08-01

    The invasion of pest insects often changes or destroys a native ecosystem, and can result in food shortages and disease endemics. Issues such as the environmental effects of chemical control methods, the economic burden of maintaining control strategies and the risk of pest resistance still remain, and mosquito-borne diseases such as malaria and dengue fever prevail in many countries, infecting over 100 million worldwide in 2010. One environmentally friendly method for mosquito control is the Sterile Insect Technique (SIT). This species-specific method of insect control relies on the mass rearing, sterilization and release of large numbers of sterile insects. An alternative transgenic method is the Release of Insects carrying a Dominant Lethal (RIDL). Our objective is to consider contrasting control strategies for two invasive scenarios via SIT and RIDL: an endemic case and an emerging outbreak. We investigate how the release rate and size of release region influence both the potential for control success and the resources needed to achieve it, under a range of conditions and control strategies, and we discuss advantageous strategies with respect to reducing the release resources and strategy costs (in terms of control mosquito numbers) required to achieve complete eradication of wild-type mosquitoes. © 2013 Elsevier Ltd.

  3. Environmental and biotic controls on the evolutionary history of insect body size.

    Science.gov (United States)

    Clapham, Matthew E; Karr, Jered A

    2012-07-03

    Giant insects, with wingspans as large as 70 cm, ruled the Carboniferous and Permian skies. Gigantism has been linked to hyperoxic conditions because oxygen concentration is a key physiological control on body size, particularly in groups like flying insects that have high metabolic oxygen demands. Here we show, using a dataset of more than 10,500 fossil insect wing lengths, that size tracked atmospheric oxygen concentrations only for the first 150 Myr of insect evolution. The data are best explained by a model relating maximum size to atmospheric environmental oxygen concentration (pO(2)) until the end of the Jurassic, and then at constant sizes, independent of oxygen fluctuations, during the Cretaceous and, at a smaller size, the Cenozoic. Maximum insect size decreased even as atmospheric pO(2) rose in the Early Cretaceous following the evolution and radiation of early birds, particularly as birds acquired adaptations that allowed more agile flight. A further decrease in maximum size during the Cenozoic may relate to the evolution of bats, the Cretaceous mass extinction, or further specialization of flying birds. The decoupling of insect size and atmospheric pO(2) coincident with the radiation of birds suggests that biotic interactions, such as predation and competition, superseded oxygen as the most important constraint on maximum body size of the largest insects.

  4. Gene Disruption Technologies Have the Potential to Transform Stored Product Insect Pest Control

    Science.gov (United States)

    Perkin, Lindsey C.; Adrianos, Sherry L.; Oppert, Brenda

    2016-01-01

    Stored product insects feed on grains and processed commodities manufactured from grain post-harvest, reducing the nutritional value and contaminating food. Currently, the main defense against stored product insect pests is the pesticide fumigant phosphine. Phosphine is highly toxic to all animals, but is the most effective and economical control method, and thus is used extensively worldwide. However, many insect populations have become resistant to phosphine, in some cases to very high levels. New, environmentally benign and more effective control strategies are needed for stored product pests. RNA interference (RNAi) may overcome pesticide resistance by targeting the expression of genes that contribute to resistance in insects. Most data on RNAi in stored product insects is from the coleopteran genetic model, Tribolium castaneum, since it has a strong RNAi response via injection of double stranded RNA (dsRNA) in any life stage. Additionally, Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) technology has been suggested as a potential resource for new pest control strategies. In this review we discuss background information on both gene disruption technologies and summarize the advances made in terms of molecular pest management in stored product insects, mainly T. castaneum, as well as complications and future needs. PMID:27657138

  5. Gene Disruption Technologies Have the Potential to Transform Stored Product Insect Pest Control.

    Science.gov (United States)

    Perkin, Lindsey C; Adrianos, Sherry L; Oppert, Brenda

    2016-09-19

    Stored product insects feed on grains and processed commodities manufactured from grain post-harvest, reducing the nutritional value and contaminating food. Currently, the main defense against stored product insect pests is the pesticide fumigant phosphine. Phosphine is highly toxic to all animals, but is the most effective and economical control method, and thus is used extensively worldwide. However, many insect populations have become resistant to phosphine, in some cases to very high levels. New, environmentally benign and more effective control strategies are needed for stored product pests. RNA interference (RNAi) may overcome pesticide resistance by targeting the expression of genes that contribute to resistance in insects. Most data on RNAi in stored product insects is from the coleopteran genetic model, Tribolium castaneum, since it has a strong RNAi response via injection of double stranded RNA (dsRNA) in any life stage. Additionally, Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) technology has been suggested as a potential resource for new pest control strategies. In this review we discuss background information on both gene disruption technologies and summarize the advances made in terms of molecular pest management in stored product insects, mainly T. castaneum, as well as complications and future needs.

  6. Gene Disruption Technologies Have the Potential to Transform Stored Product Insect Pest Control

    Directory of Open Access Journals (Sweden)

    Lindsey C. Perkin

    2016-09-01

    Full Text Available Stored product insects feed on grains and processed commodities manufactured from grain post-harvest, reducing the nutritional value and contaminating food. Currently, the main defense against stored product insect pests is the pesticide fumigant phosphine. Phosphine is highly toxic to all animals, but is the most effective and economical control method, and thus is used extensively worldwide. However, many insect populations have become resistant to phosphine, in some cases to very high levels. New, environmentally benign and more effective control strategies are needed for stored product pests. RNA interference (RNAi may overcome pesticide resistance by targeting the expression of genes that contribute to resistance in insects. Most data on RNAi in stored product insects is from the coleopteran genetic model, Tribolium castaneum, since it has a strong RNAi response via injection of double stranded RNA (dsRNA in any life stage. Additionally, Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR technology has been suggested as a potential resource for new pest control strategies. In this review we discuss background information on both gene disruption technologies and summarize the advances made in terms of molecular pest management in stored product insects, mainly T. castaneum, as well as complications and future needs.

  7. Apoptosis in amphibian organs during metamorphosis

    Science.gov (United States)

    Ishizuya-Oka, Atsuko; Hasebe, Takashi; Shi, Yun-Bo

    2012-01-01

    During amphibian metamorphosis, the larval tissues/organs rapidly degenerate to adapt from the aquatic to the terrestrial life. At the cellular level, a large quantity of apoptosis occurs in a spatiotemporally-regulated fashion in different organs to ensure timely removal of larval organs/tissues and the development of adult ones for the survival of the individuals. Thus, amphibian metamorphosis provides us a good opportunity to understand the mechanisms regulating apoptosis. To investigate this process at the molecular level, a number of thyroid hormone (TH) response genes have been isolated from several organs of Xenopus laevis tadpoles and their expression and functional analyses are now in progress using modern molecular and genetic technologies. In this review, we will first summarize when and where apoptosis occurs in typical larva-specific and larval-to-adult remodeling amphibian organs to highlight that the timing of apoptosis is different in different tissues/organs, even though all are induced by the same circulating TH. Next, to discuss how TH spatiotemporally regulates the apoptosis, we will focus on apoptosis of the X. laevis small intestine, one of the best characterized remodeling organs. Functional studies of TH response genes using transgenic frogs and culture techniques have shown that apoptosis of larval epithelial cells can be induced by TH either cell-autonomously or indirectly through interactions with extracellular matrix (ECM) components of the underlying basal lamina. Here, we propose that multiple intra- and extracellular apoptotic pathways are coordinately controlled by TH to ensure massive but well-organized apoptosis, which is essential for the proper progression of amphibian metamorphosis. PMID:20238476

  8. Energetics of insect diapause.

    Science.gov (United States)

    Hahn, Daniel A; Denlinger, David L

    2011-01-01

    Managing metabolic resources is critical for insects during diapause when food sources are limited or unavailable. Insects accumulate reserves prior to diapause, and metabolic depression during diapause promotes reserve conservation. Sufficient reserves must be sequestered to both survive the diapause period and enable postdiapause development that may involve metabolically expensive functions such as metamorphosis or long-distance flight. Nutrient utilization during diapause is a dynamic process, and insects appear capable of sensing their energy reserves and using this information to regulate whether to enter diapause and how long to remain in diapause. Overwintering insects on a tight energy budget are likely to be especially vulnerable to increased temperatures associated with climate change. Molecular mechanisms involved in diapause nutrient regulation remain poorly known, but insulin signaling is likely a major player. We also discuss other possible candidates for diapause-associated nutrient regulation including adipokinetic hormone, neuropeptide F, the cGMP-kinase For, and AMPK.

  9. Spider-venom peptides: structure, pharmacology, and potential for control of insect pests.

    Science.gov (United States)

    King, Glenn F; Hardy, Margaret C

    2013-01-01

    Spider venoms are an incredibly rich source of disulfide-rich insecticidal peptides that have been tuned over millions of years to target a wide range of receptors and ion channels in the insect nervous system. These peptides can act individually, or as part of larger toxin cabals, to rapidly immobilize envenomated prey owing to their debilitating effects on nervous system function. Most of these peptides contain a unique arrangement of disulfide bonds that provides them with extreme resistance to proteases. As a result, these peptides are highly stable in the insect gut and hemolymph and many of them are orally active. Thus, spider-venom peptides can be used as stand-alone bioinsecticides, or transgenes encoding these peptides can be used to engineer insect-resistant crops or enhanced entomopathogens. We critically review the potential of spider-venom peptides to control insect pests and highlight their advantages and disadvantages compared with conventional chemical insecticides.

  10. Feasibility, limitation and possible solutions of RNAi-based technology for insect pest control

    Institute of Scientific and Technical Information of China (English)

    Hao Zhang; Hai-Chao Li; Xue-Xia Miao

    2013-01-01

    Numerous studies indicate that target gene silencing by RNA interference (RNAi)could lead to insect death.This phenomenon has been considered as a potential strategy for insect pest control,and it is termed RNAi-mediated crop protection.However,there are many limitations using RNAi-based technology for pest control,with the effectiveness target gene selection and reliable double-strand RNA(dsRNA)delivery being two of the major challenges.With respect to target gene selection,at present,the use of homologous genes and genome-scale high-throughput screening are the main strategies adopted by researchers.Once the target gene is identified,dsRNA can be delivered by micro-injection or by feeding as a dietary component.However,micro-injection,which is the most common method,can only be used in laboratory experiments.Expression of dsRNAs directed against insect genes in transgenic plants and spraying dsRNA reagents have been shown to induce RNAi effects on target insects.Hence,RNAi-mediated crop protection has been considered as a potential new-generation technology for pest control,or as a complementary method of existing pest control strategies;however,further development to improve the efficacy of protection and range of species affected is necessary.In this review,we have summarized current research on RNAi-based technology for pest insect management.Current progress has proven that RNAi technology has the potential to be a tool for designing a new generation of insect control measures.To accelerate its practical application in crop protection,further study on dsRNA uptake mechanisms based on the knowledge of insect physiology and biochemistry is needed.

  11. Feasibility, limitation and possible solutions of RNAi-based technology for insect pest control.

    Science.gov (United States)

    Zhang, Hao; Li, Hai-Chao; Miao, Xue-Xia

    2013-02-01

    Numerous studies indicate that target gene silencing by RNA interference (RNAi) could lead to insect death. This phenomenon has been considered as a potential strategy for insect pest control, and it is termed RNAi-mediated crop protection. However, there are many limitations using RNAi-based technology for pest control, with the effectiveness target gene selection and reliable double-strand RNA (dsRNA) delivery being two of the major challenges. With respect to target gene selection, at present, the use of homologous genes and genome-scale high-throughput screening are the main strategies adopted by researchers. Once the target gene is identified, dsRNA can be delivered by micro-injection or by feeding as a dietary component. However, micro-injection, which is the most common method, can only be used in laboratory experiments. Expression of dsRNAs directed against insect genes in transgenic plants and spraying dsRNA reagents have been shown to induce RNAi effects on target insects. Hence, RNAi-mediated crop protection has been considered as a potential new-generation technology for pest control, or as a complementary method of existing pest control strategies; however, further development to improve the efficacy of protection and range of species affected is necessary. In this review, we have summarized current research on RNAi-based technology for pest insect management. Current progress has proven that RNAi technology has the potential to be a tool for designing a new generation of insect control measures. To accelerate its practical application in crop protection, further study on dsRNA uptake mechanisms based on the knowledge of insect physiology and biochemistry is needed.

  12. Encyrtid parasitoids of soft scale insects: biology, behavior, and their use in biological control.

    Science.gov (United States)

    Kapranas, Apostolos; Tena, Alejandro

    2015-01-07

    Parasitoids of the hymenopterous family Encyrtidae are one of the most important groups of natural enemies of soft scale insects and have been used extensively in biological control. We summarize existing knowledge of the biology, ecology, and behavior of these parasitoids and how it relates to biological control. Soft scale stage/size and phenology are important determinants of host range and host utilization, which are key aspects in understanding how control by these parasitoids is exerted. Furthermore, the nutritional ecology of encyrtids and their physiological interactions with their hosts affect soft scale insect population dynamics. Lastly, the interactions among encyrtids, heteronomous parasitoids, and ants shape parasitoid species complexes and consequently have a direct impact on the biological control of soft scale insects.

  13. Evidence for a conserved CCAP-signaling pathway controlling ecdysis in a hemimetabolous insect, Rhodnius prolixus

    Directory of Open Access Journals (Sweden)

    Do Hee eLee

    2013-11-01

    Full Text Available A vital feature in the success of Ecdysozoa is their ability to shed their exoskeleton (a process called ecdysis such that they can grow or change their morphology. In holometabolous insects, these behaviours are orchestrated by the sequential actions of neuropeptides, one of which is crustacean cardioactive peptide (CCAP. Little is known about the control of ecdysis in hemimetabolous insects. Here, we report that CCAP is essential for successful ecdysis in the hemimetabolous insect, Rhodnius prolixus; the vector of Chagas disease. The first indication of CCAP’s involvement in ecdysis was the observation of decreased staining intensity of CCAP-containing neurons immediately following ecdysis, indicative of the release of CCAP. The critical importance of the CCAP signaling pathway was further demonstrated by knockdown (as determined by qPCR and immunohistochemistry of the CCAP and CCAPR transcripts utilizing dsRNA. This technique reduced the staining intensity of CCAP-containing neurons, and knocked down the transcript levels by up to 92%, with lethal consequences to the insect. Insects with these transcripts knocked down had very high mortality (up to 84%, typically at the expected time of the ecdysis sequence, or had ecdysis extremely delayed. This is the first report of the susceptibility of R. prolixus to dsRNA knockdown of neuropeptide and receptor transcripts, and the data clearly demonstrates the conserved nature of the CCAP signaling pathway in ecdysis between holometabolous and hemimetabolous insects.

  14. Indomethacin reproducibly induces metamorphosis in Cassiopea xamachana scyphistomae

    Science.gov (United States)

    Cabrales-Arellano, Patricia; Islas-Flores, Tania; Thomé, Patricia E.

    2017-01-01

    Cassiopea xamachana jellyfish are an attractive model system to study metamorphosis and/or cnidarian–dinoflagellate symbiosis due to the ease of cultivation of their planula larvae and scyphistomae through their asexual cycle, in which the latter can bud new larvae and continue the cycle without differentiation into ephyrae. Then, a subsequent induction of metamorphosis and full differentiation into ephyrae is believed to occur when the symbionts are acquired by the scyphistomae. Although strobilation induction and differentiation into ephyrae can be accomplished in various ways, a controlled, reproducible metamorphosis induction has not been reported. Such controlled metamorphosis induction is necessary for an ensured synchronicity and reproducibility of biological, biochemical, and molecular analyses. For this purpose, we tested if differentiation could be pharmacologically stimulated as in Aurelia aurita, by the metamorphic inducers thyroxine, KI, NaI, Lugol’s iodine, H2O2, indomethacin, or retinol. We found reproducibly induced strobilation by 50 μM indomethacin after six days of exposure, and 10–25 μM after 7 days. Strobilation under optimal conditions reached 80–100% with subsequent ephyrae release after exposure. Thyroxine yielded inconsistent results as it caused strobilation occasionally, while all other chemicals had no effect. Thus, indomethacin can be used as a convenient tool for assessment of biological phenomena through a controlled metamorphic process in C. xamachana scyphistomae. PMID:28265497

  15. Indomethacin reproducibly induces metamorphosis in Cassiopea xamachana scyphistomae

    Directory of Open Access Journals (Sweden)

    Patricia Cabrales-Arellano

    2017-03-01

    Full Text Available Cassiopea xamachana jellyfish are an attractive model system to study metamorphosis and/or cnidarian–dinoflagellate symbiosis due to the ease of cultivation of their planula larvae and scyphistomae through their asexual cycle, in which the latter can bud new larvae and continue the cycle without differentiation into ephyrae. Then, a subsequent induction of metamorphosis and full differentiation into ephyrae is believed to occur when the symbionts are acquired by the scyphistomae. Although strobilation induction and differentiation into ephyrae can be accomplished in various ways, a controlled, reproducible metamorphosis induction has not been reported. Such controlled metamorphosis induction is necessary for an ensured synchronicity and reproducibility of biological, biochemical, and molecular analyses. For this purpose, we tested if differentiation could be pharmacologically stimulated as in Aurelia aurita, by the metamorphic inducers thyroxine, KI, NaI, Lugol’s iodine, H2O2, indomethacin, or retinol. We found reproducibly induced strobilation by 50 μM indomethacin after six days of exposure, and 10–25 μM after 7 days. Strobilation under optimal conditions reached 80–100% with subsequent ephyrae release after exposure. Thyroxine yielded inconsistent results as it caused strobilation occasionally, while all other chemicals had no effect. Thus, indomethacin can be used as a convenient tool for assessment of biological phenomena through a controlled metamorphic process in C. xamachana scyphistomae.

  16. [Effect of weak combined magnetic fields on the metamorphosis of the meal-worm beetle Tenebrio molitor].

    Science.gov (United States)

    Ermakov, A M; Lednev, V V

    2010-01-01

    The effects of weak combined magnetic fields adjusted to the parametric resonance for Ca2+ and K+ and extremely weak alternating magnetic field on the metamorphosis of the meal-worm beetle Tenebrio molitor have been studied. It was shown that the exposure of pupas of insects to all above-indicated types of fields stimulates the metamorphosis. However, after the exposure to weak combined magnetic fields adjusted to the parametric resonance for Ca2+ and K+, the number of insects with anomalies increases, which is not observed by the action of the weak alternating magnetic field.

  17. Biological insect control using Metarhizium anisopliae: morphological, molecular, and ecological aspects

    Directory of Open Access Journals (Sweden)

    Patricia Vieira Tiago

    2014-04-01

    Full Text Available Microbial control of insects is based on the rational use of pathogens to maintain environmentally balanced pest population levels, and Metarhizium anisopliae has been the most studied and most utilized fungal species for that purpose. The natural genetic variability of entomopathogenic fungi is considered one of the principal advantages of microbial insect control. The inter- and intraspecific variability and the genetic diversity and population structures of Metarhizium and other entomopathogenic fungi have been examined using ITS-RFLP, ISSR, and ISSP molecular markers. The persistence of M. anisopliae in the soil and its possible effects on the structures of resident microbial communities must be considered when selecting isolates for biological insect control.

  18. Evaluation of the control of mosquitoes with insect growth regulators.

    Science.gov (United States)

    Ho, C M; Wu, S H; Wu, C C

    1990-07-01

    In this study, the effectiveness of eight insect growth regulators (IGRs) (chlorfluazuron, diflubenzuron, EL-494, flufenoxuron, teflubenzuron, juglone, plumbagin and methoprene) against five mosquito vectors (Armigeres subalbatus, Aedes albopictus, Aedes aegypti, Culex tritaeniorhynchus, and Culex quinquefasciatus) was investigated in the laboratory. The EC50s of chlorfluazuron, diflubenzuron, EL-494, flufenoxuron, teflubenzuron, and methoprene against the five mosquitoes ranged from 0.0001 to 0.3 ppm and those of juglone and plumbagin from 3-25 ppm. The five mosquito species had similar tolerances to the test IGRs. At pH 5 to 9, the effectiveness of the first five chemicals was very stable. After ultraviolet irradiation or heat management (45 degrees C-60 degrees C), diflubenzuron and flufenoxuron were very stable. EL-494 was not stable when exposed to ultraviolet irradiation or heat. Under 0.1 ppm, teflubenzuron was not stable upon exposure to heat and chlorfluazuron and methoprene were not stable when exposed to ultraviolet irradiation. Piperonyl butoxide reduces the effectiveness of the five IGRs. Administration of diflubenzuron (1-5 ppm), flufenoxuron (0.025 ppm), and teflubenzuron (1-5 ppm) reduced Culex quinquefasciatus larvae in ditches by 40-90%. The administration of diflubenzuron (0.5 ppm) to containers reduced 97% of the Aedes albopictus larvae.

  19. Construction of ice nucleation active Enterobacter cloacae for control of insect pests

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Ice nucleation active (INA) bacteria are the most potent heterogeneous ice nuclei in nature, which have become an important biological resource for diverse applications. Many researches have proved that INA bacteria can raise the supercooling points (SCPs) of insect pests, then reduce their cold hardiness. However, INA bacteria's inefficient colonization on the surface or in the guts of insects, and the high incidence of frost injury induced by their release hampered the application of INA bacteria in controlling insect pests in agricultural fields. In this study, we constructed a recombinant plasmid mob-Tn5-iceA with the ability of broad-host-range conjugal mobilization and integration of the ina gene of iceA into chromosomal DNA of many gram-negative bacteria by Tn5 transposition. In addition, Ent. cloacae strains stably carrying iceA and expressing high ice nucleation activity (INA), even in the absence of antibiotic pressure, were constructed through conjugal mobilization and Tn5 transposition. Ent. cloacae strains have been reported to be able to efficiently colonize in the guts of insects, but have weak plant epiphytic ability. Therefore, these transgenic Ent. cloacae may be promising candidates for control of insect pests in agricultural fields.

  20. [Modulating effect of weak combined magnetic fields on duration of mealworm beetle Tenebrio molitor metamorphosis stage].

    Science.gov (United States)

    Novikov, V V; Sheĭman, I M; Iablokova, E V; Fesenko, E E

    2014-01-01

    It is shown that an exposure of pupae of the mealworm beetle Tenebrio molitor to the combined static (42 μT) and very weak alternating (250 nT) magnetic fields exerts different influence, depending on the frequency of the alternating magnetic field, on duration of metamorphosis processes in these insects. For instance, an exposure of pupae to weak combined magnetic fields, adjusted to the frequency of ion cyclotron resonance for glutaminic acid (4,4 Hz), stimulates metamorphosis process--a transitional stage from pupae to imago lasts shorter. An inhibiting effect was observed when adjusted to the frequency of ion cyclotron resonance for Ca2 (32,2 Hz). At some frequencies this effect is not seen. For instance, an exposure at a frequency of ion cyclotron resonance for K+ (16,5 Hz) exerts no noticeable effect on the duration of the pupal metamorphosis stage.

  1. The Mechanisms of the Ecdysone Pulses that Cause Metamorphosis

    DEFF Research Database (Denmark)

    Møller, Morten Erik

    Maturation in both mammals and insects is caused by pulses of steroid hormones released from glands in response to a brain-derived signal. The timing of this developmental transition is secured by the integration of many developmental cues, such as size, external environment and nutritional...... condition, with hardwired genetic programs. In holometabolous insects, pulses of the steroid hormone ecdysone cause the transition between the larval stages and the initiation of the metamorphosis, which transforms the juvenile larva to a sexually mature adult. Ecdysone is produced in the prothoracic gland...... elucidated, many questions of how the system is regulated remain unknown. The first part of the thesis focuses on a genome-wide in-vivo RNAi screen, where 90 % of the protein coding genes in Drosophila were knocked down tissue-specifically in the cells of the PG. 15.2% of the genes led to developmental...

  2. Amphibian haematology: Metamorphosis-related changes in blood cells

    DEFF Research Database (Denmark)

    Rosenkilde, Per; Sørensen, Inger; Ussing, Anne Phaff

    1995-01-01

    Zoofysiologi, Amphibian metamorphosis, Haematology, Immunosuppression, Immunological Tolerance, Protozoan Infection, metamorfose, springpadder, ontogenese, halepadder.......Zoofysiologi, Amphibian metamorphosis, Haematology, Immunosuppression, Immunological Tolerance, Protozoan Infection, metamorfose, springpadder, ontogenese, halepadder....

  3. Mechanisms of dsRNA uptake in insects and potential of RNAi for pest control: a review.

    Science.gov (United States)

    Huvenne, Hanneke; Smagghe, Guy

    2010-03-01

    RNA interference already proved its usefulness in functional genomic research on insects, but it also has considerable potential for the control of pest insects. For this purpose, the insect should be able to autonomously take up the dsRNA, for example through feeding and digestion in its midgut. In this review we bring together current knowledge on the uptake mechanisms of dsRNA in insects and the potential of RNAi to affect pest insects. At least two pathways for dsRNA uptake in insects are described: the transmembrane channel-mediated uptake mechanism based on Caenorhabditis elegans' SID-1 protein and an 'alternative' endocytosis-mediated uptake mechanism. In the second part of the review dsRNA feeding experiments on insects are brought together for the first time, highlighting the achievement of implementing RNAi in insect control with the first successful experiments in transgenic plants and the diversity of successfully tested insect orders/species and target genes. We conclude with points of discussion and concerns regarding further research on dsRNA uptake mechanisms and the promising application possibilities for RNAi in insect control.

  4. The use of phytochemicals as fumigants for the control of stored product insect pests

    OpenAIRE

    Eli Shaaya; Moshe Kostyukovsky

    2011-01-01

    The current study is aimed to evaluate the potential use of the known isothyiocyanates, as compared to a new isothyiocyanate (ITC) isolated from Eruca sativa (salad rocket) as fumigants for the control of stored product insects. The biological activity of methyl iodide (CH3I), carbon disulphide (CS2), benzaldehyde (C7H6O) and essential oils were also evaluated. The toxicity of the various fumigants was assessed against adults and larvae of a number of major stored product insects. ITCs are kn...

  5. [Basic types of respiratory system structure in insect egg envelopes, and genes controlling their formation].

    Science.gov (United States)

    Omelina, E S; Baricheva, É M; Fedorova, E V

    2012-01-01

    Insects is a taxon surprisingly rich with species and varieties, and its representatives are considered as the most fitted and "evolutionary successful" living things. Insects are distinguished by diversity and abundance of adaptations to environmental conditions, representatives of this class inhabit different ecological niches, they can be found practically in every corner of the Earth and, in particular, in close adjacency to man. Among them are those who man benefits from and those who man struggles against. This determines man's interest in studying peculiarities of their development as well as adaptations formed by them in the course of evolution to become more viable. In the paper, data are presented on morphological structure of respiratory systems in insect egg envelopes that ensure respiration process of developing embryo. Variability of these systems and their dependence on environmental conditions are demonstrated for different insect species. The information about genes controlling development of respiratory systems in fruit fly eggs is brought together, and occurrence of evolutionary conservative genes participating in development of such systems in other insect species is ascertained.

  6. Laboratory evaluation for a potential birth control diet for fruit fly sterilization insect technique (SIT)

    Science.gov (United States)

    A potential fruit fly steilizing diet was evaluated on fertility, mating, survival, and protein anaylsis for fruit fly species in Hawaii. Insects were continuously fed an agar diet with lufenuron(LFN) for an initial 7d after emergence and then switched to a control diet to simulate the actual field ...

  7. Integration of biological control and transgenic insect protection for mitigation of mycotoxins in corn

    Science.gov (United States)

    Biological control is known to be effective in reducing aflatoxin contamination of corn and some transgenic corn hybrids incur greatly reduced damage from corn earworm (Helicoverpa zea). We conducted seven field trials over two years to test the hypothesis that transgenic insect protection and biol...

  8. Performance of controlled atmosphere/heating block systems for assessing insect thermotolerance

    Science.gov (United States)

    Heated controlled atmosphere (CA) treatments have potential as alternatives to chemical fumigation for disinfesting postharvest stored products. To determine accurately the minimal thermal requirements to kill target insects over a wide range of temperatures and CA conditions, it is desirable to dev...

  9. Biological control of Otiorhynchus sulcatus by insect parasitic nematodes, Heterorhabditis spp. at low temperatures.

    NARCIS (Netherlands)

    Westerman, P.R.

    1997-01-01

    The black vine weevil, Otiorhynchus sulcatus, is an important pest in ornamentals and nursery stock in The Netherlands. The larvae, which feed on the root system of the plant, can be controlled by insect parasitic nematodes, Heterorhabditis. However, the presently available isolates of the nematode

  10. Application of irradiation in bait production to the control of crawling insects in urban areas

    Energy Technology Data Exchange (ETDEWEB)

    Migdal, W.; Owczarczyk, H.B.; Swietoslawski, J.; Swietoslawski, J

    2000-03-01

    The efficiency and palatability of two baits were studied to the control of crawling insects in urban areas: 'Cockroach Kill Gel' for control of cockroaches and Faratox B for control of ants. Ionizing energy was used in producing the baits. It was concluded, that after irradiation the palatability of Faratox B improved and palatability of Cockroach Kill Gel did not change.

  11. Insect-machine hybrid system for understanding and evaluating sensory-motor control by sex pheromone in Bombyx mori.

    Science.gov (United States)

    Kanzaki, Ryohei; Minegishi, Ryo; Namiki, Shigehiro; Ando, Noriyasu

    2013-11-01

    To elucidate the dynamic information processing in a brain underlying adaptive behavior, it is necessary to understand the behavior and corresponding neural activities. This requires animals which have clear relationships between behavior and corresponding neural activities. Insects are precisely such animals and one of the adaptive behaviors of insects is high-accuracy odor source orientation. The most direct way to know the relationships between neural activity and behavior is by recording neural activities in a brain from freely behaving insects. There is also a method to give stimuli mimicking the natural environment to tethered insects allowing insects to walk or fly at the same position. In addition to these methods an 'insect-machine hybrid system' is proposed, which is another experimental system meeting the conditions necessary for approaching the dynamic processing in the brain of insects for generating adaptive behavior. This insect-machine hybrid system is an experimental system which has a mobile robot as its body. The robot is controlled by the insect through its behavior or the neural activities recorded from the brain. As we can arbitrarily control the motor output of the robot, we can intervene at the relationship between the insect and the environmental conditions.

  12. Identification of genes differentially expressed during larval molting and metamorphosis of Helicoverpa armigera

    Directory of Open Access Journals (Sweden)

    Jiang Xiao-Juan

    2007-06-01

    Full Text Available Abstract Background Larval molting and metamorphosis are important physiological processes in the life cycle of the holometabolous insect. We used suppression subtractive hybridization (SSH to identify genes differentially expressed during larval molting and metamorphosis. Results We performed SSH between tissues from a variety of developmental stages, including molting 5th and feeding 6th instar larvae, metamorphically committed and feeding 5th instar larvae, and feeding 5th instar and metamorphically committed larvae. One hundred expressed sequence tags (ESTs were identified and included 73 putative genes with similarity to known genes, and 27 unknown ESTs. SSH results were further characterized by dot blot, Northern blot, and RT-PCR. The expression levels of eleven genes were found to change during larval molting or metamorphosis, suggesting a functional role during these processes. Conclusion These results provide a new set of genes expressed specifically during larval molt or metamorphosis that are candidates for further studies into the regulatory mechanisms of those stage-specific genes during larval molt and metamorphosis

  13. Combining pest control and resistance management: synergy of engineered insects with Bt crops.

    Science.gov (United States)

    Alphey, Nina; Bonsall, Michael B; Alphey, Luke

    2009-04-01

    Transgenic crops producing insecticidal toxins are widely used to control insect pests. Their benefits would be lost if resistance to the toxins became widespread in pest populations. The most widely used resistance management method is the high-dose/refuge strategy. This requires toxin-free host plants as refuges near insecticidal crops, and toxin doses intended to be sufficiently high to kill insects heterozygous for a resistant allele, thereby rendering resistance functionally recessive. We have previously shown by mathematical modeling that mass-release of harmless susceptible (toxin-sensitive) insects engineered with repressible female-specific lethality using release of insects carrying a dominant lethal ([RIDL] Oxitec Limited, United Kingdom) technology could substantially delay or reverse the spread of resistance and reduce refuge sizes. Here, we explore this proposal in depth, studying a wide range of scenarios, considering impacts on population dynamics as well as evolution of allele frequencies, comparing with releases of natural fertile susceptible insects, and examining the effect of seasonality. We investigate the outcome for pest control for which the plant-incorporated toxins are not necessarily at a high dose (i.e., they might not kill all homozygous susceptible and all heterozygous insects). We demonstrate that a RIDL-based approach could form an effective component of a resistance management strategy in a wide range of genetic and ecological circumstances. Because there are significant threshold effects for several variables, we expect that a margin of error would be advisable in setting release ratios and refuge sizes, especially as the frequency and properties of resistant alleles may be difficult to measure accurately in the field.

  14. Pest Control in Corn and Soybeans: Weeds - Insects - Diseases.

    Science.gov (United States)

    Doersch, R. E.; And Others

    This document gives the characteristics and application rates for herbicides used to control annual weeds in corn, annual and perennial broadleaf weeds in corn, quackgrass and yellow nutsedge in corn, and annual weeds in soybeans. It also gives insecticide use information for corn and soybeans. A brief discussion of disease control in corn and…

  15. Sequencing and structural homology modeling of the ecdysone receptor in two chrysopids used in biological control of pest insects.

    Science.gov (United States)

    Zotti, Moises João; Christiaens, Olivier; Rougé, Pierre; Grutzmacher, Anderson Dionei; Zimmer, Paulo Dejalma; Smagghe, Guy

    2012-04-01

    In insects, the process of molting and metamorphosis are mainly regulated by a steroidal hormone 20-hydroxyecdysone (20E) and its analogs (ecdysteroids) that specifically bind to the ecdysone receptor ligand-binding domain (EcR-LBD). Currently, several synthetic non-steroidal ecdysone agonists, including tebufenozide, are commercially available as insecticides. Tebufenozide exerts its activity by binding to the 20E-binding site and thus activating EcR permanently. It appears that subtle differences in the architecture among LBDs may underpin the differential binding affinity of tebufenozide across taxonomic orders. In brief, first we demonstrated the harmlessness of tebufenozide towards Chrysoperla externa (Ce). Then, a molecular analysis of EcR-LBD of two neuropteran insects Chrysoperla carnea and Ce was presented. Finally, we constructed a chrysopid in silico homology model docked ponasterone A (PonA) and tebufenozide into the binding pocket and analyzed the amino acids indentified as critical for binding to PonA and tebufenozide. Due to a restrict extent in the cavity at the bottom of the ecdysone-binding pocket a steric clash occurred upon docking of tebufenozide. The absence of harm biological effect and the docking results suggest that tebufenozide is prevented of any deleterious effects on chrysopids.

  16. Control for going from hovering to small speed flight of a model insect

    Institute of Scientific and Technical Information of China (English)

    Jianghao Wu; Mao Sun

    2009-01-01

    The longitudinal steady-state control for going from hovering to small speed flight of a model insect is studied, using the method of computational fluid dynamics to compute the aerodynamic derivatives and the techniques based on the linear theories of stability and control for deter-mining the non-zero equilibrium points. Morphological and certain kinematical data of droneflies are used for the model insect. A change in the mean stroke angle (δφ) results in a horizontal forward or backward flight; a change in the stroke amplitude (δΦ) or a equal change in the down- and upstroke angles of attack (δα1) results in a vertical climb or decent; a proper combination of δφ and δΦ controls (or δφ and δα1 controls) can give a flight of any (small) speed in any desired direction.

  17. The Current Status of Baculovirus and Their Implication for Insect Pest Control

    Directory of Open Access Journals (Sweden)

    Arman Wijonarko

    2001-07-01

    Full Text Available Baculovirus have been promoted as the promising bioinsecticides for their pest control potential for more than half a century. But only a few have been successful as biological control agent, and almost none has been proven as commercial success, or widely used for large-scale insect pest control. The bioinsecticides currently represent only a small fraction of the world pesticide market. The successful of the Bt crop marked a special achievement in the bioinsecticide market growth. How about the baculoviruses? The main hurdle for baculovirus to be developed as bioinsecticide is its poor performance compare to synthetic chemical ones, include the speed of kill, and host range. It is important to understand the nature of baculovirus, and explore the possibilities to develop new way in applying the baculovirus as bioinsecticides. Key words: current status, baculovirus, insect control

  18. Mode of action of Bacillus thuringiensis Cry and Cyt toxins and their potential for insect control.

    Science.gov (United States)

    Bravo, Alejandra; Gill, Sarjeet S; Soberón, Mario

    2007-03-15

    Bacillus thuringiensis Crystal (Cry) and Cytolitic (Cyt) protein families are a diverse group of proteins with activity against insects of different orders--Lepidoptera, Coleoptera, Diptera and also against other invertebrates such as nematodes. Their primary action is to lyse midgut epithelial cells by inserting into the target membrane and forming pores. Among this group of proteins, members of the 3-Domain Cry family are used worldwide for insect control, and their mode of action has been characterized in some detail. Phylogenetic analyses established that the diversity of the 3-Domain Cry family evolved by the independent evolution of the three domains and by swapping of domain III among toxins. Like other pore-forming toxins (PFT) that affect mammals, Cry toxins interact with specific receptors located on the host cell surface and are activated by host proteases following receptor binding resulting in the formation of a pre-pore oligomeric structure that is insertion competent. In contrast, Cyt toxins directly interact with membrane lipids and insert into the membrane. Recent evidence suggests that Cyt synergize or overcome resistance to mosquitocidal-Cry proteins by functioning as a Cry-membrane bound receptor. In this review we summarize recent findings on the mode of action of Cry and Cyt toxins, and compare them to the mode of action of other bacterial PFT. Also, we discuss their use in the control of agricultural insect pests and insect vectors of human diseases.

  19. Bacillus thuringiensis-based Products for Insect Pest Control

    NARCIS (Netherlands)

    Maagd, de R.A.

    2015-01-01

    Bacillus thuringiensis (or Bt, as it has become generally known) is one of the oldest and widely used biological control agents and has a long history of use. Bt and a number of related bacteria produce a variety of toxins, mostly—but not exclusively- localized in the parasporal crystals, which are,

  20. The Role of Vision and Mechanosensation in Insect Flight Control

    Science.gov (United States)

    2012-01-01

    intensity. We used bumblebees (Bombus terrestris), honeybees (Apis mellifera ), the common wasp (Vespa vulgaris), hornets (Vespa crabro) flies (Mousca...bees (Apis mellifera L.). J. Exp. Biol. 209, 978-984. Beyeler, A., Zufferey, J.-C. and Floreano, D. (2009). Vision-based control of near- obstacle

  1. Bacillus thuringiensis (Bt for the Control of Insect Pests in Stored Tobacco: A Review

    Directory of Open Access Journals (Sweden)

    Blanc M

    2014-12-01

    Full Text Available Among the insect species causing infestations and serious damages to stored commodities, the cigarette beetle, Lasiodermaserricorne (F. and the tobacco moth, Ephestiaelutella (Hübner are the major pests of both raw and manufactured tobacco. Post-harvest tobacco control is achieved through sanitation, insect monitoring, and fumigation with phosphine. However, insect resistance to phosphine and control failures have been reported, and increasing regulatory pressure is being exerted on fumigants. Biological control agents such as Bacillus thuringiensis (Bt appear to be environmentally sound and potentially viable alternatives to chemical control. Bt is a bacterium that produces insecticidal crystal proteins during the sporulation phase and has been, for more than 40 years, the microorganism of choice for the biocontrol of phytophagous insect pests. It produces insecticidal crystal proteins that display specific activity against certain orders of insects and become active upon ingestion by the insect. Our laboratory has conducted extensive research and worldwide surveys to evaluate the presence of Bt in stored tobacco and has confirmed previous findings indicating that Bt may be considered part of the naturally occurring phylloplanemicroflora. Several Bt strains were isolated from tobacco and characterized by DNA and protein profiling. The insecticidal activity of selected strains and of two commercial products against the larvae of L. serricorne was determined by diet incorporation assays. Moreover, the stability of Bt spores and crystal proteins on cured tobacco leaves was assessed over a storage period of time of 30 months. Cigarette prototypes were made with Bt-treated tobacco. Standard cigarette and smoke evaluations did not show any significant difference between the test and control cigarettes. Although the tested Bt strains and products did not yield satisfactory levels of mortality at the required times and doses, the experimental results

  2. The insect ecdysone receptor is a good potential target for RNAi-based pest control.

    Science.gov (United States)

    Yu, Rong; Xu, Xinping; Liang, Yongkang; Tian, Honggang; Pan, Zhanqing; Jin, Shouheng; Wang, Na; Zhang, Wenqing

    2014-01-01

    RNA interference (RNAi) has great potential for use in insect pest control. However, some significant challenges must be overcome before RNAi-based pest control can become a reality. One challenge is the proper selection of a good target gene for RNAi. Here, we report that the insect ecdysone receptor (EcR) is a good potential target for RNAi-based pest control in the brown planthopper Nilaparvata lugens, a serious insect pest of rice plants. We demonstrated that the use of a 360 bp fragment (NlEcR-c) that is common between NlEcR-A and NlEcR-B for feeding RNAi experiments significantly decreased the relative mRNA expression levels of NlEcR compared with those in the dsGFP control. Feeding RNAi also resulted in a significant reduction in the number of offspring per pair of N. lugens. Consequently, a transgenic rice line expressing NlEcR dsRNA was constructed by Agrobacterium- mediated transformation. The results of qRT-PCR showed that the total copy number of the target gene in all transgenic rice lines was 2. Northern blot analysis showed that the small RNA of the hairpin dsNlEcR-c was successfully expressed in the transgenic rice lines. After newly hatched nymphs of N. lugens fed on the transgenic rice lines, effective RNAi was observed. The NlEcR expression levels in all lines examined were decreased significantly compared with the control. In all lines, the survival rate of the nymphs was nearly 90%, and the average number of offspring per pair in the treated groups was significantly less than that observed in the control, with a decrease of 44.18-66.27%. These findings support an RNAi-based pest control strategy and are also important for the management of rice insect pests.

  3. Complications of complexity: integrating environmental, genetic and hormonal control of insect diapause.

    Science.gov (United States)

    Emerson, Kevin J; Bradshaw, William E; Holzapfel, Christina M

    2009-05-01

    Understanding gene interaction and pleiotropy are long-standing goals of developmental and evolutionary biology. We examine the genetic control of diapause in insects and show how the failure to recognize the difference between modular and gene pleiotropy has confounded our understanding of the genetic basis of this important phenotype. This has led to complications in understanding the role of the circadian clock in the control of diapause in Drosophila and other insects. We emphasize three successive modules - each containing functionally related genes - that lead to diapause: photoperiodism, hormonal events and diapause itself. Understanding the genetic basis for environmental control of diapause has wider implications for evolutionary response to rapid climate change and for the opportunity to observe evolutionary change in contemporary time.

  4. THE INSECT PATHOGENIC FUNGUS Verticillium lecanii (Zimm. Viegas AND ITS USE FOR PESTS CONTROL: A REVIEW

    Directory of Open Access Journals (Sweden)

    Thiery B C ALAVO

    2015-08-01

    Full Text Available Chemical insecticides play an important role in the control of plant damage and plant diseases. However, extensive use of these products has led to the disruption of ecosystems because of several reasons such as death of non-target species, accumulation of pesticide residues in the environment and food, and buildup of pesticide resistance in the target species. Biological control is one of the alternatives to chemical pesticides and it can be described as the limitation of the abundance of living organisms and their products by other living organisms. Predators, parasitoids, fungi and other beneficial organisms can be used for the biocontrol of insect pests. The fungus Verticillium lecanii is one of the members of Deuteromycetes and it can be used for crop protection. This paper is a review of the international literature related to V. lecanii for the bio-control of insects of agricultural importance.

  5. The Repellent DEET Potentiates Carbamate Effects via Insect Muscarinic Receptor Interactions: An Alternative Strategy to Control Insect Vector-Borne Diseases.

    Science.gov (United States)

    Abd-Ella, Aly; Stankiewicz, Maria; Mikulska, Karolina; Nowak, Wieslaw; Pennetier, Cédric; Goulu, Mathilde; Fruchart-Gaillard, Carole; Licznar, Patricia; Apaire-Marchais, Véronique; List, Olivier; Corbel, Vincent; Servent, Denis; Lapied, Bruno

    2015-01-01

    Insect vector-borne diseases remain one of the principal causes of human mortality. In addition to conventional measures of insect control, repellents continue to be the mainstay for personal protection. Because of the increasing pyrethroid-resistant mosquito populations, alternative strategies to reconstitute pyrethroid repellency and knock-down effects have been proposed by mixing the repellent DEET (N,N-Diethyl-3-methylbenzamide) with non-pyrethroid insecticide to better control resistant insect vector-borne diseases. By using electrophysiological, biochemichal, in vivo toxicological techniques together with calcium imaging, binding studies and in silico docking, we have shown that DEET, at low concentrations, interacts with high affinity with insect M1/M3 mAChR allosteric site potentiating agonist effects on mAChRs coupled to phospholipase C second messenger pathway. This increases the anticholinesterase activity of the carbamate propoxur through calcium-dependent regulation of acetylcholinesterase. At high concentrations, DEET interacts with low affinity on distinct M1/M3 mAChR site, counteracting the potentiation. Similar dose-dependent dual effects of DEET have also been observed at synaptic mAChR level. Additionally, binding and in silico docking studies performed on human M1 and M3 mAChR subtypes indicate that DEET only displays a low affinity antagonist profile on these M1/M3 mAChRs. These results reveal a selective high affinity positive allosteric site for DEET in insect mAChRs. Finally, bioassays conducted on Aedes aegypti confirm the synergistic interaction between DEET and propoxur observed in vitro, resulting in a higher mortality of mosquitoes. Our findings reveal an unusual allosterically potentiating action of the repellent DEET, which involves a selective site in insect. These results open exciting research areas in public health particularly in the control of the pyrethroid-resistant insect-vector borne diseases. Mixing low doses of DEET and a

  6. The Repellent DEET Potentiates Carbamate Effects via Insect Muscarinic Receptor Interactions: An Alternative Strategy to Control Insect Vector-Borne Diseases.

    Directory of Open Access Journals (Sweden)

    Aly Abd-Ella

    Full Text Available Insect vector-borne diseases remain one of the principal causes of human mortality. In addition to conventional measures of insect control, repellents continue to be the mainstay for personal protection. Because of the increasing pyrethroid-resistant mosquito populations, alternative strategies to reconstitute pyrethroid repellency and knock-down effects have been proposed by mixing the repellent DEET (N,N-Diethyl-3-methylbenzamide with non-pyrethroid insecticide to better control resistant insect vector-borne diseases. By using electrophysiological, biochemichal, in vivo toxicological techniques together with calcium imaging, binding studies and in silico docking, we have shown that DEET, at low concentrations, interacts with high affinity with insect M1/M3 mAChR allosteric site potentiating agonist effects on mAChRs coupled to phospholipase C second messenger pathway. This increases the anticholinesterase activity of the carbamate propoxur through calcium-dependent regulation of acetylcholinesterase. At high concentrations, DEET interacts with low affinity on distinct M1/M3 mAChR site, counteracting the potentiation. Similar dose-dependent dual effects of DEET have also been observed at synaptic mAChR level. Additionally, binding and in silico docking studies performed on human M1 and M3 mAChR subtypes indicate that DEET only displays a low affinity antagonist profile on these M1/M3 mAChRs. These results reveal a selective high affinity positive allosteric site for DEET in insect mAChRs. Finally, bioassays conducted on Aedes aegypti confirm the synergistic interaction between DEET and propoxur observed in vitro, resulting in a higher mortality of mosquitoes. Our findings reveal an unusual allosterically potentiating action of the repellent DEET, which involves a selective site in insect. These results open exciting research areas in public health particularly in the control of the pyrethroid-resistant insect-vector borne diseases. Mixing low

  7. Book Review: Insect Virology

    Science.gov (United States)

    Viruses that infect insects have long been of interest both as a means for controlling insect pest populations in an environmentally safe manner, and also as significant threats to beneficial insects of great value, such as honey bees and silkworms. Insect viruses also have been of intrinsic intere...

  8. The heterochronic gene Lin28 regulates amphibian metamorphosis through disturbance of thyroid hormone function.

    Science.gov (United States)

    Faunes, Fernando; Gundermann, Daniel G; Muñoz, Rosana; Bruno, Renzo; Larraín, Juan

    2017-05-15

    Metamorphosis is a classic example of developmental transition, which involves important morphological and physiological changes that prepare the organism for the adult life. It has been very well established that amphibian metamorphosis is mainly controlled by Thyroid Hormone (TH). Here, we show that the heterochronic gene Lin28 is downregulated during Xenopus laevis metamorphosis. Lin28 overexpression before activation of TH signaling delays metamorphosis and inhibits the expression of TH target genes. The delay in metamorphosis is rescued by incubation with exogenous TH, indicating that Lin28 works upstream or parallel to TH. High-throughput analyses performed before any delay on metamorphosis or change in TH signaling showed that overexpression of Lin28 reduces transcript levels of several hormones secreted by the pituitary, including the Thyroid-Stimulating Hormone (TSH), and regulates the expression of proteins involved in TH transport, metabolism and signaling, showing that Lin28 disrupts TH function at different levels. Our data demonstrates that the role of Lin28 in controlling developmental transitions is evolutionary conserved and establishes a functional interaction between Lin28 and thyroid hormone function introducing a new regulatory step in perinatal development with implications for our understanding of endocrine disorders. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  9. Metamorphosis

    DEFF Research Database (Denmark)

    Parigi, Dario

    2015-01-01

    between a variety of geometric parameters, structural optimization and intended spatial effects. The fabrication of the pavilion required the development of a custom developed digital fabrication machine, the Reciprocalizer robot, which marks and drills the bars at the joints position at precise angle...... and distances. Furthermore it required the development of a joint that enables handling the complexity of the free form shape and the varying bars shape with a limited set of adaptable custom developed laser-cut pieces....

  10. Controlled release of insect sex pheromones from paraffin wax and emulsions.

    Science.gov (United States)

    Atterholt, C A; Delwiche, M J; Rice, R E; Krochta, J M

    1999-02-22

    Paraffin wax and aqueous paraffin emulsions can be used as controlled release carriers for insect sex pheromones for mating disruption of orchard pests. Paraffin can be applied at ambient temperature as an aqueous emulsion, adheres to tree bark or foliage, releases pheromone for an extended period of time, and will slowly erode from bark and biodegrade in soil. Pheromone emulsions can be applied with simple spray equipment. Pheromone release-rates from paraffin were measured in laboratory flow-cell experiments. Pheromone was trapped from an air stream with an adsorbent, eluted periodically, and quantified by gas chromatography. Pheromone release from paraffin was partition-controlled, providing a constant (zero-order) release rate. A typical paraffin emulsion consisted of 30% paraffin, 4% pheromone, 4% soy oil, 1% vitamin E, 2% emulsifier, and the balance water. Soy oil and vitamin E acted as volatility suppressants. A constant release of oriental fruit moth pheromone from paraffin emulsions was observed in the laboratory for more than 100 days at 27 degreesC, with release-rates ranging from 0.4 to 2 mg/day, depending on the concentration and surface area of the dried emulsion. The use of paraffin emulsions is a viable method for direct application of insect pheromones for mating disruption. Sprayable formulations can be designed to release insect pheromones to the environment at a rate necessary for insect control by mating disruption. At temperatures below 38 degreesC, zero-order release was observed. At 38 degreesC and higher, pheromone oxidation occurred. A partition-controlled release mechanism was supported by a zero-order pheromone release-rate, low air/wax partition coefficients, and pheromone solubility in paraffin.

  11. Motor-Skill Learning in an Insect Inspired Neuro-Computational Control System

    Science.gov (United States)

    Arena, Eleonora; Arena, Paolo; Strauss, Roland; Patané, Luca

    2017-01-01

    In nature, insects show impressive adaptation and learning capabilities. The proposed computational model takes inspiration from specific structures of the insect brain: after proposing key hypotheses on the direct involvement of the mushroom bodies (MBs) and on their neural organization, we developed a new architecture for motor learning to be applied in insect-like walking robots. The proposed model is a nonlinear control system based on spiking neurons. MBs are modeled as a nonlinear recurrent spiking neural network (SNN) with novel characteristics, able to memorize time evolutions of key parameters of the neural motor controller, so that existing motor primitives can be improved. The adopted control scheme enables the structure to efficiently cope with goal-oriented behavioral motor tasks. Here, a six-legged structure, showing a steady-state exponentially stable locomotion pattern, is exposed to the need of learning new motor skills: moving through the environment, the structure is able to modulate motor commands and implements an obstacle climbing procedure. Experimental results on a simulated hexapod robot are reported; they are obtained in a dynamic simulation environment and the robot mimicks the structures of Drosophila melanogaster. PMID:28337138

  12. When wings touch wakes: understanding locomotor force control by wake wing interference in insect wings.

    Science.gov (United States)

    Lehmann, Fritz-Olaf

    2008-01-01

    Understanding the fluid dynamics of force control in flying insects requires the exploration of how oscillating wings interact with the surrounding fluid. The production of vorticity and the shedding of vortical structures within the stroke cycle thus depend on two factors: the temporal structure of the flow induced by the wing's own instantaneous motion and the flow components resulting from both the force production in previous wing strokes and the motion of other wings flapping in close proximity. These wake-wing interactions may change on a stroke-by-stroke basis, confronting the neuro-muscular system of the animal with a complex problem for force control. In a single oscillating wing, the flow induced by the preceding half stroke may lower the wing's effective angle of attack but permits the recycling of kinetic energy from the wake via the wake capture mechanism. In two-winged insects, the acceleration fields produced by each wing may strongly interact via the clap-and-fling mechanism during the dorsal stroke reversal. Four-winged insects must cope with the fact that the flow over their hindwings is affected by the presence of the forewings. In these animals, a phase-shift between the stroke cycles of fore- and hindwing modulates aerodynamic performance of the hindwing via leading edge vortex destruction and changes in local flow condition including wake capture. Moreover, robotic wings demonstrate that phase-lag during peak performance and the strength of force modulation depend on the vertical spacing between the two stroke planes and the size ratio between fore- and hindwing. This study broadly summarizes the most prominent mechanisms of wake-wing and wing-wing interactions found in flapping insect wings and evaluates the consequences of these processes for the control of locomotor forces in the behaving animal.

  13. Posthuman Metamorphosis: Narrative and Systems, New

    Directory of Open Access Journals (Sweden)

    Elke D'hoker

    2009-10-01

    Full Text Available Review of Bruce Clarke, Posthuman Metamorphosis: Narrative and Systems, New
    York: Fordham University Press, 2008. 242 pages.
    978-0-8232-2580-8 (hardback
    978-0-8232-2581-5 (paperback

  14. Species and control of insect pests and major diseases of Torreyagrandis Merrillii

    Institute of Scientific and Technical Information of China (English)

    WU Zhongliang; XU Zhihong; CHEN Xiulong; JIN Guolong; LI Suping; SHEN Yulin; LANG Xuejun; HU Zhongcheng; CHEN Lihong

    2006-01-01

    From January 2001 to December 2004,the investigation on the species of insect pests and diseases in Torreya grandis Merrillii was conducted and integrated control technologies of the main insect pests and diseases were studied in Zhuji,Shaoxin,Shenzhou,Dongyang,and Jiande counties of Zhejiang Province.Via field survey,a system of regular observations,55 species of insectpests belonging to 9 orders and 29 families,and 4 species of diseases were recorded.Among them,Lepteucosma torreyae and Macrolygus torreyae were found to be new species.The biological characteristics of the major insect pests and diseases,such as Rhyncaphytoptus abiesis,Helicobasidium compacum,Erwinia carotovora,Chlorella sp.,Macrolygus torreyae,and Lepteucosma torreyae,were primarily recorded,and their outbreaks and epidemics were researched.The forecasting method for Lepteucosma torreyae was established.Based on strengthening cultivation and management,integrated control measures were put forward including physical,biologic and chemical methods.Medications with higher effect and lower toxicity were screened by comparing the effect of different pesticide treatments.

  15. Charting the Visual Space of Insect Eyes - Delineating the Guidance, Navigation and Control of Insect Flight by Their Optical Sensor

    Science.gov (United States)

    2014-06-01

    spectral and polarization vision. Introduction The visual systems of animals sample the light properties of the surrounding world with...sizes. Predatory insects ( dragonflies , robberflies) – like predatory higher animals (hawks, falcons, lions) – have distinct foveas, i.e., areas with a...Most dragonflies and damselflies have transparent wings, which are however so thin (< 1 µm) that interference colors arise, which can be understood

  16. Multifunctional amaranth cystatin inhibits endogenous and digestive insect cysteine endopeptidases: A potential tool to prevent proteolysis and for the control of insect pests.

    Science.gov (United States)

    Valdés-Rodríguez, Silvia; Galván-Ramírez, Juan Pablo; Guerrero-Rangel, Armando; Cedro-Tanda, Alberto

    2015-01-01

    In a previous study, the amaranth cystatin was characterized. This cystatin is believed to provide protection from abiotic stress because its transcription is induced in response to heat, drought, and salinity. It has also been shown that recombinant amaranth cystatin inhibits bromelain, ficin, and cysteine endopeptidases from fungal sources and also inhibits the growth of phytopathogenic fungi. In the present study, evidence is presented regarding the potential function of amaranth cystatin as a regulator of endogenous proteinases and insect digestive proteinases. During amaranth germination and seedling growth, different proteolytic profiles were observed at different pH levels in gelatin-containing SDS-PAGE. Most of the proteolytic enzymes detected at pH 4.5 were mainly inhibited by trans-epoxysuccinyl-leucyl amido(4-guanidino)butane (E-64) and the purified recombinant amaranth cystatin. Furthermore, the recombinant amaranth cystatin was active against insect proteinases. In particular, the E-64-sensitive proteolytic digestive enzymes from Callosobruchus maculatus, Zabrotes subfasciatus, and Acanthoscelides obtectus were inhibited by the amaranth cystatin. Taken together, these results suggest multiple roles for cystatin in amaranth, specifically during germination and seedling growth and in the protection of A. hypochondriacus against insect predation. Amaranth cystatin represents a promising tool for diverse applications in the control of insect pest and for preventing undesirable proteolytic activity.

  17. Joint torques in a freely walking insect reveal distinct functions of leg joints in propulsion and posture control.

    Science.gov (United States)

    Dallmann, Chris J; Dürr, Volker; Schmitz, Josef

    2016-01-27

    Determining the mechanical output of limb joints is critical for understanding the control of complex motor behaviours such as walking. In the case of insect walking, the neural infrastructure for single-joint control is well described. However, a detailed description of the motor output in form of time-varying joint torques is lacking. Here, we determine joint torques in the stick insect to identify leg joint function in the control of body height and propulsion. Torques were determined by measuring whole-body kinematics and ground reaction forces in freely walking animals. We demonstrate that despite strong differences in morphology and posture, stick insects show a functional division of joints similar to other insect model systems. Propulsion was generated by strong depression torques about the coxa-trochanter joint, not by retraction or flexion/extension torques. Torques about the respective thorax-coxa and femur-tibia joints were often directed opposite to fore-aft forces and joint movements. This suggests a posture-dependent mechanism that counteracts collapse of the leg under body load and directs the resultant force vector such that strong depression torques can control both body height and propulsion. Our findings parallel propulsive mechanisms described in other walking, jumping and flying insects, and challenge current control models of insect walking. © 2016 The Author(s).

  18. Genetically modifying the insect gut microbiota to control Chagas disease vectors through systemic RNAi.

    Science.gov (United States)

    Taracena, Mabel L; Oliveira, Pedro L; Almendares, Olivia; Umaña, Claudia; Lowenberger, Carl; Dotson, Ellen M; Paiva-Silva, Gabriela O; Pennington, Pamela M

    2015-02-01

    Technologies based on RNA interference may be used for insect control. Sustainable strategies are needed to control vectors of Chagas disease such as Rhodnius prolixus. The insect microbiota can be modified to deliver molecules to the gut. Here, Escherichia coli HT115(DE3) expressing dsRNA for the Rhodnius heme-binding protein (RHBP) and for catalase (CAT) were fed to nymphs and adult triatomine stages. RHBP is an egg protein and CAT is an antioxidant enzyme expressed in all tissues by all developmental stages. The RNA interference effect was systemic and temporal. Concentrations of E. coli HT115(DE3) above 3.35 × 10(7) CFU/mL produced a significant RHBP and CAT gene knockdown in nymphs and adults. RHBP expression in the fat body was reduced by 99% three days after feeding, returning to normal levels 10 days after feeding. CAT expression was reduced by 99% and 96% in the ovary and the posterior midgut, respectively, five days after ingestion. Mortality rates increased by 24-30% in first instars fed RHBP and CAT bacteria. Molting rates were reduced by 100% in first instars and 80% in third instars fed bacteria producing RHBP or CAT dsRNA. Oviposition was reduced by 43% (RHBP) and 84% (CAT). Embryogenesis was arrested in 16% (RHBP) and 20% (CAT) of laid eggs. Feeding females 105 CFU/mL of the natural symbiont, Rhodococcus rhodnii, transformed to express RHBP-specific hairpin RNA reduced RHBP expression by 89% and reduced oviposition. Modifying the insect microbiota to induce systemic RNAi in R. prolixus may result in a paratransgenic strategy for sustainable vector control.

  19. Genetically modifying the insect gut microbiota to control Chagas disease vectors through systemic RNAi.

    Directory of Open Access Journals (Sweden)

    Mabel L Taracena

    2015-02-01

    Full Text Available Technologies based on RNA interference may be used for insect control. Sustainable strategies are needed to control vectors of Chagas disease such as Rhodnius prolixus. The insect microbiota can be modified to deliver molecules to the gut. Here, Escherichia coli HT115(DE3 expressing dsRNA for the Rhodnius heme-binding protein (RHBP and for catalase (CAT were fed to nymphs and adult triatomine stages. RHBP is an egg protein and CAT is an antioxidant enzyme expressed in all tissues by all developmental stages. The RNA interference effect was systemic and temporal. Concentrations of E. coli HT115(DE3 above 3.35 × 10(7 CFU/mL produced a significant RHBP and CAT gene knockdown in nymphs and adults. RHBP expression in the fat body was reduced by 99% three days after feeding, returning to normal levels 10 days after feeding. CAT expression was reduced by 99% and 96% in the ovary and the posterior midgut, respectively, five days after ingestion. Mortality rates increased by 24-30% in first instars fed RHBP and CAT bacteria. Molting rates were reduced by 100% in first instars and 80% in third instars fed bacteria producing RHBP or CAT dsRNA. Oviposition was reduced by 43% (RHBP and 84% (CAT. Embryogenesis was arrested in 16% (RHBP and 20% (CAT of laid eggs. Feeding females 105 CFU/mL of the natural symbiont, Rhodococcus rhodnii, transformed to express RHBP-specific hairpin RNA reduced RHBP expression by 89% and reduced oviposition. Modifying the insect microbiota to induce systemic RNAi in R. prolixus may result in a paratransgenic strategy for sustainable vector control.

  20. Synergistic interactions of ecosystem services: florivorous pest control boosts crop yield increase through insect pollination

    Science.gov (United States)

    Albrecht, Matthias

    2016-01-01

    Insect pollination and pest control are pivotal functions sustaining global food production. However, they have mostly been studied in isolation and how they interactively shape crop yield remains largely unexplored. Using controlled field experiments, we found strong synergistic effects of insect pollination and simulated pest control on yield quantity and quality. Their joint effect increased yield by 23%, with synergistic effects contributing 10%, while their single contributions were 7% and 6%, respectively. The potential economic benefit for a farmer from the synergistic effects (12%) was 1.8 times greater than their individual contributions (7% each). We show that the principal underlying mechanism was a pronounced pest-induced reduction in flower lifetime, resulting in a strong reduction in the number of pollinator visits a flower receives during its lifetime. Our findings highlight the importance of non-additive interactions among ecosystem services (ES) when valuating, mapping or predicting them and reveal fundamental implications for ecosystem management and policy aimed at maximizing ES for sustainable agriculture. PMID:26865304

  1. Irradiation to control insects in fruits and vegetables for export from Hawaii

    Energy Technology Data Exchange (ETDEWEB)

    Follett, P.A. E-mail: pfollett@pbarc.ars.usda.gov

    2004-10-01

    Phytosanitary or quarantine treatments are often required to disinfest host commodities of economically important arthropod pests before they are moved through market channels to areas where the pest does not occur. Irradiation is an accepted treatment to control quarantine pests in 10 fruits and five vegetables for export from Hawaii to the US mainland. Irradiation is the ideal technology for developing generic quarantine treatments because it is effective against most insect and mite pests at dose levels that do not affect the quality of most commodities. A generic dose of 150 Gy has been proposed for tephritid fruit flies. Contrary to the 150 Gy dose, approved irradiation quarantine treatment doses for Mediterranean fruit fly, melon fly, and oriental fruit fly in Hawaii are 210-250 Gy. Irradiation studies were conducted to determine if the approved doses were unnecessarily high and could be reduced. Irradiation is also a viable alternative to methyl bromide fumigation to disinfest Hawaii sweetpotatoes, and studies are in progress to identify an effective dose for two key sweetpotato insect pests. Results indicate that irradiation doses <150 Gy will control Hawaii's fruit flies, which supports the proposed generic dose. The idea of generic doses is appealing because it would greatly accelerate the process of approving irradiation quarantine treatments for specific crops, and thereby rapidly expand exports. Preliminary results show that 250-300 Gy will control Hawaii's sweetpotato pests.

  2. Controlling free flight of a robotic fly using an onboard vision sensor inspired by insect ocelli

    Science.gov (United States)

    Fuller, Sawyer B.; Karpelson, Michael; Censi, Andrea; Ma, Kevin Y.; Wood, Robert J.

    2014-01-01

    Scaling a flying robot down to the size of a fly or bee requires advances in manufacturing, sensing and control, and will provide insights into mechanisms used by their biological counterparts. Controlled flight at this scale has previously required external cameras to provide the feedback to regulate the continuous corrective manoeuvres necessary to keep the unstable robot from tumbling. One stabilization mechanism used by flying insects may be to sense the horizon or Sun using the ocelli, a set of three light sensors distinct from the compound eyes. Here, we present an ocelli-inspired visual sensor and use it to stabilize a fly-sized robot. We propose a feedback controller that applies torque in proportion to the angular velocity of the source of light estimated by the ocelli. We demonstrate theoretically and empirically that this is sufficient to stabilize the robot's upright orientation. This constitutes the first known use of onboard sensors at this scale. Dipteran flies use halteres to provide gyroscopic velocity feedback, but it is unknown how other insects such as honeybees stabilize flight without these sensory organs. Our results, using a vehicle of similar size and dynamics to the honeybee, suggest how the ocelli could serve this role. PMID:24942846

  3. Controlling free flight of a robotic fly using an onboard vision sensor inspired by insect ocelli.

    Science.gov (United States)

    Fuller, Sawyer B; Karpelson, Michael; Censi, Andrea; Ma, Kevin Y; Wood, Robert J

    2014-08-06

    Scaling a flying robot down to the size of a fly or bee requires advances in manufacturing, sensing and control, and will provide insights into mechanisms used by their biological counterparts. Controlled flight at this scale has previously required external cameras to provide the feedback to regulate the continuous corrective manoeuvres necessary to keep the unstable robot from tumbling. One stabilization mechanism used by flying insects may be to sense the horizon or Sun using the ocelli, a set of three light sensors distinct from the compound eyes. Here, we present an ocelli-inspired visual sensor and use it to stabilize a fly-sized robot. We propose a feedback controller that applies torque in proportion to the angular velocity of the source of light estimated by the ocelli. We demonstrate theoretically and empirically that this is sufficient to stabilize the robot's upright orientation. This constitutes the first known use of onboard sensors at this scale. Dipteran flies use halteres to provide gyroscopic velocity feedback, but it is unknown how other insects such as honeybees stabilize flight without these sensory organs. Our results, using a vehicle of similar size and dynamics to the honeybee, suggest how the ocelli could serve this role.

  4. Metamorphosis of cinctoblastula larvae (Homoscleromorpha, porifera).

    Science.gov (United States)

    Ereskovsky, Alexander V; Tokina, Daria B; Bézac, Chantal; Boury-Esnault, Nicole

    2007-06-01

    The metamorphosis of the cinctoblastula of Homoscleromorpha is studied in five species belonging to three genera. The different steps of metamorphosis are similar in all species. The metamorphosis occurs by the invagination and involution of either the anterior epithelium or the posterior epithelium of the larva. During metamorphosis, morphogenetic polymorphism was observed, which has an individual character and does not depend on either external or species specific factors. In the rhagon, the development of the aquiferous system occurs only by epithelial morphogenesis and subsequent differentiation of cells. Mesohylar cells derive from flagellated cells after ingression. The formation of pinacoderm and choanoderm occurs by the differentiation of the larval flagellated epithelium. This is possibly due to the conservation of cell junctions in the external surface of the larval flagellated cells and of the basement membrane in their internal surface. The main difference in homoscleromorph metamorphosis compared with Demospongiae is the persistence of the flagellated epithelium throughout this process and even in the adult since exo- and endopinacoderm remain flagellated. The antero-posterior axis of the larva corresponds to the baso-apical axis of the adult in Homoscleromorpha.

  5. Control of dengue vector by the sterile insect technique considering logistic recruitment

    Energy Technology Data Exchange (ETDEWEB)

    Esteva, L. [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico). Facultad de Ciencias. Dept. de Matematicas; Lab-Epifisma, Mexico, D.F. (Mexico); Yang, H.M. [Universidade Estadual de Campinas, SP (Brazil). Inst. de Matematica, Estatistica e Ciencia da Computacao. Dept. de Matematica Aplicada; Lab-Epifisma, Campinas, SP (Brazil)

    2006-07-01

    We propose a mathematical model to assess the effects of irradiated male insects introduction in a previously infested region, taking into account the logistic recruitment of sterile male insects. The release of sterile male insects aims to displace gradually the natural (or wild) insect from the habitat. We discuss the suitability of this release technique when applied to peridomestic adapted Aedes aegypyti mosquitoes which are transmitters of Yellow Fever and Dengue disease. (author)

  6. Kinect-based system for automated control of terrestrial insect biobots.

    Science.gov (United States)

    Whitmire, Eric; Latif, Tahmid; Bozkurt, Alper

    2013-01-01

    Centimeter scale mobile biobots offer unique advantages in uncertain environments. Our previous experimentation has demonstrated neural stimulation techniques in order to control the motion of Madagascar hissing cockroaches. These trials relied on stimulation by a human operator using a remote control. We have developed a Kinect-based system for computer operated automatic control of cockroaches. Using image processing techniques and a radio transmitter, this platform both detects the position of the roach biobot and sends stimulation commands to an implanted microcontroller-based receiver. The work presented here enables repeatable experimentation and allows precise quantification of the line following capabilities of the roach biobot. This system will help refine our model for the stimulation response of the insect and improve our ability to direct them in increasingly dynamic situations.

  7. Damage by insect pests to the Djingarey Ber Mosque in Timbuktu: detection and control

    Directory of Open Access Journals (Sweden)

    Lara Maistrello

    2011-08-01

    Full Text Available The Djingarey Ber Mosque in Timbuktu (Mali is one of the most significant earthen construction in West Africa. Originally constructed in 1327, it was included in 1988 on the World Heritage UNESCO List for its unique architecture and historical importance. During its restoration, recently undertaken by the Aga Khan Trust for Culture, the wooden parts of the roof and architraves showed clear signs of threatening insect presence. In order to identify the pests responsible of the damage, evaluate its extent and suggest a proper control strategy, a detailed survey was performed inside the Mosque complex and in its immediate surroundings. The entomological inspection, performed in the dry-cold season, allowed to detect signs of insect damage in most of the wooden elements, even in the recently replaced beams, but also in walls, pillars and the precious decorated panels. Damages in the wood elements could be attributed to Amitermes evuncifer Silvestri (Termitidae, Bostrychoplites zycheli Marseuli (Bostrichidae and Lyctus africanus Lesne (Lyctidae, which were collected alive on site. Injures in the walls and decorated panels appeared to be performed by hymenopterans such as “plasterer bees” (Colletidae and Sphecidae. From the evaluation of the type and extent of damage in relation to the architecture and materials used in its construction and decoration, the most serious pest and the worse threat for the mosque is represented by termites. Control and preventive measures, in the view of a sustainable, long-lasting integrated management are suggested.

  8. Queen control of a key life-history event in a eusocial insect.

    Science.gov (United States)

    Holland, Jacob G; Guidat, Florian S; Bourke, Andrew F G

    2013-06-23

    In eusocial insects, inclusive fitness theory predicts potential queen-worker conflict over the timing of events in colony life history. Whether queens or workers control the timing of these events is poorly understood. In the bumble-bee Bombus terrestris, queens exhibit a 'switch point' in which they switch from laying diploid eggs yielding females (workers and new queens) to laying haploid eggs yielding males. By rearing foundress queens whose worker offspring were removed as pupae and sexing their eggs using microsatellite genotyping, we found that queens kept in the complete absence of adult workers still exhibit a switch point. Moreover, the timing of their switch points relative to the start of egg-laying did not differ significantly from that of queens allowed to produce normal colonies. The finding that bumble-bee queens can express the switch point in the absence of workers experimentally demonstrates queen control of a key life-history event in eusocial insects. In addition, we found no evidence that workers affect the timing of the switch point either directly or indirectly via providing cues to queens, suggesting that workers do not fully express their interests in queen-worker conflicts over colony life history.

  9. Biomimetics Micro Robot with Active Hardware Neural Networks Locomotion Control and Insect-Like Switching Behaviour

    Directory of Open Access Journals (Sweden)

    Ken Saito

    2012-11-01

    Full Text Available In this paper, we presented the 4.0, 2.7, 2.5 mm, width, length, height size biomimetics micro robot system which was inspired by insects. The micro robot system was made from silicon wafer fabricated by micro electro mechanical systems (MEMS technology. The mechanical system of the robot was equipped with small size rotary type actuators, link mechanisms and six legs to realize the insect‐like switching behaviour. In addition, we constructed the active hardware neural networks (HNN by analogue CMOS circuits as a locomotion controlling system. The HNN utilized the pulse‐type hardware neuron model (P‐HNM as a basic component. The HNN outputs the driving pulses using synchronization phenomena such as biological neural networks. The driving pulses can operate the actuators of the biomimetics micro robot directly. Therefore, the HNN realized the robot control without using any software programs or A/D converters. The micro robot emulated the locomotion method and the neural networks of an insect with rotary type actuators, link mechanisms and HNN. The micro robot performed forward and backward locomotion, and also changed direction by inputting an external trigger pulse. The locomotion speed was 26.4 mm/min when the step width was 0.88 mm.

  10. Comparison Between Gregor and Grete in The Metamorphosis

    Institute of Scientific and Technical Information of China (English)

    曾圣勇

    2011-01-01

    This paper analyzes the metamorphosis of Gregor and Grete in detail in Franz Kafka' s The Metamorphosis to prove that the difference between their metamorphosis lead to the different results of their lives, which exposes the dehumanizing nature of the commercialized world.

  11. A computational model of insect discontinuous gas exchange: A two-sensor, control systems approach.

    Science.gov (United States)

    Grieshaber, Beverley J; Terblanche, John S

    2015-06-07

    The insect gas exchange system is characterised by branching air-filled tubes (tracheae/tracheoles) and valve-like structures in their outer integument (spiracles) which allow for a periodic gas exchange pattern known as the discontinuous gas exchange cycle (DGC). The DGC facilitates the temporal decoupling of whole animal gas exchange from cellular respiration rates and may confer several physiological benefits, which are nevertheless highly controversial (primarily reduction of cellular oxidative damage and/or respiratory water saving). The intrinsic and extrinsic factors influencing DGCs are the focus of extensive ongoing research and little consensus has been reached on the evolutionary genesis or mechanistic costs and benefits of the pattern. Despite several hypotheses and much experimental and evolutionary biology research, a mechanistic physical model, which captures various key elements of the DGC pattern, is currently lacking. Here, we present a biologically realistic computational, two-sensor DGC model (pH/carbon dioxide and oxygen setpoints) for an Orthopteran gas exchange system, and show computationally for the first time that a control system of two interacting feedback loops is capable of generating a full DGC pattern with outputs which are physiologically realistic, quantitatively matching experimental results found in this taxonomic model elsewhere. A finite-element mathematical approach is employed and various trigger sets are considered. Parameter sensitivity analyses suggest that various aspects of insect DGC are adequately captured in this model. In particular, with physiologically relevant input parameters, the full DGC pattern is induced; and the phase durations, endotracheal carbon dioxide partial pressure ranges, and pH fluctuations which arise are physically realistic. The model results support the emergent property hypothesis for the existence of DGC, and indicate that asymmetric loading and off-loading (hysteresis) in one of the sensor

  12. Control for small-speed lateral flight in a model insect

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Yanlai; Sun Mao, E-mail: m.sun@buaa.edu.cn [Ministry-of-Education Key Laboratory of Fluid Mechanics, Beijing University of Aeronautics and Astronautics, Beijing (China)

    2011-09-15

    Controls required for small-speed lateral flight of a model insect were studied using techniques based on the linear theories of stability and control (the stability and control derivatives were computed by the method of computational fluid dynamics). The main results are as follows. (1) Two steady-state lateral motions can exist: one is a horizontal side translation with the body rolling to the same side of the translation by a small angle, and the other is a constant-rate yaw rotation (rotation about the vertical axis). (2) The side translation requires an anti-symmetrical change in the stroke amplitudes of the contralateral wings, and/or an anti-symmetrical change in the angles of attack of the contralateral wings, with the down- and upstroke angles of attack of a wing having equal change. The constant-rate yaw rotation requires an anti-symmetrical change in the angles of attack of the contralateral wings, with the down- and upstroke angles of attack of a wing having differential change. (3) For the control of the horizontal side translation, control input required for the steady-state motion has an opposite sign to that needed for initiating the motion. For example, to have a steady-state left side-translation, the insect needs to increase the stroke amplitude of the left wing and decrease that of the right wing to maintain the steady-state flight, but it needs an opposite change in stroke amplitude (decreasing the stroke amplitude of the left wing and increasing that of the right wing) to enter the flight.

  13. Adaptive dynamic resource allocation in annual eusocial insects: environmental variation will not necessarily promote graded control

    Directory of Open Access Journals (Sweden)

    Strohm Erhard

    2007-12-01

    Full Text Available Abstract Background According to the classical model of Macevicz and Oster, annual eusocial insects should show a clear dichotomous "bang-bang" strategy of resource allocation; colony fitness is maximised when a period of pure colony growth (exclusive production of workers is followed by a single reproductive period characterised by the exclusive production of sexuals. However, in several species graded investment strategies with a simultaneous production of workers and sexuals have been observed. Such deviations from the "bang-bang" strategy are usually interpreted as an adaptive (bet-hedging response to environmental fluctuations such as variation in season length or food availability. To generate predictions about the optimal investment pattern of insect colonies in fluctuating environments, we slightly modified Macevicz and Oster's classical model of annual colony dynamics and used a dynamic programming approach nested into a recurrence procedure for the solution of the stochastic optimal control problem. Results 1 The optimal switching time between pure colony growth and the exclusive production of sexuals decreases with increasing environmental variance. 2 Yet, for reasonable levels of environmental fluctuations no deviation from the typical bang-bang strategy is predicted. 3 Model calculations for the halictid bee Lasioglossum malachurum reveal that bet-hedging is not likely to be the reason for the graded allocation into sexuals versus workers observed in this species. 4 When environmental variance reaches a critical level our model predicts an abrupt change from dichotomous behaviour to graded allocation strategies, but the transition between colony growth and production of sexuals is not necessarily monotonic. Both, the critical level of environmental variance as well as the characteristic pattern of resource allocation strongly depend on the type of function used to describe environmental fluctuations. Conclusion Up to now bet

  14. Insect-inspired high-speed motion vision system for robot control.

    Science.gov (United States)

    Wu, Haiyan; Zou, Ke; Zhang, Tianguang; Borst, Alexander; Kühnlenz, Kolja

    2012-10-01

    The mechanism for motion detection in a fly's vision system, known as the Reichardt correlator, suffers from a main shortcoming as a velocity estimator: low accuracy. To enable accurate velocity estimation, responses of the Reichardt correlator to image sequences are analyzed in this paper. An elaborated model with additional preprocessing modules is proposed. The relative error of velocity estimation is significantly reduced by establishing a real-time response-velocity lookup table based on the power spectrum analysis of the input signal. By exploiting the improved velocity estimation accuracy and the simple structure of the Reichardt correlator, a high-speed vision system of 1 kHz is designed and applied for robot yaw-angle control in real-time experiments. The experimental results demonstrate the potential and feasibility of applying insect-inspired motion detection to robot control.

  15. Control of the olive fruit fly using genetics-enhanced sterile insect technique

    Directory of Open Access Journals (Sweden)

    Ant Thomas

    2012-06-01

    Full Text Available Abstract Background The olive fruit fly, Bactrocera oleae, is the major arthropod pest of commercial olive production, causing extensive damage to olive crops worldwide. Current control techniques rely on spraying of chemical insecticides. The sterile insect technique (SIT presents an alternative, environmentally friendly and species-specific method of population control. Although SIT has been very successful against other tephritid pests, previous SIT trials on olive fly have produced disappointing results. Key problems included altered diurnal mating rhythms of the laboratory-reared insects, resulting in asynchronous mating activity between the wild and released sterile populations, and low competitiveness of the radiation-sterilised mass-reared flies. Consequently, the production of competitive, male-only release cohorts is considered an essential prerequisite for successful olive fly SIT. Results We developed a set of conditional female-lethal strains of olive fly (named Release of Insects carrying a Dominant Lethal; RIDL®, providing highly penetrant female-specific lethality, dominant fluorescent marking, and genetic sterility. We found that males of the lead strain, OX3097D-Bol, 1 are strongly sexually competitive with wild olive flies, 2 display synchronous mating activity with wild females, and 3 induce appropriate refractoriness to wild female re-mating. Furthermore, we showed, through a large proof-of-principle experiment, that weekly releases of OX3097D-Bol males into stable populations of caged wild-type olive fly could cause rapid population collapse and eventual eradication. Conclusions The observed mating characteristics strongly suggest that an approach based on the release of OX3097D-Bol males will overcome the key difficulties encountered in previous olive fly SIT attempts. Although field confirmation is required, the proof-of-principle suppression and elimination of caged wild-type olive fly populations through OX3097D

  16. Surface functionalization of silver nanoparticles: novel applications for insect vector control.

    Science.gov (United States)

    Sooresh, Aishwarya; Kwon, Hyeogsun; Taylor, Robert; Pietrantonio, Patricia; Pine, Michelle; Sayes, Christie M

    2011-10-01

    Every day, people and animals contract debilitating and life threatening diseases due to bites from infected flies, ticks, and mosquitoes. The current methods utilized to fight against these diseases are only partially effective or safe for humans and animals. When it comes to insect vector control, a conceptual paradigm shift is urgently needed. This work proposes a novel synthetic scheme to produce a nanoparticle-pesticide core-shell conjugate to be used as an active agent against arthropod vectors, such as mosquitoes. As a proof of concept, we conjugated nanosilver to the pyrethroid pesticide deltamethrin. First, electron microscopy and Fourier transform infrared spectroscopy verified the presence of a 15 nm nanosilver core surrounded by deltamethrin. Second, when the conjugate was exposed to mosquitoes for a 24 h bioassay, mortality was observed at 9 × 10(-4) M. Silver was detected in the hemolymph of mosquitoes exposed to the conjugate. We concluded that the newly developed nanoconjugate did not inactivate the primary function of the pesticide and was effective in killing mosquitoes at low concentrations. These results demonstrate the potential to use nanoparticle surfaces to kill insects, specifically vectors of human pathogens.

  17. A transgenic approach to control hemipteran insects by expressing insecticidal genes under phloem-specific promoters

    Science.gov (United States)

    Javaid, Shaista; Amin, Imran; Jander, Georg; Mukhtar, Zahid; Saeed, Nasir A.; Mansoor, Shahid

    2016-01-01

    The first generation transgenic crops used strong constitutive promoters for transgene expression. However, tissue-specific expression is desirable for more precise targeting of transgenes. Moreover, piercing/sucking insects, which are generally resistant to insecticidal Bacillus thuringiensis (Bt) proteins, have emerged as a major pests since the introduction of transgenic crops expressing these toxins. Phloem-specific promoters isolated from Banana bunchy top virus (BBTV) were used for the expression of two insecticidal proteins, Hadronyche versuta (Blue Mountains funnel-web spider) neurotoxin (Hvt) and onion leaf lectin, in tobacco (Nicotiana tabacum). Here we demonstrate that transgenic plants expressing Hvt alone or in combination with onion leaf lectin are resistant to Phenacoccus solenopsis (cotton mealybug), Myzus persicae (green peach aphids) and Bemisia tabaci (silver leaf whitefly). The expression of both proteins under different phloem-specific promoters resulted in close to 100% mortality and provided more rapid protection than Hvt alone. Our results suggest the employment of the Hvt and onion leaf lectin transgenic constructs at the commercial level will reduce the use of chemical pesticides for control of hemipteran insect pests. PMID:27708374

  18. Cytotoxicity against insect cells of entomopathogenic fungi of the genera Hypocrella (anamorph Aschersonia): possible agents for biological control.

    Science.gov (United States)

    Watts, Patricia; Kittakoop, Prasat; Veeranondha, Sukitaya; Wanasith, Supakit; Thongwichian, Rossukon; Saisaha, Pattama; Intamas, Suthichai; Hywel-Jones, Nigel L

    2003-05-01

    Extracts from entomopathogenic fungi of the genus Hypocrella (7 species) and its anamorph Aschersonia (11 species) were screened for cytotoxicity to Sf9 and C6/36 insect cells and L929, BHK(21)C13 and HepG2 mammalian cells. Cytotoxic extracts to insect cells (ID50's or = 10 microg ml(-1)) conformed to the criteria of the project and were considered 'lead' extracts for further investigation. 'Leads' were found in two of the Hypocrella species: H. discoidea, and H. tamurai and in three of the Aschersonia species: A. samoensis, A. badia, and A. tamurai. Bioassay-guided fractionation of the cell extract of the fungus A. samoensis BCC 1393 led to the identification of two known anthraquinone dimers, (+)rugulosin (1) and skyrin (2) which showed selective toxicity towards insect cells. (+)Rugulosin (1) and skyrin (2) exhibited strong cytotoxic activity against the insect cell line Sf9 with respective ID50 values of 1.2 and 9.6 microg ml(-1), but showed weak activity toward mammalian cells. This first report of (+)rugulosin (1) and skyrin (2) in A. samoensis is confirmed and demonstrated in another four strains of A. samoensis isolated in Thailand. The preferential cytotoxicity against Sf9 insect cells gives evidence that these insect-pathogenic fungi of the Hypocrella/Aschersonia group might be useful as an agent for pest control.

  19. Enhancement of biological control agents for use against forest insect pests and diseases through biotechnology

    Science.gov (United States)

    Slavicek, James M.

    1991-01-01

    Research and development efforts in our research group are focused on the generation of more efficacious biological control agents through the techniques of biotechnology for use against forest insect pests and diseases. Effective biological controls for the gypsy moth and for tree fungal wilt pathogens are under development. The successful use of Gypchek, a formulation of the Lymantria dispar nuclear polyhedrosis virus (LdNPV), in gypsy moth control programs has generated considerable interest in that agent. As a consequence of its specificity, LdPNV has negligible adverse ecological impacts compared to most gypsy moth control agents. However, LdNPV is not competitive with other control agents in terms of cost and efficacy. We are investigating several parameters of LdNPV replication and polyhedra production in order to enhance viral potency and efficacy thus mitigating the current disadvantages of LdNPV for gypsy moth control, and have identified LdNPV variants that will facilitate these efforts. Tree endophytic bacteria that synthesize antifungal compounds were identified and an antibiotic compound from one of these bacteria was characterized. The feasibility of developing tree endophytes as biological control agents for tree vascular fungal pathogens is being investigated.

  20. RNA interference: a new strategy in the evolutionary arms race between human control strategies and insect pests.

    Science.gov (United States)

    Machado, Vilmar; Rodríguez-García, María Juliana; Sánchez-García, Francisco Javier; Galan, Jose

    2014-01-01

    The relationship between humans and the insect pests of cultivated plants may be considered to be an indirect coevolutionary process, i.e., an arms race. Over time, humans have developed several strategies to minimize the negative impacts of insects on agricultural production. However, insects have made adaptive responses via the evolution of resistance to insecticides, and more recently against Bacillus thuriengiensis. Thus, we need to continuously invest resources in the development of new strategies for crop protection. Recent advances in genomics have demonstrated the possibility of a new weapon or strategy in this war, i.e., gene silencing, which involves blocking the expression of specific genes via mRNA inactivation. In the last decade, several studies have demonstrated the effectiveness of this strategy in the control of different species of insects. However, several technical difficulties need to be overcome to transform this potential into reality, such as the selection of target genes, the concentration of dsRNA, the nucleotide sequence of the dsRNA, the length of dsRNA, persistence in the insect body, and the life stage of the target species where gene silencing is most efficient. This study analyzes several aspects related to the use of gene silencing in pest control and it includes an overview of the inactivation process, as well as the problems that need to be resolved to transform gene silencing into an effective pest control method.

  1. Structural Elements in Franz Kafka's "The Metamorphosis."

    Science.gov (United States)

    Johnson, Scott

    1993-01-01

    Notes that Kafka's "The Metamorphosis" is not only a masterpiece of modern literature but also a work that exemplifies many ideas of structural family therapy. Examines how Kafka's novella embodies concepts such as parentified children, enmeshment, intergenerational boundaries, coalitions and triangles, structural dysfunction, and…

  2. Structural Elements in Franz Kafka's "The Metamorphosis."

    Science.gov (United States)

    Johnson, Scott

    1993-01-01

    Notes that Kafka's "The Metamorphosis" is not only a masterpiece of modern literature but also a work that exemplifies many ideas of structural family therapy. Examines how Kafka's novella embodies concepts such as parentified children, enmeshment, intergenerational boundaries, coalitions and triangles, structural dysfunction, and…

  3. Structural Elements in Franz Kafka's "The Metamorphosis."

    Science.gov (United States)

    Johnson, Scott

    1993-01-01

    Notes that Kafka's "The Metamorphosis" is not only a masterpiece of modern literature but also a work that exemplifies many ideas of structural family therapy. Examines how Kafka's novella embodies concepts such as parentified children, enmeshment, intergenerational boundaries, coalitions and triangles, structural dysfunction, and structural…

  4. A review of control methods and resistance mechanisms in stored-product insects.

    Science.gov (United States)

    Boyer, S; Zhang, H; Lempérière, G

    2012-04-01

    This review describes the major stored-product insect species and their resistance to insecticides. The economic importance of the control of those pests is highlighted with a loss of more than one billion US dollars per year worldwide. A detailed common description of species resistance throughout the world has been developed, and we observed 28 recurrent studied species involved in resistance cases disseminated on the five continents. The different mechanisms, including behavioral resistance, were studied particularly on Oryzaephilus surinamensis. The role of detoxifying enzymes and studies on the genetic resistance, involving the kdr mutation mechanisms and the transmission of the genes of resistance, are also described. A chapter clarifying definitions on cross and multiple resistance is enclosed.

  5. Microbial Pest Control Agents: Are they a Specific And Safe Tool for Insect Pest Management?

    Science.gov (United States)

    Deshayes, Caroline; Siegwart, Myriam; Pauron, David; Froger, Josy-Anne; Lapied, Bruno; Apaire-Marchais, Véronique

    2017-01-01

    Microorganisms (viruses, bacteria and fungi) or their bioactive agents can be used as active substances and therefore are referred as Microbial Pest Control Agents (MPCA). They are used as alternative strategies to chemical insecticides to counteract the development of resistances and to reduce adverse effects on both environment and human health. These natural entomopathogenic agents, which have specific modes of action, are generally considered safer as compared to conventional chemical insecticides. Baculoviruses are the only viruses being used as the safest biological control agents. They infect insects and have narrow host ranges. Bacillus thuringiensis (Bt) is the most widely and successfully used bioinsecticide in the integrated pest management programs in the world. Bt mainly produces crystal delta-endotoxins and secreted toxins. However, the Bt toxins are not stable for a very long time and are highly sensitive to solar UV. So genetically modified plants that express toxins have been developed and represent a large part of the phytosanitary biological products. Finally, entomopathogenic fungi and particularly, Beauveria bassiana and Metarhizium anisopliae, are also used for their insecticidal properties. Most studies on various aspects of the safety of MPCA to human, non-target organisms and environment have only reported acute but not chronic toxicity. This paper reviews the modes of action of MPCA, their toxicological risks to human health and ecotoxicological profiles together with their environmental persistence. This review is part of the special issue "Insecticide Mode of Action: From Insect to Mammalian Toxicity". Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  6. Assessing the Fauna of Aquatic Insects for Possible Use for Malaria Vector Control in Large River, Central Iran

    Directory of Open Access Journals (Sweden)

    Mansoureh Shayeghi

    2015-10-01

    Full Text Available Insects with over 30,000 aquatic species are known as very successful arthropods in freshwater habitats. Some of them are applied as biological indicators for water quality control, as well as the main food supply for fishes and amphibians. The faunistic studies are the basic step in entomological researches; the current study was carried out emphasizing on the fauna of aquatic insects in Karaj River, northern Iran. A field study was carried out in six various sampling site of Karaj River during spring 2013. The aquatic insects were collected using several methods such as D-frame nets, dipping and direct search on river floor stones. Specimens were collected and preserved in Ethanol and identified by standard identification keys. Totally, 211 samples were collected belonging to three orders; Plecoptera, Trichoptera and Ephemeroptera. Seven genuses (Perla, Isoperla, Hydropsyche, Cheumatopsyche, Baetis, Heptagenia and Maccafferium from five families (Perlidae, Perlodidae, Hydropsychidae, Batidae, Heptagenidae were identified. The most predominant order was Plecoptera followed by Trichoptera. Karaj River is a main and important river, which provides almost all of water of Karaj dam. So, identification of aquatic species which exist in this river is vital and further studies about systematic and ecological investigations should be performed. Also, monitoring of aquatic biota by trained health personnel can be a critical step to describe water quality in this river. Understanding the fauna of aquatic insects will provide a clue for possible biological control of medically important aquatic insects such as Anopheles as the malaria vectors.

  7. Terpenes: Natural Products for Controlling Insects of Importance to Human Health—A Structure-Activity Relationship Study

    Directory of Open Access Journals (Sweden)

    José S. Dambolena

    2016-01-01

    Full Text Available Many insects affect food production and human health, and in an attempt to control these insects the use of synthetic insecticides has become widespread. However, this has resulted in the development of resistance in these organisms, human diseases, contamination of food, and pollution of the environment. Plants natural products and essential oil components such as terpenes and phenylpropenes have been shown to have a significant potential for insect control. However, the molecular properties related to their insecticidal activity are not well understood. The purpose of this review is to provide an overview of the toxicity of terpene compounds against three insects of importance to human health: lice, cockroaches, and Triatominae bugs and to evaluate which molecular descriptors are important in the bioactivity of terpenes. For the insects studied, quantitative structure-activity relationship (QSAR studies were performed in order to predict the insecticidal activity of terpene compounds. The obtained QSAR models indicated that the activity of these compounds depends on their ability to reach the targets and to interact with them. The QSAR analysis can be used to predict the bioactivities of other structurally related molecules. Our findings may provide an important contribution in the search for new compounds with insecticidal activity.

  8. Assessing the Fauna of Aquatic Insects for Possible Use for Malaria Vector Control in Large River, Central Iran.

    Science.gov (United States)

    Shayeghi, Mansoureh; Nejati, Jalil; Shirani-Bidabadi, Leila; Koosha, Mona; Badakhshan, Mehdi; Mohammadi Bavani, Mulood; Arzamani, Kourosh; Choubdar, Nayyereh; Bagheri, Fatemeh; Saghafipour, Abedin; Veysi, Arshad; Karimian, Fateh; Akhavan, Amir Ahamd; Vatandoost, Hassan

    2015-01-01

    Insects with over 30,000 aquatic species are known as very successful arthropods in freshwater habitats. Some of them are applied as biological indicators for water quality control, as well as the main food supply for fishes and amphibians. The faunistic studies are the basic step in entomological researches; the current study was carried out emphasizing on the fauna of aquatic insects in Karaj River, northern Iran. A field study was carried out in six various sampling site of Karaj River during spring 2013. The aquatic insects were collected using several methods such as D-frame nets, dipping and direct search on river floor stones. Specimens were collected and preserved in Ethanol and identified by standard identification keys. Totally, 211 samples were collected belonging to three orders; Plecoptera, Trichoptera and Ephemeroptera. Seven genuses (Perla, Isoperla, Hydropsyche, Cheumatopsyche, Baetis, Heptagenia and Maccafferium) from five families (Perlidae, Perlodidae, Hydropsychidae, Batidae, Heptagenidae) were identified. The most predominant order was Plecoptera followed by Trichoptera. Karaj River is a main and important river, which provides almost all of water of Karaj dam. So, identification of aquatic species which exist in this river is vital and further studies about systematic and ecological investigations should be performed. Also, monitoring of aquatic biota by trained health personnel can be a critical step to describe water quality in this river. Understanding the fauna of aquatic insects will provide a clue for possible biological control of medically important aquatic insects such as Anopheles as the malaria vectors.

  9. Triclosan and anuran metamorphosis: no effect on thyroid-mediated metamorphosis in Xenopus laevis.

    Science.gov (United States)

    Fort, Douglas J; Rogers, Robert L; Gorsuch, Joseph W; Navarro, Lisa T; Peter, Robert; Plautz, James R

    2010-02-01

    Nieuwkoop and Faber stage 51 Xenopus laevis larvae were exposed for 21 days to four different concentrations of triclosan (TCS): <0.2 (control), 0.6, 1.5, 7.2, or 32.3 microg TCS/l. Primary endpoints were survival, hind limb length, body length (whole; snout to vent), developmental stage, wet whole body weight, and thyroid histology. Thyroid hormone (TH) concentrations were determined in whole thyroid and plasma samples from stage-matched exposure day 21 specimens. TH receptor-beta (TRbeta) expression was measured in stage-matched tail fin tissue samples collected at exposure days 0 and 21. Reduced larval growth occurred at exposure day 21 with 1.5 microg/l treatment. Larval developmental stage at exposure day 21 was not significantly different from controls based on observed parameters. Thyroid histology was not affected by TCS, and thyroxine (T4) levels in thyroid glands or plasma were not different from controls. A concentration-dependent increase in TRbeta expression in exposure day 21 larvae was not detected. However, increased expression was found in stage-matched larvae exposed to 1.5 or 7.2 microg TCS/l. Our study indicates that environmentally relevant TCS concentrations do not alter the normal course of thyroid-mediated metamorphosis in this standard anuran model.

  10. Pheromone use for insect control: present status and prospect in Bangladesh

    Directory of Open Access Journals (Sweden)

    Md. Azharul Islam

    2012-06-01

    Full Text Available The insect’s world is filled with many odors. Insects use these odors to cue them in a variety of complex social behaviors, including courtship, mating, and egg laying. Scientists and pest control specialists have known about these complex communication systems for decades. The main aim of this study was to visualize the availability, trends and differences in the sources of pheromone control in agricultural growth of Bangladesh. It also concerned on constrains and present use of pheromone and their possible recommendation on behalf of Bangladesh agriculture. It concentrated on the data during last three decades (1980-2010, comprising status of pheromone use in Bangladesh agriculture and its future. Review revealed that Bangladesh has been enormously successful in increasing pheromone use in agricultural production (especially for vegetables. Understanding of the nature of pheromones and their potential for pest control along with the future prospective of pheromone technique in agriculture were stated. Since the pheromone, technologies for control of major crop pests in Bangladesh are still limited. So that this review emphasized on more attention to the authority to increase the research works and project facilities related to develop and promote pheromone techniques. It is highly recommended to increase availability of pheromone in market, more investment in research and development, introduction of newly identified pheromone for specific pest, to assist government and non-government organizations to work with farmers to reduce harmful insecticide use and promote pheromone tactics as one part of integrated crop management (ICM.

  11. Limonene, a citrus extract, for control of mealybugs and scale insects.

    Science.gov (United States)

    Hollingsworth, Robert G

    2005-06-01

    In a series of bioassays with mealybugs, aqueous solutions of 1% limonene were tested that used from 0.50 to 1.50% all purpose spray adjuvant (APSA)-80 as an emulsifier/surfactant. The two ingredients were added to water or to 0.1% Silwet L-77, an agricultural surfactant. Using 1% limonene, 0.75% APSA-80 and 0.1% Silwet L-77, a semitransparent mixture (primarily a microemulsion) was obtained that was safe for most plants and provided good control of mealybugs when sprayed or used in 1-min dips. Used at half strength, this mixture controlled > or =99% of whiteflies, whereas the full-strength mixture controlled from 69 to 100% of mealybugs and scales, including > or =93% control of root mealybugs. In side-by-side greenhouse tests, this mixture was superior to a 2% solution of insecticidal soap or a 2% solution of horticultural spray oil. Mortality of green scales on potted gardenia plants averaged 95, 89, and 88% on plants sprayed with limonene, insecticidal soap, or horticultural oil, respectively. In a related test, these same sprays killed 44.1, 22.7, or 12.5% of third and fourth instar clustering mealybugs, respectively. Limonene has promise as a safe, natural pesticide for insect pests on tolerant plants. Although 1% limonene solutions damaged certain species of ferns, gingers and delicate flowers, they caused no damage to ornamentals with thick, waxy leaves, such as palms, cycads, and orchids.

  12. Fusion proteins containing insect-specific toxins as pest control agents: snowdrop lectin delivers fused insecticidal spider venom toxin to insect haemolymph following oral ingestion.

    Science.gov (United States)

    Fitches, Elaine; Edwards, Martin G; Mee, Christopher; Grishin, Eugene; Gatehouse, Angharad M R; Edwards, John P; Gatehouse, John A

    2004-01-01

    The mannose-specific snowdrop lectin (Galanthus nivalis agglutinin: GNA), when fed to insects, binds to the gut epithelium and passes into the haemolymph. The ability of GNA to act as a carrier protein to deliver an insecticidal spider venom neurotoxin (Segestria florentina toxin 1: SFI1) to the haemolymph of lepidopteran larvae was investigated. Constructs encoding SFI1 and an SFI1/GNA fusion protein were expressed in Pichia pastoris. The insecticidal activity of purified recombinant proteins on injection was found to be comparable to published values for SfI1 purified from spider venom [Toxicon 40 (2002) 125]. Whereas neither GNA nor SFI1 alone showed acute toxicity when fed to larvae of tomato moth (Lacanobia oleracea), feeding SFI1/GNA fusion at 2.5% of dietary proteins was insecticidal to first stadium larvae, causing 100% mortality after 6 days. The protein also showed a significant, dose dependent, toxicity towards fourth and fifth stadium larvae, with growth reduced by up to approximately 90% over a 4-day assay period compared to controls. Delivery of intact SFI1/GNA to the haemolymph in these insects was shown by western blotting; haemolymph samples from fusion-fed larvae contained a GNA-immunoreactive protein of the same molecular weight as the SFI1/GNA fusion. SFI1/GNA and similar fusion proteins offer a novel and effective approach for delivering haemolymph active toxins by oral administration, which could be used in crop protection by expression in transgenic plants.

  13. Observing Insects.

    Science.gov (United States)

    Arbel, Ilil

    1991-01-01

    Describes how to observe and study the fascinating world of insects in public parks, backyards, and gardens. Discusses the activities and habits of several common insects. Includes addresses for sources of beneficial insects, seeds, and plants. (nine references) (JJK)

  14. An economic comparison of biological and conventional control strategies for insect pests in cashew and mango plantations in Tanzania

    DEFF Research Database (Denmark)

    George, William Juma; Hella, Joseph; Esbjerg, Lars

    2013-01-01

    This study was undertaken to compare alternative methods of pest control for insect pests in order to determine which methods has the highest efficacy against insect pests and the least detrimental side effects, while maintaining production and profits. The analysis was based on the experimental...... treatment by Tsh. 504 989 and Tsh. 891 297 in cashew and mango plantations. The dominance and MRRanalyses shows that if cashew and mango growers change from conventional agricultural practices to weaver ants, they would earn MRR of 1621% which is above minimum acceptable rate of return (MARR) of 100%. The t...

  15. A cathepsin L-like proteinase is involved in moulting and metamorphosis in Helicoverpa armigera.

    Science.gov (United States)

    Wang, L-F; Chai, L-Q; He, H-J; Wang, Q; Wang, J-X; Zhao, X-F

    2010-02-01

    Holometabolous insects undergo larval moulting and metamorphosis within their life cycle. A cDNA encoding the cathepsin L-like proteinase Ha-cathL has been cloned from Helicoverpa armigera. It has a sequence of 1826 bp and encodes a 550-residue protein with a molecular mass of 63 kDa. Northern blot analysis indicated that Ha-cathL is specifically expressed in haemocytes, with increased expression during larval moulting and metamorphosis. In vivo experimentation revealed that Ha-cathL is up-regulated by 20-hydroxyecdysone. Meanwhile, in situ hybridization and immunocytochemistry revealed that Ha-cathL mRNA is mainly expressed in granulocytes and plasmatocytes. Knock down of cathepsin L by RNA interference results in larvae death before pupation or the formation of a chimeric pupa containing a larval head and thorax, abnormal wings and the pupal abdomen. The reason for this is that the affected haemocytes cannot become granulated, and therefore cannot participate in fat body remodelling and wing development. These facts suggest that Ha-cathL is involved in larval moulting and metamorphosis by participating in the functioning of haemocytes.

  16. Evaluation of Broiler Performance when fed insect-protected, control, or commercial varieties of dehulled Soybean Meal1.

    NARCIS (Netherlands)

    Kan, C.A.; Hartnell, G.F.

    2004-01-01

    We evaluated the nutritional value of broiler diets containing approximately 35% soybean meal from insect-protected soybean containing Cry1Ac protein, or from a similar nontransgenic control, or from 7 reference commercial soybean varieties. The feeding trial lasted 41 d, and each treatment consiste

  17. Evaluation of Broiler Performance when fed insect-protected, control, or commercial varieties of dehulled Soybean Meal1.

    NARCIS (Netherlands)

    Kan, C.A.; Hartnell, G.F.

    2004-01-01

    We evaluated the nutritional value of broiler diets containing approximately 35% soybean meal from insect-protected soybean containing Cry1Ac protein, or from a similar nontransgenic control, or from 7 reference commercial soybean varieties. The feeding trial lasted 41 d, and each treatment consiste

  18. Biological control of Otiorhynchus sulcatus by insect parasitic nematodes, Heterorhabditis spp., at low temperatures : a systems analytical approach

    NARCIS (Netherlands)

    Westerman, P.R.

    1997-01-01

    The black vine weevil, Otiorhynchus sulcatus, is an important pest in ornamentals and nursery stock in The Netherlands. The larvae, which feed on the root system of the plant, can be controlled by insect parasitic nematodes, Heterorhabditis.

  19. Gene disruption technologies have the potential to transform stored product insect pest control

    Science.gov (United States)

    Stored product insects feed on grains and processed commodities manufactured from grain post-harvest, reducing the nutritional value and contaminating food. Currently, the main defense against stored product insect pests is the pesticide fumigant phosphine. Phosphine is highly toxic to all animals, ...

  20. Seed treatments for the control of insects and diseases in sugarbeet

    Science.gov (United States)

    Insect feeding and vectoring of viruses cause serious problems in sugarbeet production worldwide. In order to ameliorate insect and disease problems on sugarbeet, two seed treatments, Poncho Beta (60 g a.i. clothianidin + 8 g a.i. beta-cyfluthrin/100,000 seed) and Cruiser Tef (60 g a.i. thiamethoxa...

  1. Role of plants and plant based products towards the control of insect pests and vectors:A novel review

    Institute of Scientific and Technical Information of China (English)

    Elumalai Kuppusamy; Saranya Jayakumar

    2016-01-01

    Insect pests bear harmful effects causing great loss to the agricultural crops, stored agricultural products and vector mosquitoes can cause diseases to human. Plants possess an array of vast repository of phytochemicals and have been used to cure many diseases and to control the infestation of insect pests from time immemorial. Plants are easily biodegradable and ecologically safe for treating on the stored or on the field crops against pests to prevent from further damage or loss of stored products or preventing human from mosquito bites, thus preventing the spreading of dreadful diseases such as chikungunya and malaria. Hence, this review can give a clear insecticidal, pesticidal and mosquitocidal property of several plants against the insect pests and vectors.

  2. Control of insects and mites in grain using a high temperature/short time (HTST) technique.

    Science.gov (United States)

    Mourier; Poulsen

    2000-07-01

    Wheat infested with grain mites (Acari) and Sitophilus granarius, and maize infested with Prostephanus truncatus, were exposed to hot air in a CIMBRIA HTST Microline toaster((R)). Inlet temperatures of the hot air were in the range of 150-750 degrees C decreasing to outlet temperatures in the range of 100-300 degrees C during the exposure period. A rotating drum, connected to a natural-gas burner was fed with grain which was in constant movement along the drum and thereby mixed thoroughly during the process. The capacity of the toaster was 1000 kg per hour.Complete control of grain mites and adult S. granarius in wheat was obtained with an inlet temperature of 300-350 degrees C and an average residence time in the drum of 6 s. More than 99% mortality was obtained for all stages of S. granarius with an inlet temperature of 300-350 degrees C and an average exposure period of 40 s. For control of P. truncatus in maize, an inlet temperature of 700 degrees C resulted in a complete disinfestation when the exposure time was 19 s.The reduction in grain moisture content was 0.5-1% at treatments giving 100% control. Germination tests indicate that it is possible to choose a combination of inlet temperatures and exposure periods which effectively kills mites and insects in small grains, without harming the functional properties of the grain.Economy of the method was considered to be competitive with fumigation using phosphine.

  3. A Stably Transgenic INA Enterobacter cloacae for Control of Insect Pests

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xin-jian; SUN Fu-zai; ZHAO Ting-chang; DING Ai-yun; TANG Chao-rong

    2003-01-01

    Using the minitransposon pMini-Tn5 and the ice-nucleation active (INA) gene of iceA, a suicide recombinant plasmid pTnice1 was constructed, which has the ability of broad-host-range conjugal mobilization and integration of iceA into chromosomal DNA of many gram-negative bacteria by Tn5 transposition.We used this plasmid to integrate the iceA into chromosomal DNA of Ent. cloacae and obtained the transgentic strain Enc1. 2022ina. In this transgenic Ent. cloacae, iceA would never be transferred elsewhere through transposition, and constantly expressed high ice nucleation activity even in the absence of antibiotic pressure.The transgenic strain was ingested by corn borer larvae. Over the 7 d after ingestion, the mean supercooling points (SCPs) of the larvae was about 10℃ higher than those of larvae treated with distilled water (control).The maintenance of these high SCPs was related to the stable gut colonization of transgenic strain. At 6th day post ingestion, the larva was exposed at - 5 or - 7℃ for 12 h, the percentages of larvae frozen to death were 85and 100%, respectively. In contrast, none or a small proportion of control larvae was frozen to death under the same conditions. Further studies demonstrated that this transgenic strain bore weak epiphytic ability.Therefore, this genetically engineered strain may be a promising candidate for control of insect pests in agricultural fields.

  4. Force encoding in stick insect legs delineates a reference frame for motor control.

    Science.gov (United States)

    Zill, Sasha N; Schmitz, Josef; Chaudhry, Sumaiya; Büschges, Ansgar

    2012-09-01

    The regulation of forces is integral to motor control. However, it is unclear how information from sense organs that detect forces at individual muscles or joints is incorporated into a frame of reference for motor control. Campaniform sensilla are receptors that monitor forces by cuticular strains. We studied how loads and muscle forces are encoded by trochanteral campaniform sensilla in stick insects. Forces were applied to the middle leg to emulate loading and/or muscle contractions. Selective sensory ablations limited activities recorded in the main leg nerve to specific receptor groups. The trochanteral campaniform sensilla consist of four discrete groups. We found that the dorsal groups (Groups 3 and 4) encoded force increases and decreases in the plane of movement of the coxo-trochanteral joint. Group 3 receptors discharged to increases in dorsal loading and decreases in ventral load. Group 4 showed the reverse directional sensitivities. Vigorous, directional responses also occurred to contractions of the trochanteral depressor muscle and to forces applied at the muscle insertion. All sensory discharges encoded the amplitude and rate of loading or muscle force. Stimulation of the receptors produced reflex effects in the depressor motoneurons that could reverse in sign during active movements. These data, in conjunction with findings of previous studies, support a model in which the trochanteral receptors function as an array that can detect forces in all directions relative to the intrinsic plane of leg movement. The array could provide requisite information about forces and simplify the control and adaptation of posture and walking.

  5. Transgenic plants for insect pest control: a forward looking scientific perspective.

    Science.gov (United States)

    Ferry, N; Edwards, M G; Gatehouse, J; Capell, T; Christou, P; Gatehouse, A M R

    2006-02-01

    One of the first successes of plant biotechnology has been the creation and commercialisation of transgenic crops exhibiting resistance to major insect pests. First generation products encompassed plants with single insecticidal Bt genes with resistance against major pests of corn and cotton. Modelling studies predicted that usefulness of these resistant plants would be short-lived, as a result of the ability of insects to develop resistance against single insecticidal gene products. However, despite such dire predictions no such collapse has taken place and the acreage of transgenic insect resistance crops has been increasing at a steady rate over the 9 years since the deployment of the first transgenic insect resistant plant. However, in order to assure durability and sustainability of resistance, novel strategies have been contemplated and are being developed. This perspective addresses a number of potentially useful strategies to assure the longevity of second and third generation insect resistant plants.

  6. Metamorphosis affects metal concentrations and isotopic signatures in a mayfly (Baetis tricaudatus): Implications for the aquatic-terrestrial transfer of metals

    Science.gov (United States)

    Wesner, Jeff S.; Walters, David; Schmidt, Travis S.; Kraus, Johanna M.; Stricker, Craig A.; Clements, William H.; Wolf, Ruth E.

    2017-01-01

    Insect metamorphosis often results in substantial chemical changes that can alter contaminant concentrations and fractionate isotopes. We exposed larval mayflies (Baetis tricaudatus) and their food (periphyton) to an aqueous zinc gradient (3-340 µg Zn/l) and measured zinc concentrations at different stages of metamorphosis: larval, subimago, and imago. We also measured changes in stable isotopes (δ15N and δ13C) in unexposed mayflies. Larval zinc concentrations were positively related to aqueous zinc, increasing 9-fold across the exposure gradient. Adult zinc concentrations were also positively related to aqueous zinc, but were 7-fold lower than larvae. This relationship varied according to adult substage and sex. Tissue concentrations in female imagoes were not related to exposure concentrations, but the converse was true for all other stage-by-sex combinations. Metamorphosis also increased δ15N by ~0.8‰, but not δ13C. Thus, the main effects of metamorphosis on insect chemistry were large declines in zinc concentrations coupled with increased δ15N signatures. For zinc, this change was largely consistent across the aqueous exposure gradient. However, differences among sexes and stages suggest that caution is warranted when using nitrogen isotopes or metal concentrations measured in one insect stage (e.g. larvae) to assess risk to wildlife that feed on subsequent life stages (e.g. adults).

  7. Generalized morphological transformation for describing nonhomotopic object metamorphosis

    Science.gov (United States)

    Li, Hua; Liu, Wen-Yu; Zhu, Yaoting; Zhu, Guang-Xi

    2001-09-01

    Metamorphosis or morphing is the process of continuously transforming one object into another, and is popular in computer animation, industrial design, and growth simulation. In this paper, a novel metamorphosis approach is presented for computing continuous shape transformation between polyhedral objects. Metamorphosis can be achieved by decomposing two objects into sets of individual convex sub- objects respectively and constructing the mapping relationship of subsets, this method can solve the metamorphosis problem of two non-homotopic objects (including concave objects and holey objects). The results of object metamorphosis are also discussed in this paper. The experiments show that this method can generate natural, high quality metamorphosis results with simple computation. This method can also be used in font composition and interpolation between two keyframes in 2D and 3D computer animation automatically.

  8. Biological Control of Tortricidae in Tea Fields in Japan Using Insect Viruses and Parasitoids

    Institute of Scientific and Technical Information of China (English)

    Madoka Nakai

    2009-01-01

    Tea is a perennial and evergreen plant. Cultivated tea trees provide a habitat for insect pests and their natural enemies. In Japan, granuloviruses (GVs) have successfully controlled two of the most important pests of tea, Adoxophyes honmai and Homona magnanima (Tortricidae: Lepidoptera). The GVs are produced in vivo and a single application sustains pesticidal efficacy throughout a year, which encompasses 4 to 5 discrete generations of both species. A. honmai and H. magnanima also have various natural enemies, especially hymenopteran parasitoids. Such resident natural enemies also play a role in reducing the pest density in virus-controlled fields, but the effect of virus infection on parasitoids sharing the same host larva has not been well studied. Survival of one of the major parasitoids ofA. honmai, Ascogaster reticulata (Braconidae: Hymenoptera), is reduced by virus infection of the host. Viruses, including GV and entomopoxvirus (EPV), and certain koinobiont endoparasitoids, including A. reticulata, are both known to regulate host endocrinology. However, the GV and EPV have distinct host regulation mechanisms, and consequently have different impacts on the survival of A. retuculata, when A. reticulata parasitizes a host that is infected with either GV or EPV. These additional effects on host regulation displayed by both viruses and parasitoids affect the outcome of virus-parasitoid interactions.

  9. Evaluation of insect associated and plant growth promoting fungi in the control of cabbage root flies.

    Science.gov (United States)

    Razinger, Jaka; Lutz, Matthias; Schroers, Hans-Josef; Urek, Gregor; Grunder, Jürg

    2014-08-01

    Delia radicum L. or cabbage maggot is an important pest for Brassicaceous crops. There are currently no registered chemical control agents for its control in Slovenia. Fungal control agents for cabbage maggot were therefore sought among nine rhizosphere-compatible and plant growth-promoting, soil-adapted, and entomopathogenic species to cabbage maggots and were assayed in in vitro and soil laboratory bioassays. In the in vitro tests, the conidial suspensions were applied directly to cabbage maggot eggs. The soil tests mimicked pathways of natural exposure of various insect life stages to the fungal strains. Conidial concentrations used in soil tests were comparable to economic rates for in-furrow application. The following fungi were tested: Trichoderma atroviride P. Karst. (2 isolates), Trichoderma koningiopsis Samuels, C. Suárez & H.C. Evans (1), Trichoderma gamsii Samuels & Druzhin. (3), Beauveria brongniartii (Saccardo) Petch (1), Beauveria bassiana (Balsamo-Crivelli) Vuillemin (2), Metarhizium robertsii J.F. Bisch., Rehner & Humber (1), Metarhizium anisopliae (Metschn.) Sorokin (4), Purpureocillium lilacinum (Thom) Luangsa-ard, Houbraken, Hywel-Jones & Samson (2), and Clonostachys solani f. nigrovirens (J.F.H. Beyma) Schroers (2). Abbott's corrected mortality in the in vitro tests ranged from 0.0 +/- 18.9 to 47.6 +/- 9.0% and in the soil test from 2.4 +/- 13.0 to 68.2 +/- 21.5%. Seven isolates (B. bassiana [isolate 1174], C. solani [1828], M. anisopliae [1154 and 1868], T. atroviride [1872], T. koningiopsis [1874], and T. gamsii [1876]) caused significant cabbage maggot mortality in either in vitro or soil tests. The importance of fungal ecology as a criterion during the screening of potential biological control agents is discussed.

  10. Metamorphosis of a butterfly-associated bacterial community.

    Science.gov (United States)

    Hammer, Tobin J; McMillan, W Owen; Fierer, Noah

    2014-01-01

    Butterflies are charismatic insects that have long been a focus of biological research. They are also habitats for microorganisms, yet these microbial symbionts are little-studied, despite their likely importance to butterfly ecology and evolution. In particular, the diversity and composition of the microbial communities inhabiting adult butterflies remain uncharacterized, and it is unknown how the larval (caterpillar) and adult microbiota compare. To address these knowledge gaps, we used Illumina sequencing of 16S rRNA genes from internal bacterial communities associated with multiple life stages of the neotropical butterfly Heliconius erato. We found that the leaf-chewing larvae and nectar- and pollen-feeding adults of H. erato contain markedly distinct bacterial communities, a pattern presumably rooted in their distinct diets. Larvae and adult butterflies host relatively small and similar numbers of bacterial phylotypes, but few are common to both stages. The larval microbiota clearly simplifies and reorganizes during metamorphosis; thus, structural changes in a butterfly's bacterial community parallel those in its own morphology. We furthermore identify specific bacterial taxa that may mediate larval and adult feeding biology in Heliconius and other butterflies. Although male and female Heliconius adults differ in reproductive physiology and degree of pollen feeding, bacterial communities associated with H. erato are not sexually dimorphic. Lastly, we show that captive and wild individuals host different microbiota, a finding that may have important implications for the relevance of experimental studies using captive butterflies.

  11. Pest control and resistance management through release of insects carrying a male-selecting transgene

    OpenAIRE

    2015-01-01

    Background Development and evaluation of new insect pest management tools is critical for overcoming over-reliance upon, and growing resistance to, synthetic, biological and plant-expressed insecticides. For transgenic crops expressing insecticidal proteins from the bacterium Bacillus thuringiensis (‘Bt crops’) emergence of resistance is slowed by maintaining a proportion of the crop as non-Bt varieties, which produce pest insects unselected for resistance. While this strategy has been largel...

  12. A flow control mechanism in wing flapping with stroke asymmetry during insect forward flight

    Institute of Scientific and Technical Information of China (English)

    Yongliang Yu; Binggang Tong

    2005-01-01

    A theoretical modeling approach as well as an unsteady analytical method is used to study aerodynamic characteristics of wing flapping with asymmetric stroke-cycles in connection with an oblique stroke plane during insect forward flight. It is revealed that the aerodynamic asymmetry between the downstroke and the upstroke due to stroke-asymmetrical flapping is a key to understand the flow physics of generation and modulation of the lift and the thrust. Predicted results for examples of given kinematics validate more specifically some viewpoints that the wing lift is more easily produced when the forward speed is higher and the thrust is harder, and the lift and the thrust are generated mainly during downstroke and upstroke, respectively. The effects of three controlling parameters, i.e. the angles of tilted stroke plane,the different downstroke duration ratios, and the different angles of attack in both down- and up-stroke, are further discussed. It is found that larger oblique angles of stroke planes generate larger thrust but smaller lift; larger downstroke duration ratios lead to larger thrust, while making little change in lift and input aerodynamic power; and again, a small increase of the angle of attack in downstroke or upstroke may cause remarkable changes in aerodynamic performance in the relevant stroke.

  13. Review of research on the insect pests of kenaf and their control in the Sudan.

    Science.gov (United States)

    Eldin, N S; El-Amin, E M

    1981-01-01

    Kenaf, Hibiscus cannabinus L., is grown in many parts of the Sudan as a fibre plant. During its various stages of growth, 17 different species of insects were detected, out of which only the cotton flea beetle Podagrica puncticollis Weise is of economic importance. The attack by this pest is most serious in the seedling stage; late sowings coupled with early light showers suffer the heaviest damage. In the leaves the beetles eat out round holes ('shot-hole effect'). The entire life cycle takes about 4 to 5 weeks, and about five generations are completed on the plant depending on the weather conditions. Cultural practices incorporating early sowing and eradication of the main host plants, Hibiscus esculentus and Abutilon spp., considerably reduce the size of the initial infestation. Chemicals tested as seed-dressing or sprays for the control of the beetle failed to give good results. However, granular insecticides showed a better performance and longer residual effect. Disyston 5G was effective for six weeks and also improved the general condition of the plants.

  14. Unusually long palindromes are abundant in mitochondrial control regions of insects and nematodes.

    Directory of Open Access Journals (Sweden)

    K P Arunkumar

    Full Text Available BACKGROUND: Palindromes are known to be involved in a variety of biological processes. In the present investigation we carried out a comprehensive analysis of palindromes in the mitochondrial control regions (CRs of several animal groups to study their frequency, distribution and architecture to gain insights into the origin of replication of mtDNA. METHODOLOGY/PRINCIPAL FINDINGS: Many species of Arthropoda, Nematoda, Mollusca and Annelida harbor palindromes and inverted repeats (IRs in their CRs. Lower animals like cnidarians and higher animal groups like chordates are almost devoid of palindromes and IRs. The study revealed that palindrome occurrence is positively correlated with the AT content of CRs, and that IRs are likely to give rise to longer palindromes. CONCLUSIONS/SIGNIFICANCE: The present study attempts to explain possible reasons and gives in silico evidence for absence of palindromes and IRs from CR of vertebrate mtDNA and acquisition and retention of the same in insects. Study of CRs of different animal phyla uncovered unique architecture of this locus, be it high abundance of long palindromes and IRs in CRs of Insecta and Nematoda, or short IRs of 10-20 nucleotides with a spacer region of 12-14 bases in subphylum Chelicerata, or nearly complete of absence of any long palindromes and IRs in Vertebrata, Cnidaria and Echinodermata.

  15. Trypsin inactivation by latex fabricated gold nanoparticles: A new strategy towards insect control.

    Science.gov (United States)

    Patil, Chandrashekhar D; Borase, Hemant P; Suryawanshi, Rahul K; Patil, Satish V

    2016-10-01

    Before applying nanotechnologies in biomedical and environmental areas it is advised to study interactions of nanoparticles and other nanomaterials with biomacromolecule present in living system. Moreover there is scarcity of reports on interactions between nanoparticles and biomaterials. In present report a rapid, ecofriendly method of fabricating stable gold nanoparticles (AuNPs) using latex of Jatropha curcas is reported for the first time. AuNPs found to have characteristic absorption maxima centered at 540nm, multiple irregular shapes with size range from 20 to 50nm and have crystalline nature. Latex fabricated AuNPs were found to inhibit catalytic potential of trypsin (a vital enzyme responsible for digestion, insecticide resistance and in several disease conditions). The interactions between AuNPs and trypsin were analyzed by UV-vis spectrophotometry and microwave plasma-atomic emission spectrometry which suggests formation of trypsin-AuNPs complex responsible for lowering catalytic activity of trypsin. Transmission electron microscopy, Fourier transform infrared spectroscopy and particle size distribution studies further confirm complex formation between trypsin and AuNPs. Diverse interactions of metal nanoparticles with proteins such as covalent interaction, electrostatic interactions and binding to SH group of amino acid may be the reasons behind inhibition of trypsin activity. In vivo studies on serum of several vectors and agriculturally important pests supported instrumental results on AuNPs induced trypsin inhibition. This work will bring a new research direction to explore eco-friendly nanoparticle in insect control via inhibition of enzyme catalytic potential.

  16. Unusually long palindromes are abundant in mitochondrial control regions of insects and nematodes.

    Science.gov (United States)

    Arunkumar, K P; Nagaraju, Javaregowda

    2006-12-20

    Palindromes are known to be involved in a variety of biological processes. In the present investigation we carried out a comprehensive analysis of palindromes in the mitochondrial control regions (CRs) of several animal groups to study their frequency, distribution and architecture to gain insights into the origin of replication of mtDNA. Many species of Arthropoda, Nematoda, Mollusca and Annelida harbor palindromes and inverted repeats (IRs) in their CRs. Lower animals like cnidarians and higher animal groups like chordates are almost devoid of palindromes and IRs. The study revealed that palindrome occurrence is positively correlated with the AT content of CRs, and that IRs are likely to give rise to longer palindromes. The present study attempts to explain possible reasons and gives in silico evidence for absence of palindromes and IRs from CR of vertebrate mtDNA and acquisition and retention of the same in insects. Study of CRs of different animal phyla uncovered unique architecture of this locus, be it high abundance of long palindromes and IRs in CRs of Insecta and Nematoda, or short IRs of 10-20 nucleotides with a spacer region of 12-14 bases in subphylum Chelicerata, or nearly complete of absence of any long palindromes and IRs in Vertebrata, Cnidaria and Echinodermata.

  17. Complex Outcomes from Insect and Weed Control with Transgenic Plants: Ecological Surprises?

    Directory of Open Access Journals (Sweden)

    Thomas Bøhn

    2017-09-01

    Full Text Available Agriculture is fundamental for human survival through food production and is performed in ecosystems that, while simplified, still operate along ecological principles and retain complexity. Agricultural plants are thus part of ecological systems, and interact in complex ways with the surrounding terrestrial, soil, and aquatic habitats. We discuss three case studies that demonstrate how agricultural solutions to pest and weed control, if they overlook important ecological and evolutionary factors, cause “surprises”: (i the fast emergence of resistance against the crop-inserted Bt-toxin in South Africa, (ii the ecological changes generated by Bt-cotton landscapes in China, and (iii the decline of the monarch butterfly, Danaus plexippus, in North America. The recognition that we work with complex systems is in itself important, as it should limit the belief in reductionist solutions. Agricultural practices lacking eco-evolutionary understanding result in “surprises” like resistance evolution both in weeds and pest insects, risking the reappearance of the “pesticide treadmill”—with increased use of toxic pesticides as the follow-up. We recommend prioritization of research that counteracts the tendencies of reductionist approaches. These may be beneficial on a short term, but with trade-off costs on a medium- to long-term. Such costs include loss of biodiversity, ecosystem services, long-term soil productivity, pollution, and reduced food quality.

  18. Post-embryonic transcriptomes of the prawn Macrobrachium rosenbergii: multigenic succession through metamorphosis.

    Directory of Open Access Journals (Sweden)

    Tomer Ventura

    Full Text Available Like many metazoans, the freshwater prawn Macrobrachium rosenbergii begins its post-embryonic life with a set of morphologically distinct planktonic larval stages, followed by a benthic post-larval stage during which the maturing organism differs from the larvae both ecologically and physiologically. Understanding of the molecular basis underlying morphogenesis in crustaceans is limited to the observation that methyl farnesoate, the non-epoxidated form of the insect juvenile hormone, acts as the active crustacean juvenoid. Molt steroids were also linked to morphogenesis and several other molecular pathways, such as Hedgehog and Wnt, are known to underlie morphogenesis in all metazoans examined and, as such, are thought to do the same in crustaceans. Using next generation sequencing, we deep-sequenced the transcriptomes of several larval and post-larval stages. De novo assembly, followed by bioinformatics analysis, revealed that many novel transcripts are over-expressed in either larvae- or post-larvae-stage prawn, shedding light on the molecular basis underlying M. rosenbergii metamorphosis. Fast larval molting rates and periodic morphological changes were reflected in over-expression of transcripts annotated to the cell cycle, DNA replication and morphogenic pathways (i.e., Hedgehog and Wnt. Further characterization of transcripts assigned to morphogenic pathways by real-time RT-PCR reconfirmed their over-expression in larvae, albeit with a more complex expression pattern when examined in the individual developmental stages. The expression level of an orthologue of cytochrome P450, 15A1, known to epoxidize methyl farnesoate in insects, was increased in the late larval and early post-larval stages, in accordance with the role of methyl farnesoate in crustacean metamorphosis. This study exemplifies the applicability of a high-throughput sequencing approach for studying complex traits, including metamorphosis, providing new insight into this

  19. Post-embryonic transcriptomes of the prawn Macrobrachium rosenbergii: multigenic succession through metamorphosis.

    Science.gov (United States)

    Ventura, Tomer; Manor, Rivka; Aflalo, Eliahu D; Chalifa-Caspi, Vered; Weil, Simy; Sharabi, Omri; Sagi, Amir

    2013-01-01

    Like many metazoans, the freshwater prawn Macrobrachium rosenbergii begins its post-embryonic life with a set of morphologically distinct planktonic larval stages, followed by a benthic post-larval stage during which the maturing organism differs from the larvae both ecologically and physiologically. Understanding of the molecular basis underlying morphogenesis in crustaceans is limited to the observation that methyl farnesoate, the non-epoxidated form of the insect juvenile hormone, acts as the active crustacean juvenoid. Molt steroids were also linked to morphogenesis and several other molecular pathways, such as Hedgehog and Wnt, are known to underlie morphogenesis in all metazoans examined and, as such, are thought to do the same in crustaceans. Using next generation sequencing, we deep-sequenced the transcriptomes of several larval and post-larval stages. De novo assembly, followed by bioinformatics analysis, revealed that many novel transcripts are over-expressed in either larvae- or post-larvae-stage prawn, shedding light on the molecular basis underlying M. rosenbergii metamorphosis. Fast larval molting rates and periodic morphological changes were reflected in over-expression of transcripts annotated to the cell cycle, DNA replication and morphogenic pathways (i.e., Hedgehog and Wnt). Further characterization of transcripts assigned to morphogenic pathways by real-time RT-PCR reconfirmed their over-expression in larvae, albeit with a more complex expression pattern when examined in the individual developmental stages. The expression level of an orthologue of cytochrome P450, 15A1, known to epoxidize methyl farnesoate in insects, was increased in the late larval and early post-larval stages, in accordance with the role of methyl farnesoate in crustacean metamorphosis. This study exemplifies the applicability of a high-throughput sequencing approach for studying complex traits, including metamorphosis, providing new insight into this unexplored area of

  20. Effect of Epinephrine on the Settlement and Metamorphosis of Manila Clam Larvae

    Institute of Scientific and Technical Information of China (English)

    LU Sumin; BAO Zhenmin; LIU Hui; FANG Jianguang

    2006-01-01

    Chemical inducement and DDRT-PCR (differential display reverse transcription PCR) are adopted to investigate the effect of epinephrine (EPI) on the settlement and metamorphosis of Manila clam larvae. Chemical inducement shows that EPI has an effect to some extent on the metamorphosis of Manila clam larvae at all concentrations and in all treatments designed. The most significant result of inducement is obtained at the concentration of 10-6 molL-1 and for 4 h. DDRT-PCR using six primer pairs shows that the gene expression pattern is quite different between EPI treatment and the control. Three hundred and forty-three amplification bands are obtained in total, among which, 67 (19.53%) are differentially appeared.Therefore, EPI has an effect on the gene expression of the eye spot larval Manila clam. It can be hypothesized that EPI is a settlement and metamorphosis inducer for Manila clam. EPI may lead to larvae settlement and metamorphosis by binding to the receptors on the membrane and then changing the gene expression of larvae cells.

  1. Can topical insect repellents reduce malaria? A cluster-randomised controlled trial of the insect repellent N,N-diethyl-m-toluamide (DEET in Lao PDR.

    Directory of Open Access Journals (Sweden)

    Vanessa Chen-Hussey

    Full Text Available BACKGROUND: Mosquito vectors of malaria in Southeast Asia readily feed outdoors making malaria control through indoor insecticides such as long-lasting insecticidal nets (LLINs and indoor residual spraying more difficult. Topical insect repellents may be able to protect users from outdoor biting, thereby providing additional protection above the current best practice of LLINs. METHODS AND FINDINGS: A double blind, household randomised, placebo-controlled trial of insect repellent to reduce malaria was carried out in southern Lao PDR to determine whether the use of repellent and long-lasting insecticidal nets (LLINs could reduce malaria more than LLINs alone. A total of 1,597 households, including 7,979 participants, were recruited in June 2009 and April 2010. Equal group allocation, stratified by village, was used to randomise 795 households to a 15% DEET lotion and the remainder were given a placebo lotion. Participants, field staff and data analysts were blinded to the group assignment until data analysis had been completed. All households received new LLINs. Participants were asked to apply their lotion to exposed skin every evening and sleep under the LLINs each night. Plasmodium falciparum and P. vivax cases were actively identified by monthly rapid diagnostic tests. Intention to treat analysis found no effect from the use of repellent on malaria incidence (hazard ratio: 1.00, 95% CI: 0.99-1.01, p = 0.868. A higher socio-economic score was found to significantly decrease malaria risk (hazard ratio: 0.72, 95% CI: 0.58-0.90, p = 0.004. Women were also found to have a reduced risk of infection (hazard ratio: 0.59, 95% CI: 0.37-0.92, p = 0.020. According to protocol analysis which excluded participants using the lotions less than 90% of the time found similar results with no effect from the use of repellent. CONCLUSIONS: This randomised controlled trial suggests that topical repellents are not a suitable intervention in addition to

  2. A preliminary identification of insect successive wave in Egypt on control and zinc phosphide-intoxicated animals in different seasons

    Directory of Open Access Journals (Sweden)

    Marah Mohammad Abd El-Bar

    2016-09-01

    Full Text Available The presented study aimed primarily to document a baseline data of the decay process of rabbits and guinea pigs and their associated arthropod fauna, which are placed in an urban city: El Abbassyia, Cairo Governorate, Egypt, during winter and summer seasons, and to compare these data with the corresponding figure for zinc phosphide-intoxicated carrions. Generally, control rabbits and control guinea pigs were faster in their decay comparing the corresponding figure of the zinc phosphide–intoxicated group. A delay in colonization of insects was noticed either in the winter season for both groups, or additionally for the zinc phosphide groups. The associated insect fauna was represented in 6 orders, 20 families, and 36 genera and species. Necrophagous arthropods that supported decomposition of carcasses were mainly of orders Diptera and Coleoptera. Calliphoridae was the first insect family that colonized the different carcasses. The mean numbers of control immature dipterous maggots and similarly, the control coleopteran larvae significantly exceeded the corresponding mean numbers for the zinc phosphide-intoxicated groups in both winter and summer seasons in either rabbits or guinea pig groups. Moreover, the mean numbers of dipterous maggots or coleopteran larvae of rabbits significantly surpassed the corresponding figures for guinea pigs in both seasons. This study may add as a reference for the succession wave arthropod fauna in Cairo Governorate in winter and summer seasons. Moreover, it is the first record of the arthropod successive wave on zinc phosphide–intoxicated remains.

  3. Coccophagus scutellaris (Hymenoptera: Aphelinidae): A Highly Effective Biological Control Agent of Soft Scale Insects (Hemiptera: Coccidae) in Egypt

    OpenAIRE

    Shaaban Abd-Rabou

    2011-01-01

    About 953000 individuals of the cosmopolitan parasitoid, Coccophagus scutellaris (Dalman) (Hymenoptera: Aphelinidae), were released and evaluated during 2009-2010 for the control of the following soft scale insects (Hemiptera: Coccidae) infesting the following economic crops in Egypt: Ceroplastes rusci on citrus in Beni Seuf, Ceroplastes floridensis Comstock on citrus in Gharbiya, Coccus hesperidum L. on guava in Giza, Pulvinaria floccifera (Westwood) on mango in Sharqiya, Pulvinaria psidii...

  4. A Southwide Rate Test of Azinphosmethyl (Guthion®) for Cone and Seed Insect Control In Loblolly Pine Seed Orchards

    Science.gov (United States)

    A.C. Mangini; L.R. Barber; R.S. Cameron; G.L. DeBarr; G.R. Hodge; J.B. Jett; W.L. Lowe; J.L. McConnell; J. Nord; J.W. Taylor

    1998-01-01

    A southwide efficiency test of reduced rates of azinphosmethyl (Guthion®) for control of seed and cone insects in loblolly pine seed orchards was conducted in 1992. In each of nine loblolly pine (Pinus taeda L.) seed orchards, an untreated (no protection) check and two of five possible rates of Guthion® (1.0, 1.5, 2.0, 2.5, or 3.0 lb ai/ac/...

  5. The microRNA toolkit of insects

    Science.gov (United States)

    Ylla, Guillem; Fromm, Bastian; Piulachs, Maria-Dolors; Belles, Xavier

    2016-01-01

    Is there a correlation between miRNA diversity and levels of organismic complexity? Exhibiting extraordinary levels of morphological and developmental complexity, insects are the most diverse animal class on earth. Their evolutionary success was in particular shaped by the innovation of holometabolan metamorphosis in endopterygotes. Previously, miRNA evolution had been linked to morphological complexity, but astonishing variation in the currently available miRNA complements of insects made this link unclear. To address this issue, we sequenced the miRNA complement of the hemimetabolan Blattella germanica and reannotated that of two other hemimetabolan species, Locusta migratoria and Acyrthosiphon pisum, and of four holometabolan species, Apis mellifera, Tribolium castaneum, Bombyx mori and Drosophila melanogaster. Our analyses show that the variation of insect miRNAs is an artefact mainly resulting from poor sampling and inaccurate miRNA annotation, and that insects share a conserved microRNA toolkit of 65 families exhibiting very low variation. For example, the evolutionary shift toward a complete metamorphosis was accompanied only by the acquisition of three and the loss of one miRNA families. PMID:27883064

  6. The Role of Unlearning in Metamorphosis and Strategic Resilience

    Science.gov (United States)

    Morais-Storz, Marta; Nguyen, Nhien

    2017-01-01

    Purpose: This paper aims to conceptualize what it means to be resilient in the face of our current reality of indisputable turbulence and uncertainty, suggest that continual metamorphosis is key to resilience, demonstrate the role of unlearning in that metamorphosis and suggest that problem formulation is a key deliberate mechanism of driving…

  7. The novel ABC transporter ABCH1 is a potential target for RNAi-based insect pest control and resistance management.

    Science.gov (United States)

    Guo, Zhaojiang; Kang, Shi; Zhu, Xun; Xia, Jixing; Wu, Qingjun; Wang, Shaoli; Xie, Wen; Zhang, Youjun

    2015-09-03

    Insect pests cause serious crop damage and develop high-level resistance to chemical insecticides and Bacillus thuringiensis (Bt) insecticidal Cry toxins. A new promising approach for controlling them and overcoming this resistance is RNA interference (RNAi). The RNAi-based insect control strategy depends on the selection of suitable target genes. In this study, we cloned and characterized a novel ABC transporter gene PxABCH1 in diamondback moth, Plutella xylostella (L.). Phylogenetic analysis showed that PxABCH1 is closely related to ABCA and ABCG subfamily members. Spatial-temporal expression detection revealed that PxABCH1 was expressed in all tissues and developmental stages, and highest expressed in head and male adult. Midgut sequence variation and expression analyses of PxABCH1 in all the susceptible and Bt-resistant P. xylostella strains and the functional analysis by sublethal RNAi demonstrated that Cry1Ac resistance was independent of this gene. Silencing of PxABCH1 by a relatively high dose of dsRNA dramatically reduced its expression and resulted in larval and pupal lethal phenotypes in both susceptible and Cry1Ac-resistant P. xylostella strains. To our knowledge, this study provides the first insight into ABCH1 in lepidopterans and reveals it as an excellent target for RNAi-based insect pest control and resistance management.

  8. Accessory gland as a site for prothoracicotropic hormone controlled ecdysone synthesis in adult male insects

    DEFF Research Database (Denmark)

    Hentze, Julie Lilith; Møller, Morten Erik; Jørgensen, Anne

    2013-01-01

    Insect steroid hormones (ecdysteroids) are important for female reproduction in many insect species and are required for the initiation and coordination of vital developmental processes. Ecdysteroids are also important for adult male physiology and behavior, but their exact function and site...... of synthesis remains unclear, although previous studies suggest that the reproductive system may be their source. We have examined expression profiles of the ecdysteroidogenic Halloween genes, during development and in adults of the flour beetle Tribolium castaneum. Genes required for the biosynthesis...... melanogaster and the gene for its receptor Torso seems to be expressed specifically in the accessory glands of males. The composite results suggest strongly that the accessory glands of adult male insects are the main source of E, but not 20E. The finding of a possible male-specific source of E raises...

  9. Metamorphosis of the invasive ascidian Ciona savignyi: environmental variables and chemical exposure

    Directory of Open Access Journals (Sweden)

    Patrick L. Cahill

    2016-02-01

    Full Text Available In this study, the effects of environmental variables on larval metamorphosis of the solitary ascidian Ciona savignyi were investigated in a laboratory setting. The progression of metamorphic changes were tracked under various temperature, photoperiod, substrate, larval density, and vessel size regimes. Metamorphosis was maximised at 18 °C, 12:12 h subdued light:dark, smooth polystyrene substrate, and 10 larvae mL−1 in a twelve-well tissue culture plate. Eliminating the air-water interface by filling culture vessels to capacity further increased the proportion of metamorphosed larvae; 87 ± 5% of larvae completed metamorphosis within 5 days compared to 45 ± 5% in control wells. The effects of the reference antifouling compounds polygodial, portimine, oroidin, chlorothalonil, and tolylfluanid on C. savignyi were subsequently determined, highlighting (1 the sensitivity of C. savignyi metamorphosis to chemical exposure and (2 the potential to use C. savignyi larvae to screen for bioactivity in an optimised laboratory setting. The compounds were bioactive in the low ng mL−1 to high µg mL−1 range. Polygodial was chosen for additional investigations, where it was shown that mean reductions in the proportions of larvae reaching stage E were highly repeatable both within (repeatability = 14 ± 9% and between (intermediate precision = 17 ± 3% independent experiments. An environmental extract had no effect on the larvae but exposing larvae to both the extract and polygodial reduced potency relative to polygodial alone. This change in potency stresses the need for caution when working with complex samples, as is routinely implemented when isolating natural compounds from their biological source. Overall, the outcomes of this study highlight the sensitivity of C. savignyi metamorphosis to environmental variations and chemical exposure.

  10. Metamorphosis in balanomorphan, pedunculated, and parasitic barnacles

    DEFF Research Database (Denmark)

    Høeg, Jens Thorvald; Maruzzo, Diego; Okano, Keiju;

    2012-01-01

    carapace in Lepas. In M. rosa, the free juvenile retains its very thin cuticle and flexible shape for some time, and shell plates do not appear until sometime after shedding of the cypris cuticles. In Sacculina carcini, the cypris settles at the base of a seta on the host crab and remains quiescent...... and aligned at an angle of ~60° to the crab's cuticle. The metamorphosis involves two molts, resulting in the formation of an elongated kentrogon stage with a hollow injection stylet. Due to the orientation of the cyprid, the stylet points directly towards the base of the crab's seta. Approximately 60¿h after...

  11. Potency of insect-specific scorpion toxins on mosquito control using Bacillus thuringiensis Cry4Aa.

    Science.gov (United States)

    Matsumoto, Riku; Shimizu, Yoshitaka; Howlader, Mohammad Tofazzal Hossain; Namba, Maho; Iwamoto, Aya; Sakai, Hiroshi; Hayakawa, Tohru

    2014-06-01

    Two insect-specific scorpion toxins, BjαIT and AahIT were produced as alkali-soluble protein inclusions in Escherichia coli. The inclusion bodies themselves exhibited no toxicity against Culex pipiens larvae. However, coadministration with Cry4Aa toxin enhanced the mosquitocidal activity by 2-3 fold. Insect-specific scorpion toxins can be good supplements for Cry toxin-based bioinsecticides. Copyright © 2013 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  12. The POU factor ventral veins lacking/Drifter directs the timing of metamorphosis through ecdysteroid and juvenile hormone signaling.

    Directory of Open Access Journals (Sweden)

    CeCe Cheng

    2014-06-01

    Full Text Available Although endocrine changes are known to modulate the timing of major developmental transitions, the genetic mechanisms underlying these changes remain poorly understood. In insects, two developmental hormones, juvenile hormone (JH and ecdysteroids, are coordinated with each other to induce developmental changes associated with metamorphosis. However, the regulation underlying the coordination of JH and ecdysteroid synthesis remains elusive. Here, we examined the function of a homolog of the vertebrate POU domain protein, Ventral veins lacking (Vvl/Drifter, in regulating both of these hormonal pathways in the red flour beetle, Tribolium castaneum (Tenebrionidae. RNA interference-mediated silencing of vvl expression led to both precocious metamorphosis and inhibition of molting in the larva. Ectopic application of a JH analog on vvl knockdown larvae delayed the onset of metamorphosis and led to a prolonged larval stage, indicating that Vvl acts upstream of JH signaling. Accordingly, vvl knockdown also reduced the expression of a JH biosynthesis gene, JH acid methyltransferase 3 (jhamt3. In addition, ecdysone titer and the expression of the ecdysone response gene, hormone receptor 3 (HR3, were reduced in vvl knockdown larvae. The expression of the ecdysone biosynthesis gene phantom (phm and spook (spo were reduced in vvl knockdown larvae in the anterior and posterior halves, respectively, indicating that Vvl might influence ecdysone biosynthesis in both the prothoracic gland and additional endocrine sources. Injection of 20-hydroxyecdysone (20E into vvl knockdown larvae could restore the expression of HR3 although molting was never restored. These findings suggest that Vvl coordinates both JH and ecdysteroid biosynthesis as well as molting behavior to influence molting and the timing of metamorphosis. Thus, in both vertebrates and insects, POU factors modulate the production of major neuroendocrine regulators during sexual maturation.

  13. Edible Insects

    NARCIS (Netherlands)

    Huis, van A.; Dunkel, F.V.

    2016-01-01

    The interest in insects as human food in the Western world is increasingly considered as a viable alternative to other protein sources. In tropical countries it is common practice and about 2000 insect species are eaten. Insects emit low levels of greenhouse gases, need little water, and require

  14. Nanoinsecticidas: Nuevas perspectivas para el control de plagas Nanoinsecticides: New perspectives on insect pest control

    Directory of Open Access Journals (Sweden)

    Teodoro Stadler

    2010-12-01

    Full Text Available La agricultura de bajo impacto ambiental demanda nuevos pesticidas que deben ajustarse a las exigentes normativas internacionales. Parte de la búsqueda de nuevos productos bio-racionales se desarrolla por fuera del marco de la síntesis orgánica, explorando diferentes sustancias de origen natural como extractos vegetales, aceites insecticidas e insecticidas inorgánicos. Los polvos insecticidas representan el grupo más antiguo de sustancias utilizadas por el hombre para el control de plagas, cuya eficacia se basa principalmente en fenómenos físicos. Con el advenimiento de los insecticidas de síntesis, los polvos insecticidas fueron relegados por casi cinco décadas a la función de carriers de principios activos dentro de los insecticidas formulados. Con el desarrollo del caolín hidrófobo en la década de los 90´, los polvos inorgánicos resurgieron como insecticidas "per se", y, recientemente, a partir del descubrimiento de los nanoinsecticidas, afloran nuevas alternativas para expandir el espectro de aplicaciones de los polvos inorgánicos. El desarrollo y registro de nuevos productos a partir de nanomateriales manufacturados se basa en el paradigma "lo mismo pero diferente", ya que éstos difieren de las sustancias con idéntica estructura y composición química respecto de algunas propiedades como reactividad,área especifica, efectos cuánticos, carga eléctrica, etc. Estas sustancias con nuevas propiedades también se destacan como herramientas muy prometedoras para la protección de cultivos y la producción de alimentos y abren nuevas fronteras para el manejo de plagas con nanoinsecticidas. La alúmina nanoestructurada exhibe varias de las propiedades del insecticida ideal, ya que se trata de un producto natural desde el punto de vista químico, no reactivo, económico, con reducidas probabilidades de provocar resistencia en los insectos y su eficacia es mayor que la de otros polvos insecticidas como el caolín o la tierra de

  15. Microbial control of wood-boring insects attacking forest and shade trees

    Science.gov (United States)

    Ann E. Hajek; Leah S. Bauer

    2007-01-01

    Wood-boring insect pests that feed on the bark, phloem, or xylem (wood) of living trees pose unique management challenges because their immature stages live in cryptic, often inaccessible, habitats within host trees. The eggs of wood borers are laid in or on tree trunks, branches, terminal shoots, or roots. After the eggs hatch, neonates tunnel in and feed on internal...

  16. Low cost production of nematodes for biological control of insect pests

    Science.gov (United States)

    Entomopathogenic nematodes are produced in two ways: in artificial media using liquid or solid fermentation methods (in vitro) or by mass producing insect hosts to be artificially exposed to mass infection by nematodes (in vivo). The yellow mealworm (Tenebrio molitor) is a good host for in vivo nema...

  17. Transitions in insect respiratory patterns are controlled by changes in metabolic rate.

    Science.gov (United States)

    Contreras, H L; Bradley, T J

    2010-05-01

    We examined the respiratory patterns of Rhodnius prolixus and Gromphadorhina portentosa as metabolic rates varied with temperature to determine whether insects transition from discontinuous (DGC), cyclical and continuous respiration as a response to increasing aerobic demand. Using flow through respirometry we: (1) determined the effects of temperature on metabolic rate; (2) objectively defined periods of spiracular closure; (3) observed whether there was a correlation between metabolic rate and length of spiracular closure. At low temperatures both species exhibit lengthy periods of spiracular closure reflecting a discontinuous respiratory pattern. As metabolic rate increased, periods of spiracular closure decreased and insects displayed a more cyclical pattern of respiration. As metabolic rates increased even further under the highest experimental temperatures, periods of spiracular closure decreased even more and a continuous respiratory pattern was employed by both species. Our results suggest that the three described respiratory patterns in insects are not distinct but are instead a continuum of respiratory responses driven by the metabolic demand experienced by the insect.

  18. Insects, vegetation, and the control of laughing gulls (Larus atricilla) at Kennedy International Airport, New York

    Science.gov (United States)

    Buckley, P.A.; McCarthy, M.

    1994-01-01

    1. In response to a purported 'bird-strike problem' at J.F. Kennedy International Airport in New York City, we examined short (5 cm) and long (45 cm) grass heights as gull deterrents, in a randomized-block experiment. 2. Vegetative cover, numbers of adult insects and of larval beetles (suspected on-airport food of the gulls) were sampled in the six-block, 36-plot study area, as well as gut contents of adult and downy young gulls in the immediately adjacent colony in the Jamaica Bay Wildlife Refuge. 3. We found that (i) Oriental beetle larvae were the most numerous and concentrated in one experimental block; (ii) beetle larvae numbers were uncorrelated with grass height; (iii) adult beetles were also uncorrelated with grass height; (iv) laughing gulls were distributed across blocks irrespective of percentage cover; (v) within blocks, laughing gulls were selecting short grass and avoiding long grass plots; (vi) laughing gull numbers were positively associated with numbers of Oriental beetle larvae; (vii) adult laughing gulls on the airport were eating lower-nutrition food of terrestrial origin (74-83% adult beetles, mostly Oriental plus green June and ground beetles); (viii) on the other hand, gull chicks in the adjacent breeding colony were being fed more easily digested, higher-protein food of marine origin (86-88% fishes, crustacea and molluscs); (ix) laughing gulls on the airport were taking their adult beetles only in short-grass plots, ignoring large numbers in adjacent long grass; (x) during the summer, on-airport gulls shifted from performing largely maintenance activities on pavement to feeding actively for beetles on newly mown short grass, the change coinciding with adult beetle emergence; (xi) standing water on the airport attracted significantly more gulls than dry areas all summer long. 4. We recommend a series of ecologically compatible, but aggressive habitat management actions for controlling laughing gulls on Kennedy Airport by rendering the airport

  19. A Sterile Insect Technique (S.I.T.) Study Project to control Medfly in a Southern region of Italy

    Energy Technology Data Exchange (ETDEWEB)

    Tata, A.; Cirio, U.; Balducci, R. [ENEA, Centro Ricerche Casaccia, Rome (Italy). Dipt. Innovazione

    1997-12-01

    Since 1967 the National Agency for New Technology, Energy and the Environment (ENEA) namely the main Italian governmental technological research organization, is carrying out R and D programmes and demonstrative projects aimed to set up S.I.T. (Sterile Insect Technique) processes. In the framework of a world-wide growing interest concerning pest control technology, the National Agency for New Technology, Energy and the Environment (ENEA) developed a very large industrial project aimed to control Medfly (Ceratitis capitata Wied.) with reference to fruit crops situation in Sicily region (Southern of Italy) through the production and spreading of over 250 million sterile flies per week.

  20. Experimentally induced metamorphosis in axolotls reduces regenerative rate and fidelity

    Science.gov (United States)

    Stier, Adrian C.; Michonneau, François; Smith, Matthew D.; Pasch, Bret; Maden, Malcolm

    2014-01-01

    Abstract While most tetrapods are unable to regenerate severed body parts, amphibians display a remarkable ability to regenerate an array of structures. Frogs can regenerate appendages as larva, but they lose this ability around metamorphosis. In contrast, salamanders regenerate appendages as larva, juveniles, and adults. However, the extent to which fundamental traits (e.g., metamorphosis, body size, aging, etc.) restrict regenerative ability remains contentious. Here we utilize the ability of normally paedomorphic adult axolotls (Ambystoma mexicanum) to undergo induced metamorphosis by thyroxine exposure to test how metamorphosis and body size affects regeneration in age‐matched paedomorphic and metamorphic individuals. We show that body size does not affect regeneration in adult axolotls, but metamorphosis causes a twofold reduction in regeneration rate, and lead to carpal and digit malformations. Furthermore, we find evidence that metamorphic blastemal cells may take longer to traverse the cell cycle and display a lower proliferative rate. This study identifies the axolotl as a powerful system to study how metamorphosis restricts regeneration independently of developmental stage, body size, and age; and more broadly how metamorphosis affects tissue‐specific changes. PMID:27499857

  1. IAEA/FAO interregional training course on use of radiation in insect control and entomology with special emphasis on the sterile insect technique. Final report, May 4--June 15, 1994

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-12-31

    The principal focus of the course was the application of Radiation in Entomology to achieve Area Wide Pest Suppression or Eradication. To achieve this objective formal lectures, discussion groups, laboratory exercises and field trips were held covering the details of: (1) principles, programs and research of all aspects of the Sterile Insect Technique; (2) insect biology and control; (3) integrated pest management; (4) population dynamics and models related to the development of SIT and insect population suppression; (5) fundamentals of computers for helping in development of SIT; (6) the importance of economic considerations in formulating area wide pest management programs. The course included tours of local laboratories of the University, USDA, and the State Division of Plant Industry (DPI), and a site visit to a citrus production area in which the pest-free zone concept of pest management for fruit export is utilized.

  2. A biological micro actuator: graded and closed-loop control of insect leg motion by electrical stimulation of muscles.

    Science.gov (United States)

    Cao, Feng; Zhang, Chao; Vo Doan, Tat Thang; Li, Yao; Sangi, Daniyal Haider; Koh, Jie Sheng; Huynh, Ngoc Anh; Bin Aziz, Mohamed Fareez; Choo, Hao Yu; Ikeda, Kazuo; Abbeel, Pieter; Maharbiz, Michel M; Sato, Hirotaka

    2014-01-01

    In this study, a biological microactuator was demonstrated by closed-loop motion control of the front leg of an insect (Mecynorrhina torquata, beetle) via electrical stimulation of the leg muscles. The three antagonistic pairs of muscle groups in the front leg enabled the actuator to have three degrees of freedom: protraction/retraction, levation/depression, and extension/flexion. We observed that the threshold amplitude (voltage) required to elicit leg motions was approximately 1.0 V; thus, we fixed the stimulation amplitude at 1.5 V to ensure a muscle response. The leg motions were finely graded by alternation of the stimulation frequencies: higher stimulation frequencies elicited larger leg angular displacement. A closed-loop control system was then developed, where the stimulation frequency was the manipulated variable for leg-muscle stimulation (output from the final control element to the leg muscle) and the angular displacement of the leg motion was the system response. This closed-loop control system, with an optimized proportional gain and update time, regulated the leg to set at predetermined angular positions. The average electrical stimulation power consumption per muscle group was 148 µW. These findings related to and demonstrations of the leg motion control offer promise for the future development of a reliable, low-power, biological legged machine (i.e., an insect-machine hybrid legged robot).

  3. A biological micro actuator: graded and closed-loop control of insect leg motion by electrical stimulation of muscles.

    Directory of Open Access Journals (Sweden)

    Feng Cao

    Full Text Available In this study, a biological microactuator was demonstrated by closed-loop motion control of the front leg of an insect (Mecynorrhina torquata, beetle via electrical stimulation of the leg muscles. The three antagonistic pairs of muscle groups in the front leg enabled the actuator to have three degrees of freedom: protraction/retraction, levation/depression, and extension/flexion. We observed that the threshold amplitude (voltage required to elicit leg motions was approximately 1.0 V; thus, we fixed the stimulation amplitude at 1.5 V to ensure a muscle response. The leg motions were finely graded by alternation of the stimulation frequencies: higher stimulation frequencies elicited larger leg angular displacement. A closed-loop control system was then developed, where the stimulation frequency was the manipulated variable for leg-muscle stimulation (output from the final control element to the leg muscle and the angular displacement of the leg motion was the system response. This closed-loop control system, with an optimized proportional gain and update time, regulated the leg to set at predetermined angular positions. The average electrical stimulation power consumption per muscle group was 148 µW. These findings related to and demonstrations of the leg motion control offer promise for the future development of a reliable, low-power, biological legged machine (i.e., an insect-machine hybrid legged robot.

  4. Insect parapheromones in olfaction research and semiochemical-based pest control strategies.

    Science.gov (United States)

    Renou, M; Guerrero, A

    2000-01-01

    The possibility of disrupting the chemical communication of insect pests has initiated the development of new semiochemicals, parapheromones, which are anthropogenic compounds structurally related to natural pheromone components. Modification at the chain and/or at the polar group, isosteric replacements, halogenation or introduction of labeled atoms have been the most common modifications of the pheromone structure. Parapheromones have shown a large variety of effects, and accordingly have been called agonists, pheromone mimics, synergists and hyperagonists, or else pheromone antagonists, antipheromones and inhibitors. Pheromone analogues have been used in quantitative structure-activity relationship studies of insect olfaction, and from a practical point of view they can replace pheromones when these are costly to prepare or unstable under field conditions.

  5. Exogenous stress hormones alter energetic and nutrient costs of development and metamorphosis.

    Science.gov (United States)

    Kirschman, Lucas J; McCue, Marshall D; Boyles, Justin G; Warne, Robin W

    2017-07-20

    Variation in environmental conditions during larval life stages can shape development during critical windows and have lasting effects on the adult organism. Changes in larval developmental rates in response to environmental conditions, for example, can trade-off with growth to determine body size and condition at metamorphosis, which can affect adult survival and fecundity. However, it is unclear how use of energy and nutrients shape trade-offs across life stage transitions because no studies have quantified these costs of larval development and metamorphosis. We used an experimental approach to manipulate physiological stress in larval amphibians, along with respirometry and (13)C-breath testing to quantify the energetic and nutritional costs of development and metamorphosis. Central to larval developmental responses to environmental conditions is the hypothalamus pituitary-adrenal/interrenal (HPA/I) axis, which regulates development, as well as energy homeostasis and stress responses across many taxa. Given these pleiotropic effects of HPA/I activity, manipulation of the HPA/I may provide insight into costs of metamorphosis. We measured the energetic and nutritional costs across the entire larval period and metamorphosis in a larval amphibian exposed to exogenous glucocorticoid (GC) hormones- the primary hormone secreted by the HPA/I axis. We measured metabolic rates and dry mass across larval ontogeny, and quantified lipid stores and nutrient oxidation via (13)C-breath testing during metamorphosis, under control and GC-exposed conditions. Changes in dry mass match metamorphic states previously reported in the literature, but dynamics of metabolism were influenced by the transition from aquatic to terrestrial respiration. GC-treated larvae had lower dry mass, fat stores, and higher oxygen consumption during stages where controls were conserving energy. GC-treated larvae also oxidized greater amounts of (13)C-labelled protein stores. These results provide

  6. Fossil evidence for key innovations in the evolution of insect diversity.

    Science.gov (United States)

    Nicholson, David B; Ross, Andrew J; Mayhew, Peter J

    2014-10-22

    Explaining the taxonomic richness of the insects, comprising over half of all described species, is a major challenge in evolutionary biology. Previously, several evolutionary novelties (key innovations) have been posited to contribute to that richness, including the insect bauplan, wings, wing folding and complete metamorphosis, but evidence over their relative importance and modes of action is sparse and equivocal. Here, a new dataset on the first and last occurrences of fossil hexapod (insects and close relatives) families is used to show that basal families of winged insects (Palaeoptera, e.g. dragonflies) show higher origination and extinction rates in the fossil record than basal wingless groups (Apterygota, e.g. silverfish). Origination and extinction rates were maintained at levels similar to Palaeoptera in the more derived Polyneoptera (e.g. cockroaches) and Paraneoptera (e.g. true bugs), but extinction rates subsequently reduced in the very rich group of insects with complete metamorphosis (Holometabola, e.g. beetles). Holometabola show evidence of a recent slow-down in their high net diversification rate, whereas other winged taxa continue to diversify at constant but low rates. These data suggest that wings and complete metamorphosis have had the most effect on family-level insect macroevolution, and point to specific mechanisms by which they have influenced insect diversity through time. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  7. Current status and future challenges for controlling malaria with the sterile insect technique: technical and social perspectives.

    Science.gov (United States)

    Oliva, Clelia F; Vreysen, Marc J B; Dupé, Sandrine; Lees, Rosemary S; Gilles, Jeremie R L; Gouagna, Louis-Clement; Chhem, Rethy

    2014-04-01

    The intolerable burden of malaria, when faced with high levels of drug resistance, increasing insecticide resistance and meagre resources at the national level, remains a great public health challenge to governments and the research/control community. Efficient control methods against the vectors of malaria are desperately needed. Control strategies for malaria that integrate the transfer of sterile sperm by released males to wild virgin females with other control tactics are currently being developed, and optimised mass-rearing, irradiation and release techniques are being validated in several field sites. However, the success of this strategy as part of wider pest control or health management programmes strongly depends on gaining public understanding and acceptance. Here we attempt to review what progress has been made and the remaining challenges surrounding the use of the sterile insect technique against malaria from technical and social perspectives. Copyright © 2013 International Atomic Energy Agency 2013. Published by Elsevier B.V. All rights reserved.

  8. Beneficial Insects: Beetles

    OpenAIRE

    Hodgson, Erin W.; Patterson, Ron

    2007-01-01

    There are many beneficial beetles in Utah besides lady beetles or ladybugs. Beetles can significantly reduce common insect and weed problems and in some cases eliminate the need for chemical control. Examples of beneficial beetles include: ground beetles, rove beetles, tiger beetles and tortoise beetles. Many of these beetles are native to Utah, while others have been purposely introduced to help control damage from exotic insect and weed pests.

  9. Hox genes require homothorax and extradenticle for body wall identity specification but not for appendage identity specification during metamorphosis of Tribolium castaneum.

    Science.gov (United States)

    Smith, Frank W; Jockusch, Elizabeth L

    2014-11-01

    The establishment of segment identity is a key developmental process that allows for divergence along the anteroposterior body axis in arthropods. In Drosophila, the identity of a segment is determined by the complement of Hox genes it expresses. In many contexts, Hox transcription factors require the protein products of extradenticle (exd) and homothorax (hth) as cofactors to perform their identity specification functions. In holometabolous insects, segment identity may be specified twice, during embryogenesis and metamorphosis. To glean insight into the relationship between embryonic and metamorphic segmental identity specification, we have compared these processes in the flour beetle Tribolium castaneum, which develops ventral appendages during embryogenesis that later metamorphose into adult appendages with distinct morphologies. At metamorphosis, comparisons of RNAi phenotypes indicate that Hox genes function jointly with Tc-hth and Tc-exd to specify several region-specific aspects of the adult body wall. On the other hand, Hox genes specify appendage identities along the anteroposterior axis independently of Tc-hth/Tc-exd and Tc-hth/Tc-exd specify proximal vs. distal identity within appendages independently of Hox genes during this stage. During embryogenesis, Tc-hth and Tc-exd play a broad role in the segmentation process and are required for specification of body wall identities in the thorax; however, contrasting with results from other species, we did not obtain homeotic transformations of embryonic appendages in response to Tc-hth or Tc-exd RNAi. In general, the homeotic effects of interference with the function of Hox genes and Tc-hth/Tc-exd during metamorphosis did not match predictions based on embryonic roles of these genes. Comparing metamorphic patterning in T. castaneum to embryonic and post-embryonic development in hemimetabolous insects suggests that holometabolous metamorphosis combines patterning processes of both late embryogenesis and

  10. Involvement of a novel p38 mitogen-activated protein kinase in larval metamorphosis of the polychaete Hydroides elegans (Haswell)

    KAUST Repository

    Wang, Hao

    2010-04-19

    Hydroides elegans is a common marine fouling organism in most tropical and subtropical waters. The life cycle of H. elegans includes a planktonic larval stage in which swimming larvae normally take 5 days to attain competency to settle. Larval metamorphosis marks the beginning of its benthic life; however, the endogenous molecular mechanisms that regulate metamorphosis remain largely unknown. In this study, a PCR-based suppressive subtractive hybridization (SSH) library was constructed to screen the genes expressed in competent larvae but not in precompetent larvae. Among the transcripts isolated from the library, 21 significantly matched sequences in the GenBank. Many of these isolated transcripts have putative roles in the reactive oxygen species (ROS) signal transduction pathway or in response to ROS stress. A putative novel p38 mitogen-activated protein kinase (MAPK), which was also isolated with SSH screen, was then cloned and characterized. The MAPK inhibitors assay showed that both p38 MAPK inhibitors SB202190 and SB203580 effectively inhibited the biofilm-induced metamorphosis of H. elegans. A cell stressors assay showed that H2O2 effectively induced larval metamorphosis of H. elegans, but the inductivity of H2O2 was also inhibited by both SB inhibitors. The catalase assay showed that the catalase could effetely inhibit H. elegans larvae from responding to inductive biofilm. These results showed that the p38 MAPK-dependent pathway plays critical role in controlling larval metamorphosis of the marine polychaete H. elegans, and the reactive oxygen radicals produced by biofilm could be the cue inducing larval metamorphosis. © 2010 Wiley-Liss, Inc.

  11. Reduced risk insecticides to control scale insects and protect natural enemies in the production and maintenance of urban landscape plants.

    Science.gov (United States)

    Frank, Steven D

    2012-04-01

    Armored scale insects are among the most difficult to manage and economically important arthropod pests in the production and maintenance of urban landscape plants. This is because of morphological traits that protect them from contact insecticides. I compared initial and season-long control of euonymus scale, Unaspis euonymi Comstock (Hemiptera: Diaspidae), by reduced-risk insecticides (insect growth regulators [IGRs], neonicotinoids, spirotetramat) to determine if they controlled scale as well as more toxic insecticides such as the organophosphate, acephate, and pyrethroid, bifenthrin. I also evaluated how these insecticides affected natural enemy abundance on experimental plants and survival when exposed to insecticide residue. All insecticides tested reduced first generation euonymus scale abundance. In 2009, reinfestation by second generation euonymus scale was highest on plants treated with acetamiprid and granular dinotefuran. In 2010, systemic neonicotinoids and spirotetramat prevented cottony cushion scale infestation 133 d after treatment whereas scale readily infested plants treated with bifenthrin and horticultural oil. Encarsia spp. and Cybocephalus spp. abundance was related to scale abundance. These natural enemies were generally less abundant than predicted by scale abundance on granular dinotefuran treated plants and more abundant on granular thiamethoxam treated plants. Bifenthrin residue killed 90-100% of O. insidiosus and E. citrina within 24 h. My results indicate that reduced risk insecticides can provide season-long scale control with less impact on natural enemies than conventional insecticides. This could have economic and environmental benefits by reducing the number of applications necessary to protect nursery and landscape plants from scale.

  12. Influence of bacterial exopolymers, conspecific adult extract and salinity on the cyprid metamorphosis of Balanus amphitrite (Cirripedia: Thoracica)

    Digital Repository Service at National Institute of Oceanography (India)

    Anil, A.C.; Khandeparker, R.

    and mixed culture epm did not promote metamorphosis. There was no appreciable change in the metamorphic rate in the control conditions at 25 ppt, 35 ppt and 45 ppt salinities and the rate was much lower than that obtained with conspecific adult extract...

  13. Embryonic development and metamorphosis of the scyphozoan Aurelia.

    Science.gov (United States)

    Yuan, David; Nakanishi, Nagayasu; Jacobs, David K; Hartenstein, Volker

    2008-10-01

    We investigated the development of Aurelia (Cnidaria, Scyphozoa) during embryogenesis and metamorphosis into a polyp, using antibody markers combined with confocal and transmission electron microscopy. Early embryos form actively proliferating coeloblastulae. Invagination is observed during gastrulation. In the planula, (1) the ectoderm is pseudostratified with densely packed nuclei arranged in a superficial and a deep stratum, (2) the aboral pole consists of elongated ectodermal cells with basally located nuclei forming an apical organ, which is previously only known from anthozoan planulae, (3) endodermal cells are large and highly vacuolated, and (4) FMRFamide-immunoreactive nerve cells are found exclusively in the ectoderm of the aboral region. During metamorphosis into a polyp, cells in the planula endoderm, but not in the ectoderm, become strongly caspase 3 immunoreactive, suggesting that the planula endoderm, in part or in its entirety, undergoes apoptosis during metamorphosis. The polyp endoderm seems to be derived from the planula ectoderm in Aurelia, implicating the occurrence of "secondary" gastrulation during early metamorphosis.

  14. Nectar and pollen feeding by insect herbivores and implications for multitrophic interactions

    NARCIS (Netherlands)

    Wäckers, F.L.; Romeis, J.; Van Rijn, P.C.J.

    2007-01-01

    Among herbivorous insects with a complete metamorphosis the larval and adult stages usually differ considerably in their nutritional requirements and food ecology. Often, feeding on plant structural tissue is restricted to the larval stage, whereas the adult stage feeds primarily or exclusively on p

  15. Nectar and pollen feeding by insect herbivores and implications for multitrophic interactions

    NARCIS (Netherlands)

    Wäckers, F.L.; Romeis, J.; Van Rijn, P.C.J.

    2007-01-01

    Among herbivorous insects with a complete metamorphosis the larval and adult stages usually differ considerably in their nutritional requirements and food ecology. Often, feeding on plant structural tissue is restricted to the larval stage, whereas the adult stage feeds primarily or exclusively on p

  16. Myoinhibitors controlling oviduct contraction within the female blood-gorging insect, Rhodnius prolixus.

    Science.gov (United States)

    Sedra, Laura; Haddad, Amir S; Lange, Angela B

    2015-01-15

    Muscle activity can be regulated by stimulatory and inhibitory neuropeptides allowing for contraction and relaxation. There are various families of neuropeptides that can be classified as inhibitors of insect muscle contraction. This study focuses on Rhodnius prolixus and three neuropeptide families that have been shown to be myoinhibitors in insects: A-type allatostatins, myoinhibiting peptides (B-type allatostatins) and myosuppressins. FGLa/AST-like immunoreactive axons and blebs were found on the anterior of the dorsal vessel and on the abdominal nerves. FGLa/AST-like immunoreactive axons were also seen in the trunk nerves and on the bursa. The effects of RhoprAST-2 (FGLa/AST or A-type allatostatins) and RhoprMIP-4 (MIP/AST or B-type allatostatins) were similar, producing dose-dependent inhibition of R. prolixus spontaneous oviduct contractions with a maximum of 70% inhibition and an EC50 at approximately 10(-8)M. The myosuppressin of R. prolixus (RhoprMS) has an unusual FMRFamide C-terminal motif (pQDIDHVFMRFa) as compared to myosuppressins from other insects. Quantitative PCR results show that the RhoprMS receptor transcript is present in adult female oviducts; however, RhoprMS does not have an inhibitory effect on R. prolixus oviduct contractions, but does have a dose-dependent inhibitory effect on the spontaneous contraction of Locusta migratoria oviducts. SchistoFLRFamide, the myosuppressin of Schistocerca gregaria and L. migratoria, also does not inhibit R. prolixus oviduct contractions. This implies that FGLa/ASTs and MIP/ASTs may play a role in regulating egg movement within the oviducts, and that the myosuppressin although myoinhibitory on other muscles in R. prolixus, does not inhibit the contractions of R. prolixus oviducts and may play another role in the reproductive system.

  17. Amphibian metamorphosis as a model for studying the developmental actions of thyroid hormone

    Institute of Scientific and Technical Information of China (English)

    TATAJAMSHENR

    1998-01-01

    The thyroid hormones L-thyroxine and triiodo-Lthyronine have profound effects on postenbryonic development of most vertebrates.Analysis of their action in mammals is vitiated by the exposure of the developing foetus to a number of maternal factors which do not allow one to specifically define the role of thyroid hormone (TH) or that of other hormones and factors that modulate its action.Amphibian metamorphosis is obligatorily dependent on TH which can initiate all the diverse physiological manifestations of this postembryonic developmental process(morphogenesis,cell death,re-structuring,etc.) in free-living embryos and larvas of most anurans.This article will first describe the salient features of metamorphosis and its control by TH and other hormones.Emphasis will be laid on the key role played by TH receptor (TR),in particular the phenomenon of TR gene autoinduction,in initiating the developmental action of TH.Finally,it will be argued that the findings on the control of amphibian metamorphosis enhance our understanding of the regulation of postembryonic development by TH in other vertebrate species.

  18. GIVING FULL PLAY TO INSECT ENEMIES IN BIOLOGICAL CONTROL%关于天敌昆虫利用保护的几个问题

    Institute of Scientific and Technical Information of China (English)

    刘军侠; 杜建玲; 王海英; 牟玉杰

    2001-01-01

    Insect natural is an important biological factor in keepingecological balance.A good natural enemy of insects which effectively controls the happen of insects should have such characteristics as high reproductive capacity, powerful hunting ability, and tallies with life cycle of the host. When we control the target insects by using insect natural, we should make investigations in order to make sure that they are native or not.If local natural enemy can′t control the insects, insect natural should be introduced from another place. We should adopt vigorous measures to protect and make use of insect natural.%天敌昆虫是维持整个森林生态系统平衡的一个重要生物因子。一种优良的天敌只有具有高的繁殖力、强的搜索力、和寄主的生活史相吻合等特点,才能有效地控制害虫的发生。利用天敌昆虫对目标害虫进行防治时,应对目标害虫进行全面调查,确定其是本地种还是外来种,当本地天敌控制不了害虫时,可以从外地引进天敌。对天敌昆虫应采取积极的措施加以保护利用。

  19. Thyroxine-induced metamorphosis in the axolotl (Ambystoma mexicanum).

    Science.gov (United States)

    Coots, Peggy S; Seifert, Ashley W

    2015-01-01

    The axolotl (Ambystoma mexicanum) has remained an important model for regeneration and developmental biology for over a century. Although axolotls in captive-bred colonies usually exist in an aquatic form, they retain the ability to undergo metamorphosis following exposure to thyroid hormone. Here we present a robust method for inducing metamorphosis in adult axolotls that results in high survivability and produces terrestrial animals that can be maintained in long-term captivity.

  20. Thyroid hormone mediates otolith growth and development during flatfish metamorphosis.

    Science.gov (United States)

    Schreiber, A M; Wang, X; Tan, Y; Sievers, Q; Sievers, B; Lee, M; Burrall, K

    2010-11-01

    Flatfish begin life as bilaterally symmetrical larvae that swim up-right, then abruptly metamorphose into asymmetrically shaped juveniles with lateralized swimming postures. Flatfish metamorphosis is mediated entirely by thyroid hormone (TH). Changes in flatfish swim posture are thought to be regulated via vestibular remodeling, although the influence of TH on teleost inner ear development remains unclear. This study addresses the role of TH on the development of the three otolith end-organs (sacculus, utricle, and lagena) during southern flounder (Paralichthys lethostigma) metamorphosis. Compared with pre-metamorphosis, growth rates of the sacculus and utricle otoliths increase dramatically during metamorphosis in a manner that is uncoupled from general somatic growth. Treatment of P. lethostigma larvae with methimazol (a pharmacological inhibitor of endogenous TH production) inhibits growth of the sacculus and utricle, whereas treatment with TH dramatically accelerates their growth. In contrast with the sacculus and utricle otoliths that begin to form and mineralize during embryogenesis, a non-mineralized lagena otolith is first visible 10-12 days after hatching. The lagena grows during pre- and pro-metamorphosis, then abruptly mineralizes during metamorphic climax. Mineralization of the lagena, but not growth, can be induced with TH treatment, whereas treatment with methimazol completely inhibits lagena mineralization without inhibiting its growth. These findings suggest that during southern flounder metamorphosis TH exerts differential effects on growth and development among the three types of otolith.

  1. Eating insects

    NARCIS (Netherlands)

    Tan, Hui Shan Grace

    2017-01-01

    In recent years, edible insects have gained global attention due to their nutritional and environmental advantages over conventional meat. While numerous species of edible insects are enjoyed in various cultures around the world, most Western consumers react with disgust and aversion towards eating

  2. Insect Keepers

    Science.gov (United States)

    Moore, Virginia J.; Chessin, Debby A.; Theobald, Becky

    2010-01-01

    Insects are fascinating creatures--especially when you and your students get up close and personal with them! To that end, the authors facilitated an inquiry-based investigation with an emphasis on identification of the different types of insects found in the school yard, their characteristics, their habitat, and what they eat, while engaging the…

  3. [Bacillus thuringiensis: general aspects. An approach to its use in the biological control of lepidopteran insects behaving as agricultural pests].

    Science.gov (United States)

    Sauka, Diego H; Benintende, Graciela B

    2008-01-01

    Bacillus thuringiensis is the most widely applied biological pesticide used to control insects that affect agriculture and forestry and which transmit human and animal pathogens. During the past decades B. thuringiensis has been the subject of intensive research. These efforts have yielded considerable data about the relationships between the structure, mechanism of action, and genetics of their pesticidal crystal proteins. As a result, a coherent picture of these relationships has emerged. Other studies have focused on the ecological role of the B. thuringiensis crystal proteins and their performance in agricultural and other natural settings. With this knowledge as background and the help of biotechnological tools, researchers are now reporting promising results in the development of more useful toxins, recombinant bacteria, new formulations and transgenic plants that express pesticidal activity, in order to assure that these products are utilized with the best efficiency and benefit. This article is an attempt to integrate all these recent developments in the study of B. thuringiensis into a context of biological control of lepidopteran insect pest of agricultural importance.

  4. Insect phylogenomics.

    Science.gov (United States)

    Behura, S K

    2015-08-01

    Phylogenomics, the integration of phylogenetics with genome data, has emerged as a powerful approach to study the evolution and systematics of species. Recently, several studies employing phylogenomic tools have provided better insights into insect evolution. Next-generation sequencing methods are now increasingly used by entomologists to generate genomic and transcript sequences of various insect species and strains. These data provide opportunities for comparative genomics and large-scale multigene phylogenies of diverse lineages of insects. Phy-logenomic investigations help us to better understand systematic and evolutionary relationships of insect species that play important roles as herbivores, predators, detritivores, pollinators and disease vectors. It is important that we critically assess the prospects and limitations of phylogenomic methods. In this review, I describe the current status, outline the major challenges and remark on potential future applications of phylogenomic tools in studying insect systematics and evolution.

  5. To whom do the results of the multicenter, randomized, controlled INSECT trial (ISRCTN 24023541 apply? - assessment of external validity

    Directory of Open Access Journals (Sweden)

    Fischer Lars

    2012-02-01

    Full Text Available Abstract A response to Seiler et al: Interrupted or continuous slowly absorbable sutures for closure of primary elective midline abdominal incisions: a multicenter randomized trial (INSECT: ISRCTN24023541. Ann Surg 2009, 249(4:576-582. Background Existing evidence suggests that the transfer of results of randomized controlled trials into clinical practice may be limited. Potential reasons can be attributed to aspects of external validity. The aim of this study is to investigate issues related to the external validity of the INSECT trial. Methods All participating surgical departments were categorized and the clinical and baseline characteristics of randomized patients were evaluated. In addition, demographic and clinical data of all screened and randomized patients at the Departments of Surgery in Heidelberg and Erlangen were analyzed. Results Twenty-five centers enrolled a total of 625 patients. These centers included eight primary, 11 secondary, and six tertiary care centers. The tertiary care centers enrolled the most patients (n = 237, 38% followed by the primary care centers (n = 199, 32% and the secondary care centers (n = 189 patients; 30%. The mean number and baseline data of randomized patients did not differ between the three types of care centers (p = 0.09. Overall, the treatment according to protocol was at least 92%. At the Department of Surgery, University of Heidelberg, 307 patients were screened and 60 out of 130 eligible patients were randomized. There were no differences in demographic and clinical baseline data between included and non-included patients. In Erlangen, 351 patients were screened and 57 out of 106 eligible patients randomized. Conclusions Results of the INSECT trial are applicable to a broad spectrum of patients treated at different hospital levels.

  6. Evolution of Ecdysis and Metamorphosis in Arthropods: The Rise of Regulation of Juvenile Hormone.

    Science.gov (United States)

    Cheong, Sam P S; Huang, Juan; Bendena, William G; Tobe, Stephen S; Hui, Jerome H L

    2015-11-01

    Arthropods are the most successful group of animals, and are found in diverse habitats; they account for more than 80% of described animal species. A rigid exoskeleton is a common feature that is shared across the different groups of arthropods. The exoskeleton offers protection and is shed between developmental stages via a unique evolutionarily conserved process known as molting/ecdysis. Molting is triggered by steroid hormones, the ecdysteroids, and the regulation of their biosynthesis has long been proposed as a contributor to the success of arthropods during evolution. Nevertheless, how novelties arose that contributed to the diversifications of arthropods remain unclear. Juvenile hormones (JHs) are sequiterpenoids that were thought to be unique to insects, modulating the timing of metamorphosis in conjunction with the actions of ecdysteroids. Here, we revisit the old question of "the role that the sesquiterpenoids play in arthropod evolution" with a focus on the neglected non-insect arthropods. We hypothesize that the sesquiterpenoid, methyl farnesoate (MF), had already established regulatory functions in the last common ancestor of arthropods, and the difference in the regulation of biosynthesis and degradation of sesquiterpenoids, such as MF and JH, was another major driving force in the successful radiation of insects. © The Author 2015. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

  7. Larger body size at metamorphosis enhances survival, growth and performance of young cane toads (Rhinella marina.

    Directory of Open Access Journals (Sweden)

    Elisa Cabrera-Guzmán

    Full Text Available Body size at metamorphosis is a key trait in species (such as many anurans with biphasic life-histories. Experimental studies have shown that metamorph size is highly plastic, depending upon larval density and environmental conditions (e.g. temperature, food supply, water quality, chemical cues from conspecifics, predators and competitors. To test the hypothesis that this developmental plasticity is adaptive, or to determine if inducing plasticity can be used to control an invasive species, we need to know whether or not a metamorphosing anuran's body size influences its subsequent viability. For logistical reasons, there are few data on this topic under field conditions. We studied cane toads (Rhinella marina within their invasive Australian range. Metamorph body size is highly plastic in this species, and our laboratory studies showed that larger metamorphs had better locomotor performance (both on land and in the water, and were more adept at catching and consuming prey. In mark-recapture trials in outdoor enclosures, larger body size enhanced metamorph survival and growth rate under some seasonal conditions. Larger metamorphs maintained their size advantage over smaller siblings for at least a month. Our data support the critical but rarely-tested assumption that all else being equal, larger body size at metamorphosis is likely to enhance an individual's long term viability. Thus, manipulations to reduce body size at metamorphosis in cane toads may help to reduce the ecological impact of this invasive species.

  8. A model of muscle atrophy based on live microscopy of muscle remodelling in Drosophila metamorphosis

    Science.gov (United States)

    Kuleesha, Yadav; Puah, Wee Choo; Wasser, Martin

    2016-01-01

    Genes controlling muscle size and survival play important roles in muscle wasting diseases. In Drosophila melanogaster metamorphosis, larval abdominal muscles undergo two developmental fates. While a doomed population is eliminated by cell death, another persistent group is remodelled and survives into adulthood. To identify and characterize genes involved in the development of remodelled muscles, we devised a workflow consisting of in vivo imaging, targeted gene perturbation and quantitative image analysis. We show that inhibition of TOR signalling and activation of autophagy promote developmental muscle atrophy in early, while TOR and yorkie activation are required for muscle growth in late pupation. We discovered changes in the localization of myonuclei during remodelling that involve anti-polar migration leading to central clustering followed by polar migration resulting in localization along the midline. We demonstrate that the Cathepsin L orthologue Cp1 is required for myonuclear clustering in mid, while autophagy contributes to central positioning of nuclei in late metamorphosis. In conclusion, studying muscle remodelling in metamorphosis can provide new insights into the cell biology of muscle wasting. PMID:26998322

  9. Bioactivities of Ketones Terpenes: Antifungal Effect on F. verticillioides and Repellents to Control Insect Fungal Vector, S. zeamais

    Directory of Open Access Journals (Sweden)

    Romina P. Pizzolitto

    2015-11-01

    Full Text Available Maize is one the most important staple foods in the world. However, numerous pests, such as fungal pathogens, e.g., Fusarium verticillioides, and insects, such as Sitophlilus zeamais, attack maize grains during storage. Many F. verticillioides strains produce fumonisins, one of the most important mycotoxin that causes toxic effects on human and animal health. This situation is aggravated by the insect fungal vector, Sitophlilus zeamais, which contributes to the dispersal of fungal spores, and through feeding damage, provide entry points for fungal infections. The aim of this study was to evaluate in vitro bioassays, the antifungal activity on F. verticillioides M3125 and repellent effects against S. zeamais of ketone terpenes. In addition, we performed Quantitative structure–activity relationship (Q-SAR studies between physico-chemical properties of ketone terpenes and the antifungal effect. Thymoquinone was the most active compound against F. verticillioides (Minimum Inhibitory Concentration, MIC: 0.87 affecting the lag phase and the growth rate showing a total inhibition of growth at concentration higher than 2 mM (p < 0.05. The Q-SAR model revealed that the antifungal activity of ketone compounds is related to the electronic descriptor, Pi energy. Thymoquinone showed a strong repellent effect (−77.8 ± 8.5, p < 0.001 against S. zeamais. These findings make an important contribution to the search for new compounds to control two stored pests of maize.

  10. Synthesis and Characteristics of Valeric Acid-Zinc Layered Hydroxide Intercalation Material for Insect Pheromone Controlled Release Formulation

    Directory of Open Access Journals (Sweden)

    Rozita Ahmad

    2016-01-01

    Full Text Available A new intercalation compound of insect pheromone, valeric acid (VA, based on zinc layered hydroxide (ZLH as host release material, was successfully prepared through coprecipitation method. The as-produced organic-inorganic nanolayered material, valerate nanohybrid, VAN, shows the formation of a new peak at lower 2θ angle with basal spacing of 19.8 Å with no ZnO reflections, which indicate that the intercalation of anion between the inorganic ZLH interlamellae was accomplished. The elemental, FTIR, and ATR analyses of the nanohybrid supported the fact that the intercalation with the percentage anion loading was calculated to be 23.0% (w/w. The thermal stability property of the resulting nanohybrid was enhanced compared to the unbound anion. Field emission scanning electron micrograph of the ZnO has a nonuniform granular structure but transforms into flake-like structure with various sizes after the intercalation process. Release kinetics of anion from the interlayer of intercalated compound exhibited a slow release behavior governed by the pseudo-second-order kinetic model at different pHs of aqueous media. The valerate anion was released from VAN with the highest release rate at pH 4. These findings provide the basis to further development of controlled release formulation for insect pheromone based on ZLH intercalation.

  11. RNAi: future in insect management.

    Science.gov (United States)

    Burand, John P; Hunter, Wayne B

    2013-03-01

    RNA interference is a post- transcriptional, gene regulation mechanism found in virtually all plants and animals including insects. The demonstration of RNAi in insects and its successful use as a tool in the study of functional genomics opened the door to the development of a variety of novel, environmentally sound approaches for insect pest management. Here the current understanding of the biogenesis of the two RNAi classes in insects is reviewed. These are microRNAs (miRNAs) and short interfering RNAs (siRNAs). Several other key approaches in RNAi -based for insect control, as well as for the prevention of diseases in insects are also reviewed. The problems and prospects for the future use of RNAi in insects are presented.

  12. 亩旺特防治桃介壳虫田间药效试验%Field Efficacy Trials of Movento Control Peach Scale Insect

    Institute of Scientific and Technical Information of China (English)

    张鹏

    2015-01-01

    In this paper,field efficacy trials of Movento,which produced by Bayer Crop Science control peach scale insect were adopted.The results showed that Movento 600 times had good effect on control peach scale insect.This study provided scientific basis for control peach scale insect.%选用拜耳作物科学公司生产的“亩旺特”进行防治桃介壳虫的田间药效试验,结果表明“亩旺特”600倍液对桃介壳虫有较好的防治效果,为控制桃介壳虫的流行提供了科学依据。

  13. Insect Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Records of past temperature and environment derived from beetle and other insect fossils. Parameter keywords describe what was measured in this data set. Additional...

  14. Integrative Proteomics and Metabolomics Analysis of Insect Larva Brain: Novel Insights into the Molecular Mechanism of Insect Wandering Behavior.

    Science.gov (United States)

    Li, Yi; Wang, Xin; Hou, Yong; Zhou, Xiaoying; Chen, Quanmei; Guo, Chao; Xia, Qingyou; Zhang, Yan; Zhao, Ping

    2016-01-04

    Before metamorphosis, most holometabolous insects, such as the silkworm studied here, undergo a special phase called the wandering stage. Insects in this stage often display enhanced locomotor activity (ELA). ELA is vital because it ensures that the insect finds a safe and suitable place to live through the pupal stage. The physiological mechanisms of wandering behavior are still unclear. Here, we integrated proteomics and metabolomics approaches to analyze the brain of the lepidopteran insect, silkworm, at the feeding and wandering stages. Using LC-MS/MS and GC-MS, in all we identified 3004 proteins and 37 metabolites at these two stages. Among them, 465 proteins and 22 metabolites were changed. Neural signal transduction proteins and metabolites, such as neurofilament, dopaminergic synapse related proteins, and glutamic acid, were significantly altered, which suggested that active neural conduction occurred in the brain at the wandering stage. We also found decreased dopamine degradation at the wandering stage. The proposed changes in active neural conduction and increased dopamine concentration might induce ELA. In addition, proteins involved in the ubiquitin proteasome system and lysosome pathway were upregulated, revealing that the brain experiences morphological remodeling during metamorphosis. These findings yielded novel insights into the molecular mechanism underlying insect wandering behavior.

  15. Photoperiodic diapause under the control of circadian clock genes in an insect

    Directory of Open Access Journals (Sweden)

    Ikeno Tomoko

    2010-09-01

    Full Text Available Abstract Background Most organisms have evolved a circadian clock in order to anticipate daily environmental changes and many of these organisms are also capable of sophisticated measurement of daylength (photoperiodism that is used to regulate seasonal events such as diapause, migration and polymorphism. It has been generally accepted that the same elements are involved in both circadian (daily and seasonal (annual rhythms because both rely upon daily light-dark cycles. However, as reasonable as this sounds, there remains no conclusive evidence of such a molecular machinery in insects. We have approached this issue by using RNA interference (RNAi in Riptortus pedestris. Results The cuticle deposition rhythm exhibited the major properties of circadian rhythms, indicating that the rhythm is regulated by a circadian clock. RNAi directed against the circadian clock genes of period and cycle, which are negative and positive regulators in the circadian clock, respectively, disrupted the cuticle deposition rhythm and distinct cuticle layers were produced by these RNAi. Simultaneously, period RNAi caused the insect to avert diapause under a diapause-inducing photoperiod whereas cycle RNAi induced diapause under a diapause-averting photoperiod. The expression patterns of juvenile hormone-regulated genes and the application of juvenile hormone analogue suggested that neither ovarian development itself nor a downstream cascade of juvenile hormone secretion, were disturbed by period and cycle RNAi. Conclusions This study revealed that the circadian clock genes are crucial not only for daily rhythms but also for photoperiodic diapause. RNAi directed against period and cycle had opposite effects not only in the circadian cuticle deposition rhythm but also in the photoperiodic diapause. These RNAi also had opposite effects on juvenile hormone-regulated gene expression. It is still possible that the circadian clock genes pleiotropically affect ovarian

  16. Recalculation of data from 1990 to 2010 on the effects of highly diluted thyroxine on the metamorphosis of highland amphibians

    Directory of Open Access Journals (Sweden)

    Peter Christian Endler

    2011-09-01

    Full Text Available Experiments on amphibian metamorphosis can vary considerably in duration. The authors had set themselves the task of defining a generally applicable pooling method for metamorphosis experiments [1]. Normalization with respect to time was done on the assumption that differences in speed of metamorphosis attributable to treatment would override differences in duration between experiments. The problem of artificial differences in variability when comparing and pooling data from several experiments was approached by normalization with respect to time based on the development of both the test and the control animals. The range from 0% to 100% over which the fraction of four-legged animals progresses in the course of an experiment is divided into 10%-intervals and mapped onto a corresponding relative scale. Each measurement is then assigned to the point on the 10%-scale to which it is closest. In this way each reference point is assigned a value giving the number or percentage of four-legged animals at that point. These values are aggregated over all experiments within the test- and control-group. The results of experiments performed over the course of two decades (1990 - 2010 on highland Rana temporaria treated with a homeopathically prepared high dilution of thyroxine (“30x” are presented in full detail based on this normalization method[1]. It was found that differences between treatment groups thus calculated were in line with those obtained with other pooling methods [2]. Thyroxine 30x does slow down metamorphosis in inert highland amphibians. This was observed by 5 researchers in 20 sub-experiments, and it seems to be the most reliable bio-assay found in amphibian research on homeopathy so far2. When experiments were performed with highland animals pretreated by hyperstimulation with molecular thyroxine, slowing down of metamorphosis was again observed (by 3 of 4 researchers in most of 10 sub-experiments.

  17. Zinc concentrations and isotopic signatures of an aquatic insect (mayfly, Baetis tricaudatus)

    Science.gov (United States)

    Wesner, Jeff S; Walters, David; Schmidt, Travis S.; Kraus, Johanna M.; Stricker, Craig A.; Clements, William H.

    2017-01-01

    Insect metamorphosis often results in substantial chemical changes that can fractionate isotopes and alter contaminant concentrations. We exposed larval mayflies (Baetis tricaudatus) to an aqueous zinc gradient (3-340 µg Zn/l) and measured the change in zinc tissue concentrations at different stages of metamorphosis. We also measured changes in stable isotopes (δ15N and δ13C) in unexposed B. tricaudatus. Zinc concentrations in larvae were positively related to aqueous zinc, increasing 9-fold across the exposure gradient. Zinc concentrations in adults were also positively related to aqueous concentrations, but were 7-fold lower than larvae. However, this relationship varied according to adult substage (subimago vs imago) and sex. Tissue concentrations in female imagoes were not related to exposure concentrations, but the converse was true for all other stage by sex combinations. Metamorphosis also altered isotopic ratios, increasing δ15N, but not δ13C. Thus, the main effects of metamorphosis on insect chemistry were large declines in zinc concentrations coupled with enriched δ15N signatures. For zinc, this change is largely consistent across the aqueous exposure gradient. However, the differences among sexes and stages suggest that caution is warranted when using isotopes or metal concentrations measured in one insect stage (e.g., larvae) to assess risk to wildlife that feed on subsequent life stages (e.g., adults).

  18. Modeling the integration of parasitoid, insecticide, and transgenic insecticidal crop for the long-term control of an insect pest.

    Science.gov (United States)

    Onstad, David W; Liu, Xiaoxia; Chen, Mao; Roush, Rick; Shelton, Anthony M

    2013-06-01

    The tools of insect pest management include host plant resistance, biological control, and insecticides and how they are integrated will influence the durability of each. We created a detailed model of the population dynamics and population genetics of the diamondback moth, Plutella xylostella L., and its parasitoid, Diadegma insulare (Cresson), to study long-term pest management in broccoli Brassica oleracea L. Given this pest's history of evolving resistance to various toxins, we also evaluated the evolution of resistance to transgenic insecticidal Bt broccoli (expressing Cry1Ac) and two types of insecticides. Simulations demonstrated that parasitism provided the most reliable, long-term control of P. xylostella populations. Use of Bt broccoli with a 10% insecticide-free refuge did not reduce the long-term contribution of parasitism to pest control. Small refuges within Bt broccoli fields can delay evolution of resistance > 30 generations if resistance alleles are rare in the pest population. However, the effectiveness of these refuges can be compromised by insecticide use. Rainfall mortality during the pest's egg and neonate stages significantly influences pest control but especially resistance management. Our model results support the idea that Bt crops and biological control can be integrated in integrated pest management and actually synergistically support each other. However, the planting and maintenance of toxin-free refuges are critical to this integration.

  19. Efficacy of a combination of beta-cyfluthrin and imidacloprid and beta-cyfluthrin alone for control of stored-product insects on concrete

    Science.gov (United States)

    The insecticidal effect of Temprid®, a formulation that contains beta-cyfluthrin and imidacloprid, was tested on concrete for control of seven stored-product insect species: the rusty grain beetle, Cryptolestes ferrugineus (Stephens); the sawtoothed grain beetle, Oryzaephilus surinamensis (L.); the ...

  20. A New Strategy of Insect Pest Control:Down-regulating Cotton Boliworm Gene Expression by Engineering Plant Double Stranded RNA

    Institute of Scientific and Technical Information of China (English)

    MAO Ying-bo; XUE Xue-yi; WANG Ling-jiang; CHEN Xiao-ya

    2008-01-01

    @@ Cotton bollworm (Helicoverpa armigera ) is an important agricultural pest that causes severeyield loss to crops,particularly to cotton.Transgenic Bt crops have been successful in protectingplants,however,Bt proteins are toxic to all lepidopteran insects but have little effects to sucking pests,such as aphids.Furthermore,the continuous use of Bt crops increases insect resistance.

  1. Neural Control and Adaptive Neural Forward Models for Insect-like, Energy-Efficient, and Adaptable Locomotion of Walking Machines

    Directory of Open Access Journals (Sweden)

    Poramate eManoonpong

    2013-02-01

    Full Text Available Living creatures, like walking animals, have found fascinating solutions for the problem of locomotion control. Their movements show the impression of elegance including versatile, energy-efficient, and adaptable locomotion. During the last few decades, roboticists have tried to imitate such natural properties with artificial legged locomotion systems by using different approaches including machine learning algorithms, classical engineering control techniques, and biologically-inspired control mechanisms. However, their levels of performance are still far from the natural ones. By contrast, animal locomotion mechanisms seem to largely depend not only on central mechanisms (central pattern generators, CPGs and sensory feedback (afferent-based control but also on internal forward models (efference copies. They are used to a different degree in different animals. Generally, CPGs organize basic rhythmic motions which are shaped by sensory feedback while internal models are used for sensory prediction and state estimations. According to this concept, we present here adaptive neural locomotion control consisting of a CPG mechanism with neuromodulation and local leg control mechanisms based on sensory feedback and adaptive neural forward models with efference copies. This neural closed-loop controller enables a walking machine to perform a multitude of different walking patterns including insect-like leg movements and gaits as well as energy-efficient locomotion. In addition, the forward models allow the machine to autonomously adapt its locomotion to deal with a change of terrain, losing of ground contact during stance phase, stepping on or hitting an obstacle during swing phase, leg damage, and even to promote cockroach-like climbing behavior. Thus, the results presented here show that the employed embodied neural closed-loop system can be a powerful way for developing robust and adaptable machines.

  2. Reducing losses inflicted by insect pests on cashew, using weaver ants as a biological control agent

    DEFF Research Database (Denmark)

    Anato, Florence; Wargui, Rosine; Sinzogan, Antonio

    2015-01-01

    BACKGROUND: Cashew (Anacardium occidentale Linnaeus) is the largest agricultural export product in Benin. However, yields and quality are lost due to inefficient pest control. Weaver ants (Oecophylla spp.) may control pests in this crop as they eat and deter pests. In Benin, cashew pest damages...

  3. Reducing losses inflicted by insect pests on cashew, using weaver ants as a biological control agent

    DEFF Research Database (Denmark)

    Anato, Florence; Wargui, Rosine; Sinzogan, Antonio

    2015-01-01

    BACKGROUND: Cashew (Anacardium occidentale Linnaeus) is the largest agricultural export product in Benin. However, yields and quality are lost due to inefficient pest control. Weaver ants (Oecophylla spp.) may control pests in this crop as they eat and deter pests. In Benin, cashew pest damages, ...

  4. A review of introductions of pathogens and nematodes for classical biological control of insects and mites

    Science.gov (United States)

    Ann E. Hajek; Michael L. McManus; Italo Delalibera Junior

    2007-01-01

    Compared with parasitoids and predators, classical biological control programs targeting arthropod pests have used pathogens and nematodes very little. However, some pathogens and nematodes that have been introduced have become established and provided excellent control and have been introduced in increasing numbers of areas over decades, often after distributions of...

  5. Optimal control of Aedes aegypti mosquitoes by the sterile insect technique and insecticide.

    Science.gov (United States)

    Thomé, Roberto C A; Yang, Hyun Mo; Esteva, Lourdes

    2010-01-01

    We present a mathematical model to describe the dynamics of mosquito population when sterile male mosquitoes (produced by irradiation) are introduced as a biological control, besides the application of insecticide. In order to analyze the minimal effort to reduce the fertile female mosquitoes, we search for the optimal control considering the cost of insecticide application, the cost of the production of irradiated mosquitoes and their delivery as well as the social cost (proportional to the number of fertilized females mosquitoes). The optimal control is obtained by applying the Pontryagin's Maximum Principle. Copyright 2009 Elsevier Inc. All rights reserved.

  6. Insect fungi for the control of brown planthopper Nilaparvata lugens, and Malayan rice bug, Scotinophara coarctata

    NARCIS (Netherlands)

    Rombach, M.C.

    1987-01-01

    Introduction : Many potential pest organisms are normally kept at densities below damage thresholds by naturally occurring natural enemies in virtually all agricultural crops. This natural control can be enhanced by introduction of new biological agents

  7. Formulation to Enhance the Insecticidal Activity of Entomopathogenic Nematodes for Control of Insect Pests of Orchards

    Science.gov (United States)

    Extended shelf life and rapid dispersion of entomopathogenic nematode (EPN) infective juveniles (IJs) in spray suspensions were the principal objectives of earlier EPN formulation development. Subsequently, formulation of EPNs for enhanced insecticidal control in greenhouses and field has been inves...

  8. Insect bite reactions

    Directory of Open Access Journals (Sweden)

    Sanjay Singh

    2013-01-01

    Full Text Available Insects are a class of living creatures within the arthropods. Insect bite reactions are commonly seen in clinical practice. The present review touches upon the medically important insects and their places in the classification, the sparse literature on the epidemiology of insect bites in India, and different variables influencing the susceptibility of an individual to insect bites. Clinical features of mosquito bites, hypersensitivity to mosquito bites Epstein-Barr virus NK (HMB-EBV-NK disease, eruptive pseudoangiomatosis, Skeeter syndrome, papular pruritic eruption of HIV/AIDS, and clinical features produced by bed bugs, Mexican chicken bugs, assassin bugs, kissing bugs, fleas, black flies, Blandford flies, louse flies, tsetse flies, midges, and thrips are discussed. Brief account is presented of the immunogenic components of mosquito and bed bug saliva. Papular urticaria is discussed including its epidemiology, the 5 stages of skin reaction, the SCRATCH principle as an aid in diagnosis, and the recent evidence supporting participation of types I, III, and IV hypersensitivity reactions in its causation is summarized. Recent developments in the treatment of pediculosis capitis including spinosad 0.9% suspension, benzyl alcohol 5% lotion, dimethicone 4% lotion, isopropyl myristate 50% rinse, and other suffocants are discussed within the context of evidence derived from randomized controlled trials and key findings of a recent systematic review. We also touch upon a non-chemical treatment of head lice and the ineffectiveness of egg-loosening products. Knockdown resistance (kdr as the genetic mechanism making the lice nerves insensitive to permethrin is discussed along with the surprising contrary clinical evidence from Europe about efficacy of permethrin in children with head lice carrying kdr-like gene. The review also presents a brief account of insects as vectors of diseases and ends with discussion of prevention of insect bites and some

  9. Interaction between perchlorate and iodine in the metamorphosis of Hyla versicolor

    Science.gov (United States)

    Sparling, D.W.; Harvey, G.; Nzengung, V.; Linder, Gregory L.; Krest, Sherry K.; Sparling, Donald W.; Little, Edward E.

    2003-01-01

    Perchlorate (ClO4-) is a water-soluble, inorganic anion that is often combined with ammonium, potassium or other cations for use in industry and agriculture. Ammonium perchlorate, for example, is a potent oxidizer and is used in various military applications including rocket fuel. It has also been found in an historically widely used fertilizer, Chilean nitrate and in other fertilizers. It has been found in ground and surface waters of over 30 states and is considered a human health risk. Because of its similar atomic radius and volume, perchlorate competes with iodide for thyroid uptake and storage and thereby inhibits production of thyroid hormones. Amphibians may be particularly affected by perchlorate because they rely on the thyroid for metamorphosis. This study exposed early larval Hyla versicolor to concentrations of perchlorate ranging from 2.2 to 50 ppm to determine the effects of perchlorate on a native amphibian. In addition, three controls, 0 perchlorate, 0 perchlorate with 0.10 ppm iodide (C + I) and 50 ppm perchlorate + 0.10 ppm iodide (50 + I) were tested. Mortality (<11% with all treatments) and growth appeared to be unaffected by perchlorate. Inhibition of development started with 2.2 ppm perchlorate and little or no development occurred at 22.9 ppm and above. This inhibition was particularly apparent at the latter stages of development including hindlimb formation and metamorphosis. The estimated EC50 for total inhibition of metamorphosis at 70 days of treatment was 3.63 ppm. There was no evidence of inhibition of development with the 50 + I, C + I, or controls, indicating that the presence of small concentrations of iodide could counter the effects of perchlorate. When tadpoles that had been inhibited by perchlorate were subsequently treated with iodide, development through prometamorphosis progressed but mortality was very high.

  10. Turbine sound may influence the metamorphosis behaviour of estuarine crab megalopae.

    Directory of Open Access Journals (Sweden)

    Matthew K Pine

    Full Text Available It is now widely accepted that a shift towards renewable energy production is needed in order to avoid further anthropogenically induced climate change. The ocean provides a largely untapped source of renewable energy. As a result, harvesting electrical power from the wind and tides has sparked immense government and commercial interest but with relatively little detailed understanding of the potential environmental impacts. This study investigated how the sound emitted from an underwater tidal turbine and an offshore wind turbine would influence the settlement and metamorphosis of the pelagic larvae of estuarine brachyuran crabs which are ubiquitous in most coastal habitats. In a laboratory experiment the median time to metamorphosis (TTM for the megalopae of the crabs Austrohelice crassa and Hemigrapsus crenulatus was significantly increased by at least 18 h when exposed to either tidal turbine or sea-based wind turbine sound, compared to silent control treatments. Contrastingly, when either species were subjected to natural habitat sound, observed median TTM decreased by approximately 21-31% compared to silent control treatments, 38-47% compared to tidal turbine sound treatments, and 46-60% compared to wind turbine sound treatments. A lack of difference in median TTM in A. crassa between two different source levels of tidal turbine sound suggests the frequency composition of turbine sound is more relevant in explaining such responses rather than sound intensity. These results show that estuarine mudflat sound mediates natural metamorphosis behaviour in two common species of estuarine crabs, and that exposure to continuous turbine sound interferes with this natural process. These results raise concerns about the potential ecological impacts of sound generated by renewable energy generation systems placed in the nearshore environment.

  11. Turbine Sound May Influence the Metamorphosis Behaviour of Estuarine Crab Megalopae

    Science.gov (United States)

    Pine, Matthew K.; Jeffs, Andrew G.; Radford, Craig A.

    2012-01-01

    It is now widely accepted that a shift towards renewable energy production is needed in order to avoid further anthropogenically induced climate change. The ocean provides a largely untapped source of renewable energy. As a result, harvesting electrical power from the wind and tides has sparked immense government and commercial interest but with relatively little detailed understanding of the potential environmental impacts. This study investigated how the sound emitted from an underwater tidal turbine and an offshore wind turbine would influence the settlement and metamorphosis of the pelagic larvae of estuarine brachyuran crabs which are ubiquitous in most coastal habitats. In a laboratory experiment the median time to metamorphosis (TTM) for the megalopae of the crabs Austrohelice crassa and Hemigrapsus crenulatus was significantly increased by at least 18 h when exposed to either tidal turbine or sea-based wind turbine sound, compared to silent control treatments. Contrastingly, when either species were subjected to natural habitat sound, observed median TTM decreased by approximately 21–31% compared to silent control treatments, 38–47% compared to tidal turbine sound treatments, and 46–60% compared to wind turbine sound treatments. A lack of difference in median TTM in A. crassa between two different source levels of tidal turbine sound suggests the frequency composition of turbine sound is more relevant in explaining such responses rather than sound intensity. These results show that estuarine mudflat sound mediates natural metamorphosis behaviour in two common species of estuarine crabs, and that exposure to continuous turbine sound interferes with this natural process. These results raise concerns about the potential ecological impacts of sound generated by renewable energy generation systems placed in the nearshore environment. PMID:23240063

  12. Calcitonin-like diuretic hormones in insects.

    Science.gov (United States)

    Zandawala, Meet

    2012-10-01

    Insect neuropeptides control various biological processes including growth, development, homeostasis and reproduction. The calcitonin-like diuretic hormone (CT/DH) is one such neuropeptide that has been shown to affect salt and water transport by Malpighian tubules of several insects. With an increase in the number of sequenced insect genomes, CT/DHs have been predicted in several insect species, making it easier to characterize the gene encoding this hormone and determine its function in the species in question. This mini review summarizes the current knowledge on insect CT/DHs, focusing on mRNA and peptide structures, distribution patterns, physiological roles, and receptors in insects.

  13. Biological Control beneath the Feet: A Review of Crop Protection against Insect Root Herbivores

    Directory of Open Access Journals (Sweden)

    Alan Kergunteuil

    2016-11-01

    Full Text Available Sustainable agriculture is certainly one of the most important challenges at present, considering both human population demography and evidence showing that crop productivity based on chemical control is plateauing. While the environmental and health threats of conventional agriculture are increasing, ecological research is offering promising solutions for crop protection against herbivore pests. While most research has focused on aboveground systems, several major crop pests are uniquely feeding on roots. We here aim at documenting the current and potential use of several biological control agents, including micro-organisms (viruses, bacteria, fungi, and nematodes and invertebrates included among the macrofauna of soils (arthropods and annelids that are used against root herbivores. In addition, we discuss the synergistic action of different bio-control agents when co-inoculated in soil and how the induction and priming of plant chemical defense could be synergized with the use of the bio-control agents described above to optimize root pest control. Finally, we highlight the gaps in the research for optimizing a more sustainable management of root pests.

  14. Biological Control beneath the Feet: A Review of Crop Protection against Insect Root Herbivores

    Science.gov (United States)

    Kergunteuil, Alan; Bakhtiari, Moe; Formenti, Ludovico; Xiao, Zhenggao; Defossez, Emmanuel; Rasmann, Sergio

    2016-01-01

    Sustainable agriculture is certainly one of the most important challenges at present, considering both human population demography and evidence showing that crop productivity based on chemical control is plateauing. While the environmental and health threats of conventional agriculture are increasing, ecological research is offering promising solutions for crop protection against herbivore pests. While most research has focused on aboveground systems, several major crop pests are uniquely feeding on roots. We here aim at documenting the current and potential use of several biological control agents, including micro-organisms (viruses, bacteria, fungi, and nematodes) and invertebrates included among the macrofauna of soils (arthropods and annelids) that are used against root herbivores. In addition, we discuss the synergistic action of different bio-control agents when co-inoculated in soil and how the induction and priming of plant chemical defense could be synergized with the use of the bio-control agents described above to optimize root pest control. Finally, we highlight the gaps in the research for optimizing a more sustainable management of root pests. PMID:27916820

  15. Kafka's Metamorphosis: Transforming the Pre-Graduation Malaise.

    Science.gov (United States)

    Thompson, Sheryl

    1998-01-01

    A teacher of an advanced placement English class of over-stressed, over-busy, and rebellious gifted seniors describes how she used Kafka's "Metamorphosis" to help them adjust to this transitional period in their lives while keeping all reading and assignments within the class period. (DB)

  16. Thyroid Hormone-disrupting Effects and the Amphibian Metamorphosis Assay.

    Science.gov (United States)

    Miyata, Kaori; Ose, Keiko

    2012-03-01

    There are continued concerns about endocrine-disrupting chemical effects, and appropriate vertebrate models for assessment of risk are a high priority. Frog tadpoles are very sensitive to environmental substances because of their habitat and the complex processes of metamorphosis regulated by the endocrine system, mainly thyroid hormones. During metamorphosis, marked alteration in hormonal factors occurs, as well as dramatic structural and functional changes in larval tissues. There are a variety of mechanisms determining thyroid hormone balance or disruption directly or indirectly. Direct-acting agents can cause changes in thyroxine synthesis and/or secretion in thyroid through effects on peroxidases, thyroidal iodide uptake, deiodinase, and proteolysis. At the same time, indirect action may result from biochemical processes such as sulfation, deiodination and glucuronidation. Because their potential to disrupt thyroid hormones has been identified as an important consideration for the regulation of chemicals, the OECD and the EPA have each established guidelines that make use of larval African clawed frogs (Xenopus laevis) and frog metamorphosis for screening and testing of potential endocrine disrupters. The guidelines are based on evaluation of alteration in the hypothalamic-pituitary-thyroid axis. One of the primary endpoints is thyroid gland histopathology. Others are mortality, developmental stage, hind limb length, snout-vent length and wet body weight. Regarding histopathological features, the guidelines include core criteria and additional qualitative parameters along with grading. Taking into account the difficulties in evaluating amphibian thyroid glands, which change continuously throughout metamorphosis, histopathological examination has been shown to be a very sensitive approach.

  17. [Metamorphosis in the Urodelan amphibians: patterns, regulation mechanisms, and evolution].

    Science.gov (United States)

    Smirnov, S V

    2006-01-01

    Patterns of metamorphosis and mechanisms of its regulation in primitive and advanced salamanders are compared. It is found that urodelan evolution was characterised by the following trends: 1) increase in the number of metamorphosing systems; 2) increase in the amplitude of metamorphic transformations of each particular system due to the progressive divergence of the larval and the adult morphology; 3) synchronization of metamorphic transformations and their concentration within a relatively short period of ontogeny; 4) increase in the role of the thyroid hormones (TH) in the regulation of metamorphosis. Structures that are induced by factors other than TH and develop independently of TH in primitive Urodela species acquire TH-dependence in phyletically more advanced salamanders. For instance, morphogenetic induction as a mechanism of ontogeny regulation is substituted by endocrine induction with TH as the inducing factor. The switch from morphogenetic to endocrine induction stimulates the following events: 1) optimization of ontogeny; 2) reduction of the metamorphosis duration; 3) formation of the dissociability of larval and post-metamorphic stages of ontogeny, which, in its turn, is a precondition for the swith to necrobiotic metamorphosis and to the direct development.

  18. 中国储藏物害虫生物防治的研究进展%ADVANCE OF BIOLOGICAL CONTROLLING STORED - PRODUCT INSECTS IN CHINA

    Institute of Scientific and Technical Information of China (English)

    邓望喜; 张宏宇; 华红霞

    2001-01-01

    This article reviewed the progress of studies on biological control of stored - product insects in China in recent twenty years.①.insect - natural enemies: successful introduction of Xylocoris flavipes (Reuter) from America, reproduction and application to controlling warehouse insects; studies on biology and predatory effect of parasites such as Peregrinator blannulipes, Xylocoris spp., Brocon hebetor, Parasitic wasps on cockroaches' eggs; investigation of fauna of insect-natural enemies. ②. entomopathogen: application of Bacillus thuringiensis to controlling some pests.③.insect pheromone: reports are concentrated on the application of insect pheromone to controlling Sitotroga cerealella (Oliver), Plodia interpunctella (Hubner) etc.④.insect growth regulator and inhibitor:studies have been done on the application of Benzoylpheny and hydrojuvenile hormone such as ZR515,ZR512.⑤.insect resistant varieties and resistance mechanism of rice, wheat, corn, legume to Sitophilus zeamais, Sitotroga cerealella, Rhizopertha dominica and bean weevil have been studied. ⑥. genetic control of insects:researches on the mutation caused by radiation and control effect of Plodia interpuctella (Hubner),Callosobruchus chinensis L.and other insects.%本文综述了中国近20年储藏物害虫生物防治的研究与应用进展。①天敌昆虫方面:从美国引进黄色花蝽室内繁殖及仓库释放取得成功,并进行了有关生物学及捕食效应的研究。对仓双环猎蝽、黄风花蝽、麦蛾茧蜂及蜚蠊卵寄生蜂进行了生物学及控制研究,开展了天敌昆虫区系调查。②病原微生物:对苏云金芽孢杆茵(Bt)进行了仓库资源的分类鉴定及遗传多样性研究、致病害虫病变研究;对蜚蠊有效的苏云金芽孢杆菌、病毒、线虫进行了分离筛选及生物测定;用Bt乳剂实仓防治绿豆象。③昆虫信息素:仓库中释放麦蛾、印度螟蛾的合成信息素取得成效

  19. Insect fungi for the control of brown planthopper, Nilaparvata lugens, and Malayan rice bug, Scotinophara coarctata.

    NARCIS (Netherlands)

    Rombach, M.C.

    1987-01-01

    Introduction : Many potential pest organisms are normally kept at densities below damage thresholds by naturally occurring natural enemies in virtually all agricultural crops. This natural control can be enhanced by introduction of new biological agents ("classical biological contro

  20. Differential patterns of accumulation and retention of dietary trace elements associated with coal ash during larval development and metamorphosis of an amphibian.

    Science.gov (United States)

    Heyes, Andrew; Rowe, Christopher L; Conrad, Phillip

    2014-01-01

    We performed an experiment in which larval gray tree frogs (Hyla chrysoscelis) were raised through metamorphosis on diets increased with a suite of elements associated with coal combustion residues (silver [Ag], arsenic [As], cadmium [Cd], chromium [Cr], copper [Cu], mercury [Hg], lead [Pb], selenium [Se], vanadium [V], and zinc [Zn]) at "low" and "high" concentrations. We quantified accumulation of metals at three life stages (mid-larval development, initiation of metamorphosis, and completion of metamorphosis) as well as effects on survival, metabolic rate, size at metamorphosis, and duration and loss of weight during metamorphosis. Most elements were accumulated in a dose-dependent pattern by some or all life stages, although this was not the case for Hg. For most elements, larval body burdens exceeded those of later life stages in some or all treatments (control, low, or high). However for Se, As, and Hg, body burdens in control and low concentrations were increased in later compared with earlier life stages. A lack of dose-dependent accumulation of Hg suggests that the presence of high concentrations of other elements (possibly Se) either inhibited accumulation or increased depuration of Hg. The duration of metamorphosis (forelimb emergence through tail resorption) was lengthened in individuals exposed to the highest concentrations of elements, but there were no other statistically significant biological effects. This study shows that patterns of accumulation and possibly depuration of metals and trace elements are complex in animals possessing complex life cycles. Further study is required to determine specific interactions affecting these patterns, in particular which elements may be responsible for affecting accumulation or retention of Hg when organisms are exposed to complex mixtures of elements.

  1. Troponin T isoform expression is modulated during Atlantic Halibut metamorphosis

    Directory of Open Access Journals (Sweden)

    Llewellyn Lynda

    2007-06-01

    Full Text Available Abstract Background Flatfish metamorphosis is a thyroid hormone (TH driven process which leads to a dramatic change from a symmetrical larva to an asymmetrical juvenile. The effect of THs on muscle and in particular muscle sarcomer protein genes is largely unexplored in fish. The change in Troponin T (TnT, a pivotal protein in the assembly of skeletal muscles sarcomeres and a modulator of calcium driven muscle contraction, during flatfish metamophosis is studied. Results In the present study five cDNAs for halibut TnT genes were cloned; three were splice variants arising from a single fast TnT (fTnT gene; a fourth encoded a novel teleost specific fTnT-like cDNA (AfTnT expressed exclusively in slow muscle and the fifth encoded the teleost specific sTnT2. THs modified the expression of halibut fTnT isoforms which changed from predominantly basic to acidic isoforms during natural and T4 induced metamorphosis. In contrast, expression of red muscle specific genes, AfTnT and sTnT2, did not change during natural metamorphosis or after T4 treatment. Prior to and after metamorphosis no change in the dorso-ventral symmetry or temporal-spatial expression pattern of TnT genes and muscle fibre organization occurred in halibut musculature. Conclusion Muscle organisation in halibut remains symmetrical even after metamorphosis suggesting TH driven changes are associated with molecular adaptations. We hypothesize that species specific differences in TnT gene expression in teleosts underlies different larval muscle developmental programs which better adapts them to the specific ecological constraints.

  2. Membrane Type-1 Matrix Metalloproteinases and Tissue Inhibitor of Metalloproteinases-2 RNA Levels Mimic Each Other during Xenopus laevis Metamorphosis

    OpenAIRE

    Walsh, Logan A.; Deanna A Carere; Cooper, Colin A.; Sashko Damjanovski

    2007-01-01

    Matrix metalloproteinases (MMPs) and their endogenous inhibitors TIMPs (tissue inhibitors of MMPs), are two protein families that work together to remodel the extracellular matrix (ECM). TIMPs serve not only to inhibit MMP activity, but also aid in the activation of MMPs that are secreted as inactive zymogens. Xenopus laevis metamorphosis is an ideal model for studying MMP and TIMP expression levels because all tissues are remodeled under the control of one molecule, thyroid hormone. Here, us...

  3. Sorghum Insect Problems and Management

    Institute of Scientific and Technical Information of China (English)

    Chunshan Guo; Wei Cui; Xue Feng; Jianzhou Zhao; Guihua Lu

    2011-01-01

    Sorghum (Sorghum bicolor) has high levels of starch, sugar, and fiber and is one of the most important energy crops in the world. Insect damage is one of the challenges that impacts sorghum biomass production. There are at least 150 insect species that can infest sorghum varieties worldwide. These insects can complete several generations within a growing season, they target various parts of sorghum plants at devel- opmental stages, and they cause significant biomass losses. Genetic research has revealed the existence of resistant genetics in sorghum and insect tolerant sorghum varieties have been identified. Various control methods have been developed, yet more effective management is needed for increasing sorghum biomass production. Although there are no transgenic sorghum products on the market yet, biotechnology has been recognized as an important tool for controlling insect pests and increasing sorghum production.

  4. Forest insect pests in Canada

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-11-01

    The papers presented in this book cover the range of forest insect pest management activities in Canada. The first section contains papers on the current status of insect pests by region, including data on insect populations and extent of defoliation caused by the insect. The next section covers pest management technology, including the use of insecticides, insect viruses, fungal pathogens, growth regulators, antifeedants, pheromones, natural predators, and aerial spraying. The third section contains papers on the application of technology and equipment for forest pest control, and includes papers on the impacts of insecticides on the forest environment. The fourth section describes operational control programs by province. The final paper presents future strategies for the management of forest pests. An author index is included.

  5. Application of some insecticides and plant crude extracts for controlling insect pests in yard long bean

    Directory of Open Access Journals (Sweden)

    Wipawadee Chamnan

    2003-05-01

    Full Text Available Tests on plant crude extracts of neem seeds, galanga and citronella grass at the rates of 200 ml/20 L of water together with synthetic insecticides, cypermethrin, methamidophos, carbosulfan and carbofuran, at the recommended rates showed that none of the treatments was effective in controlling plant damage caused by adult of bean fly (Ophiomyia phaseoli Tryon. The application of the synthetic insecticide, methamidophos, and plant crude extracts of neem seeds + galanga + citronella grass provided the highest effectiveness tocontrol aphids (Aphis craccivora Koch. Control of A. craccivora was not significantly different between the synthetic insecticide and plant crude extracts, except methamidophos. Pod damage caused by pod borer (Maruca testulalis Geyer and yields were also not significantly different among treatments. However, the highest yield of 1,224.7 kg/rai was recorded in plots treated with neem seed extracts and the synthetic insecticide, carbosulfan. In untreated plots, the lowest yield of 587.3 kg/rai was collected.

  6. Application of some insecticides and plant crude extracts for controlling insect pests in yard long bean

    OpenAIRE

    2003-01-01

    Tests on plant crude extracts of neem seeds, galanga and citronella grass at the rates of 200 ml/20 L of water together with synthetic insecticides, cypermethrin, methamidophos, carbosulfan and carbofuran, at the recommended rates showed that none of the treatments was effective in controlling plant damage caused by adult of bean fly (Ophiomyia phaseoli Tryon). The application of the synthetic insecticide, methamidophos, and plant crude extracts of neem seeds + galanga + citronella grass prov...

  7. Biological Control beneath the Feet: A Review of Crop Protection against Insect Root Herbivores

    OpenAIRE

    Alan Kergunteuil; Moe Bakhtiari; Ludovico Formenti; Zhenggao Xiao; Emmanuel Defossez; Sergio Rasmann

    2016-01-01

    Sustainable agriculture is certainly one of the most important challenges at present, considering both human population demography and evidence showing that crop productivity based on chemical control is plateauing. While the environmental and health threats of conventional agriculture are increasing, ecological research is offering promising solutions for crop protection against herbivore pests. While most research has focused on aboveground systems, several major crop pests are uniquely fee...

  8. Small GTPase Rab4b participates in the gene transcription of 20-hydroxyecdysone and insulin pathways to regulate glycogen level and metamorphosis.

    Science.gov (United States)

    Hou, Li; Cai, Mei-Juan; Liu, Wen; Song, Qian; Zhao, Xiao-Fan

    2012-11-01

    The insulin and 20-hydroxyecdysone (20E) pathways coordinately regulate insect growth and metamorphosis. However, the molecular mechanism of the interaction of these two pathways in regulating insect development is not well understood. In the present study, we found that a small GTPase Rab4b from a lepidopteran insect Helicoverpa armigera participates in gene transcription in the two pathways. The results show that RNA interference of Rab4b in larvae results in a decrease in glycogen levels, small pupae, abnormal metamorphic transition, or larval death. The molecular mechanisms are demonstrated that knockdown of Rab4b in the larvae suppresses the transcription of glycogen synthase (GS), as well as the metamorphic-initiating factor (Br) and hormone receptor 3 (HR3), but increases the transcription of Forkhead box class O (FOXO). Further studies in the cell line confirm that Rab4b is necessary for gene transcription in the insulin and 20E pathways. Rab4b locates in the cytoplasm and takes part in regulation on FOXO cytoplasmic location by insulin induction, but travels toward the cell membrane upon 20E induction without affecting the FOXO location. The transcription of Rab4b could be upregulated by insulin injection or glucose feeding to the larvae, but not by 20E or juvenile hormone analogy methoprene. Our data suggest that Rab4b takes part in metamorphosis by regulating gene transcription and glycogen level in the insulin and 20E pathways.

  9. RNAi efficiency, systemic properties, and novel delivery methods for pest insect control : what we know so far

    OpenAIRE

    Joga, Mallikarjuna; Zotti, Moises J.; Smagghe, Guy; Christiaens, Olivier

    2016-01-01

    In recent years, the research on the potential of using RNA interference (RNAi) to suppress crop pests has made an outstanding growth. However, given the variability of RNAi efficiency that is observed in many insects, the development of novel approaches toward insect pest management using RNAi requires first to unravel factors behind the efficiency of dsRNA-mediated gene silencing. In this review, we explore essential implications and possibilities to increase RNAi efficiency by delivery of ...

  10. RNAi efficiency, systemic properties and novel delivery methods for pest insect control: what we know so far.

    OpenAIRE

    Mallikarjuna Reddy Joga; Moises João Zotti; Guy Smagghe; Olivier Christiaens

    2016-01-01

    In recent years, the research on the potential of using RNA interference (RNAi) to suppress crop pests has made an outstanding growth. However, given the variability of RNAi efficiency that is observed in many insects, the development of novel approaches towards insect pest management using RNAi requires first to unravel factors behind the efficiency of dsRNA-mediated gene silencing. In this review, we explore essential implications and possibilities to increase RNAi efficiency by delivery of...

  11. Chemosterilant bait stations coupled with sterile insect technique: an integrated strategy to control the Mediterranean fruit fly (Diptera: Tephritidae).

    Science.gov (United States)

    Navarro-Llopis, V; Vacas, S; Sanchis, J; Primo, J; Alfaro, C

    2011-10-01

    During 2008 and 2009, the efficacy of the combination of two Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), control techniques, sterile insect technique (SIT) and a chemosterilant bait station system (Adress), was tested in three crops: citrus (Citrus spp.), stone fruit (Prunus spp.), and persimmon (Diospyros spp.). Two thousand sterile males were released per ha each week in the whole trial area (50,000 ha, SIT area). For 3,600 ha, within the whole trial area, 24 Adress traps per ha were hung (SIT + Adress area). Ten SIT + Adress plots and 10 SIT plots in each of three different fruit crops were arranged to assess Mediterranean fruit fly population densities and fruit damage throughout the trial period. To evaluate the efficacy of each treatment, the male and female populations were each monitored from August 2008 to November 2009, and injured fruit was assessed before harvest. Results showed a significant reduction in the C. capitata population in plots treated with both techniques versus plots treated only with the SIT. Likewise, a corresponding reduction in the percentage of injured fruit was observed. These data indicate the compatibility of these techniques and suggest the possibility of using Adress coupled with SIT to reduce C. capitata populations in locations with high population densities, where SIT alone is not sufficiently effective to suppress fruit fly populations to below damaging levels.

  12. Advances in RNA interference technology and its impact on nutritional improvement, disease and insect control in plants.

    Science.gov (United States)

    Katoch, Rajan; Thakur, Neelam

    2013-03-01

    This review highlights the advances in the knowledge of RNA interference (RNAi) and discusses recent progress on the functionality of different components RNAi machinery operating in the organisms. The silencing of genes by RNA interference has become the technology of choice for investigation of gene functions in different organisms. The refinement in the knowledge of the endogenous RNAi pathways in plants along with the development of new strategies and applications for the improvement of nutritional value of important agricultural crops through suppression of genes in different plants have opened new vistas for nutritional security. The improvement in the nutritional status of the plants and reduction in the level of toxins or antinutrients was desired for long, but the available technology was not completely successful in achieving the tissue specific regulation of some genes. In the recent years, a number of economically important crop plants have been tested successfully for improving plant nutritional value through metabolic engineering using RNAi. The implications of this technology for crop improvement programs, including nutritional enrichment, reduction of antinutrients, disease, and insect control have been successfully tested in variety of crops with commercial considerations. The enhancement of the nutraceutical traits for the desired health benefits in common crop plants through manipulation of gene expression has been elaborated in this article. The tremendous potential with RNAi technology is expected to revolutionize the modern agriculture for meeting the growing challenges is discussed.

  13. Flight Services and Aircraft Access: Active Flow Control Vertical Tail and Insect Accretion and Mitigation Flight Test

    Science.gov (United States)

    Whalen, Edward A.

    2016-01-01

    This document serves as the final report for the Flight Services and Aircraft Access task order NNL14AA57T as part of NASA Environmentally Responsible Aviation (ERA) Project ITD12A+. It includes descriptions of flight test preparations and execution for the Active Flow Control (AFC) Vertical Tail and Insect Accretion and Mitigation (IAM) experiments conducted on the 757 ecoDemonstrator. For the AFC Vertical Tail, this is the culmination of efforts under two task orders. The task order was managed by Boeing Research & Technology and executed by an enterprise-wide Boeing team that included Boeing Research & Technology, Boeing Commercial Airplanes, Boeing Defense and Space and Boeing Test and Evaluation. Boeing BR&T in St. Louis was responsible for overall Boeing project management and coordination with NASA. The 757 flight test asset was provided and managed by the BCA ecoDemonstrator Program, in partnership with Stifel Aircraft Leasing and the TUI Group. With this report, all of the required deliverables related to management of this task order have been met and delivered to NASA as summarized in Table 1. In addition, this task order is part of a broader collaboration between NASA and Boeing.

  14. Effect of atrazine on metamorphosis and sexual differentiation in Xenopus laevis.

    Science.gov (United States)

    Oka, Tomohiro; Tooi, Osamu; Mitsui, Naoko; Miyahara, Maki; Ohnishi, Yuta; Takase, Minoru; Kashiwagi, Akihiko; Shinkai, Tadashi; Santo, Noriaki; Iguchi, Taisen

    2008-05-30

    There is a growing international concern that commonly used environmental contaminants have the potential to disrupt the development and functioning of the reproductive system in amphibians. One such chemical of interests is the herbicide atrazine. Effects of atrazine on sex differentiation were studied using wild-type Xenopus laevis tadpoles and all-ZZ male cohorts of X. laevis tadpoles, produced by mating wild-type ZZ male to sex-reversed ZZ male (female phenotype). Stage 49 tadpoles were exposed to 0.1-100 ppb atrazine or 0.27 ppb (1 nM) 17beta-estradiol (E(2)) until all larvae completed metamorphosis (stage 66). Metamorphosis, gonadal morphology and histology, CYP19 (P450 aromatase) mRNA induction, and hepatic vitellogenin (VTG) induction were investigated. Effects of atrazine on VTG-induction were also assessed in vitro in primary-cultured X. laevis hepatocytes. Atrazine had no effect on metamorphosis of developing wild-type or all-male X. laevis larvae. Statistical increase in female ratios was observed in 10 and 100 ppb atrazine groups in comparison with control group. While no hermaphroditic froglet was observed in all atrazine groups. In ZZ males, sex reversal was induced by 0.27 ppb E(2), but not by atrazine at concentrations of 0.1 and 1.0 ppb. In addition, neither P450 aromatase mRNA in the gonad nor hepatic VTG were induced by atrazine. Furthermore, VTG was not induced by 1000 ppb atrazine in primary-cultured hepatocytes. Our results indicate that female ratios in developing X. laevis tadpoles were increased by 10 and 100 ppb atrazine under the present experimental conditions. While the other endpoints showed no effect in the range of 0.1-100 ppb atrazine. These results suggest that effect of atrazine on sexual differentiation was not caused by estrogenic action and has no induction ability of P450 aromatase gene in gonad.

  15. Direct plantlet inoculation with soil or insect-associated fungi may control cabbage root fly maggots.

    Science.gov (United States)

    Razinger, Jaka; Lutz, Matthias; Schroers, Hans-Josef; Palmisano, Marilena; Wohler, Christian; Urek, Gregor; Grunder, Jürg

    2014-07-01

    A potential Delia radicum biological control strategy involving cauliflower plantlet inoculation with various fungi was investigated in a series of laboratory and glasshouse experiments. In addition to entomopathogenic fungi, fungi with a high rhizosphere competence and fungi with the ability to survive as saprotrophs in soil were tested. The following fungal species were evaluated in the experiments: Trichoderma atroviride, T. koningiopsis, T. gamsii, Beauveria bassiana, Metharhizium anisopliae, M. brunneum and Clonostachys solani. A commercial carbosulfan-based insecticide was used as a positive control. Additionally, two commercial products, one based on B. bassiana (Naturalis) and one on Bacillus thuringiensis (Delfin) were used as reference biocontrol agents. The aims were (i) to assess the pathogenicity of the selected fungal isolates to Delia radicum, (ii) to evaluate the fungal isolates' rhizosphere competence, with the emphasis on the persistence of the original inoculum on the growing roots, (iii) to assess possible endophytic plant tissue colonization, and (iv) to evaluate potential plant growth stimulating effects of the added inoculi. Significant pathogenicity of tested fungi against Delia radicum was confirmed in in vitro and glasshouse experiments. All tested fungi persisted on cauliflower rhizoplane. More importantly, the added fungi were found on thoroughly washed roots outside the original point of inoculation. This provided us with evidence that our tested fungi could be transferred via or grow with the elongating roots. In addition to colonizing the rhizoplane, some fungi were found inside the plant root or stem tissue, thus exhibiting endophytic characteristics. The importance of fungal ecology as a criterion in appropriate biological control agent selection is discussed. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. 莫桑比克腰果病虫害种类及其防治%Diseases and Insect Pests of Cashew in Mozambique and Their Control

    Institute of Scientific and Technical Information of China (English)

    梁李宏; 张中润; Americo Uaciquete; 黄海杰

    2011-01-01

    The category and damage of diseases and insect pests of cashew in Nampula, Inhambane, Gaza and Maputo provinces in Mozambique were studied, 8 species of diseases and 39 species of insect pests were identified. The major diseases were powdery mildew and anthracnose, and the major insect pests were tea mosquito bug (Helopeltis schoutedeni Reuter and Helopeltis anacardii Miller), coconut bug (Pseudothe rap tits wayi Brown), cashew weevil (Mecocorynus loripes Chevrolat) and red-banded thrip (Selenothrips rubrocinctus (Ciard)). Control measures for major diseases and insect pests of cashew in Mozambique were also given in this paper.%在莫桑比克楠普拉省、伊尼扬巴内省、加扎省和马普托省对腰果病虫害进行了系统的调查,发现为害腰果的病害8种,害虫39种.其中主要病害有白粉病和炭疽病,主要害虫有棉角盲蝽、安氏角盲蝽、椰缘蝽、腰果鹰嘴象甲和红带蓟马.并对莫桑比克主要腰果病虫害提出了相应的防治措施.

  17. Effectiveness of Sulfuryl Fluoride Fumigation for the Control of Phosphine-Resistant Grain Insects Infesting Stored Wheat.

    Science.gov (United States)

    Opit, George P; Thoms, Ellen; Phillips, Thomas W; Payton, Mark E

    2016-04-01

    A field experiment was conducted in eight 13.6-MT steel bins containing 6.8 MT each of wheat to assess efficacy of sulfuryl fluoride or SF fumigant to control phosphine-resistant and susceptible Rhyzopertha dominica (F.) and Tribolium castaneum (Herbst). Approximately 400 adults of each type of beetle were added to each bin. Additionally, muslin bags containing immature stages and adults, with their respective diets, were also placed in bins. Four bins were fumigated with SF and others were untreated control bins. The SF dosages in treated bins ranged from 1,196–1,467 mg-h/liter. Mortality of adults in each bag was assessed 5 d postfumigation; diet minus adults was incubated in a jar, and number of adults counted after 8 wk. No significant change occurred in number of insect-damaged kernels in SF-treated bins. In trier samples from SF-treated bins, R. dominica numbers declined from 24 prefumigation to 0 at 3- and 6-wk postfumigation; T. castaneum numbers were unchanged. In WBII traps from SF-treated bins, numbers R. dominica and T. castaneum declined from 25 and 33, respectively, prefumigation to 0 or near 0 at 3- and 6-wk postfumigation. Mortalities of resistant and susceptible adult R. dominica, and adult and large larvae of T. castaneum in SF-treated bags was 100%. For all four types of beetles, adult numbers in jars associated with SF-treated bins were 0 or near 0. Results show SF is effective against all life stages of phosphine-resistant R. dominica and T. castaneum, and can be used for phosphine resistance management.

  18. Metal ions control product specificity of isoprenyl diphosphate synthases in the insect terpenoid pathway

    Science.gov (United States)

    Frick, Sindy; Nagel, Raimund; Schmidt, Axel; Bodemann, René R.; Rahfeld, Peter; Pauls, Gerhard; Brandt, Wolfgang; Gershenzon, Jonathan; Boland, Wilhelm; Burse, Antje

    2013-01-01

    Isoprenyl diphosphate synthases (IDSs) produce the ubiquitous branched-chain diphosphates of different lengths that are precursors of all major classes of terpenes. Typically, individual short-chain IDSs (scIDSs) make the C10, C15, and C20 isoprenyl diphosphates separately. Here, we report that the product length synthesized by a single scIDS shifts depending on the divalent metal cofactor present. This previously undescribed mechanism of carbon chain-length determination was discovered for a scIDS from juvenile horseradish leaf beetles, Phaedon cochleariae. The recombinant enzyme P. cochleariae isoprenyl diphosphate synthase 1 (PcIDS1) yields 96% C10-geranyl diphosphate (GDP) and only 4% C15-farnesyl diphosphate (FDP) in the presence of Co2+ or Mn2+ as a cofactor, whereas it yields only 18% C10 GDP but 82% C15 FDP in the presence of Mg2+. In reaction with Co2+, PcIDS1 has a Km of 11.6 μM for dimethylallyl diphosphate as a cosubstrate and 24.3 μM for GDP. However, with Mg2+, PcIDS1 has a Km of 1.18 μM for GDP, suggesting that this substrate is favored by the enzyme under such conditions. RNAi targeting PcIDS1 revealed the participation of this enzyme in the de novo synthesis of defensive monoterpenoids in the beetle larvae. As an FDP synthase, PcIDS1 could be associated with the formation of sesquiterpenes, such as juvenile hormones. Detection of Co2+, Mn2+, or Mg2+ in the beetle larvae suggests flux control into C10 vs. C15 isoprenoids could be accomplished by these ions in vivo. The dependence of product chain length of scIDSs on metal cofactor identity introduces an additional regulation for these branch point enzymes of terpene metabolism. PMID:23440195

  19. Maturation of muscle properties and its hormonal control in an adult insect.

    Science.gov (United States)

    Rose, U; Ferber, M; Hustert, R

    2001-10-01

    muscles from males (M214) revealed no comparable changes, although some minor changes occurred during reproductive development. The results suggest a gender- and segment-specific maturation of muscle properties that is related to reproductive behaviour and controlled by JH.

  20. Insect abatement system

    Science.gov (United States)

    Spiro, Clifford Lawrence (Inventor); Burnell, Timothy Brydon (Inventor); Wengrovius, Jeffrey Hayward (Inventor)

    1997-01-01

    An insect abatement system prevents adhesion of insect debris to surfaces which must be kept substantially free of insect debris. An article is coated with an insect abatement coating comprising polyorganosiloxane with a Shore A hardness of less than 50 and a tensile strength of less than 4 MPa. A method for preventing the adhesion of insect debris to surfaces includes the step of applying an insect abatement coating to a surface which must be kept substantially free of insect debris.

  1. Novel control methods for insect pests: development of a microencapsulation procedure for proteinaceous bioactives intended for oral delivery.

    Science.gov (United States)

    Richards, Elaine H; Wontner-Smith, Tim; Bradish, Hannah; Dani, M Paulina; Cotterill, Jane V

    2015-09-01

    The objective was to develop an environmentally favourable microcapsule suitable for delivery of proteinaceous bioactive agents ('bioinsecticides') to pest insects. Utilising feeding bioassays, we determined that microspheres made of alginate can be produced in a variety of sizes and are palatable and non-toxic to larvae of the lepidopteran pest Lacanobia oleracea. Dehydrated microspheres were also readily ingested by larvae. Using a novel feeding bioassay and alginate microspheres containing a fluorescent marker material (coumarin 7 encapsulated in styrene maleic anhydride beads), we determined that the microspheres successfully deliver the marker to the insect gut. Moreover, the alginate microspheres rapidly break down in the alkaline conditions of the insect gut and release their contents, the beads passing through the gut in 2-3 h. Using bovine serum albumin as a test protein and western blotting, it was determined that alginate can successfully encapsulate protein, and that the microspheres can be stored in a CaCl2 solution for up to 24 days without extensive leakage. Importantly, it was also determined that alginate and the microsphere-making procedure developed do not inactivate rVPr1 (an insect immunosuppressive protein and potential bioinsecticide). An alginate-based microsphere has potential to deliver the proteinaceous bioactive rVPr1 to pest insects. © 2014 Crown copyright. Pest Management Science © 2014 Society of Chemical Industry.

  2. Bacillus thuringiensis protein production, signal transduction, and insect control in chemically inducible PR-1a/cry1Ab broccoli plants.

    Science.gov (United States)

    Cao, Jun; Bates, Sarah L; Zhao, Jian-Zhou; Shelton, Anthony M; Earle, Elizabeth D

    2006-06-01

    In an effort to develop a chemically inducible system for insect management, we studied production of Cry1Ab Bacillus thuringiensis (Bt) protein and control of the diamondback moth (DBM), Plutella xylostella L., in inducer-treated and untreated tissues of a broccoli line transformed with a PR-1a/cry1Ab expression cassette. Spraying leaves of these plants with the inducer acibenzolar-S-methyl (= 1,2,3 benzothiadiazole-7-thiocarboxylic acid-S-methyl-ester) (ASM) triggered expression of the cry1Ab gene and produced a high level of Cry1Ab protein within 2-3 days. Cry1Ab protein persisted in leaves for at least 8 weeks, providing prolonged protection from P. xylostella attack. Signals generated in inducer-treated leaves were transferred to untreated newly emerged leaves or heads, as seen by production of Cry1Ab protein and/or protection from insect damage in these plant parts. Signal transduction proceeded in an attenuated manner up to the sixth newly emerged leaf. No Cry1Ab protein was detectable by ELISA in uninduced young leaves, but small amounts of the protein were present in uninduced leaves older than 3 weeks and caused some insect mortality. Such basal expression of Bt genes without induction may favor the evolution of resistant insect populations and therefore limits the application of the PR-1a/cry1Ab system for insect management. However, the rapid production and steady maintenance of a high level of transgenic protein upon induction, the signal transduction observed, and the fact that the chemical inducer can be used in field conditions make the PR-1a promoter attractive for chemical regulation of other agriculturally or pharmaceutically important genes for which low expression in the absence of induction is not a concern.

  3. A six-year study of insect emergence from temporary flooded wetlands in central Sweden, with and without Bti-based mosquito control.

    Science.gov (United States)

    Persson Vinnersten, T Z; Lundström, J O; Schäfer, M L; Petersson, E; Landin, J

    2010-12-01

    In temporary wetlands in the River Dalälven floodplains, recurrent but irregular floods induce massive hatching of the flood-water mosquito Aedes sticticus, which causes enormous nuisance. Flood-water mosquito control using the biological larvicide Bacillus thuringiensis var. israelensis (Bti) was commenced in parts of the floodplains during 2002, and here we report the first six years of full-season monitoring of general insect emergence from temporary wetlands with and without treatment. Emergence traps, which were emptied weekly, were used from May to September each year. A total of 137,153 insects of 13 taxonomic orders were collected. Diptera was highly dominating and especially the sub-order Nematocera with 18 families was a very prominent taxon. Bti-treatment effects were analysed by taxonomic order, by sub-order in Diptera and Hemiptera, and by family for Nematocera and Coleoptera for the whole study period. We found no significant negative effects of Bti treatments on the production of insects by taxonomic order, with the exception of Coleoptera in the long term. However, no significant negative effects were found for the Coleoptera families, neither in the short term nor in the long term. There was no significant negative treatment effect on Nematocera production, neither when analyzed for the whole sub-order nor when analyzed by family. However, abundance of Ceratopogonidae was significantly higher in experimental than in reference wetlands. We conclude that Bti-treatment effects on insect production may be minute in comparison to other environmental factors structuring the insect fauna of the temporary wetlands studied.

  4. Fungal ecdysteroid-22-oxidase, a new tool for manipulating ecdysteroid signaling and insect development.

    Science.gov (United States)

    Kamimura, Manabu; Saito, Hitoshi; Niwa, Ryusuke; Niimi, Teruyuki; Toyoda, Kinuko; Ueno, Chihiro; Kanamori, Yasushi; Shimura, Sachiko; Kiuchi, Makoto

    2012-05-11

    Steroid hormones ecdysteroids regulate varieties of developmental processes in insects. Although the ecdysteroid titer can be increased experimentally with ease, its artificial reduction, although desirable, is very difficult to achieve. Here we characterized the ecdysteroid-inactivating enzyme ecdysteroid-22-oxidase (E22O) from the entomopathogenic fungus Nomuraea rileyi and used it to develop methods for reducing ecdysteroid titer and thereby controlling insect development. K(m) and K(cat) values of the purified E22O for oxidizing ecdysone were 4.4 μM and 8.4/s, respectively, indicating that E22O can inactivate ecdysone more efficiently than other ecdysteroid inactivating enzymes characterized so far. The cloned E22O cDNA encoded a FAD-dependent oxidoreductase. Injection of recombinant E22O into the silkworm Bombyx mori interfered with larval molting and metamorphosis. In the hemolymph of E22O-injected pupae, the titer of hormonally active 20-hydroxyecdysone decreased and concomitantly large amounts of inactive 22-dehydroecdysteroids accumulated. E22O injection also prevented molting of various other insects. In the larvae of the crambid moth Haritalodes basipunctalis, E22O injection induced a diapause-like developmental arrest, which, as in normal diapause, was broken by chilling. Transient expression of the E22O gene by in vivo lipofection effectively decreased the 20-hydroxyecdysone titer and blocked molting in B. mori. Transgenic expression of E22O in Drosophila melanogaster caused embryonic morphological defects, phenotypes of which were very similar to those of the ecdysteroid synthesis deficient mutants. Thus, as the first available simple but versatile tool for reducing the internal ecdysteroid titer, E22O could find use in controlling a broad range of ecdysteroid-associated developmental and physiological phenomena.

  5. Ecdysteroids, juvenile hormone and insect neuropeptides: Recent successes and remaining major challenges.

    Science.gov (United States)

    De Loof, Arnold

    2008-01-01

    In the recent decade, tremendous progress has been realized in insect endocrinology as the result of the application of a variety of advanced methods in neuropeptidome- and receptor research. Hormones of which the existence had been shown by bioassays four decades ago, e.g. bursicon (a member of the glycoprotein hormone family) and pupariation factor (Neb-pyrokinin 2, a myotropin), could be identified, along with their respective receptors. In control of diurnal rhythms, clock genes got company from the neuropeptide Pigment Dispersing Factor (PDF), of which the receptor could also be identified. The discovery of Inka cells and their function in metamorphosis was a true hallmark. Analysis of the genomes of Caenorhabditis elegans, Drosophila melanogaster and Apis mellifera yielded about 75, 100 and 200 genes coding for putative signaling peptides, respectively, corresponding to approximately 57, 100 and 100 peptides of which the expression could already be proven by means of mass spectrometry. The comparative approach invertebrates-vertebrates recently yielded indications for the existence of counterparts in insects for prolactin, atrial natriuretic hormone and Growth Hormone Releasing Hormone (GRH). Substantial progress has been realized in identifying the Halloween genes, a membrane receptor(s) for ecdysteroids, a nuclear receptor for methylfarnesoate, and dozens of GPCRs for insect neuropeptides. The major remaining challenges concern the making match numerous orphan GPCRs with orphan peptidic ligands, and elucidating their functions. Furthermore, the endocrine control of growth, feeding-digestion, and of sexual differentiation, in particular of males, is still poorly understood. The finding that the prothoracic glands produce an autocrine factor with growth factor-like properties and secrete proteins necessitates a reevaluation of their role in development.

  6. Control Effects of Two-Batch-Duck Raising with Rice Framing on Rice Diseases, Insect Pests and Weeds in Paddy Field

    Directory of Open Access Journals (Sweden)

    Kai-ming Liang

    2012-10-01

    Full Text Available Rice-duck farming system is one of the means of organic rice farming, in which the weeds, diseases and insects could be effectively controlled with minimal or no pesticide and herbicide application. Whereas in conventional rice-duck farming system the controlling effect on diseases, insect pests and weeds was slowly disappeared after the rice heading stage at which ducks were driven out of the paddy field. To fill up the blank period of pasture activities of ducks, this study put forward two new rice-duck farming systems innovated from the conventional rice-duck farming system, in these new systems, two batches of ducks were raised with rice within one rice planting season. The results revealed that the overall controlling effect of ducks on rice diseases, insect pest and weeds was significantly enhanced in the two new rice-duck farming systems without agrochemicals application. It might be suggested that these two new systems have potential application as biocontrol agent for the organic rice agriculture.

  7. Insecticidal, repellent, antimicrobial activity and phytotoxicity of essential oils: With special reference to limonene and its suitability for control of insect pests

    Directory of Open Access Journals (Sweden)

    M.A. IBRAHIM

    2008-12-01

    Full Text Available The interest in the use of monoterpenes for insect pest and pathogen control originates from the need for pesticide products with less negative environmental and health impacts than highly effective synthetic pesticides. The expanding literature on the possibility of the use of these monoterpenes is reviewed and focused on the effects of limonene on various bioorganisms. Limonene is used as insecticide to control ectoparasites of pet animals, but it has activity against many insects, mites, and microorganisms. Possible attractive effects of limonene to natural enemies of pests may offer novel applications to use natural compounds for manipulation of beneficial animals in organic agriculture. However, in few cases limonene-treated plants have become attractive to plant damaging insects and phytotoxic effects on cultivated plants have been observed. As a plant-based natural product limonene and other monoterpenes might have use in pest and weed control in organic agriculture after phytotoxicity on crop plants and, effects on non-target soil animals and natural enemies of pest have been investigated

  8. Control of insects with fumigants at low temperatures: toxicity of mixtures of methyl bromide and acrylonitrile to three species of insects

    Energy Technology Data Exchange (ETDEWEB)

    Bond, E.J.; Buckland, C.T.

    1976-12-15

    Acrylonitrile can be mixed with methyl bromide to increase toxicity so that the quantity of methyl bromide required for control of Sitophilus granarius (L.), Tenebrio molitor L., and Tribolium confusum Jacquelin duval is reduced by one half. Mixtures of methyl bromide and acrylonitrile are considerably more effective at low temperatures than methyl bromide alone.

  9. RNAi Efficiency, Systemic Properties, and Novel Delivery Methods for Pest Insect Control: What We Know So Far.

    Science.gov (United States)

    Joga, Mallikarjuna R; Zotti, Moises J; Smagghe, Guy; Christiaens, Olivier

    2016-01-01

    In recent years, the research on the potential of using RNA interference (RNAi) to suppress crop pests has made an outstanding growth. However, given the variability of RNAi efficiency that is observed in many insects, the development of novel approaches toward insect pest management using RNAi requires first to unravel factors behind the efficiency of dsRNA-mediated gene silencing. In this review, we explore essential implications and possibilities to increase RNAi efficiency by delivery of dsRNA through non-transformative methods. We discuss factors influencing the RNAi mechanism in insects and systemic properties of dsRNA. Finally, novel strategies to deliver dsRNA are discussed, including delivery by symbionts, plant viruses, trunk injections, root soaking, and transplastomic plants.

  10. RNAi Efficiency, Systemic Properties, and Novel Delivery Methods for Pest Insect Control: What We Know So Far

    Science.gov (United States)

    Joga, Mallikarjuna R.; Zotti, Moises J.; Smagghe, Guy; Christiaens, Olivier

    2016-01-01

    In recent years, the research on the potential of using RNA interference (RNAi) to suppress crop pests has made an outstanding growth. However, given the variability of RNAi efficiency that is observed in many insects, the development of novel approaches toward insect pest management using RNAi requires first to unravel factors behind the efficiency of dsRNA-mediated gene silencing. In this review, we explore essential implications and possibilities to increase RNAi efficiency by delivery of dsRNA through non-transformative methods. We discuss factors influencing the RNAi mechanism in insects and systemic properties of dsRNA. Finally, novel strategies to deliver dsRNA are discussed, including delivery by symbionts, plant viruses, trunk injections, root soaking, and transplastomic plants. PMID:27909411

  11. Solutions to the cocktail party problem in insects: selective filters, spatial release from masking and gain control in tropical crickets.

    Directory of Open Access Journals (Sweden)

    Arne K D Schmidt

    Full Text Available Insects often communicate by sound in mixed species choruses; like humans and many vertebrates in crowded social environments they thus have to solve cocktail-party-like problems in order to ensure successful communication with conspecifics. This is even more a problem in species-rich environments like tropical rainforests, where background noise levels of up to 60 dB SPL have been measured.Using neurophysiological methods we investigated the effect of natural background noise (masker on signal detection thresholds in two tropical cricket species Paroecanthus podagrosus and Diatrypa sp., both in the laboratory and outdoors. We identified three 'bottom-up' mechanisms which contribute to an excellent neuronal representation of conspecific signals despite the masking background. First, the sharply tuned frequency selectivity of the receiver reduces the amount of masking energy around the species-specific calling song frequency. Laboratory experiments yielded an average signal-to-noise ratio (SNR of -8 dB, when masker and signal were broadcast from the same side. Secondly, displacing the masker by 180° from the signal improved SNRs by further 6 to 9 dB, a phenomenon known as spatial release from masking. Surprisingly, experiments carried out directly in the nocturnal rainforest yielded SNRs of about -23 dB compared with those in the laboratory with the same masker, where SNRs reached only -14.5 and -16 dB in both species. Finally, a neuronal gain control mechanism enhances the contrast between the responses to signals and the masker, by inhibition of neuronal activity in interstimulus intervals.Thus, conventional speaker playbacks in the lab apparently do not properly reconstruct the masking noise situation in a spatially realistic manner, since under real world conditions multiple sound sources are spatially distributed in space. Our results also indicate that without knowledge of the receiver properties and the spatial release mechanisms the

  12. Perception of insect feeding by plants.

    Science.gov (United States)

    Bonaventure, G

    2012-11-01

    The recognition of phytophagous insects by plants induces a set of very specific responses aimed at deterring tissue consumption and reprogramming metabolism and development of the plant to tolerate the herbivore. The recognition of insects by plants requires the plant's ability to perceive chemical cues generated by the insects and to distinguish a particular pattern of tissue disruption. Relatively little is known about the molecular basis of insect perception by plants and the signalling mechanisms directly associated with this perception. Importantly, the insect feeding behaviour (piercing-sucking versus chewing) is a decisive determinant of the plant's defence response, and the mechanisms used to perceive insects from different feeding guilds may be distinct. During insect feeding, components of the saliva of chewing or piercing-sucking insects come into contact with plant cells, and elicitors or effectors present in this insect-derived fluid are perceived by plant cells to initiate the activation of specific signalling cascades. Although receptor-ligand interactions controlling insect perception have yet not been molecularly described, a significant number of regulatory components acting downstream of receptors and involved in the activation of defence responses against insects has been reported. Some of these regulators mediate changes in the phytohormone network, while others directly control gene expression or the redox state of the cell. These processes are central in the orchestration of plant defence responses against insects.

  13. Mass Releases of Genetically Modified Insects in Area-Wide Pest Control Programs and Their Impact on Organic Farmers

    Directory of Open Access Journals (Sweden)

    R. Guy Reeves

    2017-01-01

    Full Text Available The mass release of irradiated insects to reduce the size of agricultural pest populations of the same species has a more than 50-year record of success. Using these techniques, insect pests can be suppressed without necessarily dispersing chemical insecticides into the environment. Ongoing release programs include the suppression of medfly at numerous locations around the globe (e.g., California, Chile and Israel and the pink bollworm eradication program across the southern USA and northern Mexico. These, and other successful area-wide programs, encompass a large number of diverse organic farms without incident. More recently, mass release techniques have been proposed that involve the release of genetically modified insects. Given that the intentional use of genetically modified organisms by farmers will in many jurisdictions preclude organic certification, this prohibits the deliberate use of this technology by organic farmers. However, mass releases of flying insects are not generally conducted by individual farmers but are done on a regional basis, often without the explicit consent of all situated farms (frequently under the auspices of government agencies or growers’ collectives. Consequently, there exists the realistic prospect of organic farms becoming involved in genetically modified insect releases as part of area-wide programs or experiments. Herein, we describe genetically modified insects engineered for mass release and examine their potential impacts on organic farmers, both intended and unintended. This is done both generally and also focusing on a hypothetical organic farm located near an approved experimental release of genetically modified (GM diamondback moths in New York State (USA.

  14. On natural metamorphosis inducers of the cnidarians Hydractinia echinata (Hydrozoa) and Aurelia aurita (Scyphozoa)

    Science.gov (United States)

    Kroiher, M.; Berking, S.

    1999-11-01

    Hydractinia echinata and Aurelia aurita produce motile larvae which undergo metamorphosis to sessile polyps when induced by external cues. The polyps are found at restricted sites, A. aurita predominantly on rocks close to the shore, H. echinata on shells inhabited by hermit crabs. It has been argued that the differential distribution of the polyps in their natural environment largely reflects the distribution of the natural metamorphosis-inducing cues. In the case of H. echinata, bacteria of the genus Alteromonas were argued to meet these conditions. We found that almost all substrates collected in the littoral to induce metamorphosis in H. echinata, and several bacterial strains isolated from the sea, including the common E. coli, induce metamorphosis efficiently. In A. aurita metamorphosis may be induced by the water-air interface, whereby metamorphosis precedes (final) settlement.

  15. Electromagnetic levitation platform for wireless study of insect flight neurophysiology.

    Science.gov (United States)

    Verderber, Alexander; McKnight, Michael; Bozkurt, Alper

    2013-01-01

    An electromagnetic levitation platform for use in a light emitting diode (LED) arena based virtual reality environment was developed for wireless recording of neural and neuromuscular signals from the flight related muscle groups in Manduca sexta. The platform incorporates the use of Early Metamorphosis Insertion Technology to implant recording electrodes into the flight muscles of late stage pupal moths. Analysis of the insects' response to changes in the LED arena rotation direction indicate that this setup could be used to perform a variety of flight behavior studies during yaw maneuvers.

  16. Developmental checkpoints and feedback circuits time insect maturation

    DEFF Research Database (Denmark)

    Rewitz, Kim Furbo; Yamanaka, Naoki; O'Connor, Michael B.

    2013-01-01

    Abstract The transition from juvenile to adult is a fundamental process that allows animals to allocate resource toward reproduction after completing a certain amount of growth. In insects, growth to a species-specific target size induces pulses of the steroid hormone ecdysone that triggers...... metamorphosis and reproductive maturation. The past few years have seen significant progress in understanding the interplay of mechanisms that coordinate timing of ecdysone production and release. These studies show that the neuroendocrine system monitors complex size-related and nutritional signals, as well...

  17. Insect Development in Altered Gravitational Environment

    Science.gov (United States)

    Tischler, Marc E.

    1996-01-01

    When tobacco hornworm (Manduca sexta) larvae burrow underground (25-30 cm) to pupate, they reorient themselves to a relatively horizontal position indicating an ability to sense gravity. To evaluate their sensitivity to gravitational environment during metamorphosis, Manduca (pharate adults) were placed in a vertical (head-up) position. Distinct morphological changes, each one reflecting ensuing phases, were used to follow adult development. Five days after pupation, the vertical group showed accelerated (P less than 0.05) development and were nearly 4 phases ahead (P less than 0.0001) after 10 days. Differences in development in the vertical group were characterized further by increased (7-48%) hemolymph concentrations of 13 amino acids, but a decrease in cys and pro and no change in arg, his, met and val (trp, undetectable). Decreased (36%) turnover of injected H-3 - phenylalanine suggested slower utilization of amino acids contributed, at least partly, to the increased concentrations. Vertically-oriented Manduca also exhibited a greater (20 %, P less than 0.001) protein content in their flight muscles near the end of development. Analysis of hemolymph sugar levels showed a redistribution of sugars from the monosaccharide glucose to the disaccharide trehalose. Since injection of 20-hydroxyecdysone decreased (49%) turnover of H-3- phenylalanine in pharate adults and since ecdysteroids are known to increase flight muscle size and control adult development, these results are consistent with our measuring a greater (+80%, P less than 0.05) ecdysteroid titer in the vertically-oriented insects. These results suggest that gravity environment influences ecdysone output by the pharate adult. When we evaluated hemolymph flow in the head-up and control positions, we found that injected C-14-inulin was distributed somewhat more rapidly in the head-up group irrespective of the sight of injection (head or abdomen) likely because in the head-up position flow of the hemolymph is

  18. Effects of dexamethasone treatment on iodothyronine deiodinase activities and on metamorphosis-related morphological changes in the axolotl (Ambystoma mexicanum).

    Science.gov (United States)

    Darras, Veerle M; Van der Geyten, Serge; Cox, Clara; Segers, Ilse B; De Groef, Bert; Kühn, Eduard R

    2002-06-15

    In amphibians, there is a close interaction between the interrenal and the thyroidal axes. Hypothalamic corticotropin-releasing hormone or related peptides stimulate thyroidal activity by increasing thyrotropin synthesis and release, while corticosterone accelerates both spontaneous and thyroid hormone-induced metamorphosis. One of the mechanisms that is thought to contribute to this acceleration is a corticosterone-induced change in peripheral deiodinating activity. The present experiments were designed to investigate further the effects of glucocorticoid treatment on amphibian deiodinase activities and to explore the possible role of these effects in metamorphosis. Neotenic axolotls (Ambystoma mexicanum) were treated either acutely or chronically with dexamethasone (DEX) and changes in type II and type III iodothyronine deiodinase (D2 and D3) activities were studied in liver, kidney, and brain. In addition, gill length, tail height, and body weight were measured at regular intervals in the chronically treated animals in search of metamorphosis-related changes. A single injection of 50 microg DEX decreased hepatic D3 activity (6-48 h) while it increased D2 activity in brain (6-48 h) and to a lesser extent in kidney (24 h). These changes were accompanied by an increase in plasma T(3) levels (48 h). Samples taken during chronic treatment with 20 or 100 microg DEX showed that both hepatic D2 and D3 activities were decreased on day 26, while renal D3 activity was decreased but only in the 20 microg dose group. All other deiodinase activities were not different from those in control animals. At 25 days, all DEX-treated axolotls showed a clear reduction in gill length, tail height, and body weight, changes typical of metamorphosis. Prolongation of the treatment up to 48 days resulted in complete gill resorption by days 44-60. Although probably several mechanisms contribute to these DEX-induced metamorphic changes, the interaction with thyroid function via a sustained

  19. Triclosan exposure results in alterations of thyroid hormone status and retarded early development and metamorphosis in Cyprinodon variegatus.

    Science.gov (United States)

    Schnitzler, Joseph G; Frédérich, Bruno; Dussenne, Mélanie; Klaren, Peter H M; Silvestre, Frédéric; Das, Krishna

    2016-12-01

    Thyroid hormones are critically involved in somatic growth, development and metamorphosis of vertebrates. The structural similarity between thyroid hormones and triclosan, an antimicrobial compound widely employed in consumer personal care products, suggests triclosan can have adverse effects on the thyroid system. The sheepshead minnow, Cyprinodon variegatus, is now used in ecotoxicological studies that have recently begun to focus on potential disruption of the thyroid axis by endocrine disrupting compounds. Here, we investigate the in vivo effects of exposure to triclosan (20, 50, and 100μgL(-1)) on the thyroid system and the embryonic and larval development of C. variegatus. Triclosan exposure did not affect hatching success, but delayed hatching time by 6-13h compared to control embryos. Triclosan exposure affected the ontogenetic variations of whole body thyroid hormone concentrations during the larval phase. The T3 peak around 12-15 dph, described to be indicative for the metamorphosis climax in C. variegatus, was absent in triclosan-exposed larvae. Triclosan exposure did not produce any deformity or allometric repatterning, but a delayed development of 18-32h was observed. We conclude that the triclosan-induced disruption of the thyroid system delays in vivo the start of metamorphosis in our experimental model. We observed a global developmental delay of 24-45h, equivalent to 4-7% prolongation of the developmental time in C. variegatus. The costs of delayed metamorphosis can lead to reduction of juvenile fitness and could be a determining factor in the outcome of competitive interactions.

  20. Insect Cell Culture

    NARCIS (Netherlands)

    Oers, van M.M.; Lynn, D.E.

    2010-01-01

    Insect cell cultures are widely used in studies on insect cell physiology, developmental biology and microbial pathology. In particular, insect cell culture is an indispensable tool for the study of insect viruses. The first continuously growing insect cell cultures were established from lepidoptera

  1. Insect Cell Culture

    NARCIS (Netherlands)

    Oers, van M.M.; Lynn, D.E.

    2010-01-01

    Insect cell cultures are widely used in studies on insect cell physiology, developmental biology and microbial pathology. In particular, insect cell culture is an indispensable tool for the study of insect viruses. The first continuously growing insect cell cultures were established from lepidoptera

  2. Compromised metamorphosis and thyroid hormone changes in wood frogs (Lithobates sylvaticus) raised on reclaimed wetlands on the Athabasca oil sands

    Energy Technology Data Exchange (ETDEWEB)

    Hersikorn, Blair D., E-mail: blair.hersikorn@usask.c [Toxicology Centre, University of Saskatchewan, 44 Campus Drive, Saskatoon, Saskatchewan, S7N 5B3 (Canada); Smits, Judit E.G., E-mail: judit.smits@ucalgary.c [Faculty of Veterinary Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, Alberta, T2N 4Z6 (Canada)

    2011-02-15

    The wet landscape approach to oil sands tailings reclamation in the Athabasca Oil Sands region involves creating wetlands from fluid tailings in mined-out pits. We measured time to metamorphosis, thyroid hormone status, and detoxification enzyme (EROD) induction in Wood frog (Lithobates sylvaticus) tadpoles raised on reclaimed oil sands wetlands of different ages [young ({<=}7 yr) vs. old (>7 yr)] and compared data with tadpoles raised on reference (control) wetlands. Metamorphosis was delayed or never occurred in tadpoles raised in young tailings; those exposed to older tailings developed similarly to those in reference wetlands. Thyroid hormone disruption likely played an important role in the metamorphosis delay as the T3:T4 ratio was lowest in tadpoles raised in young, tailings-affected wetlands. Our findings suggest tailings wetlands become less toxic with age, and that these amphibians will be able to complete their life cycle in tailing wetlands that have sufficiently detoxified with age. - This work provides guidance for reclamation of oil sands tailings and shows the usefulness of frogs and caging studies in environmental toxicology.

  3. Roles and regulation of autophagy and apoptosis in the remodelling of the lepidopteran midgut epithelium during metamorphosis

    Science.gov (United States)

    Romanelli, Davide; Casartelli, Morena; Cappellozza, Silvia; de Eguileor, Magda; Tettamanti, Gianluca

    2016-01-01

    We previously showed that autophagy and apoptosis occur in the removal of the lepidopteran larval midgut during metamorphosis. However, their roles in this context and the molecular pathways underlying their activation and regulation were only hypothesized. The results of the present study better clarify the timing of the activation of these two processes: autophagic and apoptotic genes are transcribed at the beginning of metamorphosis, but apoptosis intervenes after autophagy. To investigate the mechanisms that promote the activation of autophagy and apoptosis, we designed a set of experiments based on injections of 20-hydroxyecdysone (20E). Our data demonstrate that autophagy is induced at the end of the last larval stage by the 20E commitment peak, while the onset of apoptosis occurs concomitantly with the 20E metamorphic peak. By impairing autophagic flux, the midgut epithelium degenerated faster, and higher caspase activity was observed compared to controls, whereas inhibiting caspase activation caused a severe delay in epithelial degeneration. Our data demonstrate that autophagy plays a pro-survival function in the silkworm midgut during metamorphosis, while apoptosis is the major process that drives the demise of the epithelium. The evidence collected in this study seems to exclude the occurrence of autophagic cell death in this setting. PMID:27609527

  4. Roles and regulation of autophagy and apoptosis in the remodelling of the lepidopteran midgut epithelium during metamorphosis

    Science.gov (United States)

    Romanelli, Davide; Casartelli, Morena; Cappellozza, Silvia; de Eguileor, Magda; Tettamanti, Gianluca

    2016-09-01

    We previously showed that autophagy and apoptosis occur in the removal of the lepidopteran larval midgut during metamorphosis. However, their roles in this context and the molecular pathways underlying their activation and regulation were only hypothesized. The results of the present study better clarify the timing of the activation of these two processes: autophagic and apoptotic genes are transcribed at the beginning of metamorphosis, but apoptosis intervenes after autophagy. To investigate the mechanisms that promote the activation of autophagy and apoptosis, we designed a set of experiments based on injections of 20-hydroxyecdysone (20E). Our data demonstrate that autophagy is induced at the end of the last larval stage by the 20E commitment peak, while the onset of apoptosis occurs concomitantly with the 20E metamorphic peak. By impairing autophagic flux, the midgut epithelium degenerated faster, and higher caspase activity was observed compared to controls, whereas inhibiting caspase activation caused a severe delay in epithelial degeneration. Our data demonstrate that autophagy plays a pro-survival function in the silkworm midgut during metamorphosis, while apoptosis is the major process that drives the demise of the epithelium. The evidence collected in this study seems to exclude the occurrence of autophagic cell death in this setting.

  5. Olfactory signaling in insects.

    Science.gov (United States)

    Wicher, Dieter

    2015-01-01

    The detection of volatile chemical information in insects is performed by three types of olfactory receptors, odorant receptors (ORs), specific gustatory receptor (GR) proteins for carbon dioxide perception, and ionotropic receptors (IRs) which are related to ionotropic glutamate receptors. All receptors form heteromeric assemblies; an OR complex is composed of an odor-specific OrX protein and a coreceptor (Orco). ORs and GRs have a 7-transmembrane topology as for G protein-coupled receptors, but they are inversely inserted into the membrane. Ligand-gated ion channels (ionotropic receptors) and ORs operate as IRs activated by volatile chemical cues. ORs are evolutionarily young receptors, and they first appear in winged insects and seem to be evolved to allow an insect to follow sparse odor tracks during flight. In contrast to IRs, the ORs can be sensitized by repeated subthreshold odor stimulation. This process involves metabotropic signaling. Pheromone receptors are especially sensitive and require an accessory protein to detect the lipid-derived pheromone molecules. Signaling cascades involved in pheromone detection depend on intensity and duration of stimuli and underlie a circadian control. Taken together, detection and processing of volatile information in insects involve ionotropic as well as metabotropic mechanisms. Here, I review the cellular signaling events associated with detection of cognate ligands by the different types of odorant receptors.

  6. The Insect Neuropeptide PTTH Activates Receptor Tyrosine Kinase Torso to Initiate Metamorphosis

    DEFF Research Database (Denmark)

    Rewitz, Kim; Yamanaka, Naoki; Gilbert, Lawrence

    2009-01-01

    that Torso, a receptor tyrosine kinase that regulates embryonic terminal cell fate in Drosophila, is the PTTH receptor. Trunk, the embryonic Torso ligand, is related to PTTH, and ectopic expression of PTTH in the embryo partially rescues trunk mutants. In larvae, torso is expressed specifically...

  7. THE INFLUENCE OF INSECT JUVENILE HORMONE AGONISTTS ON METAMORPHOSIS AND REPRODUCTION IN ESTUARINE CRUSTACEANS

    Science.gov (United States)

    Comparative developmental and reproductive studies were performed on several species of estuarine crustaceans in response to three juvenile hormone agonists (JHAs) (methoprene, fenoxycarb, and pyriproxyfen). Larval development of the grass shrimp, Palaemonetes pugio, was greater ...

  8. Integrated control of sugarbeet root maggot by using resistant germplasm, an insect pathogen, and an insecticidal seed treatment

    Science.gov (United States)

    This investigation was carried out during the 2014 growing season to evaluate the following for SBRM management in the Red River Valley growing area: 1) a granular formulation of the fungal insect pathogen, Metarhizium anisopliae (Metschnikoff) Sorokin strain MA1200; 2) an experimental SBRM-resistan...

  9. Dietary selenomethionine exposure induces physical malformations and decreases growth and survival to metamorphosis in an amphibian (Hyla chrysoscelis).

    Science.gov (United States)

    Lockard, Laura; Rowe, Christopher L; Heyes, Andrew

    2013-04-01

    Selenium (Se) is an essential micronutrient with a narrow therapeutic concentration range. The relative toxicity of Se increases as it is biotransformed into organic compounds, primarily selenomethionine (SeMet), within the aquatic food chain. Effects of aquatic Se contamination are well quantified for many freshwater fish and aquatic bird species, but impacts on amphibians are not well known. This study investigated the responses of larval Cope's gray tree frogs (Hyla chrysoscelis) fed a diet enriched with one of two concentrations of SeMet (50.1 and 489.9 μg Se g(-1) dw [low and high groups, respectively]) by way of a food-limited (ration) or ad libitum (ad lib) feeding regimen. The high dose caused 100 % mortality during the larval period independent of resource provision levels. Regardless of feeding regimen, the low dose decreased larval survival and successful metamorphosis relative to control treatments. The low dose also induced rear limb deformities in ≤73 % of individuals initiating metamorphosis. Providing low-dose food by way of a rationed feeding regimen decreased observed toxicity, likely because of decreased dietary exposure to SeMet relative to the low ad lib treatment. Individuals from the low ration treatment had decreased wet mass at initiation and completion of metamorphic climax (Gosner stages 42 through 46) compared with those from the control ad lib treatment, indicating that resource limitation combined with Se exposure might negatively affect energy stores after metamorphosis. However, lipid content analyses of recently metamorphosed individuals did not reveal any influence of treatment or resource provision on energy stored as lipids. The mean tissue Se concentration of individuals that received the low dose and completed metamorphosis was significantly greater than that of control ad lib or ration individuals at the same developmental stage. This study demonstrates that larval exposure to dietary SeMet can decrease growth and survival

  10. Synthesis of model compounds derived from natural clerodane insect antifeedants

    NARCIS (Netherlands)

    Klein Gebbinck, E.A.

    1999-01-01

    Insect antifeedants are compounds with the ability to reduce or inhibit insect feeding without directly killing the insect. Such compounds offer a number of properties that are highly desirable in environmentally friendly crop protection agents. Although the principle of insect control usin

  11. Use of butterflies as nontarget insect test species and the acute toxicity and hazard of mosquito control insecticides.

    Science.gov (United States)

    Hoang, Tham C; Pryor, Rachel L; Rand, Gary M; Frakes, Robert A

    2011-04-01

    Honeybees are the standard insect test species used for toxicity testing of pesticides on nontarget insects for the U.S. Environmental Protection Agency (U.S. EPA) under the Federal Insecticide Fungicide and Rodenticide Act (FIFRA). Butterflies are another important insect order and a valued ecological resource in pollination. The current study conducted acute toxicity tests with naled, permethrin, and dichlorvos on fifth larval instar (caterpillars) and adults of different native Florida, USA, butterfly species to determine median lethal doses (24-h LD50), because limited acute toxicity data are available with this major insect group. Thorax- and wing-only applications of each insecticide were conducted. Based on LD50s, thorax and wing application exposures were acutely toxic to both caterpillars and adults. Permethrin was the most acutely toxic insecticide after thorax exposure to fifth instars and adult butterflies. However, no generalization on acute toxicity (sensitivity) of the insecticides could be concluded based on exposures to fifth instars versus adult butterflies or on thorax versus wing exposures of adult butterflies. A comparison of LD50s of the butterflies from this study (caterpillars and adults) with honeybee LD50s for the adult mosquito insecticides on a µg/organism or µg/g basis indicates that several butterfly species are more sensitive to these insecticides than are honeybees. A comparison of species sensitivity distributions for all three insecticides shows that permethrin had the lowest 10th percentile. Using a hazard quotient approach indicates that both permethrin and naled applications in the field may present potential acute hazards to butterflies, whereas no acute hazard of dichlorvos is apparent in butterflies. Butterflies should be considered as potential test organisms when nontarget insect testing of pesticides is suggested under FIFRA. Copyright © 2011 SETAC.

  12. Allergies to Insect Venom

    Science.gov (United States)

    Allergies To Insect Venom Facts About Allergies The tendency to develop allergies may be inherited. If you have allergic tendencies and ... lives of those who are sensitive to it...insect venom! Although less common than pollen allergy, insect ...

  13. Efficacy of Intercropping as a Management Tool for the Control on Insect Pests of Cabbage in Ghana 1H m 2m

    Directory of Open Access Journals (Sweden)

    Timbilla, JA.

    2001-01-01

    Full Text Available The efficacy of intercropping cabbage with other vegetables and herbs as a management tool in migitating insect pests problems of cabbage was investigated in the field at Kwadaso, Kumasi during a three season period in the forest region of Ghana. The results showed that Plutella xylostella could be effectively controlled when cabbage is intercropped with onion, spearmint and tomato. However, there is the need to control Hellula undalis in endemie areas with pesticides up to six weeks after transplanting. Both Karate (cyhalothrin and Dipel 2X (the biopesticide Bacillus thuringiensis subsp. Kurstaki were effective in mitigating the problem of H. undalis in the intercropping experiments and both are recommended.

  14. An Improved Evolvable Oscillator and Basis Function Set for Control of an Insect-Scale Flapping-Wing Micro Air Vehicle

    Institute of Scientific and Technical Information of China (English)

    John C.Gallagher; Michael W.Oppenheimer

    2012-01-01

    This paper introduces an improved evolvable and adaptive hardware oscillator design capable of supporting adaptation intended to restore control precision in damaged or imperfectly manufactured insect-scale flapping-wing micro air vehicles.It will also present preliminary experimental results demonstrating that previously used basis function sets may have been too large and that significantly improved learning times may be achieved by judiciously culling the oscillator search space.The paper will conclude with a discussion of the application of this adaptive,evolvable oscillator to full vehicle control as well as the consideration of longer term goals and requirements.

  15. Genetics and biology of Anastrepha fraterculus: research supporting the use of the sterile insect technique (SIT) to control this pest in Argentina

    Science.gov (United States)

    2014-01-01

    Two species of true fruit flies (taxonomic family Tephritidae) are considered pests of fruit and vegetable production in Argentina: the cosmopolitan Mediterranean fruit fly (Ceratitis capitata Wiedemann) and the new world South American fruit fly (Anastrepha fraterculus Wiedemann). The distribution of these two species in Argentina overlaps north of the capital, Buenos Aires. Regarding the control of these two pests, the varied geographical fruit producing regions in Argentina are in different fly control situations. One part is under a programme using the sterile insect technique (SIT) for the eradication of C. capitata, because A. fraterculus is not present in this area. The application of the SIT to control C. capitata north of the present line with the possibility of A. fraterculus occupying the niche left vacant by C. capitata becomes a cause of much concern. Only initial steps have been taken to investigate the genetics and biology of A. fraterculus. Consequently, only fragmentary information has been recorded in the literature regarding the use of SIT to control this species. For these reasons, the research to develop a SIT protocol to control A. fraterculus is greatly needed. In recent years, research groups have been building a network in Argentina in order to address particular aspects of the development of the SIT for Anastrepha fraterculus. The problems being addressed by these groups include improvement of artificial diets, facilitation of insect mass rearing, radiation doses and conditions for insect sterilisation, basic knowledge supporting the development of males-only strains, reduction of male maturation time to facilitate releases, identification and isolation of chemical communication signals, and a good deal of population genetic studies. This paper is the product of a concerted effort to gather all this knowledge scattered in numerous and often hard-to-access reports and papers and summarize their basic conclusions in a single publication

  16. Genetics and biology of Anastrepha fraterculus: research supporting the use of the sterile insect technique (SIT) to control this pest in Argentina.

    Science.gov (United States)

    Cladera, Jorge L; Vilardi, Juan C; Juri, Marianela; Paulin, Laura E; Giardini, M Cecilia; Gómez Cendra, Paula V; Segura, Diego F; Lanzavecchia, Silvia B

    2014-01-01

    Two species of true fruit flies (taxonomic family Tephritidae) are considered pests of fruit and vegetable production in Argentina: the cosmopolitan Mediterranean fruit fly (Ceratitis capitata Wiedemann) and the new world South American fruit fly (Anastrepha fraterculus Wiedemann). The distribution of these two species in Argentina overlaps north of the capital, Buenos Aires. Regarding the control of these two pests, the varied geographical fruit producing regions in Argentina are in different fly control situations. One part is under a programme using the sterile insect technique (SIT) for the eradication of C. capitata, because A. fraterculus is not present in this area. The application of the SIT to control C. capitata north of the present line with the possibility of A. fraterculus occupying the niche left vacant by C. capitata becomes a cause of much concern. Only initial steps have been taken to investigate the genetics and biology of A. fraterculus. Consequently, only fragmentary information has been recorded in the literature regarding the use of SIT to control this species. For these reasons, the research to develop a SIT protocol to control A. fraterculus is greatly needed. In recent years, research groups have been building a network in Argentina in order to address particular aspects of the development of the SIT for Anastrepha fraterculus. The problems being addressed by these groups include improvement of artificial diets, facilitation of insect mass rearing, radiation doses and conditions for insect sterilisation, basic knowledge supporting the development of males-only strains, reduction of male maturation time to facilitate releases, identification and isolation of chemical communication signals, and a good deal of population genetic studies. This paper is the product of a concerted effort to gather all this knowledge scattered in numerous and often hard-to-access reports and papers and summarize their basic conclusions in a single publication.

  17. Effect of static magnetic fields on the metamorphosis of frogs; Kaeru no hentai katei ni oyobosu jiba no eikyo ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Hiwaki, O. [Hiroshima City University, Hiroshima (Japan)

    1996-01-20

    The effect of static magnetic fields on the metamorphosis of frogs was investigated to examine the effect of static magnetic fields on the internal secretion system and nerve system in a living body. In this experiment, the growth and metamorphosis of a Rana Japonica`s larva are inhibited inside the vessel in which a magnet whose upper surface is the N pole was put at the bottom. However, no remarkable change was recognized when a magnet whose upper surface is the S pole was put at the bottom. For a bullfrog, the same result as described above was obtained. The experiment result shows that the vertical upward fields inhibit the growth and metamorphosis of a frog`s larva, but the vertical downward fields do not remarkably act on them. As a result of this experiment, the growth and metamorphosis of a frog are considered to act on the internal secretion system of a tadpole in static magnetic fields when the control by thyroxin is considered. Since the existence of action varies depending on the polarity of vertical magnetic fields, the magnet in a living body is judged to be associated with the internal secretion system of a tadpole. 17 refs., 8 figs.

  18. [Impact of microsporidia on hormonal balance in insect hosts].

    Science.gov (United States)

    Issi, I V; Tokarev, Iu S

    2002-01-01

    Microsporidia (M) is a phylum of protists parasitizing obligatory in animal cells. Long way of adaptation of M to intracellular parasitism resulted in establishment of quite close relationships between the parasite and its host. Different species of M induce in their hosts symptoms similar to those caused by misbalance of juvenile hormone (JH) and ecdysone. M infection leads to pathology of different hormone-dependent functions such as cell differentiation and specialization, molting, metamorphosis, diapause and reproduction of insects. The signs of hormonal dysfunction evidence for elevated titer of JH in M-infected insects. Two possible explanation of this could be offered: JH secretion by M or specific influence of the parasites on the insect endocrine systems. Impact on insect endogenous JH titer by M could be mediated by affection of secretory activity of corpora allata or by suppression of enzymatic degradation of JH. According to different hypotheses, insect hormonal status during microsporidiosis could be modified by a) insect host stress-reaction, b) exhaustion of insect host reserves, characteristic for acute phase of the disease, c) destruction of infected insect cells and tissues during mass sporogenesis of M. Data found in literature and provided by our experiments evidence for presence of JH analogues or juvenilizing substance in the extracts of M spores. From detailed examination of pathological process it is also seen that juvenilizing effect of M infection is usually restricted to the invaded regions of tissues (i.e. expressed locally) but not a systemic one. Ability of M to modify morpho-functional features of infected tissues at the level of hormonal regulation is undoubtfully a prominent adaptation for stabilizing "microsporidia-insect" parasite-host systems.

  19. Second-generation sequencing supply an effective way to screen RNAi targets in large scale for potential application in pest insect control.

    Science.gov (United States)

    Wang, Yubing; Zhang, Hao; Li, Haichao; Miao, Xuexia

    2011-04-11

    The key of RNAi approach success for potential insect pest control is mainly dependent on careful target selection and a convenient delivery system. We adopted second-generation sequencing technology to screen RNAi targets. Illumina's RNA-seq and digital gene expression tag profile (DGE-tag) technologies were used to screen optimal RNAi targets from Ostrinia furnalalis. Total 14690 stage specific genes were obtained which can be considered as potential targets, and 47 were confirmed by qRT-PCR. Ten larval stage specific expression genes were selected for RNAi test. When 50 ng/µl dsRNAs of the genes DS10 and DS28 were directly sprayed on the newly hatched larvae which placed on the filter paper, the larval mortalities were around 40∼50%, while the dsRNAs of ten genes were sprayed on the larvae along with artificial diet, the mortalities reached 73% to 100% at 5 d after treatment. The qRT-PCR analysis verified the correlation between larval mortality and the down-regulation of the target gene expression. Topically applied fluorescent dsRNA confirmed that dsRNA did penetrate the body wall and circulate in the body cavity. It seems likely that the combination of DGE-tag with RNA-seq is a rapid, high-throughput, cost less and an easy way to select the candidate target genes for RNAi. More importantly, it demonstrated that dsRNAs are able to penetrate the integument and cause larval developmental stunt and/or death in a lepidopteron insect. This finding largely broadens the target selection for RNAi from just gut-specific genes to the targets in whole insects and may lead to new strategies for designing RNAi-based technology against insect damage.

  20. Global patterns of insect diversification: towards a reconciliation of fossil and molecular evidence?

    Science.gov (United States)

    Condamine, Fabien L; Clapham, Matthew E; Kergoat, Gael J

    2016-01-18

    Macroevolutionary studies of insects at diverse taxonomic scales often reveal dynamic evolutionary patterns, with multiple inferred diversification rate shifts. Responses to major past environmental changes, such as the Cretaceous Terrestrial Revolution, or the development of major key innovations, such as wings or complete metamorphosis are usually invoked as potential evolutionary triggers. However this view is partially contradicted by studies on the family-level fossil record showing that insect diversification was relatively constant through time. In an attempt to reconcile both views, we investigate large-scale insect diversification dynamics at family level using two distinct types of diversification analyses on a molecular timetree representing ca. 82% of the extant families, and reassess the insect fossil diversity using up-to-date records. Analyses focusing on the fossil record recovered an early burst of diversification, declining to low and steady rates through time, interrupted by extinction events. Phylogenetic analyses showed that major shifts of diversification rates only occurred in the four richest holometabolous orders. Both suggest that neither the development of flight or complete metamorphosis nor the Cretaceous Terrestrial Revolution environmental changes induced immediate changes in diversification regimes; instead clade-specific innovations likely promoted the diversification of major insect orders.

  1. Fungal allelochemicals in insect pest management.

    Science.gov (United States)

    Holighaus, Gerrit; Rohlfs, Marko

    2016-07-01

    Interactions between insects and fungi are widespread, and important mediators of these interactions are fungal chemicals that can therefore be considered as allelochemicals. Numerous studies suggest that fungal chemicals can affect insects in many different ways. Here, we apply the terminology established by insect-plant ecologists for categorizing the effect of fungal allelochemicals on insects and for evaluating the application potential of these chemicals in insect pest management. Our literature survey shows that fungal volatile and non-volatile chemicals have an enormous potential to influence insect behavior and fitness. Many of them still remain to be discovered, but some recent examples of repellents and toxins could open up new ways for developing safe insect control strategies. However, we also identified shortcomings in our understanding of the chemical ecology of insect-fungus interactions and the way they have been investigated. In particular, the mode-of-action of fungal allelochemicals has often not been appropriately designated or examined, and the way in which induction by insects affects fungal chemical diversity is poorly understood. This review should raise awareness that in-depth ecological studies of insect-fungus interactions can reveal novel allelochemicals of particular benefit for the development of innovative insect pest management strategies.

  2. Active Flow Control (AFC) and Insect Accretion and Mitigation (IAM) System Design and Integration on the Boeing 757 ecoDemonstrator

    Science.gov (United States)

    Alexander, Michael G.; Harris, F. Keith; Spoor, Marc A.; Boyland, Susannah R.; Farrell, Thomas E.; Raines, David M.

    2016-01-01

    This paper presents a systems overview of how the Boeing and NASA team designed, analyzed, fabricated, and integrated the Active Flow Control (AFC) technology and Insect Accretion Mitigation (IAM) systems on the Boeing 757 ecoDemonstrator. The NASA Environmentally Responsible Aviation (ERA) project partnered with Boeing to demonstrate these two technology systems on a specially outfitted Boeing 757 ecoDemonstrator during the spring of 2015. The AFC system demonstrated attenuation of flow separation on a highly deflected rudder and increased the side force generated. This AFC system may enable a smaller vertical tail to provide the control authority needed in the event of an engine failure during takeoff while still operating in a conventional manner over the rest of the flight envelope. The AFC system consisted of ducting to obtain air from the Auxiliary Power Unit (APU), a control valve to modulate the system mass flow, a heat exchanger to lower the APU air temperature, and additional ducting to deliver the air to the AFC actuators located on the vertical tail. The IAM system demonstrated how to mitigate insect residue adhesion on a wing's leading edge. Something as small as insect residue on a leading edge can cause turbulent wedges that interrupt laminar flow, resulting in an increase in drag and fuel use. The IAM system consisted of NASA developed Engineered Surfaces (ES) which were thin aluminum sheet substrate panels with coatings applied to the exterior. These ES were installed on slats 8 and 9 on the right wing of the 757 ecoDemonstrator. They were designed to support panel removal and installation in one crew shift. Each slat accommodated 4 panels. Both the AFC and IAM flight test were the culmination of several years of development and produced valuable data for the advancement of modern aircraft designs.

  3. Neuronal cell death during metamorphosis of Hydractina echinata (Cnidaria, Hydrozoa).

    Science.gov (United States)

    Seipp, Stefanie; Schmich, Jürgen; Will, Britta; Schetter, Eva; Plickert, Günter; Leitz, Thomas

    2010-12-01

    In planula larvae of the invertebrate Hydractinia echinata (Cnidaria, Hydrozoa), peptides of the GLWamide and the RFamide families are expressed in distinct subpopulations of neurons, distributed in a typical spatial pattern through the larval body. However, in the adult polyp GLWamide or RFamide-expressing cells are located at body parts that do not correspond to the prior larval regions. Since we had shown previously that during metamorphosis a large number of cells are removed by programmed cell death (PCD), we aimed to analyze whether cells of the neuropeptide-expressing larval nerve net are among those sacrificed. By immunohistochemical staining and in situ hybridization, we labeled GLWamide- and RFamide-expressing cells. Double staining of neuropeptides and degraded DNA (TUNEL analysis) identified some neurosensory cells as being apoptotic. Derangement of the cytoplasm and rapid destruction of neuropeptide precursor RNA indicated complete death of these particular sensory cells in the course of metamorphosis. Additionally, a small group of RFamide-positive sensory cells in the developing mouth region of the primary polyp could be shown to emerge by proliferation. Our results support the idea that during metamorphosis, specific parts of the larval neuronal network are subject to neurodegeneration and therefore not used for construction of the adult nerve net. Most neuronal cells of the primary polyp arise by de novo differentiation of stem cells commited to neural differentiation in embryogenesis. At least some nerve cells derive from proliferation of progenitor cells. Clarification of how the nerve net of these basal eumetazoans degenerates may add information to the understanding of neurodegeneration by apoptosis as a whole in the animal kingdom.

  4. 'More than two': integrating biological control and sterile insects, from factory to field, and the possibility of its implementation in Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Cladera, Jorge L.; Viscarret, Mariana M.; Carabajal Paladino, Leonela Z.; Pietrek, Alejandro [Instituto de Tecnologia Agropecuaria (INTA), Castelar (Argentina). Inst. de Genetica; Soria, M. Alejandra; Ovruski, Sergio M. [Consejo Nacional de Investigaciones Cientificas y Tecnicas (PROIMI/CONICET), Tucuman (Argentina). Planta Piloto de Procesos Industrials Microbiolo

    2006-07-01

    No single control measure is able to provide full control of a pest. Integration of techniques like the sterile insect (SIT) with biological control practices (BC) should be intensively sough for. This possibility is revised here in connection with the fruit fly pest problems in Argentina. Theoretical reasons as well as practical conveniences for this integration are reviewed in this paper, the intention of which is to promote a discussion on how to approach the experimental study of the SIT+CB integration problem, i.e. how to measure the effects of each separate control measure as well as that of both acting together, in a repeatable manner. Arguments are advanced in favor of the joint production and releases of sterile fruit flies and parasitoids. (author)

  5. Allergy arising from exposure to airborne contaminants in an insect rearing facility: Health effects and exposure control

    Energy Technology Data Exchange (ETDEWEB)

    Wolff, D.

    1994-06-01

    In agricultural crop improvement, yield under various stress conditions and limiting factors is assessed experimentally. Of the stresses on plants which affect yield are those due to insects. Ostrinia nubilalis, the European corn borer (corn borer) is a major pest in sweet and field corn in the U.S. There are many ways to fight crop pests such as the corn borer, including (1) application of chemical insecticides, (2) application of natural predators and, (3) improving crop resistance through plant genetics programs. Randomized field trials are used to determine the effectiveness of pest management programs. These trials frequently consist of randomly selected crop plots to which well-defined input regimes are instituted. For example, corn borers might be released onto crop plots in several densities at various stages of crop development, then sprayed with different levels of pesticide. These experiments are duplicated across regions and, in some cases across the country, to determine, in this instance for example, the best pesticide application rate for a given pest density and crop development stage. In order to release these pests onto crop plots, one must have an adequate supply of the insect pest. In winter months studies are carried out in the laboratory to examine chemical and natural pesticide effectiveness, as well as such things as the role of pheromones in moth behavior. The advantage in field trials is that yield data can be garnered directly. In this country, insects are raised for crop research primarily through the US Department of Agriculture, in cooperation with public Land Grant Universities and, by the private sector agricultural concerns - seed companies and others. This study quantifies the airborne allergen exposure of persons working in a Land Grant University entomology lab were allergy to European corn borer was suspected.

  6. Development of contractile and energetic capacity in anuran hindlimb muscle during metamorphosis.

    Science.gov (United States)

    Park, Jin Cheol; Kim, Han Suk; Yamashita, Masamichi; Choi, Inho

    2003-01-01

    Anuran larvae undergo water-to-land transition during late metamorphosis. We investigated the development of the iliofibularis muscle in bullfrog tadpoles (Rana catesbeiana) between Gosner's stage 37 and stage 46 (the last stage). The tadpoles began staying in shallow water at least as early as stage 37, kicking from stage 39, active hindlimb swimming from stage 41, and emerging onto shore from stage 42. For control tadpoles kept in water throughout metamorphosis, muscle mass and length increased two- to threefold between stages 37 and 46, with rapid increases at stage 40. Large, steady increases were found in femur mass, tetanic tension, contraction rate, and power between stages 37 and 46. Concentrations of ATP and creatine phosphate and rates of the phosphagen depletion and the activity of creatine kinase increased significantly, mainly after stage 43. Shortening velocity, tetanic rise time, and half-relaxation time varied little. Energy charge (the amount of metabolically available energy stored in the adenine nucleotide pool) remained unchanged until stage 43 but decreased at stage 46. Compared with the control, experimental tadpoles that were allowed access to both water and land exhibited 1.2- to 1.8-fold greater increases in femur mass, tetanic tension, power, phosphagen depletion rates, and creatine kinase activities at late metamorphic stages but no significant differences for other parameters measured. In sum, most hindlimb development proceeds on the basis of the increasingly active use of limbs for locomotion in water. The further increases in tension, mechanical power, and "chemical power" on emergence would be advantageous for terrestrial antigravity performance.

  7. Oviposition pheromones in haematophagous insects.

    Science.gov (United States)

    Seenivasagan, T; Vijayaraghavan, R

    2010-01-01

    Pheromones influencing oviposition behavior in females of haematophagous insects have been the interest of recent past by many group of scientists working on oviposition pheromones. Finding and choosing a good site for oviposition is a challenging task for females of haematophagous insects, especially in those insects which does not have the parental care. Their decisions have far-reaching and profound consequences for the life history of the offspring. In such blood feeding insects, the choice of oviposition site is affected by pheromones, which may function either as deterrents or stimulants in short range, while they may also act as repellents or attractants in long range perception. During the location of a suitable oviposition site for egg laying or a potential host for blood feeding, haematophagous insects mainly use olfactory and visual cues. These pheromones are produced by the ovipositing female or by conspecific larvae co-occurring with gravid females. Adult females detect oviposition pheromones by odor receptors on the antennae, as well as by contact chemoreceptors on tarsi, mouthparts and antennae. Different cues exploited by gravid females from a diversified arena include egg, larva, habitat, microbes, infusions and plant produced volatiles influence the oviposition behavior. Traps baited with pheromones, infusions, and insecticides shall be promising tools for monitoring and control of target insect using integrated vector management strategies. Copyright © 2010 Elsevier Inc. All rights reserved.

  8. 鳞翅目昆虫精巢融合的研究%The Study on Fusion of Testis in Lepidoptera Insects

    Institute of Scientific and Technical Information of China (English)

    刘琳; 冯启理

    2014-01-01

    Testis is an important organ in which spermatogenesis happens and nutrition and protection for the devel-opment of sperm is provided .In insect, there usually has two bilateral symmetry testes during larval stages , but in some insects of Lepidoptera such as agriculture pest Spodoptera litura, two testes fuse together during larval to pupal metamorphosis and one single testis is formed at pupal stage .However , in lepidopteron economic insect silkworm , two testes do not fuse during metamorphosis development and always keep separated in all developmental stages .In insect, fusion of testis in Lepidoptera may be a kind of reproductive mode formed after a long natural selection and evolution and may be benefit for the reproduction and enlargement of population .In this paper , testis types of Lepi-doptera , the structure of testis , the process of spermatogenesis , fusion of testis , its biological significance and its potential application in pest control in agriculture are described and summarized .%昆虫精巢是产生精子并为精子发育提供营养和保护的重要器官。昆虫雄虫在幼虫期通常有左右对称的2个精巢。但是,部分昆虫如农业害虫斜纹夜蛾在从幼虫向蛹变态发育的过程中,2个精巢发生融合,合二为一,在蛹期最终完全融合成单个精巢;有些昆虫如经济昆虫家蚕的2个精巢并不融合,在成虫期仍保持分离。精巢融合显然是昆虫长期自然演化过程中形成的一种繁殖方式,有利于种群的繁殖和扩大。本文结合课题组的研究,对鳞翅目昆虫精巢的类型和结构、精子产生的过程、精巢融合的现象及其生物学意义以及在农业害虫防治上的潜在应用意义进行了简述。

  9. Ecdysone signaling at metamorphosis triggers apoptosis of Drosophila abdominal muscles.

    Science.gov (United States)

    Zirin, Jonathan; Cheng, Daojun; Dhanyasi, Nagaraju; Cho, Julio; Dura, Jean-Maurice; Vijayraghavan, Krishnaswamy; Perrimon, Norbert

    2013-11-15

    One of the most dramatic examples of programmed cell death occurs during Drosophila metamorphosis, when most of the larval tissues are destroyed in a process termed histolysis. Much of our understanding of this process comes from analyses of salivary gland and midgut cell death. In contrast, relatively little is known about the degradation of the larval musculature. Here, we analyze the programmed destruction of the abdominal dorsal exterior oblique muscle (DEOM) which occurs during the first 24h of metamorphosis. We find that ecdysone signaling through Ecdysone receptor isoform B1 is required cell autonomously for the muscle death. Furthermore, we show that the orphan nuclear receptor FTZ-F1, opposed by another nuclear receptor, HR39, plays a critical role in the timing of DEOM histolysis. Finally, we show that unlike the histolysis of salivary gland and midgut, abdominal muscle death occurs by apoptosis, and does not require autophagy. Thus, there is no set rule as to the role of autophagy and apoptosis during Drosophila histolysis.

  10. The reasons of metamorphosis and abundance of Kabylian vernacular houses

    Directory of Open Access Journals (Sweden)

    Walid Hamma

    2018-06-01

    Full Text Available Kabylia suffers from the abundance of its ancient villages and the metamorphosis of its traditional houses, which has led to a very advanced degradation and a loss of the authenticity of its old constructions. To understand the phenomenon of exodus, the reasons for its abundant villages and the remodeling of historical buildings, we adopted two approaches, the first is sociological through the use of questionnaire and the second is architectural through use of the method of morphological analysis. After survey, we first highlighted the reasons for the abundant which are economic at 74.89%, educational at 17.00%, social at 4.05%, political at 3.23% and religious at 0.83%. Then, the reasons for the metamorphosis of Kabyle houses, which are structural at 25.20%, functional at 31.70%, spatial at 34.95%, aesthetics at 4.06%, thermal insulation at 2.43% and sound insulation at 1.62%. Finally, the architectural parts changed are the structure at 69.10%, the materials at 13.01%, the roof at 98.37%, the facade at 39.02%, the decoration at 45.52%, the operation at 82.92%, the spaces at 85.63%, the area at 85.63% Thermal insulation at 13.82%, noise insulation at 7.31% and carpentry at 96.74%.

  11. Thyroid hormone regulation of apoptotic tissue remodeling during anuran metamorphosis

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Anuran metamorphosis involves systematic transformations of individual organs in a thyroid hormone (TH)-dependent manner. Morphological and cellular studies have shown that the removal of larval or gans/tissues such the tail and the tadpole intestinal epithelium is through programmed cell death or apop tosis. Recent molecular investigations suggest that TH regulates metamorphosis by regulating target gene expression through thyroid hormone receptors (TRs), which are DNA-binding transcription factors. Cloning and characterization of TH response genes show that diverse groups of early response genes are induced by TH. The products of these TH response genes are believed to directly or indirectly affect the expression and/or functions of cell death genes, which are conserved at both sequence and function levels in different animal species. A major challenge for future research lies at determining the signaling pathways leading to the activation of apoptotic processes and whether different death genes are involved in the regulation of apoptosis in different tissues/organs to effect tissue-specific transformations.

  12. Integrated pest management: the push-pull approach for controlling insect pests and weeds of cereals, and its potential for other agricultural systems including animal husbandry.

    Science.gov (United States)

    Hassanali, Ahmed; Herren, Hans; Khan, Zeyaur R; Pickett, John A; Woodcock, Christine M

    2008-02-12

    This paper describes the 'push-pull' or 'stimulo-deterrent diversionary' strategy in relation to current and potential examples from our own experiences. The push-pull effect is established by exploiting semiochemicals to repel insect pests from the crop ('push') and to attract them into trap crops ('pull'). The systems exemplified here have been developed for subsistence farming in Africa and delivery of the semiochemicals is entirely by companion cropping, i.e. intercropping for the push and trap cropping for the pull. The main target was a series of lepidopterous pests attacking maize and other cereals. Although the area given to the cereal crop itself is reduced under the push-pull system, higher yields are produced per unit area. An important spin-off from the project is that the companion crops are valuable forage for farm animals. Leguminous intercrops also provide advantages with regard to plant nutrition and some of the trap crops help with water retention and in reducing land erosion. A major benefit is that certain intercrop plants provide dramatic control of the African witchweed (striga). Animal husbandry forms an essential part of intensive subsistence agriculture in Africa and developments using analogous push-pull control strategies for insect pests of cattle are exemplified.

  13. Differential patterns of accumulation and depuration of dietary selenium and vanadium during metamorphosis in the Gray Treefrog (Hyla versicolor).

    Science.gov (United States)

    Rowe, Christopher L; Heyes, Andrew; Hilton, Jessica

    2011-02-01

    Selenium (Se) and vanadium (V) are contaminants commonly found in aquatic systems affected by wastes derived from fossil fuels. To examine their effects on a widely distributed species of amphibian, we exposed gray tree frogs (Hyla versicolor) to Se (as SeO₂) or V (as NaVO₃) in their diet from the early larval period to metamorphosis. Concentrations of Se in Se-enriched food were 1.0 (Se control), 7.5 (Se low), and 32.7 (Se high) μg/g dw. Concentrations of V in V-enriched food were 3.0 (V control), 132.1 (V low), and 485.7 (V high) μg/g dw. Although we observed bioaccumulation of both metals throughout the larval period, no effects on growth, survival, metabolic rate, or lipid content were observed. Se concentrations in tissues did not vary among life stages, neither in Se low nor Se high treatments, such that maximum accumulation had occurred by the mid-larval period. In addition, there was no evidence of depuration of Se in either the Se low or the Se high treatments during metamorphosis. A strikingly different pattern of accumulation and depuration occurred in V-exposed individuals. In treatments V low and V high, maximum body burdens occurred in "premetamorphs" (i.e., animals with developed forelimbs but in which tail resorption had not begun), whereas body burdens in animals having completed metamorphosis were much lower and similar to those in larvae. These results suggest that compared with Se-exposed animals, V-exposed animals were able to depurate a substantial amount of accumulated V during the metamorphic period. In an ecologic context, it appears that amphibians exposed to Se during the larval period may serve as a vector of the metal to terrestrial predators, yet potential transfer of accumulated V to predators would largely be restricted to the aquatic habitat.

  14. Aquatic Plant Control Research Program. Large-Scale Operations Management Test (LSOMT) of Insects and Pathogens for Control of Waterhyacinth in Louisiana. Volume 1. Results for 1979-1981.

    Science.gov (United States)

    1985-01-01

    Results for 1979-1981 * 7. AUTHOR(e) 8. CONTRACT OR GRANT NUMBER(s) "’ Dana R. Sanders, Sr. Edwin A. Theriot Patricia Perfetti 9. PERFORMING...Division (ERD), Environmental Laboratory (EL), WES, and Dr. Patricia Perfetti , University of Tennessee-Chattanooga, Chattanooga, Tennessee. The field...Sanders, D. R., Sr., Theriot, E. A., and Perfetti , P. 1985. "Large-Scale Operations Management Test (LSOMT) of Insects and Pathogens for Control

  15. Proteomic analysis during larval development and metamorphosis of the spionid polychaete Pseudopolydora vexillosa

    KAUST Repository

    Mok, Flora SY

    2009-12-14

    Background: While the larval-juvenile transition (metamorphosis) in the spionid polychaete Pseudopolydora vexillosa involves gradual morphological changes and does not require substantial development of juvenile organs, the opposite occurs in the barnacle Balanus amphitrite. We hypothesized that the proteome changes during metamorphosis in the spionids are less drastic than that in the barnacles. To test this, proteomes of pre-competent larvae, competent larvae (ready to metamorphose), and juveniles of P. vexillosa were compared using 2-dimensional gel electrophoresis (2-DE), and they were then compared to those of the barnacle.Results: Unlike the significant changes found during barnacle metamorphosis, proteomes of competent P. vexillosa larvae were more similar to those of their juveniles. Pre-competent larvae had significantly fewer protein spots (384 spots), while both competent larvae and juveniles expressed about 660 protein spots each. Proteins up-regulated during competence identified by MALDI-TOF/TOF analysis included a molecular chaperon (calreticulin), a signal transduction regulator (tyrosin activation protein), and a tissue-remodeling enzyme (metallopeptidase).Conclusions: This was the first time to study the protein expression patterns during the metamorphosis of a marine polychaete and to compare the proteomes of marine invertebrates that have different levels of morphological changes during metamorphosis. The findings provide promising initial steps towards the development of a proteome database for marine invertebrate metamorphosis, thus deciphering the possible mechanisms underlying larval metamorphosis in non-model marine organisms. © 2009 Mok et al; licensee BioMed Central Ltd.

  16. Proteomic analysis during larval development and metamorphosis of the spionid polychaete Pseudopolydora vexillosa

    Directory of Open Access Journals (Sweden)

    Qian Pei-Yuan

    2009-12-01

    Full Text Available Abstract Background While the larval-juvenile transition (metamorphosis in the spionid polychaete Pseudopolydora vexillosa involves gradual morphological changes and does not require substantial development of juvenile organs, the opposite occurs in the barnacle Balanus amphitrite. We hypothesized that the proteome changes during metamorphosis in the spionids are less drastic than that in the barnacles. To test this, proteomes of pre-competent larvae, competent larvae (ready to metamorphose, and juveniles of P. vexillosa were compared using 2-dimensional gel electrophoresis (2-DE, and they were then compared to those of the barnacle. Results Unlike the significant changes found during barnacle metamorphosis, proteomes of competent P. vexillosa larvae were more similar to those of their juveniles. Pre-competent larvae had significantly fewer protein spots (384 spots, while both competent larvae and juveniles expressed about 660 protein spots each. Proteins up-regulated during competence identified by MALDI-TOF/TOF analysis included a molecular chaperon (calreticulin, a signal transduction regulator (tyrosin activation protein, and a tissue-remodeling enzyme (metallopeptidase. Conclusions This was the first time to study the protein expression patterns during the metamorphosis of a marine polychaete and to compare the proteomes of marine invertebrates that have different levels of morphological changes during metamorphosis. The findings provide promising initial steps towards the development of a proteome database for marine invertebrate metamorphosis, thus deciphering the possible mechanisms underlying larval metamorphosis in non-model marine organisms.

  17. Plant spacing and weed control affect sunflower stalk insects and the girdling behavior of Dectes texanus (Coleoptera: Cerambycidae).

    Science.gov (United States)

    Michaud, J P; Stahlman, P W; Jyoti, J L; Grant, A K

    2009-06-01

    We conducted a 2-yr study to determine the effects of crop density and weeds on levels of damage caused by stalk-boring insects in rain-fed sunflowers in west-central Kansas. Weed-free sunflower had higher seed weight and oil content in 2007, but not in 2006, but weeds did not affect infestation by stalk-boring insects in either year. High-density sunflower had lower estimated seed yield per unit area than low-density sunflower in both years, but percentage oil was slightly greater in the high-density treatment in 2006. Sunflowers were more heavily infested by larvae of Ataxia hubbardi Fisher, Cylindrocopturus adspersus (Leconte), and Pelochrista womanana (Kearfott) in 2006 than in 2007, ostensibly as a result of being planted earlier. Larvae of Dectes texanus LeConte appeared unaffected by planting date and were present in > 70% of plants in both years. Conditions during the period of crop maturity were much drier in 2006 than in 2007 and were associated with higher seed oil content and earlier and faster progression of stalk girdling by D. texanus larvae in both low- and high-density plots. There was also a strong effect of plant density on girdling behavior that seemed to be mediated by effects on soil moisture. Stalk girdling began earlier in high-density plots and a larger proportion of plants were girdled compared with low-density plots on all sampling dates in both years. Certain cultural tactics, in particular reduced plant spacing, have potential to delay the onset of girdling behavior by D. texanus larvae and thus mitigate losses that otherwise result from the lodging of girdled plants.

  18. Organic nanofibers containing insect pheromone disruptants: a novel technical approach to controlled release dispensers with potential for process mechanization.

    Science.gov (United States)

    Hummel, H E; Hein, D F; Breuer, M; Lindner, I; Greiner, A; Wendorff, J H; Hellmann, C; Dersch, R; Kratt, A; Kleeberg, H; Leithold, G

    2011-01-01

    Beginning fifty years ago, the search for suitable dispensers containing insect pheromones grew with the availability of these synthetic biotechnical tools. Many economic entomologists and application engineers dearly wish they had the "smart, intelligent and ideal dispenser". More or less suitable approximations are available commercially, but none so far meets all demands. Under economic strictures, novel inexpensive systems would be advantageous with release characteristics tailored to the specific life histories of pest insects, the plants considered and the numerous requirements of growers alike. Simultaneously, their field distribution should be mechanizable and be accomplished by one (or very few) application runs. The dispensers should be biodegradable, biocompatible, sustainably applicable, and they should be based on renewable resources. This report presents first results of a novel organic, electrospun nanofiber dispenser with dimensions in the upper nanometer range. Its load of pheromone can be adjusted to be sufficient for 7 weeks of constant disruptive action in vineyards and can be directed against the European Grape Vine Moth Lobesia botrana (Lepidoptera: Tortricidae) which here serves as a readily available model. Mating disruption in L. botrana and the related Eupoecilia ambiguella is a well studied and developed engineering process. Equally, nanofiber production by electrospinning (for a comprehensive review see Greiner and Wendorff, 2007A, B) is well known and already has numerous applications in filtration technology, air conditioning, and medical wound dressing. Our goal was to bring together and successfully mate these (partly incompatible) technologies via technical tricks of a proprietary nature. Even though the lifetime and effectiveness of currently available nanofibers still must be doubled, the rather complicated system of their production and analysis is known well enough to identify the parameters that need future adjustment. Another

  19. Relationship Between Piercing-Sucking Insect Control and Internal Lint and Seed Rot in Southeastern Cotton (Gossypium hirsutum L.).

    Science.gov (United States)

    Medrano, Enrique G; Bell, Alois A; Greene, Jeremy K; Roberts, Phillip M; Bacheler, Jack S; Marois, James J; Wright, David L; Esquivel, Jesus F; Nichols, Robert L; Duke, Sara

    2015-08-01

    In 1999, crop consultants scouting for stink bugs (Hemiptera spp.) in South Carolina discovered a formerly unobserved seed rot of cotton that caused yield losses ranging from 10 to 15% in certain fields. The disease has subsequently been reported in fields throughout the southeastern Cotton Belt. Externally, diseased bolls appeared undamaged; internally, green fruit contain pink to dark brown, damp, deformed lint, and necrotic seeds. In greenhouse experiments, we demonstrated transmission of the opportunistic bacterium Pantoea agglomerans by the southern green stink bug, Nezara viridula (L.). Here, green bolls were sampled from stink bug management plots (insecticide protected or nontreated) from four South Atlantic coast states (North Carolina, South Carolina, Georgia, and Florida) to determine disease incidence in the field and its association with piercing-sucking insects feeding. A logistic regression analysis of the boll damage data revealed that disease was 24 times more likely to occur (P = 0.004) in bolls collected from plots in Florida, where evidence of pest pressure was highest, than in bolls harvested in NC with the lowest detected insect pressure. Fruit from plots treated with insecticide, a treatment which reduced transmission agent numbers, were 4 times less likely to be diseased than bolls from unprotected sites (P = 0.002). Overall, punctured bolls were 125 times more likely to also have disease symptoms than nonpunctured bolls, irrespective of whether or not plots were protected with insecticides (P = 0.0001). Much of the damage to cotton bolls that is commonly attributed to stink bug feeding is likely the resulting effect of vectored pathogens. Published by Oxford University Press on behalf of Entomological Society of America 2015. This work is written by US Government employees and is in the public domain in the US.

  20. NUMERICAL SIMULATION OF INSECT FLIGHT

    Institute of Scientific and Technical Information of China (English)

    CHENG Mu-lin; MIAO Wen-bo; ZHONG Chang-sheng

    2006-01-01

    In the non-inertial coordinates attached to the model wing, the two-dimensional unsteady flow field triggered by the motion of the model wing, similar to the flapping of the insect wings, was numerically simulated. One of the advantages of our method is that it has avoided the difficulty related to the moving-boundary problem. Another advantage is that the model has three degrees of freedom and can be used to simulate arbitrary motions of a two-dimensional wing in plane only if the motion is known. Such flexibility allows us to study how insects control their flying. Our results show that there are two parameters that are possibly utilized by insects to control their flight: the phase difference between the wing translation and rotation, and the lateral amplitude of flapping along the direction perpendicular to the average flapping plane.

  1. Contemporary frontiers in insect semiochemical research.

    Science.gov (United States)

    Tumlinson, J H

    1988-11-01

    Recent advances in analytical chemistry coupled with more definitive behavioral analyses have allowed more rigorous identification of many insect pheromones. This, in turn, has increased our understanding of the roles of pheromones in mediating insect behavior. Other semiochemicals that mediate insect behavior include those that enable parasitic and predatory insects to locate their hosts or prey. These may be produced by the host insects or by the plant on which they feed. Additionally, there are pheromones and plant-produced seminochemicals that regulate insect oviposition, a critical phase in the life cycle of insects. The challenge to chemists and biologists is to explore these areas to find new environmentally safe methods to control insect pests. One of the newer strategies used to investigate these semiochemicals is the study of the biochemistry of pheromone production and semiochemical perception in insects. These types of studies may reveal weak links in these systems that can be exploited to develop new, more effective and environmentally safe control methods.

  2. Phenoptosis in arthropods and immortality of social insects.

    Science.gov (United States)

    Kartsev, V M

    2014-10-01

    In general, there are no drastic differences in phenoptosis patterns in plant and animal organisms. However, there are some specific features characteristic for insects and other arthropods: 1) their development includes metamorphosis with different biochemical laws at consecutive developmental stages; 2) arthropods can reduce or stop development and aging when in a state of diapause or temporal cold immobility; 3) their life cycle often correlates with seasonal changes of surroundings; 4) polymorphism is widespread - conspecifics differ by their lifespans and phenoptosis features; 5) lifespan-related sexual dimorphism is common; 6) significant situational plasticity of life cycle organization is an important feature; for example, the German wasp (Paravespula germanica) is obligatorily univoltine in the temperate zone, while in tropical regions its lifespan increases and leads to repeated reproduction; 7) life cycles of closely related species may differ significantly, for example, in contrast to German wasp, some tropical hornets (Vespa) have only one reproduction period. Surprisingly, many insect species have been shown to be subjected to gradual aging and phenoptosis, like the highest mammals. However, queens of social insects and some long-lived arachnids can apparently be considered non-aging organisms. In some species, lifespan is limited to one season, while others live much longer or shorter. Cases of one-time reproduction are rather rare. Aphagia is common in insects (over 10,000 species). Cannibalism is an important mortality factor in insects as well as in spiders. In social insects, which exist only in colonies (families), the lifetime of a colony can be virtually unlimited. However, in case of some species the developmental cycle and death of a colony after its completion are predetermined. Most likely, natural selection in insects does not lengthen individual lifespan, but favors increase in reproduction efficiency based on fast succession of

  3. Reframing menstruation in India: metamorphosis of the menstrual taboo with the changing media coverage.

    Science.gov (United States)

    Yagnik, Arpan Shailesh

    2014-01-01

    In this study I hypothesize metamorphosis of the menstrual taboo by examining the image and perception shifts of two social taboos-HIV/AIDS and homosexuality-from estranged taboos to embraced social issues. Trends identified in their media framing and respective image shifts were applied to menstruation in India. Based on my understanding of theory, topic, and geographical location, I construct a metamorphosis. I contribute the hypothesized final stage of metamorphosis, and explain how framing is likely instrumental in bringing about these changes.

  4. Luminaolide, a novel metamorphosis-enhancing macrodiolide for scleractinian coral larvae from crustose coralline algae.

    Science.gov (United States)

    Kitamura, Makoto; Schupp, Peter J; Nakano, Yoshikatsu; Uemura, Daisuke

    2009-11-25

    A new metamorphosis-enhancing macrodiolide, luminaolide (1), was isolated from the crustose coralline algae (CCA) Hydrolithon reinboldii. Its structure was determined by spectroscopic analysis. A fraction (1.30 mug/mL) eluted with 80% aqueous MeOH by ODS gel column chromatography of the same CCA extract induced larval metamorphosis (25.9 +/- 7.4%) against Leptastrea purpurea, and its metamorphosis-inducing activity was further enhanced to 92.6 +/- 2.9% with the addition of 1 (25.6 ng/mL).

  5. Induction of larval metamorphosis in the sea cucumber Apostichopus japonicus by neurotransmitters

    OpenAIRE

    Matsuura, Hiroshi; Yazaki, Ikuko; Okino, Tatsufumi

    2009-01-01

    Larval metamorphosis inducers of the sea cucumber Apostichopus japonicus were screened from physiologically active compounds. Doliolaria larvae completed their metamorphosis to juveniles in 120 hours when treated with 5-10 μM of dopamine and L-DOPA, and 50 μM of L-adrenaline and L-noradrenaline. Doliolaria larvae had to be exposed to dopamine or L-DOPA for at least 24 h. D1-like dopamine receptor antagonists SKF87566 and LE300 (10 μM) inhibited metamorphosis by dopamine. However, the D2-like ...

  6. Insect Bites and Stings

    Science.gov (United States)

    Most insect bites are harmless, though they sometimes cause discomfort. Bee, wasp, and hornet stings and fire ant bites usually hurt. Mosquito and flea bites usually itch. Insects can also spread diseases. In the United States, ...

  7. Insects: An Interdisciplinary Unit

    Science.gov (United States)

    Leger, Heather

    2007-01-01

    The author talks about an interdisciplinary unit on insects, and presents activities that can help students practice communication skills (interpersonal, interpretive, and presentational) and learn about insects with hands-on activities.

  8. Insects and Scorpions

    Science.gov (United States)

    ... and Products Programs Contact NIOSH NIOSH INSECTS AND SCORPIONS Recommend on Facebook Tweet Share Compartir Stinging or biting insects or scorpions can be hazardous to outdoor workers. Stinging or ...

  9. Respiration in Aquatic Insects.

    Science.gov (United States)

    MacFarland, John

    1985-01-01

    This article: (1) explains the respiratory patterns of several freshwater insects; (2) describes the differences and mechanisms of spiracular cutaneous, and gill respiration; and (3) discusses behavioral aspects of selected aquatic insects. (ML)

  10. 2D Gel-Based Multiplexed Proteomic Analysis during Larval Development and Metamorphosis of the Biofouling Polychaete Tubeworm Hydroides elegans

    KAUST Repository

    Zhang, Yu

    2010-09-03

    Larval settlement and metamorphosis of a common biofouling polychaete worm, Hydroides elegans, involve remarkable structural and physiological changes during this pelagic to sessile habitat shift. The endogenous protein molecules and post-translational modifications that drive this larval transition process are not only of interest to ecologists but also to the antifouling paint industry, which aims to control the settlement of this biofouling species on man-made structures (e.g., ship hulls). On the basis of our recent proteomic studies, we hypothesize that rapid larval settlement of H. elegans could be mediated through changes in phosphorylation status of proteins rather than extensive de novo synthesis of proteins. To test this hypothesis, 2D gel-based multiplexed proteomics technology was used to monitor the changes in protein expression and phosphorylation status during larval development and metamorphosis of H. elegans. The protein expression profiles of larvae before and after they reached competency to attach and metamorphose were similar in terms of major proteins, but the percentage of phosphorylated proteins increased from 41% to 49% after competency. Notably, both the protein and phosphoprotein profiles of the metamorphosed individuals (adult) were distinctly different from that of the larvae, with only 40% of the proteins phosphorylated in the adult stage. The intensity ratio of all phosphoprotein spots to all total protein spots was also the highest in the competent larval stage. Overall, our results indicated that the level of protein phosphorylation might play a crucial role in the initiation of larval settlement and metamorphosis. © 2010 American Chemical Society.

  11. Insect glutathione transferases.

    Science.gov (United States)

    Ketterman, Albert J; Saisawang, Chonticha; Wongsantichon, Jantana

    2011-05-01

    This article is an overview of the current knowledge of insect glutathione transferases. Three major topics are discussed: the glutathione transferase contributions to insecticide resistance, the polymorphic nature of the insect glutathione transferase superfamily, and a summary of the current structure-function studies on insect glutathione transferases.

  12. Exploring Sound with Insects

    Science.gov (United States)

    Robertson, Laura; Meyer, John R.

    2010-01-01

    Differences in insect morphology and movement during singing provide a fascinating opportunity for students to investigate insects while learning about the characteristics of sound. In the activities described here, students use a free online computer software program to explore the songs of the major singing insects and experiment with making…

  13. Metamorphosis of Banking Products - A Perception of Bank Employees

    Directory of Open Access Journals (Sweden)

    Harshita B

    2015-08-01

    Full Text Available Banking products are undergoing major changes due to extensive use of it and changing demands of the customers in current scenario. This study basically focuses on the changes came into banking industry and its impact on customers base and bank profits. Data is collected from 50 employees of both private and public sector banks with the help of questionnaire. Hence we can conclude that all banks are providing almost similar products and services to satisfy their customers fully. The continous metamorphsis of banking products not only results in improvement of customer base but also has positive impact on the profits of the bank. Private sector banks are earning more profits as a result of metamorphosis of traditional banking products in comparison to public sector bank.

  14. 草莓主要病虫害及防治方法%Main Diseases and Insects and Control Methods of Strawberry

    Institute of Scientific and Technical Information of China (English)

    刘红松

    2015-01-01

    总结了草莓主要病虫害种类及其防治方法,包括草莓白粉病、草莓灰霉病、草莓叶斑病、叶枯病、红蜘蛛、盲蝽等,以期为草莓的高产栽培提供参考。%Main diseases and insects and control method of strawberry were summarized,including powdery mildew of strawberry,gray mold of strawberry,leaf spot and eaf blight of strawberry,spider mite,capsid bug etc,so as to provide reference for strawberry high-yield cultivation.

  15. Hindemith: Symphonic Metamorphosis on Themes of Carl Maria von Weber / Jonathan Swain

    Index Scriptorium Estoniae

    Swain, Jonathan

    1990-01-01

    Uuest heliplaadist "Hindemith: Symphonic Metamorphosis on Themes of Carl Maria von Weber, Mathis der Maler - Symphony, Nobilissima visione - suite. Atlanta Symphony Orchestra, Yoel Levi" Telarc/ Conifer CD 80 195

  16. Influence of diatom exopolymers and biofilms on metamorphosis in the barnacle Balanus amphitrite

    Digital Repository Service at National Institute of Oceanography (India)

    Patil, J.S.; Anil, A.C.

    , the proportion of monosaccharides varies with species, indicating a potential role for influencing larval metamorphosis. Free EPS of axenic diatoms had no effect, whereas biofilm EPS induced larvae to metamorphose. Amphora spp. produced more biofilm EPS, but had...

  17. Studies on some cues regulating metamorphosis of the larvae of Balanus amphitrite (Cirripedia: Thoracica)

    Digital Repository Service at National Institute of Oceanography (India)

    Khandeparker, L.

    attachment disc is the most obvious point of contact during its search. The exploratory behavior and subsequent metamorphosis response of cypris when subjected simultaneously to sugars and adult extract (AE) is reported through this study. The detection of AE...

  18. Thyroid Histopathology Assessments for the Amphibian Metamorphosis Assay to Detect Thyroid-active Substances

    Science.gov (United States)

    In support of an Organization for Economic Cooperation and Development (OECD) Amphibian Metamorphosis Assay (AMA) Test Guideline for the detection of substances that interact with the hypothalamic-pituitary-thyroid axis, a document was developed that provides a standardized appro...

  19. Hindemith: Symphonic Metamorphosis on Themes of Carl Maria von Weber / Jonathan Swain

    Index Scriptorium Estoniae

    Swain, Jonathan

    1990-01-01

    Uuest heliplaadist "Hindemith: Symphonic Metamorphosis on Themes of Carl Maria von Weber, Mathis der Maler - Symphony, Nobilissima visione - suite. Atlanta Symphony Orchestra, Yoel Levi" Telarc/ Conifer CD 80 195

  20. Relevance of biofilm bacteria in modulating the larval metamorphosis of Balanus amphitrite

    Digital Repository Service at National Institute of Oceanography (India)

    Khandeparker, L.; Anil, A.C.; Raghukumar, S.

    Balanus amphitrite, on its larval metamorphosis. The effect of multispecies bacterial film was also assessed. The production of different molecules by the bacteria was influenced by the nutrient media under which they were grown. It was observed...

  1. Interferência da metodologia nos resultados de bioensaios de seleção de fungos entomopatogênicos para o controle de insetos Interference of bioassay methods on the results of entomopathogenic fungi selection for insect control

    Directory of Open Access Journals (Sweden)

    Patricia Helena Santoro

    2007-04-01

    Full Text Available O objetivo deste trabalho foi avaliar a interferência dos métodos de bioensaios nos resultados de seleção de fungos entomopatogênicos, com a utilização de quatro isolados de Beauveria bassiana e adultos de Alphitobius diaperinus. Quanto à forma de inoculação, foram testados os seguintes métodos: imersão do inseto em suspensão de conídios; pulverização da suspensão sobre insetos; e tratamento de superfície com a suspensão em oito concentrações. Para avaliar a interferência do tempo de imersão sobre a mortalidade, os insetos foram colocados em suspensão de conídios por 1, 10, 20, 30, 40, 50 e 60 segundos. Conídios produzidos em arroz, insetos e meio sintético foram utilizados para avaliar a influência do substrato na virulência dos isolados. Os isolados UNIOESTE 4 e CG 152 foram os mais virulentos pelos métodos imersão e pulverização, respectivamente; em tratamento de superfície, a mortalidade foi baixa para todos os isolados. Observou-se que a mortalidade dos insetos é proporcional ao tempo em que ficam imersos, com tendência a se estabilizar após 40 segundos. Os isolados CG 71 e CG 152, produzidos sobre insetos, foram menos virulentos. Os métodos utilizados podem influenciar os resultados de bioensaios de seleção de fungos para o controle de insetos.The objective of this work was to evaluate the interference of bioassay methods on the entomopathogenic fungi selection, using four Beauveria bassiana isolates and Alphitobius diaperinus adults. Regarding the inoculation form on insect mortality, the following methods were tested: insects immersion in a conidia suspension; spraying of a suspension over the insects; and surface treatment with eight concentrations. In order to evaluate the interference of immersion time on mortality, insects were immersed in a fungal suspension for 1, 10, 20, 30, 40, 50, and 60 seconds. Conidia produced on rice, insects, and synthetic medium were used to evaluate the influence of

  2. Nitric oxide acts as a positive regulator to induce metamorphosis of the ascidian Herdmania momus.

    Directory of Open Access Journals (Sweden)

    Nobuo Ueda

    Full Text Available Marine invertebrates commonly have a biphasic life cycle in which the metamorphic transition from a pelagic larva to a benthic post-larva is mediated by the nitric oxide signalling pathway. Nitric oxide (NO is synthesised by nitric oxide synthase (NOS, which is a client protein of the molecular chaperon heat shock protein 90 (HSP90. It is notable, then, that both NO and HSP90 have been implicated in regulating metamorphosis in marine invertebrates as diverse as urochordates, echinoderms, molluscs, annelids, and crustaceans. Specifically, the suppression of NOS activity by the application of either NOS- or HSP90-inhibiting pharmacological agents has been shown consistently to induce the initiation of metamorphosis, leading to the hypothesis that a negative regulatory role of NO is widely conserved in biphasic life cycles. Further, the induction of metamorphosis by heat-shock has been demonstrated for multiple species. Here, we investigate the regulatory role of NO in induction of metamorphosis of the solitary tropical ascidian, Herdmania momus. By coupling pharmacological treatments with analysis of HmNOS and HmHSP90 gene expression, we present compelling evidence of a positive regulatory role for NO in metamorphosis of this species, in contrast to all existing ascidian data that supports the hypothesis of NO as a conserved negative regulator of metamorphosis. The exposure of competent H. momus larvae to a NOS inhibitor or an NO donor results in an up-regulation of NOS and HSP90 genes. Heat shock of competent larvae induces metamorphosis in a temperature dependent manner, up to a thermal tolerance that approaches 35°C. Both larval/post-larval survival and the appearance of abnormal morphologies in H. momus post-larvae reflect the magnitude of up-regulation of the HSP90 gene in response to heat-shock. The demonstrated role of NO as a positive metamorphic regulator in H. momus suggests the existence of inter-specific adaptations of NO regulation

  3. Spiritual Evolution as a Metamorphose (on the base of Victor Pelevin Novel "Life of Insects"

    Directory of Open Access Journals (Sweden)

    Tetyana Shevchuk

    2013-08-01

    Full Text Available The article deals with the aesthetic paradigm of the novel "Life of Insects" (1993, written by well-known Russian writer Victor Pelevin. Spiritual evolution or degradation of the heroes is represented by their metamorphosis from person to insect or vice versa. Actual questions of the novel are focused on the problems of spiritual vacuum, lost dignity, the meaning of life, the relationship to life as most rare and precious gift, the horror to live at the level of animal existence. The author models the reality, in which the insect mask captures the essence of the person. The focus is on the anthropocentric code of the novel, the evolutionary and regressive reasons, connected with the transmutations of the heroes.

  4. A model of transcriptional and morphological changes during thyroid hormone-induced metamorphosis of the axolotl

    Science.gov (United States)

    Page, Robert B.; Monaghan, James R.; Walker, John A.; Voss, S. Randal

    2009-01-01

    Anuran (frog) metamorphosis has long-served as a model of how thyroid hormones regulate post-embryonic development in vertebrates. However, comparatively little is known about urodele (salamander) metamorphosis. We conducted a detailed time-course study of induced metamorphosis in the Mexican axolotl (Ambystoma mexicanum) that probed metamorphic changes in morphology and gene expression in the skin. Using morphometrics, quantitative PCR, histology, and in situ hybridization we demonstrate that the development of transcriptional markers is fundamental to the resolution of early metamorphic events in axolotls. We then use linear and piecewise linear models to identify a sequence of morphological and transcriptional changes that define larval to adult remodeling events throughout metamorphosis. In addition, we show that transcriptional biomarkers are expressed in specific larval and adult cell populations of the skin and that temporal changes in these biomarkers correlate with tissue remodeling. We compare our results with other studies of natural and induced metamorphosis in urodeles and highlight what appear to be conserved features between urodele and anuran metamorphosis. PMID:19275901

  5. Segment specificity of load signal processing depends on walking direction in the stick insect leg muscle control system.

    Science.gov (United States)

    Akay, Turgay; Ludwar, Björn Ch; Göritz, Marie L; Schmitz, Josef; Büschges, Ansgar

    2007-03-21

    In terrestrial locomotion, sensory feedback from load sensors is important for altering ongoing motor output on a step-by-step basis. We investigated the influence of load signals from the leg on motoneuron pools of the thorax-coxa (ThC) joint in the stick insect walking system. Load sensors were stimulated during rhythmic, alternating activity in protractor coxae (ProCx) and retractor coxae (RetCx) motoneuron pools. Alternating activity in the segment of interest was induced by mechanical stimulation of the animal or pharmacological activation of the isolated thoracic ganglia. Load signals from the legs altered the timing of ThC motoneuron activity by resetting and entraining the activity of the central rhythm generating network of the ThC joint. In the front and middle legs, load signals induced or promoted RetCx activity and decreased or terminated ProCx activity. In the hindleg, reverse transitions were elicited, with increasing load terminating RetCx and initiating ProCx activity. Studies in semi-intact walking animals showed that the effect of load on the ThC-joint motoneurons depended on walking direction, with increased load promoting the functional stance phase motoneuron pool (in forward walking, RetCx activity; in backward walking, ProCx activity). Thus, we show that modifications of sensory feedback in a locomotor system are related to walking direction. In a final set of ablation experiments, we show that the load influence is mediated by the three groups of trochanteral campaniform sensilla.

  6. Potential applications of insect symbionts in biotechnology.

    Science.gov (United States)

    Berasategui, Aileen; Shukla, Shantanu; Salem, Hassan; Kaltenpoth, Martin

    2016-02-01

    Symbiotic interactions between insects and microorganisms are widespread in nature and are often the source of ecological innovations. In addition to supplementing their host with essential nutrients, microbial symbionts can produce enzymes that help degrade their food source as well as small molecules that defend against pathogens, parasites, and predators. As such, the study of insect ecology and symbiosis represents an important source of chemical compounds and enzymes with potential biotechnological value. In addition, the knowledge on insect symbiosis can provide novel avenues for the control of agricultural pest insects and vectors of human diseases, through targeted manipulation of the symbionts or the host-symbiont associations. Here, we discuss different insect-microbe interactions that can be exploited for insect pest and human disease control, as well as in human medicine and industrial processes. Our aim is to raise awareness that insect symbionts can be interesting sources of biotechnological applications and that knowledge on insect ecology can guide targeted efforts to discover microorganisms of applied value.

  7. Nanoformulation of poly(ethylene glycol) polymerized organic insect repellent by PIT emulsification method and its application for Japanese encephalitis vector control.

    Science.gov (United States)

    Balaji, A P B; Mishra, Prabhakar; Suresh Kumar, R S; Mukherjee, Amitava; Chandrasekaran, Natarajan

    2015-04-01

    The utilization of increased dosage of insect repellents to overcome mosquito resistance has raised environmental concerns globally. In accord to this, we have formulated an efficacious, water-dispersive, nanometric formulation of a poor water-soluble insect repellent, diethylphenylacetamide (DEPA) by poly(ethylene glycol) (PEG) polymerization followed by PIT emulsification method. The critical micelle concentration of PEG in the spontaneously emulsified conventional DEPA droplets was determined, based on the droplets physical stability. Subjecting them to PIT emulsification yielded monodispersed polymeric nanomicelles of DEPA (Nano DEPA) with hydrodynamic mean diameter of 153.74 nm. The high-resolution scanning and transmission electron microscopic studies revealed the characteristic core-shell structure of micelle. The comparative efficacy of Bulk DEPA and Nano DEPA was evaluated by larvicidal and WHO cone bioassay against the Japanese encephalitis vector Culex tritaeniorhynchus. The median lethal concentrations (48 h) for 3rd instars C. tritaeniorhynchus larvae were found to be 0.416 mg/L for Bulk DEPA and 0.052 mg/L for Nano DEPA, respectively. The median knockdown concentrations (60 min) for the two to three-day-old, sucrose-fed, female adult mosquitoes were 5.372% (v/v) and 3.471% (v/v) for Bulk and Nano DEPA, respectively. Further investigation by histopathological and biochemical studies propound that Nano DEPA exerted better bioefficacy as comparative to its bulk form even at minimal exposure concentrations. Hence, Nano DEPA will serve as an effective alternate in controlling the vector expansion with reduced dosage.

  8. Research Advances in Stored- Grain Insect Control by Botanical Insecticides%植物性杀虫剂防治储粮害虫的研究进展

    Institute of Scientific and Technical Information of China (English)

    姚英娟; 杨长举; 薛东; 华红霞

    2009-01-01

    储粮害虫的危害能够引起粮食减产和品质下降,目前使用化学农药的负面影响的出现,使得亟待发现新的环境友好型农药进行储粮害虫的防治.植物成为寻找新的环境友好型绿色农药的重要来源,很多学者在植物性杀虫剂的应用研究方面做了大量的工作.针对植物性杀虫剂在储粮害虫防治研究中所取得的成果,系统介绍了植物性杀虫剂的作用方式、作用机理、活性成分等方面的研究进展,以期为从事植物性杀虫剂研究的工作提供参考.%The stored - grain insect pests can cause serious quantitative and qualitative loss of stored- grain. The negative effects of the synthetic insecticides have highlighted the need to develop new types of environment friendly insecti-cides, of which plant has become a new potential resource. Researchers have done a great deal of work on botanical insecti-cides. Based on the achievements on the stored - grain insect control with botanical insecticides, the modes of action,function mechanism and active ingredient of botanical insecticides were systematically summarized in this paper with the in-tention to provide information for further research works.

  9. The GPCR membrane receptor, DopEcR, mediates the actions of both dopamine and ecdysone to control sex pheromone perception in an insect

    Directory of Open Access Journals (Sweden)

    Antoine eAbrieux

    2014-09-01

    Full Text Available Olfactory information mediating sexual behavior is crucial for reproduction in many animals, including insects. In male moths, the macroglomerular complex of the primary olfactory center, the antennal lobe (AL is specialized in the treatment of information on the female-emitted sex pheromone. Evidence is accumulating that modulation of behavioral pheromone responses occurs through neuronal plasticity via the action of hormones and/or catecholamines. We recently showed that a G-protein-coupled receptor (GPCR, AipsDopEcR, with its homologue known in Drosophila for its double affinity to the main insect steroid hormone 20-hydroxyecdysone (20E, and dopamine (DA, present in the ALs, is involved in the behavioral response to pheromone in the moth, Agrotis ipsilon. Here we tested the role of AipsDopEcR as compared to nuclear 20E receptors in central pheromone processing combining receptor inhibition with intracellular recordings of AL neurons. We show that the sensitivity of AL neurons for the pheromone in males decreases strongly after AipsDopEcR-dsRNA injection but also after inhibition of nuclear 20E receptors. Moreover we tested the involvement of 20E and DA in the receptor-mediated behavioral modulation in wind tunnel experiments, using ligand applications and receptor inhibition treatments. We show that both ligands are necessary and act on AipsDopEcR-mediated behavior. Altogether these results indicate that the GPCR membrane receptor, AipsDopEcR, controls sex pheromone perception through the action of both 20E and DA in the central nervous system, probably in concert with 20E action through nuclear receptors.

  10. 频振式杀虫灯在烟草害虫防治中的应用研究%The Application Research of Frequency Trembler Lamp in Control of Tobacco Insect Pest

    Institute of Scientific and Technical Information of China (English)

    孔凡全; 朱列书

    2012-01-01

    为了探索云南烟叶生产中害虫防治的有效方法,在火木龙现代烟草示范区利用频振式杀虫灯开展了烟草主要害虫防治示范试验,结果表明:该杀虫灯把杀虫工作日常化,能有效防止爆发大面积虫害;对蚜茧蜂、食蚜、蝇草蛉等天敌有一定的保护作用,对烟青虫、斜纹夜蛾、金龟子等害虫防效显著;投入成本低,控制面积大,操作简便;通过物理方法诱杀害虫,大大减少农药用量,同时不会使害虫产生抗药性,降低了烟叶农药残留,提高烟叶品质,减少对环境的污染,避免人畜中毒事件发生.这说明频振式杀虫灯具有较好的经济效益、社会效益和生态效益,可在烟草害虫防治中大面积推广使用.%In order to find effective method for controlling insect pests during production of tobacco leaves, a demonstrating experiment for controlling insect pests of tobacco by using frequency trembler lamp were conducted in Huomulong modern tobacco test area. The results showed that this frequency trembler lamp makes the killing insect pests to be routinized, and it can prevent the occurrence of large scale insect pests efficiently. The lamp has certain protection effect for the natural enemy of tobacco insect pests, such as Aphid, Syrphidae and Chrysopidae; meanwhile, it has significant control effect on tobacco insect pests, such as Heliothis assulta Guenee, Prodenia litura and Cheirotonus. The lamp has lots of good characteristics, such as low input and cost, large controlling area, easy use, etc. Using this frequency trembler lamp is a physical way to trapping and killing insect pests, so it will help to reduce pesticide consumption and pesticide residue greatly, and the insects would not have drug resistance, therefore, it can improve tobacco quality, reduce contamination on environment, and avoid poisoning of human and livestock. Therefore, the frequency trembler lamp can be popularized in a large scale for it has good

  11. Effects of nonylphenol on early embryonic development, pigmentation and 3,5,3'-triiodothyronine-induced metamorphosis in Bombina orientalis (Amphibia: Anura).

    Science.gov (United States)

    Park, Chan Jin; Kang, Han Seung; Gye, Myung Chan

    2010-11-01

    Nonylphenol (NP) is an estrogenic endocrine disruptor in many aquatic species. In an effort to highlight the developmental toxicity of NP in amphibians, we examined the effects of NP on the embryonic survival, tadpole growth, melanophore development and metamorphosis of a native Korean amphibian species, Bombina orientalis (Anura). When treated to fertilized eggs, 1 μM NP significantly decreased embryonic survival at 48 h post fertilization (p.f.), suggesting that 1 μM NP can exert systemic toxicity in B. orientalis embryos. In the surviving embryos, there were no significant differences in malformation rates between NP-treated embryos and controls at 240 h p.f., suggesting no or low teratogenicity of NP in B. orientalis embryos. Below LC(50) NP significantly decreased body growth and development of melanophores at 0.1 μM, suggesting that NP far below the LC(50) targets multiple developmental events in tadpoles of this frog species. In metamorphosis assay using the premetamorphic tadpoles (corresponding to Nieuwkoop Faber stage 53 in Xenopus laevis) exogenous 3,5,3'-triiodothyronine (T3)-induced tail resorption was significantly decreased by 1 μM NP. However, NP (0.1 and 1 μM)-only treatment did not affected total body T3 and T4 levels, suggesting that NP at tested concentrations inhibits thyroid hormones action but not the synthesis of hormones during metamorphosis.

  12. Methods of noxious insects control by radiation on example of `Stegobium paniceum L.`; Metody zwalczania szkodliwych owadow przy uzyciu radiacji na przykladzie zywiaka chlebowca (Stegobium paniceum L.)

    Energy Technology Data Exchange (ETDEWEB)

    Krajewski, A. [Szkola Glowna Gospodarstwa Wiejskiego, Warsaw (Poland)

    1997-10-01

    The radiation method of disinfestation on example of `Stegobium paniceum L.` has been described. The different stadia of insect growth have been irradiated. Their radiosensitivity have been estimated on the base of dose-response relationship. Biological radiation effects have been observed as insect procreation limitation. 26 refs, 4 figs, 1 tab.

  13. Research Progress of Ap-plication of Insect Mi-crosporidia in Biological Control of Agricultural Pests%微孢子虫在害虫生物防治中的应用研究进展

    Institute of Scientific and Technical Information of China (English)

    王玉强

    2015-01-01

    昆虫微孢子虫能引起昆虫的流行病,是一种很有应用潜力的微生物杀虫剂。综述昆虫微孢子虫在防治蝗虫、红火蚁、棉铃虫、玉米螟、云南松毛虫等农业害虫上的研究进展,并对目前存在的问题及其应用前景进行了展望。%The insect microsporidia may cause epizootics of insects, they are the potential microbial insecticides. The research progress of insect microsporidia controlling agricultural pests, such as grasshopper, red fire ant, cotton boll-worm, corn borer, Yunnan pine caterpil-lar were summarized, the current prob-lems and theirs application prospect were also described.

  14. Insects, infestations and nutrient fluxes

    Science.gov (United States)

    Michalzik, B.

    2012-04-01

    Forest ecosystems are characterized by a high temporal and spatial variability in the vertical transfer of energy and matter within the canopy and the soil compartment. The mechanisms and controlling factors behind canopy processes and system-internal transfer dynamics are imperfectly understood at the moment. Seasonal flux diversities and inhomogeneities in throughfall composition have been reported from coniferous and deciduous forests, and in most cases leaf leaching has been considered as principle driver for differences in the amount and quality of nutrients and organic compounds (Tukey and Morgan 1963). Since herbivorous insects and the processes they initiate received less attention in past times, ecologists now emphasize the need for linking biological processes occurring in different ecosystem strata to explain rates and variability of nutrient cycling (Bardgett et al. 1998, Wardle et al. 2004). Consequently, herbivore insects in the canopies of forests are increasingly identified to play an important role for the (re)cycling and availability of nutrients, or, more generally, for the functioning of ecosystems not only in outbreak situations but also at endemic (non-outbreak) density levels (Stadler et al. 2001, Hunter et al. 2003). Before, little attention was paid to insect herbivores when quantifying element and energy fluxes through ecosystems, although the numerous and different functions insects fulfill in ecosystems (e.g. as pollinators, herbivores or detritivores) were unanimously recognized (Schowalter 2000). Amongst the reasons for this restraint was the argument that the total biomass of insects tends to be relatively low compared to the biomass of trees or the pool of soil organic matter (Ohmart et al. 1983). A second argument which was put forward to justify the inferior role of insects in nutrient cycling were the supposed low defoliation losses between 5-10% of the annual leaf biomass, or net primary production, due to insect herbivory under

  15. The role of the pupal determinant broad during embryonic development of a direct-developing insect

    Science.gov (United States)

    Rynerson, Melody R.; Truman, James W.; Riddiford, Lynn M.

    2010-01-01

    Metamorphosis is one of the most common, yet dramatic of life history strategies. In insects, complete metamorphosis with morphologically distinct larval stages arose from hemimetabolous ancestors that were more direct developing. Over the past century, several ideas have emerged that suggest the holometabolous pupa is developmentally homologous to the embryonic stages of the hemimetabolous ancestor. Other theories consider the pupal stage to be a modification of a hemimetabolous nymph. To address this question, we have isolated an ortholog of the pupal determinant, broad (br), from the hemimetabolous milkweed bug and examined its role during embryonic development. We show that Oncopeltus fasciatus br (Of'br) is expressed in two phases. The first occurs during germ band invagination and segmentation when Of'br is expressed ubiquitously in the embryonic tissues. The second phase of Of'br expression appears during the pronymphal phase of embryogenesis and persists through nymphal differentiation to decline just before hatching. Knock-down of Of'br transcripts results in defects that range from posterior truncations in the least-affected phenotypes to completely fragmented embryonic tissues in the most severe cases. Analysis of the patterning genes engrailed and hunchback reveal loss of segments and a failure in neural differentiation after Of'br depletion. Finally, we show that br is constitutively expressed during embyrogenesis of the ametabolous firebrat, Thermobia domestica. This suggests that br expression is prominent during embryonic development of ametabolous and hemimetabolous insects but was lost with the emergence of the completely metamorphosing insects. PMID:20127251

  16. Diseases in insects produced for food and feed

    DEFF Research Database (Denmark)

    Eilenberg, Jørgen; Vlak, J.M.; Nielsen-Leroux, C.

    2015-01-01

    Increased production of insects on a large scale for food and feed will likely lead to many novel challenges, including problems with diseases. We provide an overview of important groups of insect pathogens, which can cause disease in insects produced for food and feed. Main characteristics of each...... pathogen group (viruses, bacteria, fungi, protists and nematodes) are described and illustrated, with a selection of examples from the most commonly produced insect species for food and feed. Honeybee and silkworm are mostly produced for other reasons than as human food, yet we can still use them...... as examples to learn about emergence of new diseases in production insects. Results from a 2014 survey about insect diseases in current insect production systems are presented for the first time. Finally, we give some recommendations for the prevention and control of insect diseases. Key words: disease...

  17. Towards the elements of successful insect RNAi.

    Science.gov (United States)

    Scott, Jeffrey G; Michel, Kristin; Bartholomay, Lyric C; Siegfried, Blair D; Hunter, Wayne B; Smagghe, Guy; Zhu, Kun Yan; Douglas, Angela E

    2013-12-01

    RNA interference (RNAi), the sequence-specific suppression of gene expression, offers great opportunities for insect science, especially to analyze gene function, manage pest populations, and reduce disease pathogens. The accumulating body of literature on insect RNAi has revealed that the efficiency of RNAi varies between different species, the mode of RNAi delivery, and the genes being targeted. There is also variation in the duration of transcript suppression. At present, we have a limited capacity to predict the ideal experimental strategy for RNAi of a particular gene/insect because of our incomplete understanding of whether and how the RNAi signal is amplified and spread among insect cells. Consequently, development of the optimal RNAi protocols is a highly empirical process. This limitation can be relieved by systematic analysis of the molecular physiological basis of RNAi mechanisms in insects. An enhanced conceptual understanding of RNAi function in insects will facilitate the application of RNAi for dissection of gene function, and to fast-track the application of RNAi to both control pests and develop effective methods to protect beneficial insects and non-insect arthropods, particularly the honey bee (Apis mellifera) and cultured Pacific white shrimp (Litopenaeus vannamei) from viral and parasitic diseases.

  18. Broadening insect gastronomy

    DEFF Research Database (Denmark)

    Halloran, Afton Marina Szasz; Münke, Christopher; Vantomme, Paul

    2015-01-01

    and visual characteristics, is an example of an area of nature that requires further gastronomic exploration. Many parts of the world consume insects, neither as a novelty nor as a fall-­back famine food (FAO, 2013). Insect-­consuming populations often eat them as a delicacy, seeing each insect......In recent years there has been a trend among chefs to diversify their ingredients and techniques, drawing inspiration from other cultures and creating new foods by blending this knowledge with the flavours of their local region. Edible insects, with their plethora of taste, aromatic, textural...... as an ingredient in its own right – not collectively as ‘insects’, as it is easy for many uninitiated to do. Many of these insects frequently fetch higher prices than other meat sources in the market, and it is this approach of investigating insects as a delicious gastronomic product that interests us. Indeed...

  19. Proteomics and insect immunity

    Directory of Open Access Journals (Sweden)

    L Shi

    2006-01-01

    Full Text Available Insect innate immunity is both a model for vertebrate immunity as well as a key system that impactsmedically important pathogens that are transmitted by insects. Recent developments in proteomics andprotein identification techniques combined with the completion of genome sequences for Anophelesgambiae and Drosophila melanogaster provided the tools for examining insect immunity at a new level ofmolecular detail. Application of proteomics to insect immunity resulted in predictions of new roles inimmunity for proteins already known in other contexts (e.g. ferritin, transferrin, Chi-lectins and helped totarget specific members of multi-gene families that respond to different pathogens (e.g. serine proteases,thioester proteins. In addition, proteomics studies verify that post-translational modifications play a keyrole in insect immunity since many of the identified proteins are modified in some way. These studiescomplement recent work on insect transcriptomes and provide new directions for further investigation ofinnate immunity.

  20. CYP450s analysis across spiny lobster metamorphosis identifies a long sought missing link in crustacean development.

    Science.gov (United States)

    Ventura, Tomer; Bose, Utpal; Fitzgibbon, Quinn P; Smith, Gregory G; Shaw, P Nicholas; Cummins, Scott F; Elizur, Abigail

    2017-07-01

    Cytochrome P450s (CYP450s) are a rapidly evolving family of enzymes, making it difficult to identify bona fide orthologs with notable lineage-specific exceptions. In ecdysozoans, a small number of the most conserved orthologs include enzymes which metabolize ecdysteroids. Ecdysone pathway components were recently shown in a decapod crustacean but with a notable absence of shade, which is important for converting ecdysone to its active form, 20-hydroxyecdysone (20HE), suggesting that another CYP450 performs a similar function in crustaceans. A CYPome temporal expression analysis throughout metamorphosis performed in this research highlights several un-annotated CYP450s displaying differential expression and provides information into expression patterns of annotated CYP450s. Using the expression patterns in the Eastern spiny lobster Sagmariasus verreauxi, followed by 3D modelling and finally activity assays in vitro, we were able to conclude that a group of CYP450s, conserved across decapod crustaceans, function as the insect shade. To emphasize the fact that these genes share the function with shade but are phylogenetically distinct, we name this enzyme system Shed. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  1. Insects and sex

    OpenAIRE

    Beukeboom, Leo

    2005-01-01

    Most organisms reproduce sexually, but the evolution of sexual reproduction is not yet well understood. Sexual reproduction leads to new variation and adaptations to the environment, but sex is also costly. Some insects reproduce without sex through parthenogenesis or paedogenesis. Almost all sexual insects have two separate sexes, male and female. There are many mechanisms of sex determination. Most insects have male heterogamety (males XY, females XX). Female heterogamety and haplodiploidy ...

  2. Religion, Ethics and Development – Method and Metamorphosis

    Directory of Open Access Journals (Sweden)

    V. Basil HANS

    2011-12-01

    Full Text Available Much has been written about the socio-cultural functions of religion. It is equally important to discuss the role and impact of religion and ethics on development and promoting reform in civil society. In today’s South Asian context it is necessary to analyse religion both as a tradition and a representation of modernity. Otherwise it is difficult to clearly understand not only the relationship of domination-subordination, together with processes of exclusions and violence prevalent in the sub-continent but also the emerging perspectives, lineages and languages of sociology in general and religion in particular. An attempt is made in this paper to examine the relationship and to evaluate the processes in the evolving discourse of sociology. It also analyses the ‘moral’ as embedded in religion and as an autonomous category emerging with secularisation. The subtleties of rights and righteousness in the method and metamorphosis of development are also dealt with in this paper.

  3. Centralspindlin is required for thorax development during Drosophila metamorphosis.

    Science.gov (United States)

    Sfregola, Michael

    2014-05-01

    Epithelial morphogenesis is an essential process in all metazoans during both normal development and pathological processes such as wound healing. The coordinated regulation of cell shape, cell size, and cell adhesion during the migration of epithelial sheets ultimately gives rise to the diversity of body plans among different organisms as well as the diversity of cellular structures and tissues within an organism. Metamorphosis of the Drosophila pupa is an excellent system to study these transformative events. During pupal development, the cells of the wing imaginal discs migrate dorsally and fuse to form the adult thorax. Here I show centralspindlin, a protein complex well known for its role in cytokinesis, is essential for migration of wing disc cells and proper thorax closure. I show the subcellular localization of centralspindlin is important for its function in thorax development. This study demonstrates the emerging role of centralspindlin in regulating cell migration and cell adhesion in addition to its previously known function during cytokinesis. © 2014 Wiley Periodicals, Inc.

  4. Frederick Sanger, Erwin Chargaff, and the metamorphosis of specificity.

    Science.gov (United States)

    Judson, H F

    1993-12-15

    That a transformation of ruling ideas in genetics and biochemistry took place at the dawn of molecular biology, in the late 1940s, is a commonplace; but the nature and components of that transformation are widely misunderstood. The change is often identified with the importation into biology of new styles of thought and new rigor by the many scientists trained in physics or chemistry who came into the nascent field--notably, Max Delbrück, Max Perutz, Francis Crick, John Kendrew, Maurice Wilkins, Rosalind Franklin. Most generally, the change is supposed to be the realization that genes are made not of protein but of nucleic acid--and this change was initiated, of course, by the work of Oswald Avery and his colleagues. These changes are not mutually exclusive, and both were surely important to the genesis of molecular biology. But logically prior to them, more fundamental, was another transformation in ruling preconceptions, one that has been neglected: the revolution in understanding of the chemical structures--the sequences of subunits--of proteins and of nucleic acids which was wrought by the work of Frederick Sanger and of Erwin Chargaff. This was a metamorphosis in the understanding of biochemical specificity, and while it astonished many biochemists it set free the small groups of those who were beginning to call themselves molecular biologists, enabling them to think of the relationship between genes and proteins in entirely new ways.

  5. The Paradigm of Decline-Metamorphosis-Rebirth in Fine Arts

    Directory of Open Access Journals (Sweden)

    Tine Germ

    2015-12-01

    Full Text Available The triad of decline-metamorphosis-rebirth constantly reappears in the history of civilisation, it is current in all historical periods and cultural environments, in different areas and the most diverse contexts. Its manifestations are countless and the same is true of its interpretations. They are especially frequent in the area of art, because the evolutionary model, grounded in the idea of cyclic development comes very handy for explanations and illustrations which seek to present complicated things in a simple and clear way. The history of art, mainly in the 19th century, advocated a tripartite development of art which seeks greater perfection and maturity and reaches its peak just to be then inevitably followed by a decline in artistic originality and power. Already for some time now the evolutionary model has been shown too ineffective in addressing scholarly questions, especially due to oversimplification and a priori classification of subject matter which cannot possibly be classified. The perception that the art of the Early Renaissance was a preliminary period for more mature and accomplished achievements of High Renaissance which at some point began to lose its drive and went into decline either by repeating outmoded forms or their decomposition, is not only naive, but simply wrong and represents a misunderstanding of the essence of art. In much the same way it would be equally wrong to label in advance the early works of a certain artist as not-mature-yet or possessing less artistic authenticity.

  6. Modern Stored-Product Insect Pest Management

    Directory of Open Access Journals (Sweden)

    Hagstrum David William

    2014-07-01

    Full Text Available Stored-product entomologists have a variety of new monitoring, decision-making, biological, chemical, and physical pest management tools available to them. Two types of stored-product insect populations are of interest: insects of immediate economic importance infesting commodities, and insects that live in food residues in equipment and facilities. The sampling and control methods change as grain and grain products move from field to consumer. There are also some changes in the major insect pest species to take into consideration. In this review, we list the primary insect pests at each point of the marketing system, and indicate which sampling methods and control strategies are most appropriate. Economic thresholds for insect infestation levels developed for raw commodity storage, processing plants, and retail business allow sampling-based pest management to be done before insect infestations cause economic injury. Taking enough samples to have a representative sample (20-30 samples will generally provide enough information to classify a population as above or below an economic threshold.

  7. 害虫遗传防治的研究历史与现状%History and status of the genetic control of insect pest

    Institute of Scientific and Technical Information of China (English)

    严盈; 万方浩

    2015-01-01

    作为防治或根除重大害虫最为有效的手段之一,害虫遗传防治在世界范围内被广泛采用并取得了巨大成功。本文综述了不育昆虫技术、雌性致死系统和昆虫显性致死技术等经典害虫遗传防治策略的发展历史、技术特点和应用情况。近年来,许多新的分子生物手段被不断提出并整合到害虫遗传防治策略中,包括归巢核酸内切酶基因、锌指核酸酶、转录激活因子样效应因子核酸酶、CRISPR/Cas9系统、Medea元件、Killer-Rescue系统、Wolbachia-细胞质不亲和性系统等。基于这些新的工具手段,许多国家已经在不同程度上启动了下一代害虫遗传防治项目。而我国在该领域的研究相对薄弱,需要在借鉴国外成功经验的同时,进一步加强害虫遗传防治的基础和应用研究,从而实现本地有害生物的可持续治理和外来入侵生物的有效狙击,确保我国未来的粮食和生态安全。%Genetic pest management ( GPM) is one of the most efficient methods to control or eradicate insect pests and has been carried out worldwide with notable successes. Some classic GPM strategies including the sterile insect technology ( SIT) , female kill-ing system ( FKS) and release of insects carrying dominant lethality ( RIDL) are reviewed here. The development history, technical characters and application of SIT, FKS and RIDL technologies are introduced. In recent years, many new molecular or biological tools like the homing endonuclease gene, zinc-finger nucleases, transcription activator-like effector nucleases, CRISPR/Cas9 sys-tem, medea element, the killer-rescue system and the Wolbachia-cytoplasmic incompatibility system were proposed to improve GPM efficiency. Some new tools were already used in control programs as next generation GPM strategies in some countries. The GPM practice in China is limited, and both basic and applied research on GPM should be enhanced, as the GPM

  8. Polycomb repressive complex 2 (PRC2) protein ESC regulates insect developmental timing by mediating H3K27me3 and activating prothoracicotropic hormone gene expression.

    Science.gov (United States)

    Lu, Yu-Xuan; Denlinger, David L; Xu, Wei-Hua

    2013-08-09

    The decision made by insects to develop into adults or halt development (enter diapause and prolong lifespan) is commonly based on environmental signals that provide reliable predictors of future seasons of adversity. For example, the short day lengths of early autumn accurately foretell the advent of winter, but little is known about the molecular mechanisms that preside over the hormonal events dictating whether the insect proceeds with development or enters diapause. In Helicoverpa armigera we show that day length affects H3K27me3 by affecting polycomb repressive complex 2 (PRC2) protein extra sex comb (ESC) and regulates the prothoracicotropic hormone (PTTH) gene, thus directly influencing developmental timing. ESC expression in brains of developing (nondiapause) pupae is higher than in brains from diapausing pupae. High ESC expression is localized in two pairs of PTTH neurosecretory cells, and H3K27me3 recruits on the PTTH promoter. Double strand ESC and PRC2 inhibitor (DzNep) treatment in vitro show that ESC triggers PTTH promoter activity, which in turn depends on PRC2 methyltransferase activity. Injection of DzNep into pupae programmed for development reduces the H3K27me3 mark and PTTH gene expression, thereby delaying development. Although ESC is best known as a transcriptional repressor, our results show that ESC prompts development and metamorphosis. We believe this is the first report showing that the PRC2 complex functions as an activator and that a low level of H3K27me3 can prolong lifespan (i.e. induce diapause) by controlling PTTH gene expression in insects.

  9. Insects and Bugs

    Science.gov (United States)

    Sutherland, Karen

    2009-01-01

    They have been around for centuries. They sting, they bite. They cause intense itching or painful sores. They even cause allergic reactions and sometimes death. There are two types of insects that are pests to humans--those that sting and those that bite. The insects that bite do so with their mouths and include mosquitoes, chiggers, and ticks.…

  10. Insects: Bugged Out!

    Science.gov (United States)

    Piehl, Kathy

    2011-01-01

    Insects really need no introduction. They have lived on earth much longer than humans and vastly outnumber people and all other animal species combined. People encounter them daily in their houses and yards. Yet, when children want to investigate insects, books can help them start their explorations. "Paleo Bugs" carries readers back to the time…

  11. Stinging Insect Allergy

    Science.gov (United States)

    ... and perfume when outdoors. Because the smell of food attracts insects, be careful outdoors when cooking, eating or drinking sweet drinks like soda or juice. Beware of insects inside straws or canned drinks. Keep food covered until eaten. Wear closed-toe shoes outdoors ...

  12. Insect bites and stings

    Science.gov (United States)

    ... likely to cause itching than pain. Insect and spider bites cause more deaths from venom reactions than bites from snakes. ... are harmless. If possible, bring the insect or spider that bit you with you when you go for medical treatment so it can be identified.

  13. Immunity in a Social Insect

    Science.gov (United States)

    Rosengaus, Rebeca B.; Traniello, James F. A.; Chen, Tammy; Brown, Julie J.; Karp, Richard D.

    Although pathogens appear to have exerted significant selective pressure on various aspects of sociality, mechanisms of disease resistance in the social insects are poorly understood. We report here on an immune response to infection by the dampwood termite, Zootermopsis angusticollis. Nymphs immunized with an injection of 7.6×107, 7.6×105, or 7.6×104 cells/ml glutaraldehyde-killed solution of the bacterium Pseudomonas aeruginosa had significantly higher survivorship than controls following a challenge with a lethal concentration of active bacteria. Similarly, nymphs exposed to a 9×10-1 spores/ml suspension of the fungus Metarhizium anisopliae had higher survivorship than controls after a challenge with a lethal concentration of spores. Prior exposure to a pathogen thus conferred upon termites a degree of protection during a subsequent encounter with the same pathogen. This represents the first demonstration of immune function in vivo in a social insect.

  14. Insects and Related Pests of Trees, Shrubs, and Lawns. MP-25R.

    Science.gov (United States)

    Spackman, Everett W.; Lawson, Fred A.

    This document discusses identification and control of the pests of trees and shrubs. The insects are grouped according to feeding habits and the type of damage caused to plants. Categories include the sucking insects and mites, leaf eating insects, pests attacking trunks and branches, and gall causing insects. (CS)

  15. Metabolomics reveals insect metabolic responses associated with fungal infection.

    Science.gov (United States)

    Xu, Yong-Jiang; Luo, Feifei; Gao, Qiang; Shang, Yanfang; Wang, Chengshu

    2015-06-01

    The interactions between insects and pathogenic fungi are complex. We employed metabolomic techniques to profile insect metabolic dynamics upon infection by the pathogenic fungus Beauveria bassiana. Silkworm larvae were infected with fungal spores and microscopic observations demonstrated that the exhaustion of insect hemocytes was coupled with fungal propagation in the insect body cavity. Metabolomic analyses revealed that fungal infection could significantly alter insect energy and nutrient metabolisms as well as the immune defense responses, including the upregulation of carbohydrates, amino acids, fatty acids, and lipids, but the downregulation of eicosanoids and amines. The insect antifeedant effect of the fungal infection was evident with the reduced level of maclurin (a component of mulberry leaves) in infected insects but elevated accumulations in control insects. Insecticidal and cytotoxic mycotoxins like oosporein and beauveriolides were also detected in insects at the later stages of infection. Taken together, the metabolomics data suggest that insect immune responses are energy-cost reactions and the strategies of nutrient deprivation, inhibition of host immune responses, and toxin production would be jointly employed by the fungus to kill insects. The data obtained in this study will facilitate future functional studies of genes and pathways associated with insect-fungus interactions.

  16. Gene expression variations during Drosophila metamorphosis in real and simulated gravity

    Science.gov (United States)

    Marco, R.; Leandro-García, L. J.; Benguría, A.; Herranz, R.; Zeballos, A.; Gassert, G.; van Loon, J. J.; Medina, F. J.

    Establishing the extent and significance of the effects of the exposure to microgravity of complex living organisms is a critical piece of information if the long-term exploration of near-by planets involving human beings is going to take place in the Future As a first step in this direction we have started to look into the patterns of gene expression during Drosophila development in real and simulated microgravity using microarray analysis of mRNA isolated from samples exposed to different environmental conditions In these experiments we used Affymetrix chips version 1 0 containing probes for more than 14 000 genes almost the complete Drosophila genome 55 of which are tagged with some molecular or functional designation while 45 are still waiting to be identified in functional terms The real microgravity exposure was imposed on the samples during the crew exchanging Soyuz 8 Mission to the ISS in October 2003 when after 11 days in Microgravity the Spanish-born astronaut Pedro Duque returned in the Soyuz 7 capsule carrying the experiments prepared by our Team Due to the constraints in the current ISS experiments in these Missions we limited the stages explored in our experiment to the developmental processes occurring during Drosophila metamorphosis As the experimental conditions at the launch site Baikonour were fairly limited we prepared the experiment in Madrid Toulouse and transp o rted the samples at 15 C in a temperature controlled container to slow down the developmental process a

  17. Ecological genomics of Boechera stricta: Identification of a QTL controlling the allocation of methionine- vs branched-chain amino acid-derived glucosinolates and levels of insect herbivory

    NARCIS (Netherlands)

    Schranz, M.E.; Manzaneda, A.J.; Windsor, A.J.; Clauss, M.; Mitchell-Olds, T.

    2009-01-01

    In the Brassicaceae, glucosinolates influence the feeding, reproduction and development of many insect herbivores. Glucosinolate production and effects on herbivore feeding have been extensively studied in the model species, Arabidopsis thaliana and Brassica crops, both of which constitutively produ

  18. The role of octopamine receptor agonists in the synergistic toxicity of certain insect growth regulators (IGRs) in controlling Dengue vector Aedes aegypti (Diptera: Culicidae) mosquito.

    Science.gov (United States)

    Ahmed, Mohamed Ahmed Ibrahim; Vogel, Christoph Franz Adam

    2016-03-01

    The synergistic action of octopamine receptor agonists (OR agonists) on many insecticide classes (e.g., organophosphorus, pyrethroids, and neonicotinoids) on Aedes aegypti L. has been reported recently. An investigation of OR agonist's effect on insect growth regulators (IGRs) was undertaken to provide a better understanding of the mechanism of action. Based on the IGR bioassay, pyriproxyfen was the most potent IGR insecticide tested (EC50=0.0019ng/ml). However, the lethal toxicity results indicate that diafenthiuron was the most potent insecticide (LC50=56ng/cm(2)) on A. aegypti adults after 24h of exposure. The same trend was true after 48 and 72h of exposure. Further, the synergistic effects of OR agonists plus amitraz (AMZ) or chlordimeform (CDM) was significant on adults. Among the tested synergists, AMZ increased the potency of the selected IGRs on adults the greatest. As results, OR agonists were largely synergistic with the selected IGRs. OR agonists enhanced the lethal toxicity of IGRs, which is a valuable new tool in the field of A. aegypti control. However, further field experiments need to be done to understand the unique potential role of OR agonists and their synergistic action on IGRs.

  19. Compatibility among entomopathogenic hyphocreales and two beneficial insects used to control Trialeurodes vaporariorum (Hemiptera: Aleurodidae) in Mediterranean greenhouses.

    Science.gov (United States)

    Hamdi, Faten; Fargues, Jacques; Ridray, Gilles; Jeannequin, Benoît; Bonato, Olivier

    2011-09-01

    The effect of the combined use of Encarsia formosa or Macrolophus caliginosus and one of three marketed mycoinsecticides, Mycotal® (Leucanicillium muscarium-based), Naturalis-L™ (Beauveria bassiana-based) and PreFeRal® (Isaria fumosorosea-based), on the control of the whitefly, Trialeurodes vaporariorum, was studied under laboratory and greenhouse conditions. The results of both types of tests, the bioassays and the greenhouse trials, for all combinations of E. Formosa with each of the three mycoinsecticides showed that the total mortality of larval populations of T. vaporariorum was not affected. The mortality of T. vaporariorum larvae treated in the second instar revealed the capacity for both B. bassiana- and L. muscarium-based formulations and E. formosa to kill the host either separately or in association. Because of its higher pathogenic activity (under our test conditions), L. muscarium provoked a large proportion of mycoses in larvae exposed to parasitization. In contrast, the efficacy of parasitization was higher in larvae treated with B. bassiana and exposed to E. formosa because of a lower pathogenic activity of the fungus. Bioassays carried out with third-instar larvae of T. vaporariorum showed a low susceptibility to both tested fungi. Consequently, mortalities recorded in larvae subjected to the combined treatments by consecutive exposures or at 2-4 days post-parasitization were mainly caused by the development of the parasitoid. Greenhouse trials showed that fungus-induced mortality of T. vaporariorum in plants treated with L. muscarium, I. fumosorosea, and B. Bassiana was significant compare to control. L. muscarium, B. bassiana and I. fumosorosea killed young whitefly larvae and limited parasitization to 10% or less. Second-instar larvae of M. caliginosus were not susceptible to L. muscarium and B. bassiana formulations with any mode of contamination: direct spraying of larvae, spraying on the foliar substrate or by contaminated T. vaporariorum

  20. An economic comparison of biological and conventional control strategies for insect pests in cashew and mango plantations in Tanzania

    DEFF Research Database (Denmark)

    George, William Juma; Hella, Joseph; Esbjerg, Lars

    2013-01-01

    budget analysis shows that a change from chemical insecticides treatment to weaver ants returned net benefits greater than zero by Tsh. 692 923 and Tsh.1019665 in cashew and mango plantations respectively. Similarly, positive net benefits was obtained when growers change from control to weaver ants...... treatment by Tsh. 504 989 and Tsh. 891 297 in cashew and mango plantations. The dominance and MRRanalyses shows that if cashew and mango growers change from conventional agricultural practices to weaver ants, they would earn MRR of 1621% which is above minimum acceptable rate of return (MARR) of 100%. The t...

  1. Metamorphosis and neoteny: alternative pathways in an extinct amphibian clade.

    Science.gov (United States)

    Schoch, Rainer R; Fröbisch, Nadia B

    2006-07-01

    The Branchiosauridae was a clade of small amphibians from the Permo-Carboniferous with an overall salamander-like appearance. The clade is distinguished by an extraordinary fossil record that comprises hundreds of well-preserved specimens, representing a wide range of ontogenetic stages. Branchiosaurids had external gills and weakly ossified skeletons, and due to this larval appearance their status as neotenic (perennibranchiate) forms has long been accepted. Despite their extensive fossil record large specimens with an adult morphology appeared to be lacking altogether, but recently two adult specimens were identified in a rich sample of Apateon gracilis collected in the 19th century from a locality near Dresden, Saxony. These specimens are unique among branchiosaurids in showing a high level of ossification, including bones that have never been reported in a branchiosaur. These highlight the successive formation of features believed to indicate terrestrial locomotion, as well as feeding on larger prey items. Moreover, these transformations occurred in a small time window (whereas the degree of size increase is used as a proxy of time) and the degree of concentration of developmental events in branchiosaurids is unique among tetrapods outside the lissamphibians. These specimens are compared with large adults of the neotenic branchiosaurid Apateon caducus from the Saar-Nahe Basin, which despite their larger body size lack the features found in the adult A. gracilis specimens. These specimens give new insight into patterns of metamorphosis (morphological transformation) in branchiosaurids that are believed to be correlated to a change of habitat, and clearly show that different life-history pathways comparable to those of modern salamanders were already established in this Paleozoic clade.

  2. Mutatas dicere formas: language at the service of metamorphosis

    Directory of Open Access Journals (Sweden)

    Cristina Martín Puente

    2010-06-01

    Full Text Available All along his work, Ovid mentions hundreds of transformations. In his narration, apart from a number of implicit allusions to metamorphoses, he creates a very complex system that combines lexical, semantic and syntactical resources, in order not to be repetitive. This allows him to expand greatly the list of verbs with which he can express explicitly the fact that an entity can change into another entity. So, if he is primarily interested in the agent or the cause of the metamorphosis, that is, the causative construction, he uses the verbs uerto, facio and muto (this last verb is his favourite one, and is probably used by Ovid for the first time with this sense in active voice; when he wants to focus on the person who undergoes the change (inacusative construction, he uses uerto, facio and muto in passive voice, or the verb fio. But if he refers to a character who has the ability to metamorphose (inergative construction, he uses uerto in passive voice, or fio. In the cases of the verbs muto (in active or passive, uerto (in active or passive, eo (in passive, abeo (in passive, flecto (in passive, confero (in active, animo (in active, etc. the result of the transformation is often expressed with in + accusative. In the cases of uerto and muto, the result can be also codified as ablative without preposition; and with muto, cum + ablative is also possible. However, when the verbs facio and have the meaning of `transforming ´or `getting transformed into´ they don´t present any special construction. On the other hand, Ovid barely uses the verbs conuerto and transformo, which were already used by other authors before him.

  3. Induced resistance in rice against insects.

    Science.gov (United States)

    Karban, R; Chen, Y

    2007-08-01

    Vaccinations are the mainstay of western preventive medicine, and they have been used to protect some crops against disease and insect pests. We consider rice as a model for protection using induced resistance since it is one of the most important staple crops and there have been significant new developments in: cross-resistance among rice insects, chemical pathways involved in induced resistance, sequencing the rice genome and expression of genes conferring resistance against rice insect pests. Insect attack has been found to cause lesions that kill planthopper eggs and early stages of gall midges. Damaged plants released volatiles that made them less likely to be chosen by planthoppers and more attractive to parasitoids. Chemical elicitors have been developed for dicotyledonous plants and these can induce resistance in rice, although rice does not fit models developed to explain signalling in dicots. For example, salicylic acid did not increase in rice after infection by pathogens and did not appear to be the mobile signal for induced resistance against pathogens although it was involved in induced responses to phloem-feeding insects. Jasmonic acid acted as a signal in some induced responses to pathogens as well as chewing insects. Many of the genes associated with induced resistance in rice have recently been mapped, and techniques are being developed to incorporate them into the genome of cultivated varieties. Attempts to control insect pests of rice will affect interactions with pathogens, predators and parasites, and other organisms in this agroecosystem.

  4. Thyroid hormone-responsive genes mediate otolith growth and development during flatfish metamorphosis.

    Science.gov (United States)

    Wang, X; Tan, Y; Sievers, Q; Sievers, B; Lee, M; Burrall, K; Schreiber, A M

    2011-01-01

    Flatfish begin life as up-right swimming, bilaterally symmetrical larvae that metamorphose into asymmetrically shaped juveniles that swim with a highly lateralized posture. We have previously shown that TH induces abrupt growth and mineralization of one component of the vestibular system, the otoliths, during early larval development and metamorphosis. Here we report that four of five vestibular-specific genes that we tested (alpha-tectorin, otogelin, otolith matrix protein, and otopetrins 1 and 2 that are known to be associated with otolith development in other vertebrates are up-regulated 1.5- to 7-fold in larval flatfish during spontaneous metamorphosis and/or following 72 h of TH treatment. These findings suggest that otolith growth and development are mediated by diverse TH-responsive genes during flatfish metamorphosis.

  5. Metabolism and Pigmentation Patterns during Metamorphosis of Plaice (Pleuronectes platessa) larvae

    DEFF Research Database (Denmark)

    Christensen, Mette Nørregaard; Korsgaard, Bodil

    1999-01-01

    Protein metabolism, growth and pigmentation patterns were studied during the process of metamorphosis in the plaice Pleuronectes platessa. Based on the morphological and concurrent metabolic observations the process of metamorphosis could be divided into three different phases: (1) premetamorphosis...... and DNA of the larvae. An increasing calcium concentration indicated the beginning of skeleton ossification. Growth during this phase was primarily hyperplastic as indicated by an increase in DNA per larva. Protein catabolism dominated, as indicated by an increase in the carbon to nitrogen ratio....... Calcium assimilation reached a plateau depicting complete ossification of the skeleton. Lipid catabolism dominated by the end of the metamorphosis process. Pigmentation appeared to develop in two marked phases. During premetamorphosis larval melanophores and xanthophores dominated the pigmentation pattern...

  6. Pre-hatching exposure to water mold reduces size at metamorphosis in the moor frog.

    Science.gov (United States)

    Uller, Tobias; Sagvik, Jörgen; Olsson, Mats

    2009-05-01

    Developmental plasticity is increasingly recognized as important for ecological and evolutionary processes. However, few studies consider the potential for delayed effects of early environments. Here, we show that tadpoles hatching from clutches exposed to water mold (Saprolegnia) have 20% decreased mass at metamorphosis, despite no further exposure subsequent to hatching. The effects were consistent across four populations that have previously been shown to vary in their resistance to infection during embryonic development. Contrary to expectations, time to hatching or metamorphosis was not affected, suggesting that the results do not reflect an evolved escape strategy from infected waters triggered by embryonic conditions. Instead, decreased mass at metamorphosis may arise from carry-over effects of impaired embryo development. Such strong links across developmental stages have potential consequences for the evolution of plasticity and the responses of populations to emergent infections.

  7. Use of Plant Hydraulic Theory to Predict Ecosystem Fluxes Across Mountainous Gradients in Environmental Controls and Insect Disturbances

    Science.gov (United States)

    Ewers, B. E.; Pendall, E.; Reed, D. E.; Barnard, H. R.; Whitehouse, F.; Frank, J. M.; Massman, W. J.; Brooks, P. D.; Biederman, J. A.; Harpold, A. A.; Naithani, K. J.; Mitra, B.; Mackay, D. S.; Norton, U.; Borkhuu, B.

    2011-12-01

    While mountainous areas are critical for providing numerous ecosystem benefits at the regional scale, the strong gradients in environmental controls make predictions difficult. A key part of the problem is quantifying and predicting the feedback between mountain gradients and plant function which then controls ecosystem cycling. The emerging theory of plant hydraulics provides a rigorous yet simple platform from which to generate testable hypotheses and predictions of ecosystem pools and fluxes. Plant hydraulic theory predicts that plant controls over carbon, water, energy and nutrient fluxes can be derived from the limitation of plant water transport from the soil through xylem and out of stomata. In addition, the limit to plant water transport can be predicted by combining plant structure (e.g. xylem diameters or root-to-shoot ratios) and plant function (response of stomatal conductance to vapor pressure deficit or root vulnerability to cavitation). We evaluate the predictions of the plant hydraulic theory by testing it against data from a mountain gradient encompassing sagebrush steppe through subalpine forests (2700 to 3400 m). We further test the theory by predicting the carbon, water and nutrient exchanges from several coniferous trees in the same gradient that are dying from xylem dysfunction caused by blue-stain fungi carried by bark beetles. The common theme of both of these data sets is a change in water limitation caused by either changing precipitation along the mountainous gradient or lack of access to soil water from xylem-occluding fungi. Across all of the data sets which range in scale from individual plants to hillslopes, the data fit the predictions of plant hydraulic theory. Namely, there was a proportional tradeoff between the reference canopy stomatal conductance to water vapor and the sensitivity of that conductance to vapor pressure deficit that quantitatively fits the predictions of plant hydraulic theory. Incorporating this result into

  8. Disease and Insect Pest Control Technical of Rosa roxburghii Tratt%刺梨病虫害防治技术

    Institute of Scientific and Technical Information of China (English)

    叶光伟; 李淼; 王德敏

    2014-01-01

    介绍了刺梨的形态特征和生物学特性,并针对其病虫害,包括白粉病、褐斑病、烟煤病、梨小食心虫、食叶害虫、月季长管蚜、白粉虱等分别总结防治技术,以期为刺梨高产栽培提供参考。%Morphological characteristics and biological characteristics of Rosa roxburghii Tratt were introduced.Disease and pest control techniques of Rosa roxburghii Tratt were summarized,including powdery mildew,brown blotch,dark mildew,oriental fruit moth,defoliator,Macrosiphum rosirvorum Zhang and Trialeurodes vaporariorum,so as to provide the reference for the high-yield cultivation of Rosa roxburghii Tratt.

  9. Identification and differential expression of microRNAs during metamorphosis of the Japanese flounder (Paralichthys olivaceus.

    Directory of Open Access Journals (Sweden)

    Yuanshuai Fu

    Full Text Available BACKGROUND: MicroRNAs (miRNAs are a class of endogenous small non-coding RNAs of 20-25 nucleotides that play a key role in diverse biological processes. Japanese flounder undergo dramatic metamorphosis in their early development. The metamorphosis is characterized by morphological transformation from a bilaterally symmetrical to an asymmetrical body shape concomitant with extensive morphological and physiological remodeling of organs. So far, only a few miRNAs have been identified in fish and there are very few reports about the Japanese flounder miRNA. METHODOLOGY/PRINCIPAL FINDINGS: Solexa sequencing technology was used to perform high throughput sequencing of the small RNA library from the metamorphic period of Japanese flounder. Subsequently, aligning these sequencing data with metazoan known miRNAs, we characterized 140 conserved miRNAs and 57 miRNA: miRNA* pairs from the small RNA library. Among these 57 miRNA: miRNA* pairs, twenty flounder miRNA precursors were amplified from genomic DNA. We also demonstrated evolutionary conservation of Japanese flounder miRNAs and miRNA* in the animal evolution process. Using miRNA microarrays, we identified 66 differentially expressed miRNAs at two metamorphic stages (17 and 29 days post hatching of Japanese flounder. The results show that miRNAs might play a key role in regulating gene expression during Japanese flounder metamorphosis. CONCLUSIONS/SIGNIFICANCE: We identified a large number of miRNAs during flounder metamorphosis, some of which are differentially expressed at two different metamorphic stages. The study provides an opportunity for further understanding of miRNA function in the regulation of flounder metamorphosis and gives us clues for further studies of the mechanisms of metamorphosis in Japanese flounder.

  10. Ecological interaction between insect pests, climatic factors and plant traits on abundance of beneficial insects in paddy field

    Directory of Open Access Journals (Sweden)

    Norazliza, R.

    2016-04-01

    Full Text Available The presences of beneficial insects in the paddy field are very important for the ecological systems of paddy field as those insects could help managing the population of the pests. Hence, it will reduce the dependence on pesticides usage to combat the population of insect pests. This study was aimed to study on ecological interaction between environmental factors such as insect pests, plant height, rainfall, temperature and humidity with abundance of beneficial insects in paddy field of Sungai Burong, Tanjung Karang, Selangor for two seasons of paddy planting. Low number of insects composition were recorded in paddy field at Sungai Burong during the vegetative phase and highest during the reproductive and maturity phases for two seasons of paddy planting. The trend of mean composition of insects were gradually increasing from vegetative to maturity phases while, the ecological interaction between insect pests, climatic factors and plant traits were acceptable as good predictor for all beneficial insects collected in this study namely Zygoptera, Gerridae, Coccinellidae and Staphylinidae except for Anisoptera. Therefore, consideration on several stated factors by maintaining or conserving ecology and controlling practices in good manner in paddy field has high potential and more reliable to control insect pests effectively using beneficial insects.

  11. Biocontrol: The Potential of Entomophilic Nematodes in Insect Management

    OpenAIRE

    Webster, John M.

    1980-01-01

    A review of the development of entomophilic nematology and a commentary on the potential of entomophilic nematodes in controlling insect pests. The paper considers some of the major contributions to our knowledge of entomophilic nematology; factors involved in insect pest management and how they are applicable to the use of nematodes; nematodes which are most promising as biological control agents; and problems to be solved to facilitate the use of entomophilic nematodes in insect management.

  12. Biocontrol: the potential of entomophilic nematodes in insect management.

    Science.gov (United States)

    Webster, J M

    1980-10-01

    A review of the development of entomophilic nematology and a commentary on the potential of entomophilic nematodes in controlling insect pests. The paper considers some of the major contributions to our knowledge of entomophilic nematology; factors involved in insect pest management and how they are applicable to the use of nematodes; nematodes which are most promising as biological control agents; and problems to be solved to facilitate the use of entomophilic nematodes in insect management.

  13. Biocontrol: The Potential of Entomophilic Nematodes in Insect Management

    OpenAIRE

    Webster, John M.

    1980-01-01

    A review of the development of entomophilic nematology and a commentary on the potential of entomophilic nematodes in controlling insect pests. The paper considers some of the major contributions to our knowledge of entomophilic nematology; factors involved in insect pest management and how they are applicable to the use of nematodes; nematodes which are most promising as biological control agents; and problems to be solved to facilitate the use of entomophilic nematodes in insect management.

  14. Single-stranded DNA fragments of insect-specific nuclear polyhedrosis virus act as selective DNA insecticides for gypsy moth control.

    Science.gov (United States)

    Oberemok, Volodymyr V; Skorokhod, Oleksii A

    2014-07-01

    This paper focuses on the DNA insecticides as a novel preparation against gypsy moth (Lymantria dispar) based on DNA fragments of the anti-apoptotic gene of its nuclear polyhedrosis virus. It was found that the external application of a solution with two single-stranded DNA fragments from BIR and RING domains of LdMNPV (L.dispar multicapsid nuclear polyhedrosis virus) IAP-3 (inhibitor of apoptosis) gene induces a significantly higher mortality of gypsy moth caterpillars in comparison with the application of the control solutions. This effect does not depend on the infection of caterpillars with LdMNPV. The results also show that DNA insecticides based on LdMNPV IAP-3 gene fragments can be selective in action, and at least are not harmful to tobacco hornworm (Manduca sexta) and black cutworm (Agrotis ipsilon). Part of the gypsy moth genome cloned with the fragments of BIR and RING domains of LdMNPV IAP-3 gene as primers, has an overlap with the corresponding part of the LdMNPV IAP-3 gene and L.dispar IAP-1 mRNA for an inhibitor of apoptosis protein with the high cover by query, allows assuming that we cloned a part of gypsy moth anti-apoptosis gene. This finding gives the grounding that proposed here DNA insecticides might act through the blocking of the mechanisms involved in post transcriptional expression of insect anti-apoptosis genes. The results show the insecticidal potential of the viral genome fragments that can be used to create safe and relatively fast-acting DNA insecticides to control the quantity of gypsy moth populations, important task for forestry and agriculture. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. Viral Delivery of dsRNA for Control of Insect Agricultural Pests and Vectors of Human Disease: Prospects and Challenges

    Science.gov (United States)

    Kolliopoulou, Anna; Taning, Clauvis N. T.; Smagghe, Guy; Swevers, Luc

    2017-01-01

    RNAi is applied as a new and safe method for pest control in agriculture but efficiency and specificity of delivery of dsRNA trigger remains a critical issue. Various agents have been proposed to augment dsRNA delivery, such as engineered micro-organisms and synthetic nanoparticles, but the use of viruses has received relatively little attention. Here we present a critical view of the potential of the use of recombinant viruses for efficient and specific delivery of dsRNA. First of all, it requires the availability of plasmid-based reverse genetics systems for virus production, of which an overview is presented. For RNA viruses, their application seems to be straightforward since dsRNA is produced as an intermediate molecule during viral replication, but DNA viruses also have potential through the production of RNA hairpins after transcription. However, application of recombinant virus for dsRNA delivery may not be straightforward in many cases, since viruses can encode RNAi suppressors, and virus-induced silencing effects can be determined by the properties of the encoded RNAi suppressor. An alternative is virus-like particles that retain the efficiency and specificity determinants of natural virions but have encapsidated non-replicating RNA. Finally, the use of viruses raises important safety issues which need to be addressed before application can proceed. PMID:28659820

  16. Knockdown of genes in the Toll pathway reveals new lethal RNA interference targets for insect pest control.

    Science.gov (United States)

    Bingsohn, L; Knorr, E; Billion, A; Narva, K E; Vilcinskas, A

    2017-02-01

    RNA interference (RNAi) is a promising alternative strategy for ecologically friendly pest management. However, the identification of RNAi candidate genes is challenging owing to the absence of laboratory strains and the seasonality of most pest species. Tribolium castaneum is a well-established model, with a strong and robust RNAi response, which can be used as a high-throughput screening platform to identify potential RNAi target genes. Recently, the cactus gene was identified as a sensitive RNAi target for pest control. To explore whether the spectrum of promising RNAi targets can be expanded beyond those found by random large-scale screening, to encompass others identified using targeted knowledge-based approaches, we constructed a Cactus interaction network. We tested nine genes in this network and found that the delivery of double-stranded RNA corresponding to fusilli and cactin showed lethal effects. The silencing of cactin resulted in 100% lethality at every developmental stage from the larva to the adult. The knockdown of pelle, Dorsal-related immunity factor and short gastrulation reduced or even prevented egg hatching in the next generation. The combination of such targets with lethal and parental RNAi effects can now be tested against different pest species in field studies.

  17. Influence of 50-Hz Electromagnetic Field on Anurian (Xenopus laevis Metamorphosis

    Directory of Open Access Journals (Sweden)

    S. Grimaldi

    2004-01-01

    Full Text Available In this study, we show the effect of a 1-mT magnetic field AC at 50 Hz on Xenopus laevis tadpole populations. In the course of a 65-day exposure to the field, tadpole survival showed a small, but significant, decrease (p < 0.0004, together with a striking parallel 6-day shift in tadpole maturation frequency and a significant impairment of their metamorphosis. Particularly, metamorphosis was successful for 85% of individuals in the unirradiated tadpole population and for 45% of individuals in the irradiated tadpole population, respectively.

  18. Vision in flying insects.

    Science.gov (United States)

    Egelhaaf, Martin; Kern, Roland

    2002-12-01

    Vision guides flight behaviour in numerous insects. Despite their small brain, insects easily outperform current man-made autonomous vehicles in many respects. Examples are the virtuosic chasing manoeuvres male flies perform as part of their mating behaviour and the ability of bees to assess, on the basis of visual motion cues, the distance travelled in a novel environment. Analyses at both the behavioural and neuronal levels are beginning to unveil reasons for such extraordinary capabilities of insects. One recipe for their success is the adaptation of visual information processing to the specific requirements of the behavioural tasks and to the specific spatiotemporal properties of the natural input.

  19. Beneficial Insects and Insect Pollinators on Milkweed in South Georgia

    Science.gov (United States)

    Insect pollinators are essential for the reproduction of more than two-thirds of the world’s crops, and beneficial insects play an important role in managing pest insects in agricultural farmscapes. These insects depend on nectar for their survival in these farmscapes. The flowers of tropical milkwe...

  20. 茶树病虫害智能化防治专家系统研究与应用%Study and Application of the Intelligentized Controlled Expert System on the Tea Plant Diseases and Insect Pests

    Institute of Scientific and Technical Information of China (English)

    汪辉进

    2011-01-01

    On the basis of the biological characteristics of tea plant diseases and insect pests in the south of Anhui province, and the relevant knowledge of artificial intelligence, the intelligentized controlled expert system was studied, so as to explore a new technology for the intelligentized control of tea plant diseases and insect pests.%根据皖南茶区茶树病虫害的生物学特点,依据人工智能化的相关知识,开展茶树病虫害智能化防治专家系统的研究,力求为我国茶园病虫害智能化防治探索一种新技术.

  1. 无公害鲜食葡萄病虫害综合防治新技术%New Technologies for the Prevention and Control of Diseases and Insect Pests of Pollution-free Table Grapes

    Institute of Scientific and Technical Information of China (English)

    张飞跃

    2014-01-01

    Pesticide usage of production of pollution-free table grapes were introduced,critical period and key measures to prevent and control of diseases and insect pests of table grapes were analyzed.New technologies for the prevention and control of diseases and insect pests of pollution-free table grapes were summarized,so as to provide the reference for the cultivation of pollution-free table grapes.%介绍了无公害葡萄生产中的农药使用方法,分析了葡萄病虫害的关键期和关键防治措施,并总结了无公害鲜食葡萄病虫害综合防治技术,以期为无公害鲜食葡萄的栽培提供参考。

  2. Genome-wide comparison of genes involved in the biosynthesis, metabolism, and signaling of juvenile hormone between silkworm and other insects

    Directory of Open Access Journals (Sweden)

    Daojun Cheng

    2014-06-01

    Full Text Available Juvenile hormone (JH contributes to the regulation of larval molting and metamorphosis in insects. Herein, we comprehensively identified 55 genes involved in JH biosynthesis, metabolism and signaling in the silkworm (Bombyx mori as well as 35 in Drosophila melanogaster, 35 in Anopheles gambiae, 36 in Apis mellifera, 47 in Tribolium castaneum, and 44 in Danaus plexippus. Comparative analysis showed that each gene involved in the early steps of the mevalonate (MVA pathway, in the neuropeptide regulation of JH biosynthesis, or in JH signaling is a single copy in B. mori and other surveyed insects, indicating that these JH-related pathways or steps are likely conserved in all surveyed insects. However, each gene participating in the isoprenoid branch of JH biosynthesis and JH metabolism, together with the FPPS genes for catalyzing the final step of the MVA pathway of JH biosynthesis, exhibited an obvious duplication in Lepidoptera, including B. mori and D. plexippus. Microarray and real-time RT-PCR analysis revealed that different copies of several JH-related genes presented expression changes that correlated with the dynamics of JH titer during larval growth and metamorphosis. Taken together, the findings suggest that duplication-derived copy variation of JH-related genes might be evolutionarily associated with the variation of JH types between Lepidoptera and other insect orders. In conclusion, our results provide useful clues for further functional analysis of JH-related genes in B. mori and other insects.

  3. Exploiting natural variation to identify insect-resistance genes.

    Science.gov (United States)

    Broekgaarden, Colette; Snoeren, Tjeerd A L; Dicke, Marcel; Vosman, Ben

    2011-10-01

    Herbivorous insects are widespread and often serious constraints to crop production. The use of insect-resistant crops is a very effective way to control insect pests in agriculture, and the development of such crops can be greatly enhanced by knowledge on plant resistance mechanisms and the genes involved. Plants have evolved diverse ways to cope with insect attack that has resulted in natural variation for resistance towards herbivorous insects. Studying the molecular genetics and transcriptional background of this variation has facilitated the identification of resistance genes and processes that lead to resistance against insects. With the development of new technologies, molecular studies are not restricted to model plants anymore. This review addresses the need to exploit natural variation in resistance towards insects to increase our knowledge on resistance mechanisms and the genes involved. We will discuss how this knowledge can be exploited in breeding programmes to provide sustainable crop protection against insect pests. Additionally, we discuss the current status of genetic research on insect-resistance genes. We conclude that insect-resistance mechanisms are still unclear at the molecular level and that exploiting natural variation with novel technologies will contribute greatly to the development of insect-resistant crop varieties.

  4. 不同药剂防控稻水象甲幼虫试验%The Control Efficiency of Different Insect Pesticides against Lissorhoptrus oryzophilus Larvae

    Institute of Scientific and Technical Information of China (English)

    何永福; 张忠民; 叶照春; 张昌容; 陈小均; 何海永; 朱峰; 江兆春; 李鸿波

    2016-01-01

    [目的]试验研究5种杀虫剂不同剂量对稻水象甲幼虫的防治效果,筛选5%丁硫克百威颗粒剂的替代药剂.[方法]进行盆栽、田间小区试验.[结果]20%呋虫胺可溶粒剂90.00、120.00、150.00 g a.i./hm2,0.5%噻虫胺颗粒剂225.00、300.00g a.i./hm2,4%吡虫·毒死蜱颗粒剂2400.00g a.i./hm2,50%氟啶虫胺腈水分散粒剂150.00、187.50g a-i./hm2处理防控稻水象甲幼虫,药后15d防效均在70%以上.[结论]20%呋虫胺可溶粒剂、0.5%噻虫胺颗粒剂、50%氟啶虫胺腈水分散粒剂、4%吡虫·毒死蜱颗粒剂可以作为5%丁硫克百威颗粒剂的替代药剂,防控稻水象甲幼虫,建议在生产中交替使用.%[Aims] The experiment aims to screen out better alternative pesticides of 5% Ding Like Budweiser to control Lissorhoptrus oryzophilus larvae from five pesticides.[Methods] Pot and field experiment were used to evaluate control efficiency for five insect pesticides against L.oryzophilus larvae.[Results] Our experiments showed that dinotefuran 20% SG (90.00,120.00,150.00 g a.i./ha),clothianidin 0.5% GR (225.00,300.00 g a.i./ha),imidacloprid ·chlorpyrifos 0.4% GR(2400 g a.i./ha),sulfoxaflor 50% WG (150.00,187.50 g a.i./ha) could control L.oryzophilus larvae efficiently,and the efficiency after 15 days were above 70%.[Conclusions] Therefore,dinotefuran,clothianidin,imidacloprid ·chlorpyrifos and sulfoxaflor could be used as alternative pesticides for L.oryzophilus larvae control.

  5. Exploring Insect Vision

    Science.gov (United States)

    Damonte, Kathleen

    2005-01-01

    A fly is buzzing around in the kitchen. You sneak up on it with a flyswatter, but just as you get close to it, it flies away. What makes flies and other insects so good at escaping from danger? The fact that insects have eyesight that can easily detect moving objects is one of the things that help them survive. In this month's Science Shorts,…

  6. Experience-based modulation of behavioural responses to plant volatiles and other sensory cues in insect herbivores.

    Science.gov (United States)

    Anderson, P; Anton, S

    2014-08-01

    Plant volatiles are important cues for many herbivorous insects when choosing a suitable host plant and finding a mating partner. An appropriate behavioural response to sensory cues from plants and other insects is crucial for survival and fitness. As the natural environment can show both large spatial and temporal variability, herbivores may need to show behavioural plasticity to the available cues. By using earlier experiences, insects can adapt to local variation of resources. Experience is well known to affect sensory-guided behaviour in parasitoids and social insects, but there is also increasing evidence that it influences host plant choice and the probability of finding a mating partner in herbivorous insects. In this review, we will focus upon behavioural changes in holometabolous insect herbivores during host plant choice and localization of mating partners, modulated by experience to sensory cues. The experience can be acquired during both the larval and the adult stage and can influence later responses to plant volatiles and other sensory cues not only within the developmental stage but also after metamorphosis. Furthermore, we will address the neurophysiological mechanisms underlying the experience-dependent behavioural adaptations and discuss ecological and evolutionary aspects of insect behavioural plasticity based upon experience.

  7. The Sterile Insect Technique as a method of pest control; La Tecnica del Insecto Esteril como metodo de lucha contra plagas

    Energy Technology Data Exchange (ETDEWEB)

    Argiles Herrero, R.

    2011-07-01

    In the Valencia community is doing one of the most ambitious project in the field of plant protection at European level: the fight against fruit fly, one of the most damaging pests of citrus and fruit; by Insect Technique Sterile. This technique consists of laboratory breeding and release into the fields of huge quantities of insects of the pest species that have previously been sterilized. Sterile insect looking for wild individuals of the same species to mate with them and the result is a clutch of viable eggs, causing a decrease in pest populations. After three years of application of the technique on an area of 150,000 hectares, the pest populations have been reduced by 90%. Other benefits have been the reduced used of insecticides and improved the quality of exported fruit. (Author)

  8. Insect juvenile hormone: from "status quo" to high society

    Directory of Open Access Journals (Sweden)

    K. Hartfelder

    2000-02-01

    Full Text Available Juvenile hormone (JH exerts pleiotropic functions during insect life cycles. The regulation of JH biosynthesis by neuropeptides and biogenic amines, as well as the transport of JH by specific binding proteins is now well understood. In contrast, comprehending its mode of action on target organs is still hampered by the difficulties in isolating specific receptors. In concert with ecdysteroids, JH orchestrates molting and metamorphosis, and its modulatory function in molting processes has gained it the attribute "status quo" hormone. Whereas the metamorphic role of JH appears to have been widely conserved, its role in reproduction has been subject to many modifications. In many species, JH stimulates vitellogenin synthesis and uptake. In mosquitoes, however, this function has been transferred to ecdysteroids, and JH primes the ecdysteroid response of developing follicles. As reproduction includes a variety of specific behaviors, including migration and diapause, JH has come to function as a master regulator in insect reproduction. The peak of pleiotropy was definitely reached in insects exhibiting facultative polymorphisms. In wing-dimorphic crickets, differential activation of JH esterase determines wing length. The evolution of sociality in Isoptera and Hymenoptera has also extensively relied on JH. In primitively social wasps and bumble bees, JH integrates dominance position with reproductive status. In highly social insects, such as the honey bee, JH has lost its gonadotropic role and now regulates division of labor in the worker caste. Its metamorphic role has been extensively explored in the morphological differentiation of queens and workers, and in the generation of worker polymorphism, such as observed in ants.

  9. Insect immunology and hematopoiesis.

    Science.gov (United States)

    Hillyer, Julián F

    2016-05-01

    Insects combat infection by mounting powerful immune responses that are mediated by hemocytes, the fat body, the midgut, the salivary glands and other tissues. Foreign organisms that have entered the body of an insect are recognized by the immune system when pathogen-associated molecular patterns bind host-derived pattern recognition receptors. This, in turn, activates immune signaling pathways that amplify the immune response, induce the production of factors with antimicrobial activity, and activate effector pathways. Among the immune signaling pathways are the Toll, Imd, Jak/Stat, JNK, and insulin pathways. Activation of these and other pathways leads to pathogen killing via phagocytosis, melanization, cellular encapsulation, nodulation, lysis, RNAi-mediated virus destruction, autophagy and apoptosis. This review details these and other aspects of immunity in insects, and discusses how the immune and circulatory systems have co-adapted to combat infection, how hemocyte replication and differentiation takes place (hematopoiesis), how an infection prepares an insect for a subsequent infection (immune priming), how environmental factors such as temperature and the age of the insect impact the immune response, and how social immunity protects entire groups. Finally, this review highlights some underexplored areas in the field of insect immunobiology.

  10. Cantaloupe Insects: Ecology and Control

    Science.gov (United States)

    Cantaloupe (Cucumis melo L.) is a member of the Cucurbitaceae family that includes squash, cucumber, watermelon, pumpkin and gourds along with many wild species. Numerous varieties of cantaloupe are grown in temperate and tropical zones across the globe and depend on honeybees for pollination and h...

  11. Irradiation Dose for the Insect Disinfestation and Mildew Control of Peanut%花生辐照杀虫防霉工艺剂量确定

    Institute of Scientific and Technical Information of China (English)

    冯敏; 朱佳廷; 李澧; 李淑荣; 杨萍; 王德宁; 顾贵强

    2014-01-01

    The bulk peanuts were used as the materials. After γ-ray irradiation of different doses, the peanuts were stored up at room temperature, and the degree of pest infection and gradient of mould infection were observed regularly. The results showed that insects began to appear in the unirradiated peanuts in 2 months, while after 4 months, the pest infection rate increased with the prolonged storage time, and the pest infection rate reached up to 58%-100% after 6 months of storage. However, the irradiated peanuts did not suffer from the pest infection throughout the storage. The unirradiated peanuts were contaminated by moulds after three months of storage, while the peanuts with an irradiation dose of 0.3 -0.5 kGy were mildewed after 6 months of storage, while those with an irradiation dose of 1.0, 4.0 kGy had no mould after 12 months of storage. Combined with relevant international and national standards as wel as the findings of scholars at home and abroad, the minimum effective irradiation dose for insect disinfestations of peanuts was 0.3 kGy, and the minimum effective irradiation dose for mildew control was 1.0 kGy, while the maximum tolerance dose was 4.0 kGy.%以散装花生为材料,经不同剂量的γ射线辐照处理后在室温下贮藏,定期观察害虫侵染程度及霉菌感染程度。结果表明:未经辐照的花生贮存2个月开始生虫,贮存4个月害虫侵染率随贮存时间延长而提高,贮存6个月时害虫侵染率达58%~100%,经辐照处理的花生始终未受害虫侵染。未经辐照的花生贮存3个月后出现霉变,辐照剂量为0.3~0.5 kGy的花生贮存6个月后出现霉变,辐照剂量为1.0、4.0 kGy的花生在辐照后12个月内都未发生霉变。结合相关国际、国内标准以及国内外学者的研究结果,确定花生辐照杀虫的最低有效剂量为0.3 kGy,辐照防霉最低有效剂量为1.0 kGy,最高耐受剂量为4.0 kGy。

  12. Strong Delayed Interactive Effects of Metal Exposure and Warming: Latitude-Dependent Synergisms Persist Across Metamorphosis.

    Science.gov (United States)

    Debecker, Sara; Dinh, Khuong V; Stoks, Robby

    2017-02-21

    As contaminants are often more toxic at higher temperatures, predicting their impact under global warming remains a key challenge for ecological risk assessment. Ignoring delayed effects, synergistic interactions between contaminants and warming, and differences in sensitivity across species' ranges could lead to an important underestimation of the risks. We addressed all three mechanisms by studying effects of larval exposure to zinc and warming before, during, and after metamorphosis in Ischnura elegans damselflies from high- and low-latitude populations. By integrating these mechanisms into a single study, we could identify two novel patterns. First, during exposure zinc did not affect survival, whereas it induced mild to moderate postexposure mortality in the larval stage and at metamorphosis, and very strongly reduced adult lifespan. This severe delayed effect across metamorphosis was especially remarkable in high-latitude animals, as they appeared almost insensitive to zinc during the larval stage. Second, the well-known synergism between metals and warming was manifested not only during the larval stage but also after metamorphosis, yet notably only in low-latitude damselflies. These results highlight that a more complete life-cycle approach that incorporates the possibility of delayed interactions between contaminants and warming in a geographical context is crucial for a more realistic risk assessment in a warming world.

  13. Quantitative proteomics identify molecular targets that are crucial in larval settlement and metamorphosis of bugula neritina

    KAUST Repository

    Zhang, Huoming

    2011-01-07

    The marine invertebrate Bugula neritina has a biphasic life cycle that consists of a swimming larval stage and a sessile juvenile and adult stage. The attachment of larvae to the substratum and their subsequent metamorphosis have crucial ecological consequences. Despite many studies on this species, little is known about the molecular mechanism of these processes. Here, we report a comparative study of swimming larvae and metamorphosing individuals at 4 and 24 h postattachment using label-free quantitative proteomics. We identified more than 1100 proteins at each stage, 61 of which were differentially expressed. Specifically, proteins involved in energy metabolism and structural molecules were generally down-regulated, whereas proteins involved in transcription and translation, the extracellular matrix, and calcification were strongly up-regulated during metamorphosis. Many tightly regulated novel proteins were also identified. Subsequent analysis of the temporal and spatial expressions of some of the proteins and an assay of their functions indicated that they may have key roles in metamorphosis of B. neritina. These findings not only provide molecular evidence with which to elucidate the substantial changes in morphology and physiology that occur during larval attachment and metamorphosis but also identify potential targets for antifouling treatment. © 2011 American Chemical Society.

  14. Caring about Strangers: A Lingisian Reading of Kafka's "Metamorphosis"

    Science.gov (United States)

    Hung, Ruyu

    2013-01-01

    This article explores a significant question, implicit in Kafka's novel "Metamorphosis," explicitly asked by Rorty: "Can I care about a stranger?" Alphonso Lingis's view is adopted to overcome a mainstream belief that there is a distinction between my community and the stranger's community, or us community and…

  15. Are G-protein-coupled receptors involved in mediating larval settlement and metamorphosis of coral planulae?

    Science.gov (United States)

    Tran, Cawa; Hadfield, Michael G

    2012-04-01

    Larvae of the scleractinian coral Pocillopora damicornis are induced to settle and metamorphose by the presence of marine bacterial biofilms, and the larvae of Montipora capitata respond to a combination of filamentous and crustose coralline algae. The primary goal of this study was to better understand metamorphosis of cnidarian larvae by determining what types of receptors and signal-transduction pathways are involved during stimulation of metamorphosis of P. damicornis and M. capitata. Evidence from studies on larvae of hydrozoans suggests that G-protein-coupled receptors (GPCRs) are good candidates. Settlement experiments were conducted in which competent larvae were exposed to neuropharmacological agents that affect GPCRs and their associated signal-transduction pathways, AC/cAMP and PI/DAG/PKC. On the basis of the results of these experiments, we conclude that GPCRs and these pathways do not mediate settlement and metamorphosis in either coral species. Two compounds that had an effect on both species, forskolin and phorbol-12-myristate-13-acetate (TPA), may be acting on other cellular processes not related to GPCRs. This study strengthens our understanding of the underlying physiological mechanisms that regulate metamorphosis in coral larvae.

  16. Characterization and expression of calmodulin gene during larval settlement and metamorphosis of the polychaete Hydroides elegans

    KAUST Repository

    Chen, Zhangfan

    2012-08-01

    The polychaete . Hydroides elegans (Serpulidae, Lophotrochozoa) is a problematic marine fouling organism in most tropical and subtropical coastal environment. Competent larvae of . H. elegans undergo the transition from the swimming larval stage to the sessile juvenile stage with substantial morphological, physiological, and behavior changes. This transition is often referred to as larval settlement and metamorphosis. In this study, we examined the possible involvement of calmodulin (CaM) - a multifunctional calcium metabolism regulator, in the larval settlement and metamorphosis of . H. elegans. A full-length . CaM cDNA was successfully cloned from . H. elegans (. He-CaM) and it contained an open reading frame of 450. bp, encoding 149 amino acid residues. It was highly expressed in 12. h post-metamorphic juveniles, and remained high in adults. . In situ hybridization conducted in competent larvae and juveniles revealed that . He-CaM gene was continuously expressed in the putative growth zones, branchial rudiments, and collar region, suggesting that . He-CaM might be involved in tissue differentiation and development. Our subsequent bioassay revealed that the CaM inhibitor W7 could effectively inhibit larval settlement and metamorphosis, and cause some morphological defects of unsettled larvae. In conclusion, our results revealed that CaM has important functions in the larval settlement and metamorphosis of . H. elegans. © 2012 Elsevier Inc..

  17. Intra-cavity metamorphosis of a Gaussian beam to flat-top distribution

    CSIR Research Space (South Africa)

    Naidoo, Darryl

    2014-02-01

    Full Text Available We explore an intra-cavity beam shaping approach to generate a Gaussian distribution by the metamorphosis of a Gaussian beam into a flat-top distribution on opposing mirrors. The concept is tested external to the cavity through the use of two...

  18. Consequences of metamorphosis for the locomotor performance and thermal physiology of the newt Triturus cristatus.

    Science.gov (United States)

    Wilson, Robbie S

    2005-01-01

    During metamorphosis, most amphibians undergo rapid shifts in their morphology that allow them to move from an aquatic to a more terrestrial existence. Two important challenges associated with this shift in habitat are the necessity to switch from an aquatic to terrestrial mode of locomotion and changes in the thermal environment. In this study, I investigated the consequences of metamorphosis to the burst swimming and running performance of the European newt Triturus cristatus to determine the nature and magnitude of any locomotor trade-offs that occur across life-history stages. In addition, I investigated whether there were any shifts in the thermal dependence of performance between life-history stages of T. cristatus to compensate for changes in their thermal environment during metamorphosis. A trade-off between swimming and running performance was detected across life-history stages, with metamorphosis resulting in a simultaneous decrease in swimming and increase in running performance. Although the terrestrial habitat of postmetamorphic stages of the newt T. cristatus experienced greater daily fluctuations in temperature than the aquatic habitat of the larval stage, no differences in thermal sensitivity of locomotor performance were detected between the larval aquatic and postmetamorphic stages. The absence of variation across life-history stages of T. cristatus may indicate that thermal sensitivity may be a conservative trait across ontogenetic stages in amphibians, but further studies are required to investigate this assertion.

  19. The thyroid gland and thyroid hormones in Senegalese sole (Solea senegalensis) during early development and metamorphosis.

    Science.gov (United States)

    Klaren, Peter H M; Wunderink, Yvette S; Yúfera, Manuel; Mancera, Juan M; Flik, Gert

    2008-02-01

    We here describe the ontogeny and morphology of the thyroid gland in Senegalese sole (Solea senegalensis), and correlate these with whole body concentrations of thyroid hormones during early development and metamorphosis. Under our rearing conditions at 19.5 degrees C, most larvae entered metamorphosis in stage 1 at 15 days post-hatching (dph), and completed metamorphosis in stage 4 at 25dph. The onset of metamorphosis coincided with surges in whole body T4 and T3 concentrations. Crossmon's trichrome stain colored the lumen of follicular structures brightly red, and this co-localized with a T4-immunoreactivity. Thyroid follicles were first observed in stage 0 pre-metamorphic larvae at 5dph of age, and were detected exclusively in the subpharyngeal region, surrounding the ventral aorta. Increases in whole body thyroid hormone levels coincided with a 2(1/2)-fold increase in the total thyroidal colloid area in stage 1 larvae (aged 15dph) compared to stage 0 larvae (12dph). This was preceded by an approximately 40%-increase in the follicles' epithelial cell height in stage 0 larvae at 12dph compared to larvae at 5dph, and by an increase in the whole body T3/T4 ratio, indicative of an increase in outer ring deiodination. We conclude that in S. senegalensis there is a clear chronology in the activation of the thyroid gland that starts in early pre-metamorphic larvae.

  20. Effects of marine persistent organic pollutants on early life development and metamorphosis of echinoids

    NARCIS (Netherlands)

    Drs Anselmo, H.M.R.

    2012-01-01

    This thesis presents the development of three new bioassays for the detection of compounds disrupting the early development of echinoid larvae from hatching to metamorphosis, and the interference with cellular efflux pumps. These assays come in addition to the already existing sea urchin fertilizati

  1. Mechanical Control of Whole Body Shape by a Single Cuticular Protein Obstructor-E in Drosophila melanogaster.

    Directory of Open Access Journals (Sweden)

    Reiko Tajiri

    2017-01-01

    Full Text Available Body shapes are much more variable than body plans. One way to alter body shapes independently of body plans would be to mechanically deform bodies. To what extent body shapes are regulated physically, or molecules involved in physical control of morphogenesis, remain elusive. During fly metamorphosis, the cuticle (exoskeleton covering the larval body contracts longitudinally and expands laterally to become the ellipsoidal pupal case (puparium. Here we show that Drosophila melanogaster Obstructor-E (Obst-E is a protein constituent of the larval cuticle that confers the oriented contractility/expandability. In the absence of obst-E function, the larval cuticle fails to undergo metamorphic shape change and finally becomes a twiggy puparium. We present results indicating that Obst-E regulates the arrangement of chitin, a long-chain polysaccharide and a central component of the insect cuticle, and directs the formation of supracellular ridges on the larval cuticle. We further show that Obst-E is locally required for the oriented shape change of the cuticle during metamorphosis, which is associated with changes in the morphology of those ridges. Thus, Obst-E dramatically affects the body shape in a direct, physical manner by controlling the mechanical property of the exoskeleton.

  2. Mechanical Control of Whole Body Shape by a Single Cuticular Protein Obstructor-E in Drosophila melanogaster

    Science.gov (United States)

    Ogawa, Nobuhiro; Fujiwara, Haruhiko

    2017-01-01

    Body shapes are much more variable than body plans. One way to alter body shapes independently of body plans would be to mechanically deform bodies. To what extent body shapes are regulated physically, or molecules involved in physical control of morphogenesis, remain elusive. During fly metamorphosis, the cuticle (exoskeleton) covering the larval body contracts longitudinally and expands laterally to become the ellipsoidal pupal case (puparium). Here we show that Drosophila melanogaster Obstructor-E (Obst-E) is a protein constituent of the larval cuticle that confers the oriented contractility/expandability. In the absence of obst-E function, the larval cuticle fails to undergo metamorphic shape change and finally becomes a twiggy puparium. We present results indicating that Obst-E regulates the arrangement of chitin, a long-chain polysaccharide and a central component of the insect cuticle, and directs the formation of supracellular ridges on the larval cuticle. We further show that Obst-E is locally required for the oriented shape change of the cuticle during metamorphosis, which is associated with changes in the morphology of those ridges. Thus, Obst-E dramatically affects the body shape in a direct, physical manner by controlling the mechanical property of the exoskeleton. PMID:28076349

  3. Effect of thyroid hormone concentration on the transcriptional response underlying induced metamorphosis in the Mexican axolotl (Ambystoma

    Directory of Open Access Journals (Sweden)

    Samuels Amy K

    2008-02-01

    Full Text Available Abstract Background Thyroid hormones (TH induce gene expression programs that orchestrate amphibian metamorphosis. In contrast to anurans, many salamanders do not undergo metamorphosis in nature. However, they can be induced to undergo metamorphosis via exposure to thyroxine (T4. We induced metamorphosis in juvenile Mexican axolotls (Ambystoma mexicanum using 5 and 50 nM T4, collected epidermal tissue from the head at four time points (Days 0, 2, 12, 28, and used microarray analysis to quantify mRNA abundances. Results Individuals reared in the higher T4 concentration initiated morphological and transcriptional changes earlier and completed metamorphosis by Day 28. In contrast, initiation of metamorphosis was delayed in the lower T4 concentration and none of the individuals completed metamorphosis by Day 28. We identified 402 genes that were statistically differentially expressed by ≥ two-fold between T4 treatments at one or more non-Day 0 sampling times. To complement this analysis, we used linear and quadratic regression to identify 542 and 709 genes that were differentially expressed by ≥ two-fold in the 5 and 50 nM T4 treatments, respectively. Conclusion We found that T4 concentration affected the timing of gene expression and the shape of temporal gene expression profiles. However, essentially all of the identified genes were similarly affected by 5 and 50 nM T4. We discuss genes and biological processes that appear to be common to salamander and anuran metamorphosis, and also highlight clear transcriptional differences. Our results show that gene expression in axolotls is diverse and precise, and that axolotls provide new insights about amphibian metamorphosis.

  4. Effect of thyroid hormone concentration on the transcriptional response underlying induced metamorphosis in the Mexican axolotl (Ambystoma).

    Science.gov (United States)

    Page, Robert B; Voss, Stephen R; Samuels, Amy K; Smith, Jeramiah J; Putta, Srikrishna; Beachy, Christopher K

    2008-02-11

    Thyroid hormones (TH) induce gene expression programs that orchestrate amphibian metamorphosis. In contrast to anurans, many salamanders do not undergo metamorphosis in nature. However, they can be induced to undergo metamorphosis via exposure to thyroxine (T4). We induced metamorphosis in juvenile Mexican axolotls (Ambystoma mexicanum) using 5 and 50 nM T4, collected epidermal tissue from the head at four time points (Days 0, 2, 12, 28), and used microarray analysis to quantify mRNA abundances. Individuals reared in the higher T4 concentration initiated morphological and transcriptional changes earlier and completed metamorphosis by Day 28. In contrast, initiation of metamorphosis was delayed in the lower T4 concentration and none of the individuals completed metamorphosis by Day 28. We identified 402 genes that were statistically differentially expressed by > or = two-fold between T4 treatments at one or more non-Day 0 sampling times. To complement this analysis, we used linear and quadratic regression to identify 542 and 709 genes that were differentially expressed by > or = two-fold in the 5 and 50 nM T4 treatments, respectively. We found that T4 concentration affected the timing of gene expression and the shape of temporal gene expression profiles. However, essentially all of the identified genes were similarly affected by 5 and 50 nM T4. We discuss genes and biological processes that appear to be common to salamander and anuran metamorphosis, and also highlight clear transcriptional differences. Our results show that gene expression in axolotls is diverse and precise, and that axolotls provide new insights about amphibian metamorphosis.

  5. Effect of thyroid hormone concentration on the transcriptional response underlying induced metamorphosis in the Mexican axolotl (Ambystoma)

    Science.gov (United States)

    Page, Robert B; Voss, Stephen R; Samuels, Amy K; Smith, Jeramiah J; Putta, Srikrishna; Beachy, Christopher K

    2008-01-01

    Background Thyroid hormones (TH) induce gene expression programs that orchestrate amphibian metamorphosis. In contrast to anurans, many salamanders do not undergo metamorphosis in nature. However, they can be induced to undergo metamorphosis via exposure to thyroxine (T4). We induced metamorphosis in juvenile Mexican axolotls (Ambystoma mexicanum) using 5 and 50 nM T4, collected epidermal tissue from the head at four time points (Days 0, 2, 12, 28), and used microarray analysis to quantify mRNA abundances. Results Individuals reared in the higher T4 concentration initiated morphological and transcriptional changes earlier and completed metamorphosis by Day 28. In contrast, initiation of metamorphosis was delayed in the lower T4 concentration and none of the individuals completed metamorphosis by Day 28. We identified 402 genes that were statistically differentially expressed by ≥ two-fold between T4 treatments at one or more non-Day 0 sampling times. To complement this analysis, we used linear and quadratic regression to identify 542 and 709 genes that were differentially expressed by ≥ two-fold in the 5 and 50 nM T4 treatments, respectively. Conclusion We found that T4 concentration affected the timing of gene expression and the shape of temporal gene expression profiles. However, essentially all of the identified genes were similarly affected by 5 and 50 nM T4. We discuss genes and biological processes that appear to be common to salamander and anuran metamorphosis, and also highlight clear transcriptional differences. Our results show that gene expression in axolotls is diverse and precise, and that axolotls provide new insights about amphibian metamorphosis. PMID:18267027

  6. Genetic differentiation among Maruca vitrata F. (Lepidoptera: Crambidae) populations on cultivated cowpea and wild host plants: implications for insect resistance management and biological control strategies

    Science.gov (United States)

    Maruca vitrata is a polyphagous insect pest on a wide variety of leguminous plants in the tropics and subtropics. The contribution of host-associated genetic variation on population structure was investigated using analysis mitochondrial cox1 sequence and microsatellite marker data from M. vitrata c...

  7. Agricultural disease and insect-pest control via agro-ecological landscape construction%以病虫害控制为中心的农业生态景观建设

    Institute of Scientific and Technical Information of China (English)

    段美春; 刘云慧; 张鑫; 曾为刚; 宇振荣

    2012-01-01

    Chemical pesticides for controlling plant diseases and insect-pests in farmlands cause a series of serious problems including residue effects, environmental pollution, etc. Bio-pesticides and bio-controls are, on the other hand, slowly effective, high cost, and, always with certain targets. Integrated, high-efficient and environment-friendly disease and insect-pest control measures are in increasing demand today. Landscape ecological research has shown that the populations of pathogenic bacteria, pests and their natural enemies are largely affected by landscape patterns. This has provided a new insight into plant disease and insect-pest control. Rational planning of agro-landscape patterns at landscape scale and reasonable arrangement of planting structures and farming activities constituted a beneficial control of agricultural diseases and insect-pests in farmlands. This paper discussed control measures of agricultural diseases and insect-pests from the point of view of agro-landscape at the landscape, field and farm management levels. At the landscape level, control measures of plant diseases and insect-pests included increasing area portions of semi-natural habitats, enriching semi-natural and farm crop habitats and enhancing heterogeneity of landscape structures. It was also necessary to keep the degree of connections among landscapes so as to maintain a balanced migration of natural enemies and prevention of the spread of plant diseases and insect-pests. Low-quality semi-natural habitat plaques also needed to be unproved. At the field level, original farmland boundaries needed to be preserved. Also building of new farmland buffers were needed to control plant diseases and insect-pests in adjacent farmlands. Constructed farmland buffers needed to be integrated into original semi-natural habitat and farmland boundaries. Furthermore, it was important that farmland buffers were rationally configured for plant species, weeding,fertilization, spray pesticide and

  8. Insects recycle endosymbionts when the benefit is over.

    Science.gov (United States)

    Vigneron, Aurélien; Masson, Florent; Vallier, Agnès; Balmand, Séverine; Rey, Marjolaine; Vincent-Monégat, Carole; Aksoy, Emre; Aubailly-Giraud, Etienne; Zaidman-Rémy, Anna; Heddi, Abdelaziz

    2014-10-06

    Symbiotic associations are widespread in nature and represent a driving force in evolution. They are known to impact fitness, and thereby shape the host phenotype. Insects subsisting on nutritionally poor substrates have evolved mutualistic relationships with intracellular symbiotic bacteria (endosymbionts) that supply them with metabolic components lacking in their diet. In many species, endosymbionts are hosted within specialized host cells, called the bacteriocytes, and transmitted vertically across host generations. How hosts balance the costs and benefits of having endosymbionts, and whether and how they adjust symbiont load to their physiological needs, remains largely unexplored. By investigating the cereal weevil Sitophilus association with the Sodalis pierantonius endosymbiont, we discover that endosymbiont populations intensively multiply in young adults, before being rapidly eliminated within few days. We show that young adults strongly depend on endosymbionts and that endosymbiont proliferation after metamorphosis matches a drastic host physiological need for the tyrosine (Tyr) and phenylalanine (Phe) amino acids to rapidly build their protective exoskeleton. Tyr and Phe are precursors of the dihydroxyphenylalanine (DOPA) molecule that is an essential component for the cuticle synthesis. Once the cuticle is achieved, DOPA reaches high amounts in insects, which triggers endosymbiont elimination. This elimination relies on apoptosis and autophagy activation, allowing digestion and recycling of the endosymbiont material. Thus, the weevil-endosymbiont association reveals an adaptive interplay between metabolic and cellular functions that minimizes the cost of symbiosis and speeds up the exoskeleton formation during a critical phase when emerging adults are especially vulnerable.

  9. Migration strategies of insects.

    Science.gov (United States)

    Dingle, H

    1972-03-24

    Physiological and ecological results from a variety of species are consistent with what seem to be valid general statements concerning insect migration. These are as follows: (i)During migration locomotory functions are enhanced and vegetative functions such as feeding and reproduction are suppressed. (ii) Migration usually occurs prereproductively in the life of the adult insect (the oogenesis-flight syndrome). (iii)Since migrant individuals are usually prereproductive, their reproductive values, and hence colonizing abilities, are at or near maximum. (iv) Migrants usually reside in temporary habitats. (v)Migrants have a high potential for population increase, r, which is also advantageous for colonizers. (vi)Both the physiological and ecological parameters of migration are modifiable by environmental factors (that is, phenotypically modifiable)to suit the prevailing conditions. Taken together, these criteria establish a comprehensive theory and adumbrate the basic strategy for migrant insects. This basic strategy is modified to suit the ecological requirements of individual species. Comparative studies of these modifications are of considerable theoretical and practical interest, the more so since most economically important insects are migrants. No satisfactory general statements can as yet be made with respect to the genotype and migration. Certainly we expect colonizing populiations to possess genotypes favoring a high r, but genotypic variation in r depends on the heritabilities of life table statistics, and such measurements are yet to be made (10, 53). The fact that flight duration can be increased by appropriate selection in Oncopeltus fasciatus, and the demonstration of additive genetic variance for this trait in Lygaeus kalmii, suggest that heritability studies of migratory behavior would also be worth pursuing. Most interesting of course, will be possible genetic correlations between migration and life history parameters. Also, migration often

  10. Triclosan exposure alters postembryonic development in a Pacific tree frog (Pseudacris regilla) Amphibian Metamorphosis Assay (TREEMA)

    Energy Technology Data Exchange (ETDEWEB)

    Marlatt, Vicki L. [Nautilus Environmental, 8864 Commerce Court, Burnaby, B.C. V5A 4N7 (Canada); Veldhoen, Nik [Department of Biochemistry and Microbiology, University of Victoria, P.O. Box 3055 Stn CSC, Victoria, B.C. V8W 3P6 (Canada); Lo, Bonnie P. [Nautilus Environmental, 8864 Commerce Court, Burnaby, B.C. V5A 4N7 (Canada); Bakker, Dannika; Rehaume, Vicki; Vallee, Kurtis [Department of Biochemistry and Microbiology, University of Victoria, P.O. Box 3055 Stn CSC, Victoria, B.C. V8W 3P6 (Canada); Haberl, Maxine; Shang, Dayue; Aggelen, Graham C. van; Skirrow, Rachel C. [Pacific and Yukon Laboratory for Environmental Testing, Emergencies Operational Analytical Laboratories and Research Support Division, Environment Canada, 2645 Dollarton Highway, North Vancouver, B.C. V7H 1B1 (Canada); Elphick, James R. [Nautilus Environmental, 8864 Commerce Court, Burnaby, B.C. V5A 4N7 (Canada); Helbing, Caren C., E-mail: chelbing@uvic.ca [Department of Biochemistry and Microbiology, University of Victoria, P.O. Box 3055 Stn CSC, Victoria, B.C. V8W 3P6 (Canada)

    2013-01-15

    The Amphibian Metamorphosis Assay (AMA), developed for Xenopus laevis, is designed to identify chemicals that disrupt thyroid hormone (TH)-mediated biological processes. We adapted the AMA for use on an ecologically-relevant North American species, the Pacific tree frog (Pseudacris regilla), and applied molecular endpoints to evaluate the effects of the antibacterial agent, triclosan (TCS). Premetamorphic (Gosner stage 26-28) tadpoles were immersed for 21 days in solvent control, 1.5 {mu}g/L thyroxine (T{sub 4}), 0.3, 3 and 30 {mu}g/L (nominal) TCS, or combined T{sub 4}/TCS treatments. Exposure effects were scored by morphometric (developmental stage, wet weight, and body, snout-vent and hindlimb lengths) and molecular (mRNA abundance using quantitative real time polymerase chain reaction) criteria. T{sub 4} treatment alone accelerated development concomitant with altered levels of TH receptors {alpha} and {beta}, proliferating cell nuclear antigen, and gelatinase B mRNAs in the brain and tail. We observed TCS-induced perturbations in all of the molecular and morphological endpoints indicating that TCS exposure disrupts coordination of postembryonic tadpole development. Clear alterations in molecular endpoints were evident at day 2 whereas the earliest morphological effects appeared at day 4 and were most evident at day 21. Although TCS alone (3 and 30 {mu}g/L) was protective against tadpole mortality, this protection was lost in the presence of T{sub 4}. The Pacific tree frog is the most sensitive species examined to date displaying disruption of TH-mediated development by a common antimicrobial agent.

  11. Acoustic communication in insect disease vectors

    Directory of Open Access Journals (Sweden)

    Felipe de Mello Vigoder

    2013-01-01

    Full Text Available Acoustic signalling has been extensively studied in insect species, which has led to a better understanding of sexual communication, sexual selection and modes of speciation. The significance of acoustic signals for a blood-sucking insect was first reported in the XIX century by Christopher Johnston, studying the hearing organs of mosquitoes, but has received relatively little attention in other disease vectors until recently. Acoustic signals are often associated with mating behaviour and sexual selection and changes in signalling can lead to rapid evolutionary divergence and may ultimately contribute to the process of speciation. Songs can also have implications for the success of novel methods of disease control such as determining the mating competitiveness of modified insects used for mass-release control programs. Species-specific sound “signatures” may help identify incipient species within species complexes that may be of epidemiological significance, e.g. of higher vectorial capacity, thereby enabling the application of more focussed control measures to optimise the reduction of pathogen transmission. Although the study of acoustic communication in insect vectors has been relatively limited, this review of research demonstrates their value as models for understanding both the functional and evolutionary significance of acoustic communication in insects.

  12. Converting pest insects into food

    DEFF Research Database (Denmark)

    Offenberg, Hans Joachim; Wiwatwittaya, Decha

    2010-01-01

    Canopy dwelling weaver ants (Oecophylla spp.) are used to control a variety of pests in a number of tropical tree crops. What is less familiar is the existence of commercial markets where these ants and their brood are sold for (i) human consumption, (ii) pet food or (iii) traditional medicine...... by pest insects, problematic pests are converted into food and additional earnings. To assess the profitability of providing additional food for the ants, O. smaragdina food conversion efficiency (ECI) was estimated in the laboratory. This estimate suggests the feeding of weaver ants in ant farms...

  13. Behavioral Immunity in Insects

    Directory of Open Access Journals (Sweden)

    Thierry Lefèvre

    2012-08-01

    Full Text Available Parasites can dramatically reduce the fitness of their hosts, and natural selection should favor defense mechanisms that can protect hosts against disease. Much work has focused on understanding genetic and physiological immunity against parasites, but hosts can also use behaviors to avoid infection, reduce parasite growth or alleviate disease symptoms. It is increasingly recognized that such behaviors are common in insects, providing strong protection against parasites and parasitoids. We review the current evidence for behavioral immunity in insects, present a framework for investigating such behavior, and emphasize that behavioral immunity may act through indirect rather than direct fitness benefits. We also discuss the implications for host-parasite co-evolution, local adaptation, and the evolution of non-behavioral physiological immune systems. Finally, we argue that the study of behavioral immunity in insects has much to offer for investigations in vertebrates, in which this topic has traditionally been studied.

  14. CONTROL EFFECTS OF INERT DUST AGAINST STORED-GRAIN INSECT PESTS IN DIFFERENT TYPES OF GRANARIES%不同仓型惰性粉防治储粮害虫效果研究

    Institute of Scientific and Technical Information of China (English)

    王晶磊; 徐威; 曹阳; 李燕羽

    2011-01-01

    To evaluate the control effects of inert dust against stored-grain insect pests in different types of granaries, by mixing 50 cm thick grain on the surface with the inert dust, the test has been carried out in the com and wheat loaded recently in the large granary, squat silo and silo respectively. The results showed that the inert duct could prevent effectively insect pests occurrence in grain hulks for a longer period, and delay the occurrence time and density of insect. There were no effects on temperature, humidity of the granary and grain quality, instead of the usual chemicals to some extent.%为了评价惰性粉杀虫剂在不同仓型中杀虫应用效果,采用粮堆表层至50 cm处拌粮的方法对高大平房仓、浅圆仓、立筒仓内新入库的玉米和小麦进行试验研究.结果表明:此种惰性粉杀虫剂能在较长的一段时间有效防治粮堆内的害虫发生,并延迟了害虫的发生时间和密度,对仓内温、湿度、粮食品质基本无影响,可以部分取代目前使用的化学防护剂.

  15. Structural changes under low evolutionary constraint may decrease the affinity of dibenzoylhydrazine insecticides for the ecdysone receptor in non-lepidopteran insects.

    Science.gov (United States)

    Zotti, M J; Christiaens, O; Rougé, P; Grutzmacher, A D; Zimmer, P D; Smagghe, G

    2012-10-01

    Understanding how variations in genetic sequences are conveyed into structural and biochemical properties is of increasing interest in the field of molecular evolution. In order to gain insight into this process, we studied the ecdysone receptor (EcR), a transcription factor that controls moulting and metamorphosis in arthropods. Using an in silico homology model, we identified a region in the lepidopteran EcR that has no direct interaction with the natural hormone but is under strong evolutionary constraint. This region causes a small indentation in the three-dimensional structure of the protein which facilitates the binding of tebufenozide. Non-Mecopterida are considered much older, evolutionarily, than Lepidoptera and they do not have this extended cavity. This location shows differences in evolutionary constraint between Lepidoptera and other insects, where a much lower constraint is observed compared with the Lepidoptera. It is possible that the higher flexibility seen in the EcR of Lepidoptera is an entirely new trait and the higher constraint could then be an indication that this region does have another important function. Finally, we suggest that Try123, which is evolutionarily constrained and is up to now exclusively present in Lepidoptera EcRs, could play a critical role in discriminating between steroidal and non-steroidal ligands.

  16. Tracing the evolutionary origins of insect renal function.

    Science.gov (United States)

    Halberg, Kenneth A; Terhzaz, Selim; Cabrero, Pablo; Davies, Shireen A; Dow, Julian A T

    2015-04-21

    Knowledge on neuropeptide receptor systems is integral to understanding animal physiology. Yet, obtaining general insight into neuropeptide signalling in a clade as biodiverse as the insects is problematic. Here we apply fluorescent analogues of three key insect neuropeptides to map renal tissue architecture across systematically chosen representatives of the major insect Orders, to provide an unprecedented overview of insect renal function and control. In endopterygote insects, such as Drosophila, two distinct transporting cell types receive separate neuropeptide signals, whereas in the ancestral exopterygotes, a single, general cell type mediates all signals. Intriguingly, the largest insect Order Coleoptera (beetles) has evolved a unique approach, in which only a small fraction of cells are targets for neuropeptide action. In addition to demonstrating a universal utility of this technology, our results reveal not only a generality of signalling by the evolutionarily ancient neuropeptide families but also a clear functional separation of the types of cells that mediate the signal.

  17. Insect Repellents: Protect Your Child from Insect Bites

    Science.gov (United States)

    ... Español Text Size Email Print Share Choosing an Insect Repellent for Your Child Page Content Mosquitoes, biting ... sunscreen needs to be reapplied often. Reactions to Insect Repellents If you suspect that your child is ...

  18. The Comet assay in insects--Status, prospects and benefits for science.

    Science.gov (United States)

    Augustyniak, Maria; Gladysz, Marcin; Dziewięcka, Marta

    2016-01-01

    The Comet assay has been recently adapted to investigate DNA damage in insects. The first reports of its use in Drosophila melanogaster appeared in 2002. Since then, the interest in the application of the Comet assay to studies of insects has been rapidly increasing. Many authors see substantial potential in the use of the Comet assay in D. melanogaster for medical toxicology studies. This application could allow the testing of drugs and result in an understanding of the mechanisms of action of toxins, which could significantly influence the limited research that has been performed on vertebrates. The possible perspectives and benefits for science are considered in this review. In the last decade, the use of the Comet assay has been described in insects other than D. melanogaster. Specifically, methods to prepare a cell suspension from insect tissues, which is a difficult task, were analyzed and compared in detail. Furthermore, attention was paid to any differences and modifications in the research protocols, such as the buffer composition and electrophoresis conditions. Various scientific fields in addition to toxicological and ecotoxicological research were considered. We expect the Comet assay to be used in environmental risk assessments and to improve our understanding of many important phenomena of insect life, such as metamorphosis, molting, diapause and quiescence. The use of this method to study species that are of key importance to humans, such as pests and beneficial insects, appears to be highly probable and very promising. The use of the Comet assay for DNA stability testing in insects will most likely rapidly increase in the future.

  19. A Fungal Insecticide Engineered for Fast Per Os Killing of Caterpillars Has High Field Efficacy and Safety in Full-Season Control of Cabbage Insect Pests

    Science.gov (United States)

    Liu, Yong-Jie; Liu, Jing; Ying, Sheng-Hua; Liu, Shu-Sheng

    2013-01-01

    Fungal insecticides developed from filamentous pathogens of insects are notorious for their slow killing action through cuticle penetration, depressing commercial interest and practical application. Genetic engineering may accelerate their killing action but cause ecological risk. Here we show that a Beauveria bassiana formulation, HV8 (BbHV8), engineered for fast per os killing of caterpillars by an insect midgut-acting toxin (Vip3Aa1) overexpressed in conidia has both high field efficacy and safety in full-season protection of cabbage from the damage of an insect pest complex dominated by Pieris rapae larvae, followed by Plutella xylostella larvae and aphids. In two fields repeatedly sprayed during summer, BbHV8 resulted in overall mean efficacies of killing of 71% and 75%, which were similar or close to the 70% and 83% efficacies achieved by commercially recommended emamectin benzoate but much higher than the 31% and 48% efficacies achieved by the same formulation of the parental wild-type strain (WT). Both BbHV8 and WT sprays exerted no adverse effect on a nontarget spider community during the trials, and the sprays did not influence saprophytic fungi in soil samples taken from the field plots during 4 months after the last spray. Strikingly, BbHV8 and the WT showed low fitness when they were released into the environment because both were decreasingly recovered from the field lacking native B. bassiana strains (undetectable 5 months after the spray), and the recovered isolates became much less tolerant to high temperature and UV-B irradiation. Our results highlight for the first time that a rationally engineered fungal insecticide can compete with a chemical counterpart to combat insect pests at an affordable cost and with low ecological risk. PMID:23956386

  20. Phosphoproteome analysis during larval development and metamorphosis in the spionid polychaete Pseudopolydora vexillosa

    KAUST Repository

    Chandramouli, Kondethimmanahalli

    2011-05-25

    Background: The metamorphosis of the spionid polychaete Pseudopolydora vexillosa includes spontaneous settlement onto soft-bottom habitats and morphogenesis that can be completed in a very short time. A previous study on the total changes to the proteome during the various developmental stages of P. vexillosa suggested that little or no de novo protein synthesis occurs during metamorphosis. In this study, we used multicolor fluorescence detection of proteins in 2-D gels for differential analysis of proteins and phosphoproteins to reveal the dynamics of post-translational modification proteins in this species. A combination of affinity chromatography, 2D-PAGE, and mass spectrometry was used to identify the phosphoproteins in pre-competent larvae, competent larvae, and newly metamorphosed juveniles. Results: We reproducibly detected 210, 492, and 172 phosphoproteins in pre-competent larvae, competent larvae, and newly metamorphosed juveniles, respectively. The highest percentage of phosphorylation was observed during the competent larval stage. About 64 stage-specific phosphoprotein spots were detected in the competent stage, and 32 phosphoproteins were found to be significantly differentially expressed in the three stages. We identified 38 phosphoproteins, 10 of which were differentially expressed during metamorphosis. These phosphoproteins belonged to six categories of biological processes: (1) development, (2) cell differentiation and integrity, (3) transcription and translation, (4) metabolism, (5) protein-protein interaction and proteolysis, and (6) receptors and enzymes. Conclusion: This is the first study to report changes in phosphoprotein expression patterns during the metamorphosis of the marine polychaete P. vexillosa. The higher degree of phosphorylation during the process of attaining competence to settle and metamorphose may be due to fast morphological transitions regulated by various mechanisms. Our data are consistent with previous studies showing a

  1. Protecting Yourself from Stinging Insects

    Science.gov (United States)

    ... plants when possible. ■■ Keep work areas clean. Some insects are attracted to discarded food. ■■ Remain calm and still if a single stinging insect is flying around. (Swatting may cause it to ...

  2. Eicosanoid actions in insect immunity

    Science.gov (United States)

    Insects express three lines of protection from infections and invasions. Their cuticles and peritrophic membranes are physical barriers. Infections and invasions are quickly recognized within insect bodies; recognition launches two lines of innate immune reactions. Humoral reactions involve induc...

  3. Two-stage baculovirus production in insect-cell bioreactors.

    NARCIS (Netherlands)

    Lier, van F.L.J.

    1995-01-01

    Baculoviruses are insect-pathogenic viruses with a narrow host range. The viruses can be an alternative to chemical insecticides. From research aimed at improving the efficacy of the viruses in insect control another application evolved: the use of the baculovirus to express foreign proteins in inse

  4. Two-stage baculovirus production in insect-cell bioreactors

    NARCIS (Netherlands)

    Lier, van F.

    1995-01-01

    Baculoviruses are insect-pathogenic viruses with a narrow host range. The viruses can be an alternative to chemical insecticides. From research aimed at improving the efficacy of the viruses in insect control another application evolved: the use of the baculovirus to express foreign protein

  5. Integrating insect-resistant GM Crops in pest management systems

    Science.gov (United States)

    In 2006, GM cotton and maize with insect resistance were grown on 12.1 and 20.1 million hectares in 9 and 13 countries, respectively. These insect resistant GM crops produce various Cry toxins from Bacillus thuringiensis (Bt) and provide highly selective and effective control of lepidopteran and col...

  6. A computer model of insect traps in a landscape

    Science.gov (United States)

    Attractant-based trap networks are important elements of invasive insect detection, pest control, and basic research programs. We present a landscape-level spatially explicit model of trap networks that incorporates variable attractiveness of traps and a movement model for insect dispersion. We desc...

  7. Retrospection of Alien Invasive Forest Insect Pests in China

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Eleven species of alien invasive forest insect pests have been found since the early time that insect species had been taken recorded in China. Their origins, inland distribution, invasive time, hosts, causing damage are recorded in this paper for the evidence of biological invasion. Their control methods are also studied or discussed.

  8. Dependency on de novo protein synthesis and proteomic changes during metamorphosis of the marine bryozoan Bugula neritina

    KAUST Repository

    Wong, Yue Him

    2010-05-24

    Background: Metamorphosis in the bryozoan Bugula neritina (Linne) includes an initial phase of rapid morphological rearrangement followed by a gradual phase of morphogenesis. We hypothesized that the first phase may be independent of de novo synthesis of proteins and, instead, involves post-translational modifications of existing proteins, providing a simple mechanism to quickly initiate metamorphosis. To test our hypothesis, we challenged B. neritina larvae with transcription and translation inhibitors. Furthermore, we employed 2D gel electrophoresis to characterize changes in the phosphoproteome and proteome during early metamorphosis. Differentially expressed proteins were identified by liquid chromatography tandem mass spectrometry and their gene expression patterns were profiled using semi-quantitative real time PCR.Results: When larvae were incubated with transcription and translation inhibitors, metamorphosis initiated through the first phase but did not complete. We found a significant down-regulation of 60 protein spots and the percentage of phosphoprotein spots decreased from 15% in the larval stage to12% during early metamorphosis. Two proteins--the mitochondrial processing peptidase beta subunit and severin--were abundantly expressed and phosphorylated in the larval stage, but down-regulated during metamorphosis. MPPbeta and severin were also down-regulated on the gene expression level.Conclusions: The initial morphogenetic changes that led to attachment of B. neritina did not depend on de novo protein synthesis, but the subsequent gradual morphogenesis did. This is the first time that the mitochondrial processing peptidase beta subunit or severin have been shown to be down-regulated on both gene and protein expression levels during the metamorphosis of B. neritina. Future studies employing immunohistochemistry to reveal the expression locality of these two proteins during metamorphosis should provide further evidence of the involvement of these two

  9. Using bacterial extract along with differential gene expression in Acropora millepora larvae to decouple the processes of attachment and metamorphosis.

    Directory of Open Access Journals (Sweden)

    Nachshon Siboni

    Full Text Available Biofilms of the bacterium Pseudoalteromonas induce metamorphosis of acroporid coral larvae. The bacterial metabolite tetrabromopyrrole (TBP, isolated from an extract of Pseudoalteromonas sp. associated with the crustose coralline alga (CCA Neogoniolithon fosliei, induced coral larval metamorphosis (100% with little or no attachment (0-2%. To better understand the molecular events and mechanisms underpinning the induction of Acropora millepora larval metamorphosis, including cell proliferation, apoptosis, differentiation, migration, adhesion and biomineralisation, two novel coral gene expression assays were implemented. These involved the use of reverse-transcriptase quantitative PCR (RT-qPCR and employed 47 genes of interest (GOI, selected based on putative roles in the processes of settlement and metamorphosis. Substantial differences in transcriptomic responses of GOI were detected following incubation of A. millepora larvae with a threshold concentration and 10-fold elevated concentration of TBP-containing extracts of Pseudoalteromonas sp. The notable and relatively abrupt changes of the larval body structure during metamorphosis correlated, at the molecular level, with significant differences (p<0.05 in gene expression profiles of 24 GOI, 12 hours post exposure. Fourteen of those GOI also presented differences in expression (p<0.05 following exposure to the threshold concentration of bacterial TBP-containing extract. The specificity of the bacterial TBP-containing extract to induce the metamorphic stage in A. millepora larvae without attachment, using a robust, low cost, accurate, ecologically relevant and highly reproducible RT-qPCR assay, allowed partially decoupling of the transcriptomic processes of attachment and metamorphosis. The bacterial TBP-containing extract provided a unique opportunity to monitor the regulation of genes exclusively involved in the process of metamorphosis, contrasting previous gene expression studies that

  10. Sterol metabolism of insects

    NARCIS (Netherlands)

    Ritter, F.J.; Wientjens, W.H.J.M.

    1967-01-01

    This article surveys the present knowledge of the sterol metabolism of insects. It is emphasized that a high degree of purity of the dietary sterols and the climination of the influence of symbionts are essential to present ambiguity in interpreting results. It is pointed out that a sharp distinctio

  11. Recycled Insect Models

    Science.gov (United States)

    Rule, Audrey C.; Meyer, Mary Ann

    2007-01-01

    This article presents an engaging activity in which high school students use a dichotomous key to guide the creation and classification of model insects from recycled plastic lids and containers. Besides teaching the use of a dichotomous key and the effect of evolutionary descent upon groupings of organisms, this activity focuses on an…

  12. Insects and sex

    NARCIS (Netherlands)

    Beukeboom, Leo

    2005-01-01

    Most organisms reproduce sexually, but the evolution of sexual reproduction is not yet well understood. Sexual reproduction leads to new variation and adaptations to the environment, but sex is also costly. Some insects reproduce without sex through parthenogenesis or paedogenesis. Almost all sexual

  13. Broadening insect gastronomy

    DEFF Research Database (Denmark)

    Halloran, Afton Marina Szasz; Münke, Christopher; Vantomme, Paul;

    2015-01-01

    In recent years there has been a trend among chefs to diversify their ingredients and techniques, drawing inspiration from other cultures and creating new foods by blending this knowledge with the flavours of their local region. Edible insects, with their plethora of taste, aromatic, textural...

  14. Colour constancy in insects.

    Science.gov (United States)

    Chittka, Lars; Faruq, Samia; Skorupski, Peter; Werner, Annette

    2014-06-01

    Colour constancy is the perceptual phenomenon that the colour of an object appears largely unchanged, even if the spectral composition of the illuminating light changes. Colour constancy has been found in all insect species so far tested. Especially the pollinating insects offer a remarkable opportunity to study the ecological significance of colour constancy since they spend much of their adult lives identifying and choosing between colour targets (flowers) under continuously changing ambient lighting conditions. In bees, whose colour vision is best studied among the insects, the compensation provided by colour constancy is only partial and its efficiency depends on the area of colour space. There is no evidence for complete 'discounting' of the illuminant in bees, and the spectral composition of the light can itself be used as adaptive information. In patchy illumination, bees adjust their spatial foraging to minimise transitions between variously illuminated zones. Modelling allows the quantification of the adaptive benefits of various colour constancy mechanisms in the economy of nature. We also discuss the neural mechanisms and cognitive operations that might underpin colour constancy in insects.

  15. Investigation--Insects!

    Science.gov (United States)

    Fay, Janice

    2000-01-01

    Presents activities on insects for second grade students. In the first activity, students build a butterfly garden. In the second activity, students observe stimuli reactions with mealworms in the larval stage. Describes the assessment process and discusses the effects of pollution on living things. (YDS)

  16. Resistance to Insecticides in Insects

    OpenAIRE

    2005-01-01

    In recent years, the frequent usage of insecticides in struggle aganist insects, has caused development of resistance to those chemicals in insects. The increase in dosage of insecticide used due to development of resistance in insects, causes important problems in terms of environment and human health. This study includes topics such as insecticides which are used frequently in insect struggle, insecticide resistant types, genetic changes posing resistance, enzymes of resistance and resistan...

  17. Occurrence and control techniques of major diseases and insect pests of bitter gourd in Hainan Province%海南苦瓜主要病虫害的发生及防治技术

    Institute of Scientific and Technical Information of China (English)

    刘子记; 杨衍

    2012-01-01

    Hainan Province is one of the most important export bases for cucurbits and vegetables in China; bitter gourd is one of the main winter-planting cucurbit and vegetable types, but continuous cropping of bitter gourd, high temperature , and humid climate conditions in Hainan Province can easily attract diseases and insect pests against bitter gourd growth. The present study focused on the occurrence characteristics and control methods of major diseases and insect pests of bitter gourd in Hainan Province. Comprehensive prevention and control measures should be adopted in the production of bitter gourd to promote the sustainable development in cucurbits and vegetables production of Hainan Province. The production measures included breeding and planting high-resistant and fine-quality bitter gourd varieties, strengthening the cultivation management, improving the cultivation level, adjusting crop production structure, avoiding continuous cropping, and using physical control on diseases and insect pests.%海南省是我国最重要的外运型瓜菜基地之一,苦瓜是其中的主要冬种瓜菜种类,苦瓜连作及海南地区高温高湿的气候条件容易造成苦瓜病虫害的发生与蔓延.文章介绍了海南苦瓜主要病虫害的发生特点及防治方法,提出在苦瓜病虫害防治中应重点采取培育和种植高抗、优质苦瓜品种,加强栽培管理、提高栽培水平,调整种植结构,避免瓜类作物连作和病虫害物理防治等措施,以促进海南省瓜菜生产的可持续发展.

  18. Ascidians as excellent chordate models for studying the development of the nervous system during embryogenesis and metamorphosis.

    Science.gov (United States)

    Sasakura, Yasunori; Mita, Kaoru; Ogura, Yosuke; Horie, Takeo

    2012-04-01

    The swimming larvae of the chordate ascidians possess a dorsal hollowed central nervous system (CNS), which is homologous to that of vertebrates. Despite the homology, the ascidian CNS consists of a countable number of cells. The simple nervous system of ascidians provides an excellent experimental system to study the developmental mechanisms of the chordate nervous system. The neural fate of the cells consisting of the ascidian CNS is determined in both autonomous and non-autonomous fashion during the cleavage stage. The ascidian neural plate performs the morphogenetic movement of neural tube closure that resembles that in vertebrate neural tube formation. Following neurulation, the CNS is separated into five distinct regions, whose homology with the regions of vertebrate CNS has been discussed. Following their larval stage, ascidians undergo a metamorphosis and become sessile adults. The metamorphosis is completed quickly, and therefore the metamorphosis of ascidians is a good experimental system to observe the reorganization of the CNS during metamorphosis. A recent study has shown that the major parts of the larval CNS remain after the metamorphosis to form the adult CNS. In contrast to such a conserved manner of CNS reorganization, most larval neurons disappear during metamorphosis. The larval glial cells in the CNS are the major source for the formation of the adult CNS, and some of the glial cells produce adult neurons.

  19. Using bacterial extract along with differential gene expression in Acropora millepora larvae to decouple the processes of attachment and metamorphosis.

    Science.gov (United States)

    Siboni, Nachshon; Abrego, David; Seneca, Francois; Motti, Cherie A; Andreakis, Nikos; Tebben, Jan; Blackall, Linda L; Harder, Tilmann

    2012-01-01

    Biofilms of the bacterium Pseudoalteromonas induce metamorphosis of acroporid coral larvae. The bacterial metabolite tetrabromopyrrole (TBP), isolated from an extract of Pseudoalteromonas sp. associated with the crustose coralline alga (CCA) Neogoniolithon fosliei, induced coral larval metamorphosis (100%) with little or no attachment (0-2%). To better understand the molecular events and mechanisms underpinning the induction of Acropora millepora larval metamorphosis, including cell proliferation, apoptosis, differentiation, migration, adhesion and biomineralisation, two novel coral gene expression assays were implemented. These involved the use of reverse-transcriptase quantitative PCR (RT-qPCR) and employed 47 genes of interest (GOI), selected based on putative roles in the processes of settlement and metamorphosis. Substantial differences in transcriptomic responses of GOI were detected following incubation of A. millepora larvae with a threshold concentration and 10-fold elevated concentration of TBP-containing extracts of Pseudoalteromonas sp. The notable and relatively abrupt changes of the larval body structure during metamorphosis correlated, at the molecular level, with significant differences (pcrustose coralline algae, biofilms or with GLW-amide neuropeptides that stimulate the entire onset of larval metamorphosis and attachment.

  20. Ecdysteroids: the overlooked sex steroids of insects? Males: the black box

    Institute of Scientific and Technical Information of China (English)

    ARNOLD DE LOOF

    2006-01-01

    The paradigm, still around in textbooks, that 'in insects sex is strictly genetic,thus that they do not have sex hormones', is mainly based on a wrong interpretation of the 'gynandromorph argument'. It is no longer tenable. Given the fact that vertebrates and invertebrates probably had a common, sexually reproducing ancestor, there is no reason to assume that only vertebrates need sex hormones. The major function of sex hormones is to inform the somatoplasm about developmental changes that take place in the gonads. In contrast to juvenile hormone and neuropeptides, ecdysteroids meet all criteria to act as sex hormones, which was probably their ancient role. Their much better documented role in moulting and metamorphosis was a secondary acquisition that enabled arthropods to cope with growth problems, imposed by a rigid cuticle. Female insects use 20-hydroxyecdysone (20E), secreted by the follicle cells of the ovary, in a similar way as females of egg-laying vertebrates use estrogens. For a variety of reasons, the possibility that ecdysteroids, in particular ecdysone (E), might also act as sex hormones in male insects, thus as the counterpart of testosterone of vertebrates, has been very much overlooked. Thanks to the recent discovery of the molecular basis of the haploid-diploid system of sex determination in the honeybee, the characterization of Halloween genes, proteomics, RNAi and so on, it now becomes possible to verify whether in insects, as with vertebrates, males are the endocrinologically default gender form.