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transformation of presumptive precursors to frontalin and exo-brevicomin by bark beetles and west indian sugarcane weevil (coleoptera).(z)-6-nonen-2-one (1) has recently been shown to be the biosynthetic precursor for the aggregation pheromone exo-brevicomin (2) in mountain pine beetle (mpb) males, dendroctonus ponderosae (hopkins). we tested the hypotheses that (1) 6-methyl-6-hepten-2-one (3) is the biosynthetic precursor for the aggregation pheromone frontalin (4) in the spruce beetle (sb), dendroctonus rufipennis (kirby), and (2) that frontalin and exo-brevicomin are produced from 3 and 1, respectively, only by beetles that ...19968733625
paternal care enhances male reproductive success in pine engraver beetles.male pine engravers, ips pini, assist their mates during reproduction by clearing debris from breeding galleries constructed beneath the bark of host trees. i measured duration of parental care provided by individual male pine engravers in the field, as well as the reproductive success of these males as indicated by the total number of eggs laid in their galleries and the mean distance between the eggs. males remained in their galleries for 13-54 days (n=78, x+/-se=33.0+/-0.9 days). male residen ...19989784207
specialization of midgut cells for synthesis of male isoprenoid pheromone components in two scolytid beetles, dendroctonus jeffreyi and ips pini.endodermal or midgut cells have only recently been recognized as the site of pheromone synthesis in bark beetles. midgut cells are not only specialized for digestion, but they have also been recruited to form isoprenoid compounds that function as pheromone components in ips pini and dendroctonus jeffreyi. male bark beetle midgut cells are competent to produce isoprenoid pheromones after feeding or stimulation by juvenile hormone (jh) iii. competent midgut cells share many ultrastructural feature ...200212176306
a novel sex-specific and inducible monoterpene synthase activity associated with a pine bark beetle, the pine engraver, ips pini.ecological interactions of conifers and coniferophagous bark beetles are determined in part by terpenoids (isoprenoids), which are major defense metabolites of conifer oleoresin. curiously, similar compounds are important aggregation pheromones of conifer-attacking bark beetles. terpene synthases are responsible for generating the enormous variety of terpenoid carbon skeletons found in nature. these catalysts convert short-chain prenyl diphosphates to a diverse assortment of hemiterpene, monoter ...200312712251
comparison of gene representation in midguts from two phytophagous insects, bombyx mori and ips pini, using expressed sequence tags.midgut proteins may provide new molecular targets for insect control. this could be particularly important for some pests, such as pine bark beetles, which are difficult to control by conventional methods. expressed sequence tags (ests) provide information about the activity of a particular tissue, and, in the case of pest insects, may quickly identify potential targets. we present here an est project representing 574 tentative unique genes (tugs) expressed in the midgut of the male pine engrave ...200314563559
importance of log size on host selection and reproductive success of ips pini (coleoptera: scolytidae) in ponderosa pine slash of northern arizona and western montana.pine engraver, ips pini (say), often use thinning slash, and their populations are known to be influenced by the condition of this material. in our study, we evaluated the importance of three log diameters (5, 10, and 20 cm) and three lengths (60,120, and 240 cm) on various parameters of bark beetle host attack, development, and emergence. evaluation of slash colonization in northern arizona (near flagstaff) and western montana (near missoula) over several years, during both spring and summer re ...200415154466
coordinated gene expression for pheromone biosynthesis in the pine engraver beetle, ips pini (coleoptera: scolytidae).in several pine bark beetle species, phloem feeding induces aggregation pheromone production to coordinate a mass attack on the host tree. male pine engraver beetles, ips pini (say) (coleoptera: scolytidae), produce the monoterpenoid pheromone component ipsdienol de novo via the mevalonate pathway in the anterior midgut upon feeding. to understand how pheromone production is regulated in this tissue, we used quantitative real-time pcr to examine feeding-induced changes in gene expression of seve ...200415257386
juvenile hormone regulates de novo isoprenoid aggregation pheromone biosynthesis in pine bark beetles, ips spp., through transcriptional control of hmg-coa reductase.evidence is presented for transcriptional regulation of de novo pheromone biosynthesis in ips spp. bark beetles, but the comparative biochemical and molecular approach reveals a dichotomy between species in the pini and grandicollis subgeneric groups. radiotracer studies with 14c-acetate demonstrate that feeding on host phloem stimulates biosynthesis in males of three ips spp. however, treatment with juvenile hormone iii (jh iii) stimulates biosynthesis only in ips pini. thus, two species in the ...200415724966
attraction of southern pine engravers and associated bark beetles (coleoptera: scolytidae) to ipsenol, ipsdienol, and lanierone in southeastern united states.we determined the response of the small southern pine engraver, ips avulsus (eichhoff); eastern fivespined ips, ips grandicollis (eichhoff); sixspined ips, ips calligraphus (germar); and pine engraver, ips pini (say) to the pheromones (+/-)-ipsenol, (+/-)-ipsdienol, and lanierone in the southeastern united states. catches of i. avulsus and i. grandicollis to baited multiple-funnel traps were increased by (+/-)-ipsenol and (+/-)-ipsdienol in florida, georgia, louisiana, and north carolina. in all ...200516539133
effects of juvenile hormone on gene expression in the pheromone-producing midgut of the pine engraver beetle, ips pini.juvenile hormone iii (jh iii) stimulates biosynthesis of the monoterpenoid aggregation pheromone component, ipsdienol, in the anterior midgut of the male pine engraver beetle, ips pini (say). to understand better the hormonal regulation of pheromone biosynthesis in this forest pest, and identify jh iii-responsive genes, microarrays were prepared and hybridized to cdna from midguts of jh iii-treated beetles. expression patterns were confirmed by quantitative real-time rt-pcr. jh iii co-ordinately ...200616640731
evaluation of insecticides for protecting southwestern ponderosa pines from attack by engraver beetles (coleoptera: curculionidae: scolytinae).insecticides that might protect pine trees from attack by engraver beetles (ips spp.) have not been rigorously tested in the southwestern united states. we conducted two field experiments to evaluate the efficacy of several currently and potentially labeled preventative insecticides for protecting high-value ponderosa pine, pinus ponderosa dougl ex. laws., from attack by engraver beetles. preventative sprays (0.19% permethrin [permethrin plus c]; 0.03, 0.06, and 0.12% bifenthrin [onyx]; and 1.0 ...200616686137
genetic control of the enantiomeric composition of ipsdienol in the pine engraver, ips pini.the genetic nature of pheromone variation within species has rarely been studied, and never for male-produced long-range pheromones. males from western north american populations of ips pini produce predominantly (r)-(-)-ipsdienol, whereas those from eastern north american populations produce higher proportions of (s)-(+)-ipsdienol. from a population in the hybrid zone, we divergently selected lines for the opposing pheromonal types and then created f1, f2, and backcross lines. we formed additio ...200616739020
functional expression of a bark beetle cytochrome p450 that hydroxylates myrcene to ipsdienol.the final steps in the pheromone-biosynthetic pathway of the pine engraver beetle, ips pini (say) (coleoptera: scolytidae) are unknown, but likely involve myrcene (7-methyl-3-methylene-1,6-octadiene) hydroxylation to produce the aggregation pheromone component, ipsdienol (2-methyl-6-methylene-2,7-octadien-4-ol). we have isolated a full-length i. pini cdna encoding a cytochrome p450, cyp9t2. the recovered cdna is 1.83kb and the open reading frame encodes a 532 amino acid protein. cyp9t2 is regula ...200617046597
ips pini (curculionidae: scolytinae) is a vector of the fungal pathogen, sphaeropsis sapinea (coelomycetes), to austrian pines, pinus nigra (pinaceae).sphaeropsis sapinea (fr.:fr.) dyko and sutton, is among the most common and widely distributed pathogens of conifers worldwide. s. sapinea is disseminated over short distances by rain splash and moist wind, but significant knowledge gaps regarding long-range dispersal remain. our objective was to determine whether or not the pine engraver beetle, ips pini say, is a vector of the pathogen onto austrian pines (pinus nigra arnold). in 2004 and 2005, individuals of i. pini were collected with pherom ...200717349124
isolation, endocrine regulation and transcript distribution of a putative primary jh-responsive gene from the pine engraver, ips pini (coleoptera: scolytidae).we isolated a cdna of unknown function from a juvenile hormone iii (jh iii)-treated male midgut cdna library prepared from the pine engraver beetle, ips pini, and examined its genomic structure. the gene, tentatively named "ipi10g08", encoded a 410 amino acid translation product that shared 26-37% identity with unannotated matches from several insects. semi-quantitative rt-pcr analysis of ipi10g08 following application of a 10 microg dose of jh iii demonstrated an early induction for both male a ...200818207085
parasitoids and dipteran predators exploit volatiles from microbial symbionts to locate bark beetles.host location by parasitoids and dipteran predators of bark beetles is poorly understood. unlike coleopteran predators that locate prey by orienting to prey pheromones, wasps and flies often attack life stages not present until after pheromone production ceases. bark beetles have important microbial symbionts, which could provide sources of cues. we tested host trees, trees colonized by beetles and symbionts, and trees colonized by symbionts alone for attractiveness to hymenopteran parasitoids a ...200818348806
lack of genetic differentiation in aggressive and secondary bark beetles (coleoptera: curculionidae, scolytinae) from arizona.bark beetles (coleoptera: curculionidae, scolytinae) play an important role as disturbance agents in ponderosa pine (pinus ponderosa douglas ex lawson) forests of arizona. however, from 2001 to 2003, elevated bark beetle activity caused unprecedented levels of ponderosa pine mortality. a better understanding of the population structure of these species will facilitate analysis of their dispersal patterns and improve management strategies. here, we use fluorescently labeled amplified fragment len ...200818559189
unique animal prenyltransferase with monoterpene synthase activity.monoterpenes are structurally diverse natural compounds that play an essential role in the chemical ecology of a wide array of organisms. a key enzyme in monoterpene biosynthesis is geranyl diphosphate synthase (gpps). gpps is an isoprenyl diphosphate synthase that catalyzes a single electrophilic condensation reaction between dimethylallyl diphosphate (c(5)) and isopentenyl diphosphate (c(5)) to produce geranyl diphosphate (gdp; c(10)). gdp is the universal precursor to all monoterpenes. subseq ...200919277597
impacts of silvicultural thinning treatments on beetle trap captures and tree attacks during low bark beetle populations in ponderosa pine forests of northern arizona.our research used a combination of passive traps, funnel traps with lures, baited trees, and surveys of long-term thinning plots to assess the impacts of different levels of stand basal area (ba) on bark beetle tree attack and on trap captures of ips spp., dendroctonus spp., and their predators. the study occurred at two sites in ponderosa pine, pinus ponderosa dougl. ex laws., forests, from 2004 to 2007 during low bark beetle populations. residual stand ba ranged from 9.0 to 37.0 m2/ha. more pr ...201021061969
test of nonhost angiosperm volatiles and verbenone to protect trap trees for sirex noctilio (hymenoptera: siricidae) from attacks by bark beetles (coleoptera: scolytidae) in the northeastern united states.sirex noctilio f. (hymenoptera: siricidae) is an invasive woodwasp, currently established in northeastern north america. in other regions of the world, stressed trap trees are used to monitor populations of s. noctilio and to provide inoculation points for the biological control nematode deladenus siricidicola bedding. however, the operational use of trap trees for s. noctilio in north america may be compromised by the large community of native organisms that inhabit stressed and dying pine tree ...201021309230
gut-associated bacteria throughout the life cycle of the bark beetle dendroctonus rhizophagus thomas and bright (curculionidae: scolytinae) and their cellulolytic activities.dendroctonus rhizophagus thomas and bright (curculionidae: scolytinae) is an endemic economically important insect of the sierra madre occidental in mexico. this bark beetle has an atypical behavior within the genus because just one beetle couple colonizes and kills seedlings and young trees of 11 pine species. in this work, the bacteria associated with the dendroctonus rhizophagus gut were analyzed by culture-dependent and culture-independent methods. analysis of 16s rrna sequences amplified di ...201222234511
β-phellandrene: kairomone for pine engraver,ips pini (say) (coleoptera: scolytidae).the responses ofips pini (scolytidae) to multiple-funnel traps baited with the pheromone, ipsdienol, and various monoterpenes were determined in stands of lodgepole pine in southern and central british columbia.ips pini was attracted to both ipsdienol and β-phellandrene, demonstrating that β-phellandrene is a kairomone for this species.lasconotus complex (colydiidae) and acorticeus sp. (tenebrionidae) were attracted to both ipsdienol and β-phellandrene. thecorticeus sp. exhibited a synergistic r ...199024264217
arboreal insects associated with herbicide-stressed pinus resinosa and pinus sylvestris used as sirex noctilio trap trees in new york.in september of 2004, sirex noctilio f. (hymenoptera: siricidae) was detected in new york state and later found to be established over a larger area, including parts of southeastern canada and the northeastern united states. a key component of s. noctilio detection and management plans in other parts of the world where s. noctilio has become established are chemically girdled trap trees. trap tree usage in north america is confounded by the presence of diverse communities of organisms that inhab ...201223321081
ipsdienol dehydrogenase (idoldh): a novel oxidoreductase important for ips pini pheromone production.ipsdienone (2-methyl-6-methylene-2,7-octadien-4-one) is an important intermediate in the biosynthesis of pheromonal ipsdienol (2-methyl-6-methylene-2,7-octadien-4-ol) and ipsenol (2-methyl-6-methylene-7-octen-4-ol) in male pine engraver beetles, ips pini (say). a novel ipsdienol dehydrogenase (idoldh) with a pheromone-biosynthetic gene expression pattern was cloned, expressed, functionally characterized, and its cellular localization analyzed. the cdna has a 762nt orf encoding a 253 amino acid p ...201122101251
two regulatory mechanisms of monoterpenoid pheromone production in ips spp. of bark beetles.bark beetles use aggregation pheromones to coordinate host colonization and mating. these monoterpenoid chemical signals are produced de novo in midgut cells via the mevalonate pathway, and pheromone production is induced when an adult beetle feeds on phloem of a host tree. in ips pini, juvenile hormone (jh) iii influences key regulatory enzymes along the mevalonate pathway that leads to pheromone production. in fact, topically applied jh iii is sufficient to stimulate pheromone production in un ...200919554371
female mate choice tactics in a resource-based mating system: field tests of alternative models.in this study we test theoretical models of female mate choice tactics in natural populations of pine engravers, ips pini (say) (coleoptera: scolytidae), a species with a resource-based mating system and high search costs. we first develop distinguishing predictions for each of four models of mate choice: random, comparison tactics, and fixed and adjustable thresholds. these predictions relate to commonly collected field data that include the visiting behavior of females and the quality of accep ...199718811277
can chemical communication be cryptic? adaptations by herbivores to natural enemies exploiting prey semiochemistry.predators and parasites commonly use chemical cues associated with herbivore feeding and reproduction to locate prey. however, we currently know little about mechanisms by which herbivores may avoid such natural enemies. pheromones are crucial to many aspects of herbivore life history, so radical alterations of these compounds could be disadvantageous despite their exploitation by predators. instead, minor modifications in pheromone chemistry may facilitate partial escape while maintaining intra ...200717618465
isolation, endocrine regulation and mrna distribution of the 3-hydroxy-3-methylglutaryl coenzyme a synthase (hmg-s) gene from the pine engraver, ips pini (coleoptera: scolytidae).we isolated a full-length cdna encoding 3-hydroxy-3-methylglutaryl coenzyme a synthase (hmg-s) from the pine engraver beetle, ips pini (say), and examined its genomic structure. the intron-less gene has a predicted 460 amino acid cytosolic protein product with 73% identity to hmg-s from dendroctonus jeffreyi, and high identity (58-64%) with other insect hmg-ss. topically applied juvenile hormone (jh) iii induced hmg-s mrna levels up to 6.5-fold in both sexes, mostly in the anterior midgut, thoug ...200616640729
isolation and functional expression of an animal geranyl diphosphate synthase and its role in bark beetle pheromone biosynthesis.geranyl diphosphate synthase (gpps) catalyzes the condensation of dimethylallyl diphosphate and isopentenyl diphosphate to form geranyl diphosphate. geranyl diphosphate is the precursor of monoterpenes, a large family of natural occurring c(10) compounds predominantly found in plants. similar to plants but unique to animals, some bark beetle genera (coleoptera: scolytidae) produce monoterpenes that function in intraspecific chemical communication as aggregation and dispersion pheromones. the rel ...200515983375
leptographium wingfieldii introduced into north america and found associated with exotic tomicus piniperda and native bark beetles.leptographium wingfieldii is a well-known fungal associate of the pine shoot beetle, tomicus piniperda, in europe. this fungus is pathogenic to pines and is an important cause of blue-stain in the sapwood of infested trees. tomicus piniperda was first found in a christmas tree plantation in ohio, usa, 1992, but isolation of the fungi associated with these intercepted insects was not attempted. fungal strains resembling l. wingfieldii were recently isolated from pines attacked by t. piniperda, de ...200415209281
de novo biosynthesis of the aggregation pheromone components ipsenol and ipsdienol by the pine bark beetles ips paraconfusus lanier and ips pini (say) (coleoptera: scolytidae).the california five-spined ips, ips paraconfusus lanier, produces the myrcene-derived acyclic monoterpene alcohols ipsenol (2-methyl-6-methylene-7-octen-4-ol) and ipsdienol (2-methyl-6-methylene-2,7-octadien-4-ol) as components of its aggregation pheromone. the pine engraver beetle, ips pini (say), produces only ipsdienol. previous studies have shown that myrcene, a monoterpene in the pines colonized by these beetles, is a direct precursor to these pheromone components. in vivo radiolabeling stu ...199511607576
effect of host tree seasonal phenology on substrate suitability for the pine engraver (coleoptera: scolytidae): implications for population dynamics and enemy free space.this study evaluated the effects of seasonal phenology on the substrate quality of susceptible hosts to the pine engraver, ips pini (say). we also determined the effects of the duration and method of storage on host quality for purposes of laboratory rearing. live red pine trees were felled at various times during the season, and i. pini adults from a laboratory colony were established on the logs. subsamples of logs were stored for various intervals, and then provided to beetles. subsamples of ...200111561841
a model for peak and width of signaling windows: ips duplicatus and chilo partellus pheromone component proportions--does response have a wider window than production?pheromone communication systems have a reliable signal with a restricted window of amounts and ratios released and perceived. we propose a model based on a gaussian response profile that allows a quantification of the response peak (location of optimum) and a measure of the peak width (response window). interpreting the gaussian curve, fitted by nonlinear regression (nlr), as a standard normal distribution, the peak location equals the mean (it) and the window width equals 2 x the standard devia ...200111504040
use of acoustics to deter bark beetles from entering tree material.acoustic technology is a potential tool to protect wood materials and eventually live trees from colonization by bark beetles. bark beetles such as the southern pine beetle dendroctonus frontalis, western pine beetle d. brevicomis and pine engraver ips pini (coleoptera: curculionidae) use chemical and acoustic cues to communicate and to locate potential mates and host trees. in this study, the efficacy of sound treatments on d. frontalis, d. brevicomis and i. pini entry into tree materials was t ...201424376044
variation in complex semiochemical signals arising from insects and host plants.chemical communication by many insect species involves complex signals of both insect and plant origin. much attention has been focused on the behavioral activities of these components but less on their sources of variation, despite implications for evolutionary theory and pest management. we studied variation in chemical signaling at host, tree-within-host, and beetle-on-tree scales using tunneling male pine engravers [ips pini (say)] on jack, pinus banksiana lamb, red, p. resinosa aiton, and w ...201020550801
myrcene hydroxylases do not determine enantiomeric composition of pheromonal ipsdienol in ips spp.myrcene (7-methyl-3-methylene-1,6-octadiene) hydroxylation is likely one of the final reactions involved in the production of the ips spp. (coleoptera: scolytidae) aggregation pheromone components, ipsdienol (2-methyl-6-methylene-2,7-octadien-4-ol) and ipsenol (2-methyl-6-methylene-7-octen-4-ol). to gain insight into the evolution of pheromone production, we isolated a full-length cdna from the pinyon ips, ips confusus (leconte), that encodes a pheromone-biosynthetic cytochrome p450, i. confusus ...200819034575
gender- and sequence-dependent predation within group colonizers of defended plants: a constraint on cheating among bark beetles?bark beetles engage in one of the most pronounced examples of group procurement of defended plants. their aggregation pheromones attract both sexes and are essential to overcome constitutive and rapidly inducible lethal defenses. the relative benefits to senders versus receivers of these signals are only partly understood. because the initial stage of host entry can be hazardous, there may be benefit to a cheating strategy, whose practitioners respond to pheromones but do not engage in host sear ...200414625768
pheromone production in bark beetles.the first aggregation pheromone components from bark beetles were identified in 1966 as a mixture of ipsdienol, ipsenol and verbenol. since then, a number of additional components have been identified as both aggregation and anti-aggregation pheromones, with many of them being monoterpenoids or derived from monoterpenoids. the structural similarity between the major pheromone components of bark beetles and the monoterpenes found in the host trees, along with the association of monoterpenoid prod ...201020727970
density-dependent effects of multiple predators sharing a common prey in an endophytic habitat.multiple predator species feeding on a common prey can lead to higher or lower predation than would be expected by simply combining their individual effects. such emergent multiple predator effects may be especially prevalent if predators share feeding habitat. despite the prevalence of endophagous insects, no studies have examined how multiple predators sharing an endophytic habitat affect prey or predator reproduction. we investigated density-dependent predation of thanasimus dubius (coleopter ...200414968356
midgut tissue of male pine engraver, ips pini, synthesizes monoterpenoid pheromone component ipsdienol de novo.for over three decades the site and pathways of bark beetle aggregation pheromone production have remained elusive. studies on pheromone production in ips spp. bark beetles have recently shown de novo biosynthesis of pheromone components via the mevalonate pathway. the gene encoding a key regulated enzyme in this pathway, 3-hydroxy-3-methylglutaryl-coa reductase (hmg-r), showed high transcript levels in the anterior midgut of male pine engravers, ips pini (say) (coleoptera:scolytidae). hmg-r exp ...200212046626
antennally mediated negative feedback regulation of pheromone production in the pine engraver beetle, ips pini.bark beetles use monoterpenoid aggregation pheromones to coordinate host colonization and mating. these chemical signals are produced de novo in midgut cells via the mevalonate pathway, and pheromone production may be regulated by a negative feedback system mediated through the antennae. in this study, we explored the effect of antennectomy on pheromone production and transcript levels of key mevalonate pathway genes in juvenile hormone iii-treated male pine engraver beetles, ips pini (say). ant ...200717093975
response of mountain pine beetle,dendroctonus ponderosae hopkins, and pine engraver,ips pint (say), to ipsdienol in southwestern british columbia.in bioassays conducted with walking beetles in the laboratory (s)-(+)-, (r)-(-)-, and (±)-ipsdienol were attractive alone, but reduced the attraction of both sexes of the mountain pine beetle,dendroctonus ponderosae hopkins, to extracts of female frass. field trapping studies indicated that attraction ofd. ponderosae to a stimulus composed of myrcene +trans-verbenol +exo-brevicomin was significantly reduced with the addition of (±)- and sometimes (s)-(±)-ipsdienol. thus, (s)-(+)-ipsdienol produc ...198824277010
disruptive selection maintains variable pheromone blends in the bark beetle ips pini.the presence of heritable variation is a prerequisite for evolution, but natural selection typically reduces genetic variation. variation can be maintained in traits under selection through spatial or temporal variation in fitness surfaces, frequency-dependent selection, or disruptive selection. we evaluated the maintenance of variation in the enantiomeric blend of pheromones employed by the bark beetle ips pini (say). in natural populations, we quantified fitness surfaces for mating success an ...201122217770
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