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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 41 (1986), S. 219-230 
    ISSN: 1570-7458
    Keywords: Coleoptera ; Scolytidae ; Ips typographus ; Y-tube olfactometer ; bioassay ; pheromone ; attack phase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Un olfactomètre à tube en Y, dont la description est donnée, a été utilisé pour examiner les réactions d'I. typographus L. par la marche à la présence de phéromones de congénères creusant des galeries dans des bûches d'Epicéa (Picea abies L.). Les insectes dans les bûches ont été répartis en 7 classes séquentielles, depuis l'élaboration de la chambre nuptiale par le mâle (phases 1–3), l'accouplement (4), et la ponte jusqu'à ce que les galeries de ponte aient 5 cm (5–7). Les mâles dans les phases précoces (1–2) étaient attractifs pour les 2 sexes dès 0,5 à 2,5 h après leur introduction, et ils le restaient pendant plus de 2 semaines. Les femelles qui se déplacent par la marche ont préféré nettement les bûches avec des mâles vierges à des bûches non habitées. De même elles ont préféré des bûches avec des mâles unis aux femelles à des bûches sans Ips. Ayant à choisir entre des bûches infestées par des mâles vierges ou expérimentés, les femelles ont préféré nettement les mâles vierges. Les mâle ont présenté une plus faible attraction aussi bien pour les bûches avec mâles vierges qu'avec mâles expérimentés, ils n'ont pas manifesté de préférence entre les 2. Les résultats sont interprétés comme des réponses adaptatives des 2 sexes aux variations dans la libération de phéromones par les insectes pendant les phases successives d'attaque et de colonisation de l'hôte.
    Notes: Abstract A Y-tube olfactometer is described which was used to assay the response of walking Ips typographus (L.) towards the pheromone from beetles excavating galleries in logs of Norway spruce [Picea abies (L.) Karst]. Beetles in the logs were categorized into seven sequential attack phases. Males in the early attack phases were attractive as early as 0.5 to 2.5 h after their introduction. These logs remained attractive for more than 2 weeks. Walking females strongly preferred logs with unmated males over uninfested logs and over logs containing males and females. They also preferred logs with males and females over uninfested logs. Responding males showed a weaker attraction than females to logs with unmated males. The results are interpreted as adaptive responses of the sexes to variation of pheromone release from beetles in the host during subsequent phases of attack and colonization.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-1561
    Keywords: Ips typographus ; spruce bark beetle ; Coleoptera ; Scolytidae ; 2-methyl-3-buten-2-ol ; ipsenol ; cis-verbenol ; ipsdienol ; trans-verbenol ; verbenone ; myrtenol ; trans-myrtanol ; 2-phenylethanol ; ß-isophorone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Ips typographus beetles were collected in the field, separated into eight attack phases (from beetles walking on the trunk of a tree under attack to those excavating gallery systems with a mother gallery longer than 4 cm), and immediately frozen in liquid nitrogen. 2-Methyl-3-buten-2-ol,cis- andtrans-verbenol, verbenone, myrtenol, trans-myrtanol, ipsenol, ipsdienol, and 2-phenylethanol were quantified from excised hindguts against an internal standard, heptyl acetate, in the extraction solvent. Methylbutenol, the pinene alcohols, and 2-phenylethanol showed the same pattern of variation between attack phases in males, with the largest amounts present before accepting females and then a fast decline. Ipsenol and ipsdienol were not detected in males before the females were accepted, and the amounts increased when the females start their egg laying. Verbenone occurred only in trace amounts. The beetles were sampled from five Norway spruce trees (Picea abies) of differing resin flow. The correlations between the nine pheromone components and five major host monoterpenes in the gut showed that the variation in the amount of methyl-butenol, ipsenol, and ipsdienol could not be explained by the variation in the amounts of host monoterpenes. In contrast over 80% of the quantitative variation ofcis-verbenol,trans-verbenol, and myrtenol was explained by the amount of α-pinene. The nine pheromone components from 36 individual males were also quantified. Both methylbutenol andcis-verbenol showed a large variation in both amounts and proportions. Females containedtrans-verbenol and traces of most other components found in males. When accepted by the male, they also contained a female-specific compound, β-isophorone. Behavioral and biosynthetic implications of the results are discussed.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1573-1561
    Keywords: Synergism ; aggregation pheromone ; Pityogenes chalcographus ; Coleoptera ; Scolytidae ; chalcogran ; methyl (2E,4Z)-2,4-decadienoate ; enantiomers ; isomers ; stereoisomers ; synthesis ; bioassay ; structure-activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Syntheses of all four Stereoisomers (2S,5S; 2S,5R;2R,5R; and2R,5S) of chalcogran, a major component of the aggregation pheromone ofPityogenes chalcographus, and of all four isomers (2Z,4Z; 2Z,4E; 2E,4E; and 2E,4Z) of methyl 2,4-decadienoate (MD), the second major pheromone component, are briefly described. Attraction responses of walking beetles of both sexes were tested to mixtures of the synergistic pheromone components or analogs. These bioassays showed that theE,Z isomer of MD is the most active when tested with chalcogran. When tested with (E,Z)-MD, (2S,5R)-chalcogran was the most active stereoisomer, while 2R,5R and 2R,5S isomers had intermediate activities, and the 2S,5S isomer was inactive. There was no evidence that the relatively less active Stereoisomers of chalcogran inhibited or promoted attraction to (2S,5R)-chalcogran with (E,Z)-MD. Male beetles only produce the activeE,Z isomer of MD (inactive alone) and their hindguts contain the most active (2S,5R)- and least active (2S,5S)-chalcogran. A mixture of all MD isomers with racemic chalcogran was not significantly different in attractivity compared to (E,Z)-MD with racemic chalcogran, indicating no synergistic or inhibitory effects of the inactive isomers of MD.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1573-1561
    Keywords: 2-Methyl-3-buten-2-ol ; cis-verbenol ; trans-verbenol ; myrtenol ; trans-myrtanol ; 2-phenylethanol ; ipsdienol ; subtractive assay ; Ips typographus ; Coleoptera ; Scolytidae ; Picea abies ; host volatiles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Six compounds previously identified from hindguts of unmated maleIps typographus (L.) during host colonization: 2-methyl-3-buten-2-ol (MB),cis-verbenol (cV),trans-verbenol (tV), myrtenol (Mt),trans-myrtanol (tM), and 2-phenylethanol (PE), were tested for their attractivity in the field with a subtractive method. The amounts of MB and cV released from a pipe trap were similar to those given off from the commercial bait Ipslure as well as that from a Norway spruce tree,Picea abies (L.) Karst., under mass attack. The blend of the compounds became nonattractive when either MB or cV was subtracted, while subtraction of any of the other four compounds had no effect. Addition of ipsdienol (Id) to the blend did not significantly increase the attraction. In a second comparative test, the addition of three compounds as a group (tV + Mt + PE) to MB + cV again had no effect on the attraction, but the addition of Id increased the catch somewhat. Addition of host logs to a bait releasing MB + cV at a rate lower than in previous experiments did not influence the attraction to pipe traps. Sticky traps containing natural pheromone sources (50 males in a log), which released 1–5 mg/day of MB as determined by aerations with deuterated MB as internal standard, were less attractive than a synthetic source releasing similar amounts of MB.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1573-1561
    Keywords: 2-methyl-3-buten-2-ol ; cis-verbenol ; ipsdienol ; ipsenol ; sex ratio ; attraction ; inhibition ; Ips duplicatus ; Thanasimus ; switching ; Ips typographus ; Coleoptera ; Scolytidae ; Ceeridae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The density of bark-beetle colonization of a tree could be regulated by a quantitative effect of the pheromone signal from beetles in the tree (cessation of release of attractive pheromone) or by a qualitative effect (production of pheromone components inhibiting attraction). The quantitative hypothesis was tested onIps typographus by varying the release rate of the two known attractive compounds, 2-methyl-3-buten-2-ol (MB) and (4S)-cis-verbenol (cV). The highest number of beetles were captured at traps with the highest release rates. The catch was nearly proportional to the release of MB and cV at a distance between traps of 12 m or more. At 6-, 3-, and 1.5-m distances between traps deployed in a triangular arrangement there was still a good discrimination between release rates, but relatively more beetles, especially males, were caught on the blank. The lower release rates caught an equal sex ratio while the highest release rate caught only about 30% males. The qualitative hypothesis was tested by releasing the suspected inhibitors ipsdienol (Id) and ipsenol (Ie), from traps in the same amounts as cV. Only small effects were noted forI. typographus. However, the competitorI. duplicatus was attracted to Id and inhibited by Ie, while the predatorThanasimus formicarius was attracted to both compounds. On the other hand, when the ratio of Id or Ie to cV was 10∶1 or 0.1∶1 rather than 1∶1, they affected the numbers ofI. typographus attracted. A small amount of Id combined with the attractants increased trap catch, while large amounts of Id or Ie decreased attraction, especially when combined. Attack density regulation is modeled as an effect of both quantitative and qualitative mechanisms acting in sequence.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1573-1561
    Keywords: Host attraction ; pheromone ; Pinus sylveslris ; trans-verbenol ; 3-carene-10-ol ; myrtenol ; verbenone ; EAG ; kairomone ; Blastophagus ; Tomicus minor ; Tomicus piniperda ; Coleoptera ; Scolytidae ; pine shoot beetles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The chemical ecology of host- and mate-finding in the pine shoot beetles,Tomicus minor andT. piniperda, was studied in southern Sweden. Beetles were collected in the field from defined attack phases on Scots pine. Using gas chromatography-mass spectroscopy, a number of oxygen-containing monoterpenes, e.g., 3-carene-10-ol, myrtenol,trans-verbenol, and verbenone, were identified from hindgut extracts of both sexes of both species. Compared toT. minor,T. piniperda contained additional compounds and in larger amounts. The amounts were highest in both species at the time when the beetles had bored into contact with the resin-producing xylem-phloem tissue. The synthesis of (1S,6R)-3-carene-10-ol by photooxidatipn of (+)-(1S,6R)-3-carene is described. In comparative electroantennogram (EAG) measurements on males and females of both species, the most active of the tested compounds wastrans-verbenol. Laboratory bioassays of walking beetles showed thatT. piniperda was attracted to uninfestèd pine logs.T. minor was more strongly attracted to pine logs infested with females than to uninfested pine logs, indicating a female-produced aggregation pheromone. Field tests confirmed thatT. piniperda was strongly attracted to pine logs. The attraction ofT. minor to logs was significant only when logs were combined with racemictrans-verbenol and (1S,6R)-3-carene-10-ol.T. minor was also attracted to a combination of these monoterpene alcohols alone. We suggest that host and mate location inT. piniperda is achieved by means of a kairomone composed of host monoterpenes, whileT. minor utilizes a primitive pheromone synergized by host odors. Evolution of host colonization strategies of the two beetles are discussed.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1573-1561
    Keywords: Pheromone ; bark beetle ; Coleoptera ; Scolytidae ; Pityogenes chalcographus ; methyl (E,Z)-2,4-decadienoate ; chalcogran ; Picea abies ; synergist ; subtractive-combination bioassay ; two-dimensional fractionation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Capillary gas chromatography with columns of different polarity and two-dimensional fractionation of effluents were used with novel subtrac-tive-combination bioassays to rigorously isolate host- and insect-produced pheromone synergists of the bark beetlePityogenes chalcographus (Coleop-tera: Scolytidae). Methyl (E,Z)-2,4-decadienoate (E,Z-MD) and the previously identified chalcogran were found to be synergistically attractive to both sexes.E,Z-MD was produced sex-specifically in males, and only when they had fed on host-plant tissue. A Norway spruce monoterpene fraction (including α-pinene, β-pinene, and camphene) increased the attractive response to the pheromone components. Dose-response curves forE,Z-MD and chalcogran in the laboratory bioassay indicated the two components are highly synergistic. The isolation methods are important for further progress in identifying certain semiochemical synergists found in trace amounts in complex chemical mixtures, such as when insects must feed in host plants in order to produce pheromone.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 23 (1997), S. 1833-1850 
    ISSN: 1573-1561
    Keywords: Agrotis segetum ; Lepidoptera ; (Z)-5-decenyl acetate ; (Z)-7-dodecenyl acetate ; (Z)-9-tetradecenyl acetate ; sex pheromone ; individual variation ; repeatability ; effluvia entrainment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Individual variation of the female sex pheromone signal in Agrotis segetum was determined by gas chromatographic analysis. The individuals varied extensively, both in absolute and relative amounts of the three major pheromone components; Z5–10:OAc, Z7–12:OAc and Z9–14:OAc. Within individuals there was a strong correspondence between the sex pheromone gland content and the signal actually emitted. Both pheromone amounts and proportions of components were correlated with effluvia and extracts; with coefficients of 0.55 for total amounts and 0.66 for proportions. In addition, the repeatability of emitted pheromone components by individual females over three calling periods was high, with correlation coefficients between 0.43 and 0.72. Variation among individual females, however, was observed. There were no significant differences between wild-collected and laboratory-reared females in average ratios of the major pheromone components in pheromone gland extracts, only in total amounts. The biological significance of the inter-individual variation among females is discussed in the context of population dynamics and sexual selection.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1573-1561
    Keywords: Agrotis segetum ; turnip moth ; Lepidoptera ; Noctuidae ; sex pheromone ; (Z)-5-decenyl acetate ; (Z)-7-dodecenyl acetate ; (Z)-9-tetradecenyl acetate ; individual variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Female turnip moths (Agrotis segetum) from a laboratory culture inbred for more than 30 generations, and the offspring (first and third generation) from field-collected insects were analyzed individually for acetates and alcohols in the pheromone gland. Quantitative analysis of individual components was performed at the subnanogram level by gas chromatographymass spectrometry (selected ion monitoring). The titer of the pheromone, i.e., the sum of the homologous acetates (Z)-5-decenyl acetate, (Z)-7-dodecenyl acetate, and (Z)-9-tetradecenyl acetate was 2.0 ± 0.3 ng in the laboratory culture and 3.2 ± 0.6 ng in the “wild strain.” There was no correlation between pheromone titer and female weight. The relative proportion of the pheromone components varied substantially between individuals, but there was no statistically significant difference between the two populations. The percentages of the respective compounds (¯X ± coefficient of variation) were 14.8 ± 127% for Z5-10:OAc, 55.6 ± 32% for Z7-12:OAc, and 29.6 ± 59% forZ9-14:OAc. The pheromone composition varied more in the wild strain than in the laboratory culture. The significance of the pheromone variation to the attraction of males was tested in a field experiment. The ratio of males trapped by the most attractive blend versus the least attractive one was 2.2.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1573-1561
    Keywords: Ips typographus ; Coleoptera ; Scolytidae ; bark beetle ; individual variation ; 2-methyl-3-buten-2-ol ; cis-verbenol ; trans-verbenol ; ips-dienol ; ipsenol ; α-pinene ; biosynthesis ; principal component analysis ; aggregation pheromone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The total amounts of, and proportions among, components of the aggregation pheromone produced byIps typographus were found to vary considerably among individuals excised from attacks on standing spruce trees. Chemical analyses of 392 individual male beetles were made by GC-MS. Both unmated and mated males had log-normal frequency distributions in their content of the pheromone components 2-methyl-3-buten-2-ol (MB) andcis-verbenol (cV), since a large fraction of males had a low content. The amount of MB in male hindguts varied independently of cV and the other oxygenated monoterpenes, while the amount of cV covaried with the other pinene alcohols and showed a variation between beetles from different spruce trees. Mated males had, on average, lower amounts of MB than unmated, while the average content of cV in mated males varied with the resin content of their host trees. Ipsdienol and ipsenol were only found in mated males, but in less than 40% and 10%, respectively, of these mated males. Even-aged males exposed to α-pinene in the laboratory showed slightly less variation in the amounts of verbenols, and the variations in ratio between cV and tV were similar to those among males attacking the same spruce tree.
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