| 1. |
- Jakobsson, Johan, et al.
(författare)
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Visual cues of oviposition sites and spectral sensitivity of Cydia strobilella L.
- 2017
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Ingår i: Journal of Insect Physiology. - : Elsevier BV. - 0022-1910. ; 101, s. 161-168
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Tidskriftsartikel (refereegranskat)abstract
- We investigated whether the spruce seed moth (Cydia strobilella L., Tortricidae: Grapholitini), an important pest in seed orchards of Norway spruce (Picea abies (L.) Karst.), can make use of the spectral properties of its host when searching for flowers to oviposit on. Spectral measurements showed that the flowers, and the cones they develop into, differ from a background of P. abies needles by a higher reflectance of long wavelengths. These differences increase as the flowers develop into mature cones. Electroretinograms (ERGs) in combination with spectral adaptation suggest that C. strobilella has at least three spectral types of photoreceptor; an abundant green-sensitive receptor with maximal sensitivity at wavelength λmax = 526 nm, a blue-sensitive receptor with λmax = 436 nm, and an ultraviolet-sensitive receptor with λmax = 352 nm. Based on our spectral measurements and the receptor properties inferred from the ERGs, we calculated that open flowers, which are suitable oviposition sites, provide detectable achromatic, but almost no chromatic contrasts to the background of needles. In field trials using traps of different spectral properties with or without a female sex pheromone lure, only pheromone-baited traps caught moths. Catches in baited traps were not correlated with the visual contrast of the traps against the background. Thus, visual contrast is probably not the primary cue for finding open host flowers, but it could potentially complement olfaction as a secondary cue, since traps with certain spectral properties caught significantly more moths than others.
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| 2. |
- Svensson, Glenn, et al.
(författare)
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Assessment of genetic and pheromonal diversity of the Cydia strobilella species complex (Lepidoptera: Tortricidae)
- 2013
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Ingår i: Systematic Entomology. - : Wiley. - 1365-3113 .- 0307-6970. ; 38:2, s. 305-315
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Tidskriftsartikel (refereegranskat)abstract
- Combining pheromone trapping and genetic analyses can be useful whentrying to resolve complexes of closely related insect taxa that are difficult to distinguishbased on morphological characters. Nearctic and Palearctic populations of the spruceseed moth, Cydia strobilella L., have been considered taxonomically synonymoussince 1983, but more recent work revealing distinct sex pheromones for Canadianand Swedish moths suggest that populations in the two regions belong to differentspecies. In order to test this hypothesis, we performed field trapping using differentpheromone lures at ten sites in North America, Europe and Asia, and reconstructedphylogenetic relationships among trapped moths using mitochondrial (cytochromeoxidase subunit I ) and nuclear (elongation factor 1 alpha) DNA sequence data.Trapping data and tree topologies for both genes revealed distinct pherotypes in NorthAmerica and Eurasia. A genetically distinct population from China was investigatedfurther with respect to its sex pheromone. Electrophysiological data indicated thatChinese females produce a deviant ratio of the sex pheromone components (dienicacetates) compared to Swedish females. However, trapping experiments in both areasrevealed a similar broad response profile in males to a wide range of acetate ratios,and these populations should be considered taxonomically synonymous. A previoussuggestion of an agonistic effect on the attraction of C. strobilella males in Swedenwhen adding the corresponding alcohols to the binary acetate blend was also testedin Sweden as well as in China, with no observed effect on attraction of males. In conclusion, our study demonstrates the great potential of using pheromone trappingas a tool for identification and delimitation of taxa within cryptic species complexes.Based on our data, Nearctic and Palearctic populations of C. strobilella should beconsidered different species, and C. youngana Kearfott stat. rev. is resurrected hereas valid name for North American populations, which was the case before the revisionin 1983.
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| 3. |
- Svensson, Glenn P., et al.
(författare)
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Challenges of pheromone-based mating disruption of Cydia strobilella and Dioryctria abietella in spruce seed orchards
- 2018
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Ingår i: Journal of Pest Science. - : Springer Science and Business Media LLC. - 1612-4758 .- 1612-4766. ; 91, s. 639-650
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Tidskriftsartikel (refereegranskat)abstract
- Seed orchards function as the primary source of high-quality seeds for reforestation in many European countries, but their seed yields can be severely reduced due to seed- and cone-feeding insects. We evaluated various parameters of pheromone-based mating disruption for control of the moths Cydia strobilella and Dioryctria abietella, which are major pests in European Picea abies seed orchards. We applied different types of pheromone dispensers (rubber septa or wax droplets) at different densities and heights, and with different amounts of active components, covering whole orchards or part of an orchard. The efficacy of the treatment was evaluated by analysing male captures in pheromone-baited assessment traps, and presence of larvae in cones. A dramatic decrease (94–100%) in capture of males in traps occurred in all pheromone-treated plots compared to control plots for both moth species. In contrast, a subsequent reduction in larval numbers in cones was only achieved when wax droplets were used as the dispensing formulation at high density and at the highest pheromone dose tested, and only in half of the trials for each pest species. Electrophysiological recordings using antennae of male C. strobilella indicated elevated pheromone concentrations in a treated plot versus a control plot. Our results show that mating disruption has potential to reduce cone damage in spruce seed orchards caused by C. strobilella and D. abietella, but optimisation of the technique is required to achieve consistent and efficient population suppression of these pests.
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| 4. |
- Wang, Hong-Lei, et al.
(författare)
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Sex pheromone of the cloaked pug moth, Eupithecia abietaria (Lepidoptera: Geometridae), a pest of spruce cones
- 2015
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Ingår i: Journal of Applied Entomology. - : Wiley. - 0931-2048 .- 1439-0418. ; 139:5, s. 352-360
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Tidskriftsartikel (refereegranskat)abstract
- The sex pheromone of the cloaked pug moth, Eupithecia abietaria Götze, an important cone-feeding pest in spruce seed orchards in Europe, was investigated. Chemical and electrophysiological analyses of pheromone gland extracts of female moths and analogous analyses of synthetic hydrocarbons and epoxides of chain length C19 and C21 revealed (3Z,6Z,9Z)-3,6,9-nonadecatriene (3Z,6Z,9Z-19:H) and 3Z,6Z-cis-9,10-epoxynonadecadiene (3Z,6Z-cis-9,10-epoxy-19:H) as candidate pheromone components, which were found in a gland extract in a ratio of 95 : 5. In field trapping experiments, conspecific males were only attracted to a combination of 3Z,6Z,9Z-19:H and the (9S,10R)-enantiomer of 3Z,6Z-cis-9,10-epoxy-19:H. The (9R,10S)-enantiomer was not attractive, which is in agreement with studies on other Eupithecia species, for which males have only been attracted by the (9S,10R)-enantiomer of epoxides. Subsequent experiments showed that E. abietaria males were attracted to a wide range of ratios of the two active compounds and that trap catches increased with increasing dose of the binary blend. A two-component bait containing 300 μg 3Z,6Z,9Z-19:H and 33 μg of the (9S,10R)-enantiomer of 3Z,6Z-cis-9,10-epoxy-19:H was efficient for monitoring E. abietaria in spruce seed orchards in southern Sweden, where this species has probably been overlooked as an important pest in the past. With sex pheromones recently identified for two other moths that are major pests on spruce cones, the spruce seed moth, Cydia strobilella L., and the spruce coneworm, Dioryctria abietella Denis & Schiffermüller, pheromone-based monitoring can now be achieved for the whole guild of cone-feeding moths in European spruce seed orchards.
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| 5. |
- Anderbrant, Olle, et al.
(författare)
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Article sex pheromone of the introduced pine sawfly, diprion similis, revisited to define a useful monitoring lure : Deviating chiral composition and behavioural responses compared to earlier reports
- 2021
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Ingår i: Insects. - : MDPI. - 2075-4450. ; 12:10
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Tidskriftsartikel (refereegranskat)abstract
- Extracts of Diprion similis females contained about 15 ng of the sex pheromone precursor 3,7‐dimethylpentadecan‐2‐ol per female. After derivatisation with (S)‐2‐acetoxypropanoyl chloride, we found that the major stereoisomer in the extract was (2S,3R,7R)‐3,7‐dimethylpentadecan‐2‐ol. Small amounts of other stereoisomers of 3,7‐dimethylpentadecan‐2‐ol were also identified in the extract, namely 1% of (2R,3S,7S), 0.3% (2R,3R,7R) and 0.4% of (2R,3R,7S). An unknown fifth substance showed a very similar spectrum to 3,7‐dimethylpentadecan‐2‐ol, both in SIM and full scan mode. None of the earlier suggested behavioural synergistic isomers ((2S,3S,7S), (2S,3S,7R) and (2S,3R,7S)) were detected in the extracts. In field tests in Ontario, Canada, the earlier identified main pheromone component, viz. the propanoate of (2S,3R,7R)‐3,7‐dimethylpentadecan‐2‐ol, was tested alone and in combination with other stereoisomers, earlier reported to be synergistic. No synergistic effects were detected and the threo four‐isomer blend was as attractive as the pure main compound. Thus, one of the few examples of a diprionid sawfly using more than one substance in its sex pheromone could not be confirmed. The results also suggest that monitoring programs can use the more easily synthesized threo‐blend without losing efficiency. Furthermore, the study suggests that other diprionid pheromones may benefit from a reinvestigation, to clarify possible synergistic effects of stereoisomers.
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| 6. |
- Anderbrant, Olle, et al.
(författare)
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Attraction of Male Pine Sawflies, Diprion jingyuanensis, to Synthetic Pheromone Candidates: Synergism between Two Stereoisomers
- 2023
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Ingår i: Forests. - : MDPI. - 1999-4907. ; 14:6
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Tidskriftsartikel (refereegranskat)abstract
- The pine sawfly Diprion jingyuanensis Xiao and Zhang (Hymenoptera: Diprionidae) is a serious pest of Pinus tabulaeformis Carr. in the Shanxi, Gansu, and Inner Mongolia provinces in P. R. China. The sex pheromone of D. jingyuanensis was shown to be the propionate ester of 3,7-dimethyl-2-tridecanol. Virgin females contained an approximate 1:3 blend of the pheromone precursors erythro-(2S,3S,7R/S and 2R,3R,7R/S)-3,7-dimethyl-2-tridecanol and threo-(2S,3R,7R/S and 2R,3S,7R/S)-3,7-dimethyl-2-tridecanol, but the exact stereoisomers were not determined. Males responded the strongest to the propionate ester of the two threo-isomers, (2S,3R,7R) and (2S,3R,7S), in electroantennogram (EAG) recordings, followed by a significant EAG response to the (2S,3R,7R) propionate of diprionol (pheromone component of D. similis), whereas the remaining two isomers (2S,3S,7S and 2S,3S,7R) of the propionate ester of 3,7-dimethyl-2-tridecanol and the acetate of the (2S,3R,7R) isomer (one of the two pheromone components of D. pini) did not elicit any significant increase in antennal response. In the field, the strongly EAG-active (2S,3R,7R)-isomer alone was only weakly (but significantly) attractive to D. jingyuanensis males at 100 & mu;g, while the equally EAG- active (2S,3R,7S)-isomer alone at the same loading was 8-14 times more attractive than was the (2S,3R,7R)-isomer alone. Traps baited with the same amounts of the two threo-isomers ((2S,3R,7R) and (2S,3R,7S), 100 & mu;g + 100 & mu;g) caught significantly more males than did traps baited with other isomers, either of the two isomers alone or other proportions of the two isomers. Thus, the (2S,3R,7S)-isomer is considered as a strong and essential sex-attractant component for D. jingyuanensis males, whereas the (2S,3R,7R)-isomer is a weak but synergistic sex-attractant. This is one of the few examples of a pine sawfly responding significantly stronger to a binary blend of stereoisomers in a synergistic fashion than to a single stereoisomer alone.
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| 7. |
- Anderbrant, Olle, et al.
(författare)
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Causes and effects of individual quality in bark beetles
- 1989
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Ingår i: Ecography. - : Wiley. - 0906-7590 .- 1600-0587. ; 12:4, s. 488-493
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Tidskriftsartikel (refereegranskat)abstract
- A summary of the present knowledge of variation in individual quality within a bark beetle population is given, with emphasis on the spruce bark beetle Ips typogrophus, A major causal factor is density, mediated by competition during larval development. Density negatively influences individual quality measured as weight, fat content and pheromone production. Together with decreasing mean values at higher densities, the skewness of the frequency distributions goes from negative to positive, while variance changes little. High densities, which often occur in the field, thus result in a large fraction of “low quality beetles”. They have lower reproductive capacity and presumably lesser dispersal ability, lower survival, and earlier response to pheromone. This might concentrate the population in the next generation with increased competition as a result. It is suggested that a decrease in beetle “quality” due to increasingly intense intraspecific competition can contribute to the decline of an epidemic population.
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| 8. |
- Anderbrant, Olle, et al.
(författare)
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Development of mating disruption for control of pine sawfly populations
- 1995
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Ingår i: Entomologia Experimentalis et Applicata. - : Wiley. - 0013-8703. ; 74:1, s. 83-90
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Tidskriftsartikel (refereegranskat)abstract
- Mating disruption of the pine sawfly Neodiprion sertifer (Geoffroy) (Hymenoptera: Diprionidae) was strongly indicated by reduced male trap catches in pine plantations permeated with the sex pheromone, (2S, 3S, 7S)‐diprionyl acetate. The trap catch reduction was 95 to near 100% when dispensers every 10 m were used, giving a total release of about 3 mg per hectare and day. Two mg of pheromone per cotton roll dispenser maintained low catches for the whole season (about 2 months) without any renewal of disruption dispensers. An erythro‐mixture was as effective as the pure pheromone isomer. The effects of the experiments on population density and sex ratio were not possible to investigate, due to a general collapse of the population, also outside experimental plots, the year after the experiments. 1995 The Netherlands Entomological Society
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| 9. |
- Anderbrant, Olle, et al.
(författare)
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Differences in morphology and sexual size dimorphism between the Dutch elm disease vectors Scolytus laevis and Scolytus scolytus (Col., Scolytidae)
- 1987
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Ingår i: Journal of Applied Entomology. - : Wiley. - 0931-2048 .- 1439-0418. ; 103:1-5, s. 378-386
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Tidskriftsartikel (refereegranskat)abstract
- The external differences between the well‐documented S. scolytus and the little studied S. laevis are clarified with the help of SEM micrographs of the frons and abdomen of both sexes of the two species. The convex frons of both male and female S. scolytus is densely covered with short hairs. S. laevis males have a flat frons with long hairs in a pair of bundles, whereas the females have a convex and nearly bald frons. Males of S. scolytus are readily distinguished from females by their long yellow tufts of hair on the anal segment. The pronotal width and elytron length are significantly larger for S. scolytus females than for males. In S. laevis males and females are of the same size but significantly smaller than S. scolytus. The difference between the species in inter‐sexual size variation and frontal hair cover suggests differences in their mating systems. Unterschiede in Morphologie und geschlechtsspezifischem Größendimorphismus zwischen Scolytus laevis und Scolytus scolytus (Col., Scolytidae), zwei Überträgern des Ulmensterben‐Erregers Äußere Unterschiede zwischen der gut untersuchten Art Scolytus scolytus und der bisher nur wenig beachteten Art S. laevis wurden mit Hilfe rasterelektronenmikroskopischer Aufnahmen von Frons und Abdomen beider Arten und Geschlechter dokumentiert. Die konvexe Stirn der S. scolytus‐Männchen und ‐Weibchen ist dicht mit kurzen Haaren bedeckt. S. laevis‐Männchen haben eine flache Stirn, mit langen, in zwei Büscheln angeordneten Haaren; die Weibchen dieser Art hingegen haben eine konvexe und beinahe kahle Stirn. S. scolytus‐Männchen unterscheiden sich durch lange, gelbe Haarbüschel auf dem Analsegment von den weiblichen Käfern, wobei zusätzlich deren Pronotum breiter und deren Flügeldecken signifikant länger sind als diejenigen der Männchen. S. laevis‐Männchen und ‐Weibchen sind gleich groß, aber signifikant kleiner als S. scolytus. Die Unterschiede zwischen den Arten hinsichtlich der geschlechtsspezifischen Größenvariation und der Stirnbehaarung lassen Unterschiede in ihrem Kopulationsverhalten vermuten. 1987 Blackwell Verlag GmbH
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| 10. |
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