| 1. |
- Månsson, P. E., et al.
(författare)
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Nonanoic acid, other alkanoic acids and related compounds as antifeedants in Hylobius abietis pine weevils
- 2006
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Ingår i: Entomologia Experimentalis et Applicata. - : Wiley. - 0013-8703 .- 1570-7458. ; 121:3, s. 191-201
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Tidskriftsartikel (refereegranskat)abstract
- A medium-length, straight-chain alkanoic acid, nonanoic acid, is known from laboratory microassays to be an antifeedant in adults of the large pine weevil, Hylobius abietis (L.) (Coleoptera: Curculionidae). Our hypothesis was that we could find new, less volatile alkanoic acids or related compounds suitable for field application and with improved long-term duration. Alkanoic acids of varying chain lengths (C6-C13) were tested for antifeedant activity in H. abietis adults. Microassay choice tests showed that straight-chain (C6-C11) alkanoic acids were active. However, high activities were restricted to the (C6-C10) acids, with the C9 (nonanoic acid) at 4 μmol cm-2 being the most active one. In a no-choice test on pine twigs, the antifeedant effect of C10 acid was lower than that of the C8 and C9 acids. In microassays, less volatile methyl-branched alkanoic acids exhibited lower antifeedant activities than did the corresponding straight-chain ones. However, the most active of the methyl-branched acids, 2-methyldecanoic acid, had an activity similar to that of nonanoic acid. Compounds related to nonanoic acid were either active (1-nonanol), weakly active (nonanoic anhydride), or inactive (nonanal, sodium nonanoate). The anhydride was highly active in the microassay, but less active on twigs. The antifeedant effects of the straight chain (C8-C10) alkanoic acids against pine weevil feeding were tested in the field. In contrast to the results from the twig tests, the less volatile C10 acid was more active in the field for the protection of transplants on fresh clear cuts over a 3-month period than both the C8 and C9 acids. Phytotoxic effects of the alkanoic acids were observed both in the field and in laboratory studies. If a protective layer of paraffin was applied to the stem prior to application of the alkanoic acids, these undesired side effects were reduced.
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| 2. |
- Månsson, Per E., et al.
(författare)
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Nonanoic acid, other long-chain carboxylic acids and related compounds as antifeedants in Hylobius abietis pine weevils
- 2006
-
Ingår i: Entomologia Experimentalis et Applicata. - : Wiley. - 0013-8703 .- 1570-7458. ; 121:3, s. 191-201
-
Tidskriftsartikel (refereegranskat)abstract
- A medium-length, straight-chain alkanoic acid, nonanoic acid, is known from laboratory microassays to be an antifeedant in adults of the large pine weevil, Hylobius abietis (L.) (Coleoptera: Curculionidae). Our hypothesis was that we could find new, less volatile alkanoic acids or related compounds suitable for field application and with improved long-term duration. Alkanoic acids of varying chain lengths (C6-C13) were tested for antifeedant activity in H. abietis adults. Microassay choice tests showed that straight-chain (C6-C11) alkanoic acids were active. However, high activities were restricted to the (C6-C10) acids, with the C9 (nonanoic acid) at 4 mu mol cm(-2) being the most active one. In a no-choice test on pine twigs, the antifeedant effect of C10 acid was lower than that of the C8 and C9 acids. In microassays, less volatile methyl-branched alkanoic acids exhibited lower antifeedant activities than did the corresponding straight-chain ones. However, the most active of the methyl-branched acids, 2-methyldecanoic acid, had an activity similar to that of nonanoic acid. Compounds related to nonanoic acid were either active (1-nonanol), weakly active (nonanoic anhydride), or inactive (nonanal, sodium nonanoate). The anhydride was highly active in the microassay, but less active on twigs. The antifeedant effects of the straight chain (C8-C10) alkanoic acids against pine weevil feeding were tested in the field. In contrast to the results from the twig tests, the less volatile C10 acid was more active in the field for the protection of transplants on fresh clear cuts over a 3-month period than both the C8 and C9 acids. Phytotoxic effects of the alkanoic acids were observed both in the field and in laboratory studies. If a protective layer of paraffin was applied to the stem prior to application of the alkanoic acids, these undesired side effects were reduced.
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| 3. |
- Ban, Liping, et al.
(författare)
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Infection with an insect virus affects olfactory behaviour and interactions with host plant and natural enemies in an aphid
- 2008
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Ingår i: Entomologia Experimentalis et Applicata. - : Wiley. - 0013-8703 .- 1570-7458. ; 127:2, s. 108-117
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Tidskriftsartikel (refereegranskat)abstract
- Aphid ecology and population dynamics are affected by a series of factors including behavioural responses to ecologically relevant chemical cues, capacity for population growth, and interactions with host plants and natural enemies. Using the aphid Rhopalosiphum padi (L.) (Homoptera: Aphididae), we showed that these factors were affected by infection with Rhopalosiphum padi virus (RhPV). Uninfected aphids were attracted to odour of uninfected aphids on the host plant, an aggregation mechanism. However, infected aphids were not attracted, and neither infected nor uninfected aphids were attracted to infected aphids on the plant. Infected aphids did not respond to methyl salicylate, a cue denoting host suitability. Infected aphids were more behaviourally sensitive to aphid alarm pheromone, and left the host plant more readily in response to it. RhPV reduced the lifespan and population growth rate of the aphid. The predacious ladybird, Coccinella septempunctata (L.) (Coleoptera: Coccinellidae), consumed more infected aphids than uninfected aphids in a 24-h period, and the aphid parasitoid Aphidius ervi Haliday (Hymenoptera: Aphidiidae) attacked more infected than uninfected aphids. However, the proportion of mummies formed was lower with infected aphids. The results represent further evidence that associated organisms can affect the behaviour and ecology of their aphid hosts.
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| 4. |
- Björkman, Maria, et al.
(författare)
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Neighboring monocultures enhance the effect of intercropping in turnip root flies (Delia floralis).
- 2007
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Ingår i: Entomologia Experimentalis et Applicata. - : Wiley. - 0013-8703 .- 1570-7458. ; 124, s. 319-326
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Tidskriftsartikel (refereegranskat)abstract
- Knowledge of insect behaviour is essential for accurately interpreting studies of diversification and to develop diversified agroecosystems that have a reliable pest-suppressive effect. In this study, we investigated the egg-laying behaviour of the turnip root fly, Delia floralis (Fall.) (Diptera: Anthomyiidae), in an intercrop-monoculture system. We examined both the main effect of intercropping and the effect on oviposition in the border zone between a cabbage monoculture [Brassica oleracea L. var. capitata (Brassicaceae)] and a cabbage-red clover intercropping system [Trifolium pratense L. (Fabaceae)]. To investigate the border-effect, oviposition was measured along a transect from the border between the treatments to the centre of experimental plots. Intercropping reduced the total egg-laying of D. floralis with 42% in 2003 and 55% in 2004. In 2004, it was also found that the spatial distribution of eggs within the experimental plots was affected by distance from the adjoining treatment. The difference in egg-laying between monoculture and intercropping was most pronounced close to the border, where egg-laying was 68% lower on intercropped plants. This difference in egg numbers decreased gradually up to a distance of 3.5 m from the border, where intercropped plants had 43% fewer eggs than the corresponding monocultured plants. The reason behind this oviposition pattern is most likely that flies in intercropped plots have a higher probability of entering the monoculture if they are close to the border than if they are in the centre of a plot. When entering the monoculture, flies can pursue their egg-laying behaviour without being disrupted by the clover. As the final decision to land is visually stimulated, flies could also be attracted to fly from the intercropped plots into the monoculture, where host plants are more visually apparent. Visual cues could also hinder flies in a monoculture from entering an intercropped plot. Other possible patterns of insect attack due to differences in insect behaviour are discussed, as well as the practical application of the results of this study.
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| 5. |
- El-Sayed, A M, et al.
(författare)
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Sex pheromone of a North American population of the spotted tentiform leafminer, Phyllonorycter blancardella
- 2005
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Ingår i: Entomologia Experimentalis et Applicata. - : Wiley. - 0013-8703 .- 1570-7458. ; 116:2, s. 143-148
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Tidskriftsartikel (refereegranskat)abstract
- The major sex pheromone compound of the spotted tentiform leafminer, Phyllonorycter blancardella (F.) (Lepidoptera: Gracillariidae), from Ontario, Canada, was identified as (10E)-dodecen-1-yl acetate (E10-12:Ac) using chemical analysis and field trapping experiments. The minor compounds (10E)-dodecen-1-ol (E10-12:OH) (4.6%), dodecan-1-ol (12:OH) (2.3%), and (10Z)-dodecen-1-yl acetate (Z10-12:Ac) 1.6% were also identified. The dienic acetate (4E,10E)-dodecadien-1-yl acetate (E4,E10-12:Ac), a compound reported to be attractive to P. blancardella, was not found in the glands of this population. A two-component blend of the major and one of each the three minor compounds, in ratios similar to those found in the sex pheromone gland, did not increase the attractiveness of traps baited with synthetic pheromone. The minor compounds E10-12:OH and 12:OH were not attractive to P. blancardella when tested individually. Z10-12:Ac was attractive to P. blancardella, although traps baited with this compound captured only 2% of the moths that were captured in traps baited with the main compound. A four-component blend of the major and each of the three minor compounds (100 : 1 : 1 : 1) was not more attractive than the major compound alone. The related species Phyllonorycter mespilella was captured in traps baited with E10-12:Ac.
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| 6. |
- Niemi, Lena, et al.
(författare)
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Insect feeding preferences and plant phenolic glucosides in the system Gonioctena linnaeana-Salix triandra
- 2005
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Ingår i: Entomologia Experimentalis et Applicata. - Amsterdam : North-Holland Pub. Co.. - 0013-8703 .- 1570-7458. ; 115:1, s. 61-66
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to investigate the preference of a leaf beetle to different Salix clones, and to relate this preference to plant chemistry. The preference of Gonioctena linnaeana Schrank (Coleoptera: Chrysomelidae) was tested in cafeteria experiments using its host Salix triandra L. (Salicaeae) from three Swedish isolated populations and one Russian population from the main distribution range of the host. The leaves from the different host clones were used to analyse the content of phenolic glucosides and the amount of condensed tannins. The larvae did not show any feeding preferences for host clones from the population they originated from, but all Swedish host populations were preferred over the Russian host population. This suggests a preference for regional hosts. We analyzed whether leaf chemistry parameters may explain host plant preferences. Chemical analysis of the leaves showed that the quantities, but not the quality, of the phenolic compounds differed between populations. A Principal Component Analysis of the chemical data also highlighted a difference between the Swedish and Russian host plant populations. The two most important compounds separating Russian from Swedish clones were gallocatechin and salidroside. However, the difference in preference could also be a result of, for example, nutritional quality, water content, or leaf texture. The relative importance of these different factors should be evaluated in future experiments.
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| 7. |
- Ninkovic, Velemir, et al.
(författare)
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Weed-barley interactions affect plant acceptance by aphids in laboratory and field experiments
- 2009
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Ingår i: Entomologia Experimentalis et Applicata. - : Wiley. - 0013-8703 .- 1570-7458. ; 133, s. 38-45
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Tidskriftsartikel (refereegranskat)abstract
- Increased botanical diversity can lead to suppression of insect pests. One route by which botanical diversity is increased in crops is through the occurrence of weeds, which increasingly interact with crop plants as organic production expands. However, the mechanisms by which this might affect insect herbivores are poorly understood. This study examined whether volatile chemical interactions between weeds and barley, Hordeum vulgare L. (Poaceae), can affect plant acceptance by the bird cherry oat aphid, Rhopalosiphum padi L. (Hemiptera: Aphididae). In laboratory experiments, exposure of barley to volatiles from Chenopodium album L. (Amaranthaceae) and Solanum nigrum L. (Solanaceae) resulted in significantly reduced aphid acceptance compared with unexposed plants. In a series of field experiments in which the occurrence of weeds was manipulated in plots of barley, significantly lower aphid acceptance was recorded on barley plants grown in plots with C. album compared with barley plants in weedless plots. The results indicate that interaction between weeds and barley can affect aphid-plant interactions in the field as well as in the laboratory and provide further evidence that the effects of chemical interactions between visibly undamaged plants can extend to higher trophic levels.
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| 8. |
- Olsson, Christian, et al.
(författare)
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Attraction and oviposition of Ephestia kuehniella induced by volatiles identified from chocolate products
- 2006
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Ingår i: Entomologia Experimentalis et Applicata. - : Wiley. - 1570-7458 .- 0013-8703. ; 119:2, s. 137-144
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Tidskriftsartikel (refereegranskat)abstract
- Host-plant volatiles or other volatiles that attract moths, especially females, could be useful as trap baits or as a complement to pheromones in pest management. Three chocolate products, which had previously been found to be attractive to other pyralid moths, were screened by combined gas chromatography-electrophysiology for compounds that could be used for trapping of Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) moths. Nine compounds were identified as electrophysiologically active using the antennae of both sexes of E. kuehniella. Three of them, namely, benzyl alcohol, nonanal, and phenylacetaldehyde (PAA), showed a clear dose-dependent electroantennogram (EAG) response on both female and male antennae. In addition, vanillin and ethyl vanillin were electrophysiologically active on male antennae. A blend of benzyl alcohol, nonanal, and PAA was found to trap males in a small-scale tent experiment. Females were not trapped, but oviposition was induced by each of the three volatiles individually. The results indicate that the volatiles show potential to be used in monitoring of E. kuehniella.
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| 9. |
- Rode, Nicolas O., et al.
(författare)
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An examination of genetic variation and selection on condition in Drosophila melanogaster males
- 2009
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Ingår i: Entomologia Experimentalis et Applicata. - : Wiley. - 0013-8703 .- 1570-7458. ; 131:2, s. 167-177
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Tidskriftsartikel (refereegranskat)abstract
- According to the genic capture hypothesis, the maintenance of additive genetic variation in fitness-related traits is due to both condition-dependence of these traits and high genetic variation for condition. Evidence supporting this latter assumption is scarce. In this study, we investigated, using hemiclonal analysis, standing genetic variation for condition and relative adult fitness in male Drosophila melanogaster (Meigen) (Diptera: Drosophilidae). The absolute fat and the relative fat content were used as indices of body condition and were measured along with adult relative fitness from males reared in high or low larval densities. The results did not demonstrate genetic variation for condition or adult relative fitness. However, the larval density encountered during development had a strong and significant effect on all traits. Surprisingly, although not significant, negative selection gradients acting on absolute fat and relative fat content were also found in both treatments. These findings challenge one of the main assumptions of the genic capture hypothesis and the use of fat content as an ideal index of condition.
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| 10. |
- Sieminska, Edyta, et al.
(författare)
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Long-term pheromone-mediated mating disruption of the Mediterranean flour moth, Ephestia kuehniella, in a flourmill
- 2009
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Ingår i: Entomologia Experimentalis et Applicata. - : Wiley. - 1570-7458 .- 0013-8703. ; 131:3, s. 294-299
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Tidskriftsartikel (refereegranskat)abstract
- Several studies have indicated that mating disruption (MD) successfully reduces population densities of stored product moths, for example, the Mediterranean flour moth, Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae). However, practical issues, such as finding control plots, replication, and lack of similarity between replicates, often incur problems in full-scale investigations and often draw focus from the added results. We here present results from long-term monitoring of E. kuehniella populations in two similar flourmills in Poland, one treated with pheromone for MD and one left untreated and used as control. Pheromone-mediated MD was applied during 2 years. Thirty pheromone dispensers (one per 100 m(3) factory volume), each releasing about 2 mg (Z,E)-9,12-tetradecadienyl acetate per day, were used. Pheromone-baited traps were used to monitor the moth populations in the MD mill and in a nearby untreated mill. The reduction in trap catch during the MD treatment was about 90% or more, compared with the untreated mill or pre-treatment periods of the MD mill. The reduction was larger during the 2nd year of MD than during the 1st year. These results contribute to the picture that MD is an effective method to control moth species infesting stored products.
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