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  • 1. Andersson, J.
    et al.
    Borg-Karlson, Anna-Karin
    KTH, Superseded Departments, Chemistry.
    Wiklund, C.
    Antiaphrodisiacs in pierid butterflies: A theme with variation!2003In: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561, Vol. 29, no 6, p. 1489-1499Article in journal (Refereed)
    Abstract [en]

    Male Pieris napi butterflies previously have been shown to synthesize and transfer an antiaphrodisiac, methyl salicylate (MeS), to females at mating. This substance curtails courtship and decreases the likelihood of female remating. Here, we show that similar systems occur in Pieris rapae and Pieris brassicae. In P. rapae, C-13-labeling studies showed that males utilize the amino acids phenylalanine and tryptophan as precursors to MeS and indole, respectively. These volatiles are transferred to females at mating and function as antiaphrodisiacs, as demonstrated by field tests entailing painting MeS, indole, or a mixture on the abdomens of virgin females and assessing their attractiveness to wild males. With P. brassicae, C-13-labeling studies showed that males use phenylalanine as a precursor to synthesize benzyl cyanide, which was demonstrated to function as an antiaphrodisiac by field tests similar to those for P. rapae. This communication system exhibits both similarities and differences among the three species; in P. napi and P. rapae, males are fragrant but transfer a volatile antiaphrodisiac to females that is completely different from the male odor, whereas in P. brassicae the antiaphrodisiac transferred by male to female is identical with male odor.

  • 2.
    Azeem, Muhammad
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Kuttuva Rajarao, Gunaratna
    KTH, School of Biotechnology (BIO), Environmental Microbiology (closed September 2009).
    Nordenhem, Henrik
    SLU, Uppsala.
    Nordlander, Göran
    SLU, Uppsala.
    Borg-Karlson, Anna Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Penicillium expansum Volatiles Reduce Pine Weevil Attraction to Host Plants2013In: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561, Vol. 39, no 1, p. 120-128Article in journal (Refereed)
    Abstract [en]

    The pine weevil Hylobius abietis (L.) is a severe pest of conifer seedlings in reforested areas of Europe and Asia. To identify minimally toxic and ecologically sustainable compounds for protecting newly planted seedlings, we evaluated the volatile metabolites produced by microbes isolated from H. abietis feces and frass. Female weevils deposit feces and chew bark at oviposition sites, presumably thus protecting eggs from feeding conspecifics. We hypothesize that microbes present in feces/frass are responsible for producing compounds that deter weevils. Here, we describe the isolation of a fungus from feces and frass of H. abietis and the biological activity of its volatile metabolites. The fungus was identified by morphological and molecular methods as Penicillium expansum Link ex. Thom. It was cultured on sterilized H. abietis frass medium in glass flasks, and volatiles were collected by SPME and analyzed by GC-MS. The major volatiles of the fungus were styrene and 3-methylanisole. The nutrient conditions for maximum production of styrene and 3-methylanisole were examined. Large quantities of styrene were produced when the fungus was cultured on grated pine bark with yeast extract. In a multi-choice arena test, styrene significantly reduced male and female pine weevils' attraction to cut pieces of Scots pine twigs, whereas 3-methylanisole only reduced male weevil attraction to pine twigs. These studies suggest that metabolites produced by microbes may be useful as compounds for controlling insects, and could serve as sustainable alternatives to synthetic insecticides.

  • 3. Bohman, B.
    et al.
    Nordlander, G.
    Nordenhem, H.
    Sunnerheim, K.
    Borg-Karlson, Anna-Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Unelius, C. R.
    Structure-activity relationships of phenylpropanoids as antifeedants for the pine weevil Hylobius abietis2008In: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561, Vol. 34, no 3, p. 339-352Article in journal (Refereed)
    Abstract [en]

    Ethyl cinnamate has been isolated from the bark of Pinus contorta in the search for antifeedants for the pine weevil, Hylobius abietis. Based on this lead compound, a number of structurally related compounds were synthesized and tested. The usability of the Topliss scheme, a flow diagram previously used in numerous structure-activity relationship (SAR) studies, was evaluated in an attempt to find the most potent antifeedants. The scheme was initially followed stepwise; subsequently, all compounds found in the scheme were compared. In total, 51 phenylpropanoids were tested and analyzed for SARs by using arguments from the field of medicinal chemistry (rational drug design). Individual Hansch parameters based on hydrophobicity, steric, and electronic properties were examined. The effects of position and numbers of substituents on the aromatic ring, the effects of conjugation in the molecules, and the effects of the properties of the parent alcohol part of the esters were also evaluated. It proved difficult to find strong SARs derived from single physicochemical descriptors, but our study led to numerous new, potent, phenylpropanoid antifeedants for the pine weevil. Among the most potent were methyl 3-phenylpropanoates monosubstituted with chloro, fluoro, or methyl groups and the 3,4-dichlorinated methyl 3-phenylpropanoate.

  • 4.
    Borg-Karlson, Anna-Karin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Nordlander, R.
    Mudalige, A.
    Nordenhem, H.
    Unelius, C. R.
    Antifeedants in the feces of the pine weevil Hylobius abietis: Identification and biological activity2006In: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561, Vol. 32, no 5, p. 943-957Article in journal (Refereed)
    Abstract [en]

    Egg-laying females of the pine weevil, Hylobius abietis (L.), regularly deposit feces adjacent to each egg. Egg cavities are gnawed in the bark of roots of recently dead conifer trees. After egg deposition, the cavity is sealed by feces and a plug of bark fragments. Root bark containing egg cavities with feces is avoided as food by pine weevils, which indicates the presence of natural antifeedants. Here we present the first results of the isolation and chemical analyses of antifeedant compounds in the feces of H. abietis. In feeding bioassays, methanol extracts of the feces revealed strong antifeedant properties. Methanol extracts were fractionated by medium-pressure liquid chromatography and the antifeedant effects were mainly found in the fractions of highest polarity. Volatile compounds in the active fractions were identified by gas chromatography-mass spectrometry (GC-MS) and the nonvolatile compounds were characterized by pyrolysis-GC-MS. Based on mass spectra, a number of compounds with various chemical structures were selected to be tested for their antifeedant properties. Antifeedant effects were found among compounds apparently originating from lignin: e.g., a methylanisol, guaiacol, veratrol, dihydroxybenzenes, and dihydroconiferyl alcohol. A weak effect by fatty acid derivatives was found. The types of naturally occurring antifeedant compounds identified in this study may become useful for the protection of planted conifer seedlings against damage by H. abietis.

  • 5.
    Borg-Karlson, Anna-Karin
    et al.
    KTH, Superseded Departments, Chemistry.
    Tengo, J.
    Valterova, I.
    Unelius, C. R.
    Taghizadeh, T.
    Tolasch, T.
    Francke, W.
    (S)-(+)-linalool, a mate attractant pheromone component in the bee Colletes cunicularius2003In: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561, Vol. 29, no 1, p. 1-14Article in journal (Refereed)
    Abstract [en]

    Enantiomerically pure (S)-(+)- linalool was the main constituent in the extracts of the cephalic secretions of virgin females, mated females, freshly emerged males, and patrolling males of the solitary bee Colletes cunicularius. After copulation, the content of (S)-(+)- linalool emitted by the female was strongly reduced. Electrophysiological experiments revealed that both enantiomers of linalool elicited responses from the antennae of the males. Field tests using the pure enantiomers and the racemate of linalool showed that the number of male bees attracted was highest for (S)-(+)- linalool. The search flight activity in the mating flight area increased dramatically when patrolling males were presented with (S)-(+)- linalool vs (R)-(+)- linalool. Taken together, these data indicate a mate attractant pheromone function of (S)-(+)- linalool.

  • 6. Buda, Vincas
    et al.
    Mozuraitis, Raimondas
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Kutra, Jonas
    Borg-Karlson, Anna-Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    p-Cresol: A Sex Pheromone Component Identified from the Estrous Urine of Mares2012In: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561, Vol. 38, no 7, p. 811-813Article in journal (Refereed)
    Abstract [en]

    Previously it was shown that m- and p-cresols in the urine of mares exhibits a temporally reproducible pattern that is dependent on ovarian activity and, thus, provides information about the timing of ovulation. New behavioral data demonstrate 1) that stallions spend significantly more time sniffing p-cresol as compared to o-, and m-cresols, and, 2) that the extent of stallions' erections differ significantly in response to different types of samples. The lowest erection level was recorded for the pure-water control, a moderate erection level was elicited by the urine of diestrous mares, and the highest erection level was elicited by urine of a diestrous mare containing synthetic p-cresol at a quantity equivalent to half of the amount of p-cresol found in the urine of estrous mares. Consequently, p-cresol is at least one of the components of a horse sex pheromone.

  • 7. El-Sayed, A M
    et al.
    Wainman, L I
    Santangelo, Ellen
    KTH, Superseded Departments, Chemistry.
    Unelius, C. Rikard
    KTH, Superseded Departments, Chemistry.
    Trimble, R M
    Relative attractiveness of (10E)-dodecen-1-yl acetate and (4E,10E)-dodecadien-1-yl acetate to male spotted tentiform leafminers Phyllonorycter blancardella (F.)2004In: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561, Vol. 30, no 9, p. 1827-1838Article in journal (Refereed)
    Abstract [en]

    The antennae of male spotted tentiform leafminers, Phyllonorycter blancardella, from Ontario, Canada, exhibited similar electroantennogram responses when stimulated with E10-12:Ac or E4,E10-12:Ac. In field trapping experiments, E10-12:Ac was two-fold or more attractive than E4, E10-12:Ac, and E4,E10-12:Ac did not enhance the attractiveness of E10-12:Ac. E4,E10-12:Ac has not been identified in the pheromone of P. blancardella and it is hypothesized that the structural similarity of this compound and E10-12:Ac, the major pheromone compound of this species, may be responsible for the electrophysiological and behavioral responses to E4,E10-12:Ac. The possible reasons for the disparity between the results of our field trapping experiments and those carried out in Nova Scotia, Canada, and Massachusetts, USA., where E4,E10-12:Ac was found to be two to four times more attractive to P. blancardella than E10-12:Ac, are discussed.

  • 8. Eriksson, Carina
    et al.
    Månsson, Per E.
    Sjödin, Kristina
    Schlyter, Fredrik
    Antifeedants and feeding stimulants in bark extracts of ten woody non-host species of the pine weevil, Hylobius abietis2008In: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561, Vol. 34, no 10, p. 1290-1297Article in journal (Refereed)
    Abstract [en]

    Bark of ten woody species, known to be rejected as a food source by the pine weevil, Hylobius abietis, were sequentially extracted by a Soxhlet apparatus with pentane followed by methanol. Species were alder (Alnus glutinosa), aspen (Populus tremula), beech (Fagus sylvatica), guelder rose (Viburnum opulus), holly (Ilex aquifolium), horse chestnut (Aesculus hippocastanum), lilac (Syringa vulgaris), spindle tree (Evonymus europaeus), walnut (Juglans regia), and yew (Taxus baccata). Bark of each species was collected in southern Scandinavia during the summer. Resulting extracts were tested for antifeedant activity against the pine weevil by a micro-feeding choice assay. At a dose corresponding to that in the bark, methanol extracts from Aesculus, Taxus, Ilex, and Populus were antifeedant active, while pentane extracts of Aesculus, Fagus, Syringa, and Viburnum were stimulatory. Four known antifeedants against H. abietis, the straight-chained carboxylic acids, hexanoic and nonanoic acid (C6 and C9), carvone, and carvacrol were identified by gas chromatography (GC)-mass spectrometry (MS) in several extracts. The major constituents were identified and tested for feeding deterrence. The aromatic compounds benzyl alcohol and 2-phenylethanol are new non-host plant-derived feeding deterrents for the pine weevil. Additionally, two feeding stimulants, beta-sitosterol and 5-(hydroxymethyl)-2-furaldehyde, were identified. One active methanol extract of Aesculus bark was sequentially fractionated by liquid chromatography, and major compounds were tentatively identified as branched alcohols and esters of hexanoic acid. Five commercially available hexanoate esters and two commercially available branched alcohols were identified as new active antifeedants. Both stimulatory and inhibiting compounds were found in the same extracts and co-eluted in the same or adjacent fractions. The mix of semiochemicals of opposite activity in each extract or fraction could explain the stimulatory-, inhibitory-, or sometimes neutral activity. Generally, such co-occurrence confounds the isolation of antifeedants.

  • 9. Faldt, Jenny
    et al.
    Solheim, Halvor
    Langstrom, Bo
    Borg-Karlson, Anna-Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Influence of fungal infection and wounding on contents and enantiomeric compositions of monoterpenes in phloem of Pinus sylvestris2006In: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561, Vol. 32, no 8, p. 1779-1795Article in journal (Refereed)
    Abstract [en]

    To identify chemical resistant markers induced by fungal or mechanical injury, young trees of Scots pine (Pinus sylvestris) were subjected to inoculations of blue stain fungi associated with the pine shoot beetles Tomicus piniperda and T. minor. Among the 20 trees selected for chemical analyses, 16 were divided into four groups: one as control and three were pretreated by wounding only, or by inoculation with either the blue stain fungus Leptographium wingfieldii or Ophiostoma canum. Four wk after pretreatment, all 16 pretreated trees were mass-inoculated with L. wingfieldii. The absolute and relative amounts, as well as the enantiomeric compositions of monoterpene hydrocarbons in the phloem, were determined via a small sample of the phloem before and after the pretreatment and mass inoculation, by using two-dimensional gas chromatography (2D GC) and GC-mass spectrometry (MS). After mass inoculation, the absolute amounts of most of the monoterpenes decreased in the phloem sampled > 20 cm from the fungal infection, and were higher in the phloem sampled within the infected reaction zone. The relative amounts of both (-)-beta-pinene and (-)-limonene increased in phloem samples taken > 20 cm above the fungal inoculation in the preinoculated trees compared with phloem sampled from the remaining four control trees. The enantiomeric compositions of beta-pinene and limonene changed, after fungal growth, at defined distances from the inoculation site: the proportion of the (-)-enantiomers was highest in the phloem sampled > 20 cm from the fungal inoculation. Four wk after pretreatment, monoterpene production in the phloem at the site of inoculation was more enhanced by L. wingfieldii than by O. canum. However, the different virulence levels of the fungi did not affect the enantiomeric composition of the monoterpenes. The biosynthesis of monoterpene enantiomers is discussed in relation to induced pathogen resistance.

  • 10. Francke, W.
    et al.
    Karalius, V.
    Plass, E.
    Lehmann, L.
    Dos Santos, A.
    Buda, V.
    Borg-Karlson, Anna-Karin
    KTH, Superseded Departments, Chemistry.
    Mozuraitis, Raimondas
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    New type of sesiidae sex pheromone identified from the hornet moth Sesia apiformis2004In: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561, Vol. 30, no 4, p. 805-817Article in journal (Refereed)
    Abstract [en]

    Two components of the female-produced sex pheromone of the hornet moth, Sesia apiformis, were identified as (3Z, 13Z)-octadeca-3,13-dien-1-ol (3Z, 13Z-18:OH) and (2E, 13Z)-octadeca-2,13-dienal (2E, 13Z-18:Al), a pheromone structure new in Sesiidae. Pooled gland extracts showed the two major compounds in a proportion of ca. 2:3, while SPME-investigations on single calling females revealed a ratio of ca. 1:7. Although the single compounds were not attractive, a 2: 3 mixture proved to be highly active towards males in field tests. Small amounts of (2E, 13Z)-octadecadienol (2E, 13Z-18:OH) were found in the sex pheromone gland of females, however, the biological significance of the compound remains unclear. Methyl sulfide was found to readily react with 2-alkenals, providing an effective new method for the characterization of this type of compound upon GC/MS. The derivatives, 1,1,3-tris(methylthio)alkanes, are the products of the addition of methyl sulfide to the double bond and the transformation of the carbonyl group into the corresponding bis(methylthio)acetal. The mass spectra of these compounds are characterized by diagnostic signals at m/z 107 and/or m/z 121. These fragments represent the first carbon unit or the first two carbon units of the derivative, respectively. The parent signal in the spectra of thiomethyl derivatives of 2-alkenals showing no other double bonds is represented by m/z M+-121, formed upon loss of the first two carbon units. By employing a solution of methyl sulfide in dimethyl sulfide, the double bond positions in 2E, 13Z-18:Al could be fully characterized by GC/MS.

  • 11.
    Kännaste, Astrid
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Nordenhem, Henrik
    Department of Ecology, Swedish University of Agricultural Sciences.
    Nordlander, Göran
    Department of Ecology, Swedish University of Agricultural Sciences.
    Borg-Karlson, Anna-Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Volatiles from a Mite-Infested Spruce Clone and Their Effects on Pine Weevil Behavior2009In: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561, Vol. 35, no 10, p. 1262-1271Article in journal (Refereed)
    Abstract [en]

    Induced responses by Norway spruce (Picea abies) seedlings to feeding damage by two mite species were studied by analyzing the volatiles emitted during infestation. Four specimens of a Norway spruce (Picea abies L.) clone were infested with mites of Nalepella sp., another four with Oligonychus ununguis, and four were kept mite-free as controls. After a year of infestation, spruce volatiles were collected, analyzed, and identified using SPME-GC-MS. In addition, enantiomers of chiral limonene and linalool were separated by two-dimensional GC. Methyl salicylate (MeSA), (-)-linalool, (E)-beta-farnesene, and (E,E)-alpha-farnesene were the main volatiles induced by both species of mites, albeit in different proportions. The ability of the main compounds emitted by the mite-infested spruces to attract or repel the pine weevil, Hylobius abietis (L.), was tested. (E)-beta-farnesene was found to be attractive in the absence of spruce odor, whereas methyl salicylate had a deterrent effect in combination with attractive spruce odor. The other tested compounds had no significant effects on the behavior of the weevils.

  • 12. Larsdotter-Mellström, Helena
    et al.
    Murtazina, Rushana
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Borg-Karlson, Anna-Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Wiklund, Christer
    Timing of Male Sex Pheromone Biosynthesis in a Butterfly - Different Dynamics under Direct or Diapause Development2012In: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561, Vol. 38, no 5, p. 584-591Article in journal (Refereed)
    Abstract [en]

    The life history traits and behavior of the butterfly are well-known, as the species is often used as a model organism for evolutionary and ecological studies. The species has two or more generations per year in the major part of its temperate distribution, and as different selection pressures affect the different generations, both behavioral and physiological seasonal polyphenisms have been shown previously. Here, we explored the dynamics of male sex pheromone production. The two generations are shown to have significantly different scent compositions early in life; the direct developers-who have shorter time for pupal development-need the first 24 hr of adult life after eclosion to synthesize the sex pheromone citral (geranial and neral 1:1)-whereas the diapausing individuals who have spent several months in the pupal stage eclose with adult scent composition. Resource allocation and biosynthesis also were studied in greater detail by feeding butterflies C-13 labeled glucose either in the larval or adult stage, and recording incorporation into geranial, neral, and other volatiles produced. Results demonstrate that the pheromone synthesized by newly eclosed adult males is based on materials ingested in the larval stage, and that adult butterflies are able to synthesize the pheromone components geranial and neral and the related alcohols also from adult intake of glucose. In summary, our study shows that time-stress changes the timing in biosynthesis of the complete pheromone between generations, and underpins the importance of understanding resource allocation and the physiological basis of life history traits.

  • 13.
    Lundborg, Lina
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Nordlander, Goran
    Bjorklund, Niklas
    Nordenhem, Henrik
    Borg-Karlson, Anna-Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Methyl Jasmonate-Induced Monoterpenes in Scots Pine and Norway Spruce Tissues Affect Pine Weevil Orientation2016In: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561, Vol. 42, no 12, p. 1237-1246Article in journal (Refereed)
    Abstract [en]

    In large parts of Europe, insecticide-free measures for protecting conifer plants are desired to suppress damage by the pine weevil Hylobius abietis (L.). Treatment with methyl jasmonate (MeJA), a chemical elicitor already used in crop production, may enhance expression of chemical defenses in seedlings in conifer regenerations. However, in a previous experiment, MeJA treatment resulted in substantially better field protection for Scots pine (Pinus sylvestris L.) than for Norway spruce (Picea abies (L.) Karst.). Hypothesizing that the variations may be at least due partly to volatiles released by MeJA-treated seedlings and their effects on pine weevil orientation, we examined tissue extracts of seedlings (from the same batches as previously used) by two-dimensional GC-MS. We found that the MeJA treatment increased contents of the monoterpene (-)-beta-pinene in phloem (the weevil's main target tissue) of both tree species, however, the (-)-beta-pinene/(-)-alpha-pinene ratio increased more in the phloem of P. sylvestris. We also tested the attractiveness of individual monoterpenes found in conifer tissues (needles and phloem) for pine weevils using an arena with traps baited with single-substance dispensers and pine twigs. Trap catches were reduced when the pine material was combined with a dispenser releasing (-)-beta-pinene, (+)-3-carene, (-)-bornyl acetate or 1,8-cineole. However, (-)-alpha-pinene did not have this effect. Thus, the greater field protection of MeJA-treated P. sylvestris seedlings may be due to the selective induction of increases in contents of the deterrent (-)-beta-pinene, in contrast to strong increases in both non-deterrent (-)-alpha-pinene and the deterrent (-)-beta-pinene in P. abies seedlings.

  • 14. Mozuraitis, R.
    et al.
    Buda, V.
    Liblikas, I.
    Unelius, C. R.
    Borg-Karlson, Anna-Karin
    KTH, Superseded Departments, Chemistry.
    Parthenogenesis, calling behavior, and insect-released volatiles of leafminer moth Phyllonorycter emberizaepenella2002In: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561, Vol. 28, no 6, p. 1191-1208Article in journal (Refereed)
    Abstract [en]

    We proved that the leafminer moth Phyllonorycter emberizaepenella (Lepidoptera: Gracillariidae) reproduces by parthenogenesis of the thelytoky type. Despite a complete absence of males, parthenogenetically reproducing females diurnally demonstrated the calling posture normally used for releasing signaling compounds. Two compounds, which we collected from a calling female, were identified as potential sex pheromone components: (8E,10E)-8,10-tetradecadienyl acetate and (8E,10E)-8,10-tetradecadienol, the latter occurring only in trace amounts. In field experiments, no males were attracted to traps baited with either the potential sex pheromone or with virgin females. Both the pattern of behavior and the chemical characteristics of the pheromone of Ph. emberizaepenella species were similar to those known for Lepidoptera with the usual amphimictic mode of reproduction. Theoretical speculations that in thelytoky, where there is no need to find a sexual partner, the individuals would obtain certain advantages due to reduction in their sexual behavior, were, thus, not confirmed for Ph. emberizaepenella.

  • 15.
    Mozuraitis, Raimondas
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Buda, Vincas
    Intra- and Interspecific Activities of Semiochemicals from the Sex Pheromone Gland of the Welsh Clearwing, Synanthedon Scoliaeformis2013In: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561, Vol. 39, no 8, p. 1066-1069Article in journal (Refereed)
    Abstract [en]

    Analysis of the sex pheromone gland of virgin Synanthedon scoliaeformis females by gas chromatography/mass spectrometry revealed six compounds structurally related to sex pheromone components of other clearwing moths: (E,Z)-2,13-octadecadienyl acetate (E2,Z13-18:OAc), (E,Z)-2,13-octadecadienol, octadecanol acetate, octadecanol, (Z,Z)-3,13-octadecadienyl acetate (Z3,Z13-18:OAc), and (Z)-13-octadecenyl acetate. Trapping tests demonstrated that E2,Z13-18:OAc is the sex pheromone of S. scoliaeformis and is essential for attracting males; addition of the other compounds did not enhance catch. Synanthedon scoliaeformis and S. tipuliformis are the only Palearctic clearwing moths whose distribution range and seasonal flight periods overlap and that are known to use E2,Z13-18:OAc in sex pheromonal communication. Hourly monitoring of male catches in traps revealed that sex pheromone communication in S. scoliaeformis and S. tipuliformis species follows different diurnal patterns. Z3,Z13-18:OAc, found in S. scoliaeformis females, is a known behavioral antagonist against S. tipuliformis males, while (E,Z)-3,13-octadecadienyl acetate, a minor sex pheromone component of S. tipuliformis, is an antagonist against S. scoliaeformis males. The effect of sex pheromones and antagonists, combined with different diurnal mate searching times, contribute to the specificity of sex communication channels in these two clearwing moth species.

  • 16. Månsson, Per E.
    et al.
    Eriksson, Carina
    Sjödin, Kristina
    Antifeedants against Hylobius abietis pine weevils: An active compound in extract of bark of Tilia cordata linden2005In: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561, Vol. 31, no 5, p. 989-1001Article in journal (Refereed)
    Abstract [en]

    Linden (Tilia cordata) bark was shown to contain an antifeedant effective against the large pine weevil, Hylobius abietis. Soxhlet extraction of inner and outer bark resulted in an extract that showed antifeedant activity in a microfeeding assay. The extract was fractionated by chromatography on silica gel using gradient elution with solvents of increasing polarity. The content of the fractions obtained was monitored by thin layer- and gas chromatography. Fractions of similar chemical composition were merged. Two of the 17 fractions showed antifeedant activity in the microfeeding assay. Nonanoic acid was identified in both of these fractions. Subsequent testing in the microfeeding assay showed that nonanoic acid possessed strong antifeedant activity against H. abietis adults.

  • 17. Olsson, P. O. C.
    et al.
    Anderbrant, O.
    Lofstedt, C.
    Borg-Karlson, Anna-Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Liblikas, I.
    Electrophysiological and behavioral responses to chocolate volatiles in both sexes of the pyralid moths Ephestia cautella and Plodia interpunctella2005In: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561, Vol. 31, no 12, p. 2947-2961Article in journal (Refereed)
    Abstract [en]

    Volatiles from chocolate mediate upwind flight behavior in Ephestia cautella and Plodia interpunctella. We used gas chromatography with electroantennographic detection and found 12 active compounds derived from three different chocolate types, i.e., plain, nut-containing, and rum-flavored. Eight of the compounds were identified with mass spectrometry, and the activity of three compounds, ethyl vanillin, nonanal, and phenylacetaldehyde (PAA), was subsequently confirmed in both electrophysiological and behavioral assays. In the electroantennogram experiment, PAA and nonanal were consistently eliciting responses in both species and sexes. Ethyl vanillin was active in males of both species, and also in P. interpunctella females. E. cautella females showed no antennal activity in response to ethyl vanillin. All three volatiles were attractive to E. cautella males and P. interpunctella females in a flight tunnel. E. cautella females were significantly attracted only to ethyl vanillin. P. interpunctella males were attracted to PAA. Ethyl vanillin is a novel insect attractant, whereas both nonanal and phenylacetaldehyde mediate behavior in many insect species. A final experiment revealed that a blend of the three volatiles was required to induce landing in the flight tunnel bioassay, and that the landing rate was dependent on dose. The three-component blend attracted both sexes of P. interpunctella and females of E. cautella, whereas E. cautella males were not attracted.

  • 18. Sjodin, K.
    et al.
    Persson, M.
    Faldt, J.
    Ekberg, I.
    Borg-Karlson, Anna-Karin
    KTH, Superseded Departments, Chemistry.
    Occurrence and correlations of monoterpene hydrocarbon enantiomers in Pinus sylvestris and Picea abies2000In: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561, Vol. 26, no 7, p. 1701-1720Article in journal (Refereed)
    Abstract [en]

    The relative amounts and enantiomeric compositions of monoterpene hydrocarbons in branch and trunk xylem, in needles, and in resin from apical buds in 18 Pinus sylvestris trees have been determined and compared with the terpene content in branch xylem and needles of Picea abies. Besides the high amount of (+)-3-carene, an excess of (+)-alpha-pinene has been found in P. sylvestris, whereas in P. abies (-)-alpha-pinene dominates over (+)-alpha-pinene. In P. sylvestris, clear positive correlations were found between (+)-alpha-pinene and (+)-camphene in the four tissues analyzed. Good positive correlations were also observed between (-)-alpha-pinene and (-)-camphene in the two types of xylem, between (+)-alpha-pinene and (+)-beta-pinene in the resin, and between tricyclene and (-)-camphene in resin and needles. In P. abies, positive correlations were found between (+)-alpha-pinene and (+)-camphene in the branch xylem and between tricyclene and (-)-camphene as well as between (-)-alpha-pinene and (-)-camphene in the needles. Complex relationships between (-)-alpha-pinene and (-)-beta-pinene were found both in the P. abies and in the P. sylvestris tissues. The importance of the enantiomeric composition of alpha-pinene for the host selection of Ips typographus, Tomicus piniperda, and Hylobius abietis is discussed.

  • 19. Unelius, C. Rikard
    et al.
    Nordlander, Goran
    Nordenhem, Henrik
    Hellqvist, Claes
    Legrand, Sacha
    Borg-Karlson, Anna-Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Structure-activity relationships of benzoic acid derivatives as antifeedants for the pine weevil, Hylobius abietis2006In: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561, Vol. 32, no 10, p. 2191-2203Article in journal (Refereed)
    Abstract [en]

    Aromatic organic compounds found in the feces of the pine weevil, Hylobius abietis (L.) (Coleoptera: Curculionidae), have been shown to deter feeding behavior in this species, which is a serious pest of planted conifer seedlings in Europe. We evaluated 55 benzoic acid derivatives and a few homologs as antifeedants for H. abietis. Structure-activity relationships were identified by bioassaying related compounds obtained by rational syntheses of functional group analogs and structural isomers. We identified five main criteria of efficiency as antifeedants among the benzoic acid derivatives. By predicting optimal structures for H. abietis antifeedants, we attempted to find a commercial antifeedant to protect conifer seedlings against damage by H. abietis in regenerating forests. New, highly effective antifeedants are methyl 2,4-dimethoxybenzoate, isopropyl 2,4-dimethoxybenzoate, methyl 2-hydroxy-3-methoxybenzoate, methyl (3,5-dimethoxyphenyl)acetate, and methyl (2,5-dimethoxyphenyl)acetate. Of these, methyl 2,4-dimethoxybenzoate and isopropyl 2,4-dimethoxybenzoate have the highest antifeedant indices of all substances tested and are the best candidates for practical applications in order to protect planted seedlings in the field.

  • 20.
    Zhao, Tao
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Axelsson, Karolin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Krokene, P.
    Borg-Karlson, Anna-Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Fungal Symbionts of the Spruce Bark Beetle Synthesize the Beetle Aggregation Pheromone 2-Methyl-3-buten-2-ol2015In: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561Article in journal (Refereed)
    Abstract [en]

    Tree-killing bark beetles depend on aggregation pheromones to mass-attack their host trees and overwhelm their resistance. The beetles are always associated with phytopathogenic ophiostomatoid fungi that probably assist in breaking down tree resistance, but little is known about if or how much these fungal symbionts contribute to the beetles’ aggregation behavior. In this study, we determined the ability of four major fungal symbionts of the spruce bark beetle Ips typographus to produce beetle aggregation pheromones. The fungi were incubated on Norway spruce Picea abies bark, malt agar, or malt agar amended with 0.5 % 13C glucose. Volatiles present in the headspace of each fungus were analyzed for 7 days after incubation using a SPME autosampler coupled to a GC/MS. Two Grosmannia species (G. penicillata and G. europhioides) produced large amounts of 2-methyl-3-buten-2-ol (MB), the major component in the beetles’ aggregation pheromone blend, when growing on spruce bark or malt agar. Grosmannia europhioides also incorporated 13C glucose into MB, demonstrating that the fungi can synthesize MB de novo using glucose as a carbon source. This is the first clear evidence that fungal symbionts of bark beetles can produce components in the aggregation pheromone blend of their beetle vectors. This provides new insight into the possible ecological roles of fungal symbionts in bark beetle systems and may deepen our understanding of species interactions and coevolution in these important biological systems.

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