| 1. |
- Valeur, Peter G., et al.
(författare)
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Real-time measurement of pheromone release from individual female moths and synthetic dispensers in a wind tunnel by recording of single receptor-neurone responses
- 1999
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Ingår i: Physiological Entomology. - : Wiley. - 0307-6962 .- 1365-3032. ; 24:3, s. 240-250
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Tidskriftsartikel (refereegranskat)abstract
- Measurements of single neurone activity in the peripheral pheromone receptors of male Agrotis segetum (Denis and Schiffermuller) (Lepidoptera: Noctuidae) were performed in a wind tunnel using a portable electrophysiological recording unit. Filter paper and rubber septa loaded with synthetic sex pheromone, as well as individual conspecific female glands, were used as pheromone sources. Recordings, up to 3 h long, were analyzed for temporal variation in spiking activity. The recordings were performed 2 m downwind of the source, where the pheromone plume had a width of approximately 12 cm, as could be measured with the single cell preparations. The system allowed reliable measurements of relative pheromone concentration with a 20-s time resolution. The release rate from rubber septa loaded with pheromone was more or less constant over time, whereas the release rate from filter paper loaded with pheromone decreased to one tenth of the initial value within 6 min from the application of the pheromone. The release of pheromone from female pheromone glands was pulsed with an interval of 2-10 min between bursts. This pulsing was not caused by retraction of the gland, as the glands were forcibly extruded during the entire experiment, but should reflect variation in transport of pheromone to the gland surface and subsequent release. The demonstrated stability of the preparations using tungsten electrodes, the reliable monitoring of female-produced pheromone plumes at several metres distance, and the time resolution obtained are important steps towards field monitoring of natural pheromone plumes, as well as pheromone concentration and distribution in applications for mating disruption.
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| 2. |
- Valeur, Peter
(författare)
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Male moth behaviour and perception in pheromone plumes
- 1998
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Behaviour of male moths and electrophysiological responses of male pheromone-specific olfactory receptor neurones were studied in two model species, the oriental fruit moth Grapholita molesta and the turnip moth Agrotis segetum. The studies were aimed at elucidating the relative importance of different mating disruption mechanisms. In a wind tunnel study of G. molesta, behavioural response to a reference pheromone source was tentatively suppressed by pheromone released from a second treatment source. Manipulations of the treatment composition and concentration, revealed that the adaptation/habituation of the olfactory system had the biggest effect, followed by the false trail following mechanism, and that the complete blend was better than any reduced blend. In a study where A. segetum males were preexposed to a series of blends and concentrations of pheromone, the behavioural performance was significantly more affected than electroantennographic responses. Central nervous habituation is thus the most likely explanation to most of the observed behavioural effects. A comparison with field data in the literature showed that long-term adaptation/habituation is an unlikely explanation to the mating disruption effect observed in practical field applications. In a wind tunnel, a portable single-neurone recording unit was used to analyse pheromone plumes from female glands and different dispensers. Behavioural in-flight arrestment started occurring at concentrations that elicited maximum spiking activity in peripheral receptor neurones. Individual female pheromone release rates were measured in real time, and compared to the release rate from synthetic dispensers. A hitherto unknown degree of short-time variation in female pheromone release rate was revealed. With the help of a novel radar technique, up to 300 m long flight tracks of individual A. segetum males were recorded. Males tended to fly straight crosswind outside of pheromone plumes and up or downwind when in an area with pheromone.
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| 3. |
- Zhu, J. W., et al.
(författare)
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Reidentification of the female sex pheromone of the Indian meal moth, Plodia interpunctella : evidence for a four-component pheromone blend
- 1999
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Ingår i: Entomologia Experimentalis et Applicata. - : Wiley. - 0013-8703 .- 1570-7458. ; 92:2, s. 137-146
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Tidskriftsartikel (refereegranskat)abstract
- Pheromone gland extracts from calling female Plodia interpunctella contained at least seven compounds that consistently elicited electroantennographic responses from male antennae upon gas chromatographic analysis. Three of these compounds were found to be the previously identified gland constituents, i.e., (Z,E)-9,12-tetradecadienyl acetate (Z9,E12-14:OAc), (Z,E)-9,12-tetradecadienal (Z9,E12-14:Ald) and (Z,E)-9,12-tetradecadienol (Z9,E12-14:OH). A fourth EAD-active compound was identified as (Z)-9-tetradecenyl acetate (Z9-14:OAc). The homologue (Z)-11-hexadecenyl acetate (Z11-16:OAc) was also identified in the extracts, but showed no EAD activity. The identity of all five compounds was confirmed by comparison of GC retention times and mass spectra with those of synthetic standards. In flight tunnel tests there were no significant differences in response of male P. interpunctella to the bait containing all four EAD-active compounds and the responses to female gland extacts. A behavioural assay of different two-compound blends in the flight tunnel showed that only addition of the corresponding aldehyde to the major pheromone component Z9,E12-14:OAc raised the male response. A subtractive assay, however, revealed that the exclusion of any of the compounds from the complete four-compound blend reduced its activity significantly. We thus conclude that the female-produced sex pheromone of P. interpunctella consists of at least four components, i.e., Z9,E12-14:OAc, Z9,E12-14:Ald, Z9,E12-14:OH and Z9-14:OAc. In a field trapping test performed in a storage facility, the four-component blend attracted significantly more males of P. interpunctella than traps baited with Z9,E12-14:OAc alone. In contrast, the highest number of Ephestia kuehniella males was found in the traps baited with this major component, suggesting that the secondary pheromone components contribute to the species specificity of the blend.
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