Say

Distribution by Scientific Domains
Distribution within Humanities and Social Sciences

Kinds of Say

  • culex quinquefasciatu say
  • quinquefasciatu say


  • Selected Abstracts


    To Laputa and back: a missing chapter of Gulliver's Travels To the memory of Edward Said, citizen-scholar

    CRITICAL QUARTERLY, Issue 1-2 2005
    Darko Suvin
    The article is divided into three parts. Part 1, 'Entering Laputa in the winter of our discontent', deals with general presuppositions, including those on intellectuals in Post-Fordism and as members of de facto English departments. Part 2, 'Visiting the word-machine', deals with some aporias of literary and English studies. Part 3, 'How to leave Laputa', asks what might be some components of our agenda today. It includes a plea for English studies as an independent, international field of inquiry and teaching, and discusses some possible orientations for us. [source]


    He Said, She Said: Gender Differences in Mother , Adolescent Conversations about Sexuality

    JOURNAL OF RESEARCH ON ADOLESCENCE, Issue 2 2002
    Eva S. Lefkowitz
    This study examined gender differences in self-reported and observed conversations about sexual issues. Fifty mother ,adolescent dyads reported on their conversations about sexual issues and participated in videotaped conversations about dating and sexuality in a laboratory setting. Gender differences (more mother , daughter than mother ,son) were found in the extent of sexual communication based on adolescents' reports, but no gender differences were found based on mothers' reports, or on observations of conversations. Aspects of laboratory interactions, however, did distinguish mother, daughter and mother , son dyads, and related to self-report measures. Girls' reported sexuality communication frequency related to behavior in the laboratory setting. During mother , son conversations, one person usually took on the role of questioner, whereas the other did not. In contrast, there was evidence for mutuality of positive emotions for mother , daughter dyads, but not for mother , son dyads. [source]


    Metaphor and What is Said

    MIND & LANGUAGE, Issue 3 2006
    CATHERINE WEARING
    First, I show that two other possibilities,the Gricean account of metaphor as implicature and the strictly semantic account developed by Josef Stern,face several serious problems. In their place, I propose an account that takes metaphorical content to cross-cut the semantic-pragmatic distinction. This requires re-thinking the notion of metaphorical content, as well as the relation between the metaphorical and the literal. [source]


    The Lost Inner World of Grantmaking Foundations (or, as Willie Sutton Once Said, "That's Where the Money Is")

    NONPROFIT MANAGEMENT & LEADERSHIP, Issue 2 2001
    William A. Diaz
    How Foundations Work: What Grantseekers Need to Know About the Many Faces of Foundations, by Dennis P. McIlnay. San Francisco: Jossey-Bass, 1998. 204 pp., $29.95 cloth. Give and Take: A Candid Account of Corporate Philanthropy, by Reynold Levy. Boston: Harvard Business School Press, 1999. 235 pp., $24.95 cloth. [source]


    Speaker Meaning, What is Said, and What is Implicated

    NOUS, Issue 2 2002
    Jennifer M. Saul
    First page of article [source]


    Cuban Anti-slavery Narrative through Postcolonial Eyes: Gertrudis Gómez de Avellaneda's Sab

    BULLETIN OF LATIN AMERICAN RESEARCH, Issue 2 2008
    CLAUDETTE WILLIAMS
    Gertrudis Gómez de Avellaneda's Sab (1841) has come to be regarded as an iconic work in the canon of nineteenth-century Cuban fiction, celebrated as much for its literary pedigree as for its radical combination of anti-slavery and feminist ideas. Yet it has been the subject of very divergent critical appraisals. This essay sets out to breathe new life into Avellaneda's novel by interpreting it through a postcolonial optic. Drawing on ideas from the scholarship of Edward Said and Frantz Fanon, as well as the ideas of literary theorist Mikhail Bakhtin, these pages explore the implications of its nationalist, racial, sexual and feminist politics for Sab's anti-slavery meaning. This postcolonial reading provides a possible solution for the conflicts between its various interpretations. [source]


    Feeding by Hessian fly [Mayetiola destructor (Say)] larvae does not induce plant indirect defences

    ECOLOGICAL ENTOMOLOGY, Issue 2 2007
    JOHN F. TOOKER
    Abstract 1.,Recent research has addressed the function of herbivore-induced plant volatiles in attracting natural enemies of feeding herbivores. While many types of insect herbivory appear to elicit volatile responses, those triggered by gall insects have received little attention. Previous work indicates that at least one gall insect species induces changes in host-plant volatiles, but no other studies appear to have addressed whether gall insects trigger plant indirect defences. 2.,The volatile responses of wheat to feeding by larvae of the Hessian fly Mayetiola destructor (Say) (Diptera: Cecidomyiidae) were studied to further explore indirect responses of plants to feeding by gall insects. This specialist gall midge species did not elicit a detectable volatile response from wheat plants, whereas a generalist caterpillar triggered volatile release. Moreover, Hessian fly feeding altered volatile responses to subsequent caterpillar herbivory. 3.,These results suggest that Hessian fly larvae exert a degree of control over the defensive responses of their host plants and offer insight into plant-gall insect interactions. Also, the failure of Hessian fly larvae to elicit an indirect defensive response from their host plants may help explain why natural enemies, which often rely on induced volatile cues, fail to inflict significant mortality on M. destructor populations in the field. [source]


    Brochosome influence on parasitisation efficiency of Homalodisca coagulata (Say) (Hemiptera: Cicadellidae) egg masses by Gonatocerus ashmeadi Girault (Hymenoptera: Mymaridae)

    ECOLOGICAL ENTOMOLOGY, Issue 5 2005
    Hans-Paul Velema
    Abstract., 1.,Many cicadellid females in the tribe Proconiini (Hemiptera: Cicadellidae) cover their egg masses with specialised, usually rod-shaped, brochosomes as the eggs are being laid. The brochosomes are produced in Golgi complexes in the Malpighian tubules of Cicadellidae. In contrast to the gravid females, adult males, pre-reproductive adult females, and nymphal males and females produce specialised, usually spherically shaped brochosomes. Brochosomes are also used to cover the external surfaces of nymphs and newly moulted adult males and females. 2.,The function of the brochosome covering the egg masses is unknown but various hypotheses have been suggested, including protecting the eggs against pathogens, predators, and parasitoids. Based on preliminary observations of Gonatocerus ashmeadi Girault (Hymenoptera: Mymaridae) parasitising the eggs of the cicadellid, Homalodisca coagulata (Say), it is speculated here that brochosomes covering an egg mass hinder parasitisation of eggs by G. ashmeadi. This hypothesis was tested by observing G. ashmeadi females foraging on leaves with H. coagulata egg masses heavily covered with rod-shaped brochosomes vs. those lacking brochosomes. 3.,Cox's proportional hazards model was used to evaluate the probability, per unit time, that a female G. ashmeadi displayed the sequence of behaviours that ended in successful oviposition as influenced by five variables: (a) presence or absence of brochosomes on an egg mass, (b) the leaf surface, upper or lower, being searched by the parasitoid (the egg masses are laid in the parenchyma on the lower leaf surface), (c) the parasitoid's previous ovipositional experience, (d) egg mass size, and (e) the parasitoid's age. 4.,Brochosomes significantly decreased oviposition efficacy of G. ashmeadi females. Scanning electron microscopy showed that females exposed to brochosome-covered egg masses had brochosomes adhering to their tarsi, legs, antennae, and eyes, all of which prompted extensive bouts of grooming. [source]


    Does aggregation benefit bark beetles by diluting predation?

    ECOLOGICAL ENTOMOLOGY, Issue 2 2004
    Links between a group-colonisation strategy, the absence of emergent multiple predator effects
    Abstract., 1. Aggregation in bark beetles (Coleoptera: Scolytidae) aids in mate attraction and resource procurement when colonising well-defended plants; however, some species colonise primarily poorly defended plants, and intraspecific competition increases mortality. The hypothesis that decreased risk of predation was a potential benefit to aggregation in such circumstances was tested, using the pine engraver, Ips pini (Say) and its two major predators Thanasimus dubius (F.) (Coleoptera: Cleridae) and Platysoma cylindrica (Paykull) (Coleoptera: Histeridae). Both single- and multiple-predator effects, across a range of prey densities, were tested. 2. Both male and female colonisation events increased with herbivore density, in an asymptotic fashion. 3. Predators decreased the number of colonisers in a density-dependent manner, consistent with a type II functional response. 4. The proportional impact of predators decreased with increased herbivore colonisation densities. These findings indicate that predator dilution may be a viable benefit to aggregation. 5. Total emergence of the herbivore also increased with density, although the net replacement rate during one generation was independent of initial arrival density. This was likely due to larval predation, which negates potential relationships between per capita reproductive success and establishment density. 6. Each predator species decreased I. pini's net replacement rate by approximately 42%, and their combined effect was approximately 70%. 7. Overall, these predators modified their prey's establishment and adult mortality relationships in additive manners. This is somewhat surprising, given the potential for emergent effects due to interactions between multiple predators foraging within a common habitat. The persistence of additivity, rather than risk reduction or enhancement to the prey, may increase the predator-swamping benefit to aggregation for this herbivore. 8. The effects of these predators are substitutable, and likely exert equivalent selective pressures to mask signals at the whole-plant level. [source]


    What Do Data Say About Monetary Policy, Bank Liquidity and Bank Risk Taking?

    ECONOMIC NOTES, Issue 2 2007
    Marcella Lucchetta
    This paper tests empirically the linkage between banks' investment and interbank lending decisions in response to interest rate changes. We draw conclusions for the monetary policy, which uses the interest rate as its main tool. Across European countries we find that the risk-free (i.e. monetary policy) interest rate negatively affects the liquidity retained by banks and the decision of a bank to be a lender in the interbank market. Instead, the interbank interest rate has a positive impact on these decisions. We also find that banks who lend show less risk-taking behaviour and tend to be smaller than those who are borrowers. Most importantly, the risk-free interest rate is positively correlated with loans investment and bank risk-taking behaviour. [source]


    Choosing natural enemies for conservation biological control: use of the prey detectability half-life to rank key predators of Colorado potato beetle

    ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 1 2010
    Matthew H. Greenstone
    Abstract Determining relative strengths of trophic links is critical for ranking predators for conservation biological control. Molecular gut-content analysis enables ranking by incidence of prey remains in the gut, but differential digestive rates bias such rankings toward predators with slower rates. This bias can be reduced by indexing each predator's half-life to that of the middle-most half-life in a predator complex. We demonstrate this with data from key species in the predator complex of Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), comprising adults and immatures of four taxonomically diverse species. These animals display order-of-magnitude variation in detectability half-life for the cytochrome oxidase I DNA sequence of a single CPB egg: from 7.0 h in larval Coleomegilla maculata (DeGeer) (Coleoptera: Coccinellidae) to 84.4 h in nymphal Perillus bioculatus (Fabricius) (Hemiptera: Pentatomidae). The raw species-specific incidence of L. decemlineata DNA in the guts of 351 field-collected predators ranged from 11 to 95%, ranking them as follows: C. maculata adults < Lebia grandis Hentz (Coleoptera: Carabidae) adults < Podisus maculiventris (Say) (Hemiptera: Pentatomidae) adults < P. maculiventris nymphs < P. bioculatus adults < P. bioculatus nymphs. Half-life adjustment reorders the rankings: C. maculata adults < P. bioculatus adults < P. bioculatus nymphs < P. maculiventris nymphs < L. grandis adults < P. maculiventris adults. These changes in status demonstrate the value of half-life-adjusted molecular gut-content data for ranking predators. This is the first study to measure prey detectability half-lives for the key arthropod predators of a major insect pest, and to use them to evaluate the relative impact of all adults and immatures in this predator complex. [source]


    Genetic analysis of larval survival and larval growth of two populations of Leptinotarsa decemlineata on tomato

    ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 2 2001
    Wenhua Lu
    Abstract The genetics of adaptation to tomato in Leptinotarsa decemlineata (Say) were investigated in reciprocal F1, F2, and backcross populations generated from crosses between beetles from a tomato adapted population and from a population that was poorly adapted to tomato. Larvae from the parent and test populations were reared on tomato for four days, after which survivorship and larval weights were recorded. Most results indicate that differences in larval growth and survival on tomato between the parent populations are largely determined by autosomal, polygenic mechanisms, the inheritance of which involves a significant dominance component. However, results from F2 crosses are not consistent with this conclusion. A significant difference in larval weights, but not in survival, between reciprocal F1 populations in an analysis of combined data from four separate experiments suggests that maternal cytoplasmic effects may contribute to differences in larval performance on tomato between the adapted and unadapted populations. The unusual results obtained from F2 crosses in this study are not atypical of results from previous studies of the genetics of adaptation to host plants by the Colorado potato beetle. Host plant adaptation by Colorado potato beetles may therefore involve unusual genetic mechanisms that are not easily assessed by classical Mendelian analysis. [source]


    Context-dependent effects of freshwater mussels on stream benthic communities

    FRESHWATER BIOLOGY, Issue 6 2006
    DANIEL E. SPOONER
    Summary 1. We asked whether unionid mussels influence the distribution and abundance of co-occurring benthic algae and invertebrates. In a yearlong field enclosure experiment in a south-central U.S. river, we examined the effects of living mussels versus sham mussels (shells filled with sand) on periphyton and invertebrates in both the surrounding sediment and on mussel shells. We also examined differences between two common unionid species, Actinonaias ligamentina (Lamarck 1819) and Amblema plicata (Say 1817). 2. Organic matter concentrations and invertebrate densities in the sediment surrounding mussels were significantly higher in treatments with live mussels than treatments with sham mussels or sediment alone. Organic matter was significantly higher in the sediment surrounding Actinonaias than that surrounding Amblema. Actinonaias was more active than Amblema and may have increased benthic organic matter through bioturbation. 3. Living mussels increased the abundance of periphyton on shells and the abundance and richness of invertebrates on shells, whereas effects of sham mussels were similar to sediment alone. Differences in the amount of periphyton growing on the shells of the two mussel species reflected differences in mussel activity and shell morphology. 4. Differences between living and sham mussel treatments indicate that biological activities of mussels provide ecosystem services to the benthic community beyond the physical habitat provided by shells alone. In treatments containing live mussels we found significant correlations between organic matter and chlorophyll a concentrations in the sediment, organic matter concentrations and invertebrate abundance in the sediment and the amount of chlorophyll a on the sediment and invertebrate abundance. There were no significant correlations among these response variables in control treatments. Thus, in addition to providing biogenic structure as habitat, mussels likely facilitate benthic invertebrates by altering the availability of resources (algae and organic matter) through nutrient excretion and biodeposition. 5. Effects of mussels on sediment and shell periphyton concentrations, organic matter concentrations and invertebrate abundance, varied seasonally, and were strongest in late summer during periods of low water volume, low flow, and high water temperature. 6. Our study demonstrates that freshwater mussels can strongly influence the co-occurring benthic community, but that effects of mussels are context-dependent and may vary among species. [source]


    Environmental stresses induce the expression of putative glycine-rich insect cuticular protein genes in adult Leptinotarsa decemlineata (Say)

    INSECT MOLECULAR BIOLOGY, Issue 3 2008
    J. Zhang
    Abstract The deposition of cuticular proteins in insects usually occurs during the moulting process. Three putative glycine-rich insect cuticular proteins, Ld-GRP1 to 3, were identified and characterized from the Colorado potato beetle, Leptinotarsa decemlineata. The Ld-GRPs contained conserved GXGX and/or GGXG sequence repeats. Ld-GRP1 also contained a conserved AAPA/V motif commonly found in cuticular proteins. The transcripts of Ld-GRP1 and Ld-GRP2 were detected in the epidermal cell layer by in situ hybridization, making them putative insect cuticular proteins. The putative cuticular protein genes were highly induced by the insecticide azinphosmethyl (organophosphorous) 2,3 weeks after adult moulting. Putative cuticular protein gene expression level was higher in azinphosmethyl-resistant beetles than in susceptible beetles. Furthermore, two of the putative cuticular protein genes were highly induced by dry environmental conditions. These results suggest that the insect might increase cuticular component deposition in the adult stage in response to environmental stresses. This ability may allow the insect to adapt to new or changing environments. [source]


    Disruption of the Wolbachia surface protein gene wspB by a transposable element in mosquitoes of the Culex pipiens complex (Diptera, Culicidae)

    INSECT MOLECULAR BIOLOGY, Issue 2 2007
    Y. O. Sanogo
    Abstract Culex pipiens quinquefasciatus Say and Culex pipiens pipiens Linnaeus are sibling species incriminated as important vectors of emerging and re-emerging infectious diseases worldwide. The two forms differ little morphologically and are differentiated mainly based upon ecological, behavioural, physiological and genetic traits. Within the North American zone of sympatry, populations of Cx. p. quinquefasciatus and Cx. p. pipiens undergo extensive introgression and hybrid forms have been reported in nature. Both Cx. p. quinquefasciatus and Cx. p. pipiens are infected with the endosymbiotic bacteria Wolbachia pipientis. Here, we report the presence of a transposable element belonging to the IS256 family (IS256wPip) associated with Wolbachia in both Cx. p. quinquefasciatus and Cx. p. pipiens populations. Using reverse transcriptase PCR and sequence analysis, we show that IS256wPip has disrupted the wspB locus, a paralogue of the Wolbachia outer membrane protein (wspA) gene. The inactivation of the wspB appears to be specific to Cx. p. quinquefasciatus and to hybrids of the two forms, and was not observed in the surveyed Cx. p. pipiens mosquitoes. Our results support the hypothesis of a different origin of North American Cx. p. quinquefasciatus and Cx. p. pipiens populations. The flux of mobile genetic elements in the Wolbachia wPip genome could explain the high level of crossing types observed among different Culex populations. The insertion of IS256wPip into wspB may comprise a genetic candidate for discriminating Wolbachia symbionts in Culex. [source]


    Tiny genomes and endoreduplication in Strepsiptera

    INSECT MOLECULAR BIOLOGY, Issue 6 2004
    J. S. Johnston
    Abstract Using flow cytometry, the genome sizes of two species of Strepsiptera were studied: that of male Caenocholax fenyesi texensis Kathirithamby & Johnston (Myrmecolacidae) at 108 Mb, which is the smallest insect genome documented to date; and those of male and female Xenos vesparum Rossi (Stylopidae), which are 1C = 130 and 133 Mb, respectively. The genome sizes of the following were analysed for comparative purposes: (a) the Hessian fly, Mayetiola destructor (Say), which was previously reported to be the smallest among insects: the male measured at 1C = 121 Mb and the female at 1C = 158 Mb; and (b) the female parasitic, haplodiploid, microhymenopteran wasp, Trichogramma brassicae Bezdenko, which measured at 1C = 246 Mb. The hosts of the strepsipterans were also measured: male Solenopsis invicta Buren, the red imported fire ant (host of male C. f. texensis), which is 1C = 753.3 Mb, and female Polistes dominulus Christ, the paper wasp (host of X. vesparum), is 1C = 301.4 Mb. Endoreduplication (4C) of the genome of the thorax of the male strepsipteran, and higher levels of endoduplication (4, 8, 16C) in the body of the larger female was observed. In contrast, little or no endoreduplication was observed, either in the Hessian fly, or in the parasitic wasp. [source]


    Resistance of stored bean varieties to Acanthoscelides obtectus (Coleoptera: Bruchidae)

    INSECT SCIENCE, Issue 4 2008
    Edson L.L. Baldin
    Abstract During bean seed storage, yield can be lost due to infestations of Acanthoscelides obtectus Say, the bean weevil. The use of resistant varieties has shown promising results in fighting these insects, reducing infestation levels and eliminating chemical residues from the beans. The expression of resistance to A. obtectus in bean varieties is frequently attributed to the presence of phytohemagglutinins, protease inhibitors and alpha-amylase, and especially to variants of the protein arcelin, which reduce the larval viability of these insects. To evaluate the effect of bean seed storage time on the resistance expression of bean varieties to A. obtectus, tests with seeds of three ages (freshly-harvested, 4-month-old, and 8-month-old) were conducted in the laboratory, using four commercial varieties: Carioca Pitoco, Ipa 6, Porrillo 70, ônix; four improved varieties containing arcelin protein: Arc.1, Arc.2, Arc. 3, Arc.4; and three wild varieties also containing arcelin protein: Arc.1S, Arc.3S, and Arc. 5S. The Arc.5S, Arc.1S, and Arc.2 varieties expressed high antibiosis levels against the weevil; Arc.1 and Arcs expressed the same mechanism, but at lower levels. The occurrence of oviposition non-preference was also observed in Arc.5S and Arc.1S. The Arc.3 and Arc. 4 varieties expressed low feeding non-preference levels against A. obtectus. The expression of resistance in arcelin-bearing, wild or improved varieties was affected during the storage of seeds, and was high under some parameters but low in others. The results showed that addition of chemical resistance factors such as protein arcelin via genetic breeding may be beneficial in improving the performance of bean crops. [source]


    Genes encoding a group of related small secreted proteins from the gut of Hessian fly larvae [Mayetiola destructor (Say)]

    INSECT SCIENCE, Issue 5 2006
    MING-SHUN CHEN
    Abstract A group of related genes has been isolated and characterized from the gut of Hessian fly larvae [Mayetiola destructor (Say)]. Members in this group appear to encode proteins with secretary signal pep tides at the N-terminals. The mature putative proteins are small, acidic proteins with calculated molecular masses of 14.5 to 15.3 kDa, and isoelectric points from 4.56 to 4.88. Northern blot analysis revealed that these genes are expressed predominantly in the gut of Hessian fly larvae and pupae. Two related genes, G10K1 and G10K2, were isolated as tandem repeats. Both genes contain three exons and two introns. The intron/exon boundaries were conserved in terms of amino acid encoding, suggesting that they arose by gene duplication. The fact that the frequency of this group of clones in a gut cDNA library higher than that of total cDNA clones encoding digestive enzymes suggested that this group of proteins may perform an important function in the gut physiology of this insect. However, the exact functions of these proteins are as yet known since no sequence similarity could be identified between these proteins and any known sequences in public databases using standard methods. [source]


    Accuracy (or Lack Thereof) of Nursing Home Medical Records: What Do Industry and Professional Organizations Have to Say?

    JOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 8 2004
    Joseph G. Ouslander MD
    First page of article [source]


    Compatibility of a natural enemy, Coleomegilla maculata lengi (Col., Coccinellidae) and four insecticides used against the Colorado potato beetle (Col., Chrysomelidae)

    JOURNAL OF APPLIED ENTOMOLOGY, Issue 3 2004
    É. Lucas
    Abstract:, ,The toxicity of four insecticides used to control the Colorado potato beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), imidacloprid (Admire®), cryolite (Kryocide®), cyromazine (Trigard®), and Bacillus thuringiensis var. tenebrionis (Novodor®), to one of its natural enemies, the 12-spotted lady beetle, Coleomegilla maculata lengi Timberlake (Coleoptera: Coccinellidae) was determined in the laboratory. Toxicity assays against C. maculata adults and larvae consisted of (1) topical applications and (2) exposures to treated foliage and prey, using concentrations up to 10 times the manufacturer's recommendations. Over a 6-day period, cyromazine (insect growth regulator) and B. t. var. tenebrionis (microbial insecticide) had no lethal effects on first and third instars C. maculata. For both larval and adult stages, cryolite (inorganic insecticide) caused very low predator mortality when topically applied and moderate mortality when ingested through contaminated eggs of Colorado potato beetles. Imidacloprid (systemic organic insecticide) was highly toxic to adult and larval C. maculata. Its estimated LD50 at 6 days following treatment, corresponded to 0.02,0.09 times the recommended field concentration, depending on the developmental stage and mode of contamination. These results indicate that integrated pest management programmes for Colorado potato beetles using imidacloprid or, to a lesser degree, cryolite, would be detrimental to C. maculata. Cyromazine and B. t. var. tenebrionis seem to present a better compatibility with the protection of C. maculata populations. [source]


    Expectations Formation and Risk in Three Financial Markets: Surveying What the Surveys Say

    JOURNAL OF ECONOMIC SURVEYS, Issue 1 2000
    Ronald MacDonald
    This paper attempts to provide a logical overview of the literature which exploits survey data to examine issues of expectations formation and risk aversion in financial markets. Our survey suggests that: short term expectations are excessively volatile and exhibit bandwagon effects, while longer term expectations appear to be regressive and therefore stabilising; in bond and foreign exchange markets the standard result of forward rate biasedness is due in part to time-varying premia; recent research using disaggregate foreign exchange survey data demonstrates the importance of heterogeneous expectations. [source]


    Two-year oscillation cycle in abundance of soybean aphid in Indiana

    AGRICULTURAL AND FOREST ENTOMOLOGY, Issue 3 2010
    Marc Rhainds
    1The present study evaluated the population dynamics of the heteroecious soybean aphid Aphis glycines Matsumura (Hemiptera: Aphididae) during an 8-year period in Indiana, shortly after its detection in North America. Sampling conducted at multiple locations revealed that A. glycines exhibited a 2-year oscillation cycle that repeated itself four times between 2001 and 2008: years of low aphid abundance were consistently followed by years of high aphid abundance. 2Similar patterns of abundance of A. glycines and coccinellids (Coleoptera: Coccinellidae) in soybean fields, both within and between-years, suggest that late season predation by coccinellids plays a role in the oscillatory cycle of aphids. Insidious flower bugs Orius insidiosus (Say) (Hemiptera: Anthocoridae) were numerically more abundant than coccinellids, although the lack of synchrony between aphids and predatory bugs suggests that O. insidiosus has a limited influence on between-year variations in aphid density. 3The inverse relationship between aphid densities before and after the start of the autumn migratory period changes direction in alternate years. High aphid density on soybean in the summer is associated with a reduced number of alate migrants produced in the autumn. Conversely, years with low density aphids on soybean in the summer are characterized by high numbers of alates that migrate to the primary host in the autumn. 4From a pest management perspective, the 2-year oscillation cycle of A. glycines is a desirable attribute with respect to population dynamics because it implies that aphids cause significant economic damage only in alternate years (as opposed to every year). Cultural practices enhancing the conservation biological control of Coccinellidae may help to preserve the periodicity of aphid infestation and restrict the pest status of A. glycines. [source]


    Wood-feeding beetles and soil nutrient cycling in burned forests: implications of post-fire salvage logging

    AGRICULTURAL AND FOREST ENTOMOLOGY, Issue 1 2010
    Tyler P. Cobb
    1Rising economic demands for boreal forest resources along with current and predicted increases in wildfire activity have increased salvage logging of burned forests. Currently, the ecological consequences of post-fire salvage logging are insufficiently understood to develop effective management guidelines or to adequately inform policy decision-makers. 2We used both field and laboratory studies to examine the effects of post-fire salvage logging on populations of the white-spotted sawyer Monochamus scutellatus scutellatus (Say) (Coleoptera: Cerambycidae) and its ecological function in boreal forest. 3Monochamus s. scutellatus adults were relatively abundant in both burned and clear-cut logged sites but were absent from salvage logged sites. 4An in situ mesocosm experiment showed that the abundance of M. s. scutellatus larvae in burned white spruce bolts was linked to changes in total organic nitrogen and carbon in mineral soil. 5Organic nutrient inputs in the form of M. s. scutellatus frass increased mineral soil microbial respiration rates by more than three-fold and altered the availability of nitrogen. Changes in nitrogen availability corresponded with decreased germination and growth of Epilobium angustifolium and Populus spp. but not Calamagrostis canadensis. 6Although the present study focused on local scale effects, the reported findings suggest that continued economic emphasis on post-fire salvage logging may have implications beyond the local scale for biodiversity conservation, nutrient cycling and plant community composition in forest ecosystems recovering from wildfire. [source]


    Effects of sunlight exposure and log size on pine engraver (Coleoptera: Curculionidae) reproduction in ponderosa pine slash in Northern Arizona, U.S.A.

    AGRICULTURAL AND FOREST ENTOMOLOGY, Issue 3 2009
    Christopher J. Hayes
    Abstract 1,Abiotic conditions within logs can affect pine engraver Ips pini (Say) reproductive success, and slash management techniques have been developed that exploit these relationships to reduce brood production. In the present study, we investigated the affect of sunlight exposure on phloem temperature and moisture in logs of two diameters and the subsequent effects on pine engraver reproduction. 2,Logs, 30 cm in length, with diameters of 10 and 15 cm, were cut, left in the field for natural colonization by I pini, and then placed in an open meadow and under shade cloth, providing 27% and 66% shade, until offspring beetles had left the logs. Phloem temperature and moisture were recorded over the duration of the experiment and, at the end of the field experiment, logs were dissected and galleries were measured to gauge beetle reproductive success. 3,As sunlight exposure increased, phloem temperatures increased and potentially lethal temperatures were often reached in the high-sunlight exposure but seldom in the low-sunlight. Smaller diameter logs had drier phloem than larger diameter logs. All logs dried with time but sunlight level did not affect desiccation rates. Ips pini preferred attacking larger logs and the bottom side of logs. Sunlight exposure had a significant effect on net reproductive success in smaller diameter logs, with very little net reproductive success in high-sunlight exposed logs, and the highest reproductive success was found in small diameter logs in the low-sunlight treatments. 4,Management implications of these results are discussed. [source]


    Use of sperm precedence to infer the overwintering cost of insecticide resistance in the Colorado potato beetle

    AGRICULTURAL AND FOREST ENTOMOLOGY, Issue 3 2008
    Mitchell B. Baker
    Abstract 1,Resistance to insecticides is a model system for studying adaptation. Although selection for resistance is always strong in areas and seasons where populations are exposed to insecticides, costs of resistance, which may only be expressed in the absence of insecticide use, will shape how quickly resistance will evolve. 2,We used sperm precedence to measure the shifts in resistance to imidacloprid in a natural population during winter diapause in the Colorado potato beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae). Because adult beetles overwinter with viable autumn sperm, but sperm from spring matings take precedence over stored sperm, we used the difference in resistance of springmated and autumn-mated overwintered females to estimate the shift in resistance during the winter. Offspring of autumn-mated females were 2.7- or 2.5-fold more resistant compared with offspring from spring-mated females in two replicate trials. 3,We also measured the resistance of late summer and spring emergent adults in fields treated and untreated with imidacloprid in the first year. Adults from the treated field were 13.7-fold more resistant and adults from the untreated field were 2.6-fold more resistant compared with the next spring's emergers. 4,These large costs of resistance observed in the field and inferred from resistance declines during diapause help to explain the observation that imidacloprid resistance has increased only slowly over the decade of widespread use against this species, and how insecticide resistance in general can cycle annually. [source]


    Seasonal pheromone response by Ips pini in northern Arizona and western Montana, U.S.A.

    AGRICULTURAL AND FOREST ENTOMOLOGY, Issue 3 2008
    Brytten E. Steed
    Abstract 1,Populations of Ips pini (Say) in northern Arizona and western Montana, U.S.A., were studied to determine regional pheromone response and to evaluate seasonal shifts in that response. A range of enantiomeric blends of the attractant ipsdienol, alone and in the presence of the synergist lanierone, were tested during spring and summer seasons over several years. 2,Both populations were most attracted to high levels of (R)-(,)-ipsdienol, and lanierone was highly synergistic. 3,A significant seasonal shift in pheromone response between spring and summer seasons was found in both regions in both years. Shifts resulted in a more specific preference for the pheromone treatment of 97% (R)-(,)-ipsdienol with lanierone. 4,Several coleopteran insect associates of I. pini also displayed responses to the ipsdienol and lanierone treatments. Temnochila chlorodia (Mannerheim) (Trogositidae), Enoclerus sphegeus (F.) (Cleridae) and, to a limited extent, Lasconotus laqueatus (LeConte) (Colydiidae) were attracted to higher proportions of (R)-(,)-ipsdienol with no apparent reaction to the presence of lanierone. Orthotomicus latidens (LeConte) (Curculionidae: Scolytinae) was strongly attracted to (S)-(+)-ipsdienol with Enoclerus lecontei (Wolcott) (Cleridae), Pityogenes carinulatus (LeConte) (Curculionidae: Scolytinae) and Hylurgops porosus (LeConte) (Curculionidae: Scolytinae) demonstrating some preferences for the (S)-(+)-enantiomer. However, lanierone was synergistic for E. lecontei and P. carinulatus, inhibitory for O. latidens, and produced no significant reaction for H. porosus. Elacatis sp. (Salpingidae, previously Othniidae) was attracted to the presence of ipsdienol but displayed no preference to the enantiomeric ratios of ipsdienol or the presence of lanierone. [source]


    Potential of a synthetic aggregation pheromone for integrated pest management of Colorado potato beetle

    AGRICULTURAL AND FOREST ENTOMOLOGY, Issue 1 2006
    T. P. Kuhar
    Abstract 1The relative number of colonizing adult Colorado potato beetles (CPB) Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae) coming to pitfall traps baited with the aggregation pheromone (S)-3,7-dimethyl-2-oxo-oct-6-ene-1,3-diol [(S)-CPB I] and the use of the pheromone in a trap crop pest management strategy were evaluated in the field for the first time. 2More than five-fold more adult L. decemlineata were caught in pitfall traps baited with the pheromone compared with controls. However, attraction to the pheromone diminished after 5 days in the field. 3In the trap crop management strategy, more colonizing adults were present in pheromone-treated rows of potatoes compared with untreated middle rows. 4Significantly fewer L. decemlineata egg masses and larvae were found in potato plots that were bordered by pheromone-treated rows, or bordered by imidacloprid + pheromone-treated rows, or rows treated at-planting with imidacloprid compared with untreated (control) potato plots. 5Densities of L. decemlineata egg masses and larvae and percentage defoliation were significantly lower, and marketable tuber yield significantly higher, in conventional imidacloprid-treated potatoes compared with all other treatments. 6Although our results demonstrate the potential for use of the aggregation pheromone in the management of L. decemlineata in the field, more research is needed to optimize the release rates of the attractant and incorporate control methods for cohabiting pests. [source]


    Selective manipulation of predators using pheromones: responses to frontalin and ipsdienol pheromone components of bark beetles in the Great Lakes region

    AGRICULTURAL AND FOREST ENTOMOLOGY, Issue 3 2005
    Brian H. Aukema
    Abstract 1,One proposed approach to improving biological control of bark beetles (Coleoptera: Scolytidae; alt. Curculionidae: Scolytinae) is to manipulate predator movement using semiochemicals. However, selective manipulation is impeded by attraction of both predators and pests to bark beetle pheromones. 2,The primary bark beetle affecting pine plantations in Wisconsin, U.S.A., is the pine engraver, Ips pini (Say). Other herbivores include Ips grandicollis (Eichhoff) and Dryophthorus americanus Bedel (Curculionidae). The predominant predators are the beetles Thanasimus dubius (Cleridae) and Platysoma cylindrica (Histeridae). 3,We conducted field assays using two enantiomeric ratios of ipsdienol, and frontalin plus ,-pinene. Ipsdienol is the principal pheromone component of I. pini, and frontalin is produced by a number of Dendroctonus species. ,-Pinene is a host monoterpene commonly incorporated into commercial frontalin lures. 4,Thanasimus dubius was attracted to frontalin plus ,-pinene, and also to racemic ipsdienol. By contrast, I. pini was attracted to racemic ipsdienol, but showed no attraction to frontalin plus ,-pinene. Platysoma cylindrica was attracted to 97%-(,)-ipsdienol and, to a lesser extent, racemic ipsdienol, but not to frontalin plus ,-pinene. Ips grandicollis was attracted to frontalin plus ,-pinene but not to ipsdienol. Dryophthorus americanus was attracted to both ipsdienol and frontalin plus ,-pinene. 5,This ability to selectively attract the predator T. dubius without attracting the principal bark beetle in the system, I. pini, provides new opportunities for research into augmentative biological control and basic population dynamics. Moreover, the attraction of T. dubius, but not P. cylindrica, to frontalin plus ,-pinene creates opportunities for selective manipulation of just one predator. 6,Patterns of attraction by predators and bark beetles to these compounds appear to reflect various degrees of geographical and host tree overlap with several pheromone-producing species. [source]


    Between ends and fibers

    JOURNAL OF GRAPH THEORY, Issue 2 2007
    C. Paul Bonnington
    Abstract Let , be an infinite, locally finite, connected graph with distance function ,. Given a ray P in , and a constant C , 1, a vertex-sequence is said to be regulated by C if, for all n,,, never precedes xn on P, each vertex of P appears at most C times in the sequence, and . R. Halin (Math. Ann., 157, 1964, 125,137) defined two rays to be end-equivalent if they are joined by infinitely many pairwise-disjoint paths; the resulting equivalence classes are called ends. More recently H. A. Jung (Graph Structure Theory, Contemporary Mathematics, 147, 1993, 477,484) defined rays P and Q to be b-equivalent if there exist sequences and VQ regulated by some constant C , 1 such that for all n,,; he named the resulting equivalence classes b-fibers. Let denote the set of nondecreasing functions from into the set of positive real numbers. The relation (called f-equivalence) generalizes Jung's condition to . As f runs through , uncountably many equivalence relations are produced on the set of rays that are no finer than b -equivalence while, under specified conditions, are no coarser than end-equivalence. Indeed, for every , there exists an "end-defining function" that is unbounded and sublinear and such that implies that P and Q are end-equivalent. Say if there exists a sublinear function such that . The equivalence classes with respect to are called bundles. We pursue the notion of "initially metric" rays in relation to bundles, and show that in any bundle either all or none of its rays are initially metric. Furthermore, initially metric rays in the same bundle are end-equivalent. In the case that , contains translatable rays we give some sufficient conditions for every f -equivalence class to contain uncountably many g -equivalence classes (where ). We conclude with a variety of applications to infinite planar graphs. Among these, it is shown that two rays whose union is the boundary of an infinite face of an almost-transitive planar map are never bundle- equivalent. © 2006 Wiley Periodicals, Inc. J Graph Theory 54: 125,153, 2007 [source]


    Characterization of Wheat Random Amplified Polymorphic DNA Markers Associated with the H11 Hessian Fly Resistance Gene

    JOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 8 2006
    Dhia Bouktila
    Abstract In Tunisia, the Hessian fly Mayetiola destructor Say is a major pest of durum wheat (Triticum durum Desf.) and bread wheat (T. aestivum L.). Genetic resistance is the most efficient and economical method of control of this pest. To date, 31 resistance genes, designated H1,H31, have been identified in wheat. These genes condition resistance to the insect genes responsible for virulence. Using wheat cultivars differing for the presence of an individual Hessian fly resistance gene and random amplified polymorphic DNA (RAPD) analysis, we have identified a polymorphic 386-bp DNA marker (Xgmib1-1A.1) associated with the H11 Hessian fly resistance gene. Blast analysis showed a high identity with a short region in the wild wheat (T. monococcum) genome, adjacent to the leaf rust resistance Lr10 gene. A genetic linkage was reported between this gene (Lr10) and Hessian fly response in wheat. These data were used for screening Hessian fly resistance in Tunisian wheat germplasm. Xgmib1-1A.1-like fragments were detected in four Tunisian durum and bread wheat varieties. Using these varieties in Hessian fly breeding programs in Tunisia would be of benefit in reducing the damage caused by this fly. (Managing editor: Li-Hui Zhao) [source]