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Team:Valencia UPV/Project/modules/methodology/windtunnel
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Project > Modules > Methodology > Electroantennogram
Wind tunnel is a tool used for insect flight studies where the biological response of an insect to a certain stimuli, usually an odorant molecule, is tested. It consists of a rectangular cabinet of transparent walls with a laminar air flow system. The stimulant source is placed at the side where the air is entering the chamber and at the opposite extreme of the wind tunnel a male moth is placed on the ground or preferably elevated over a base.
Saturation ambient in the cabinet is difficult to achieve as the laminar flow allows the air renewal at each instant, preventing the receptor saturation inside the tunnel. Therefore in these set up the odorant molecule is not expected to act a disruptant but as an attractant.
Figure 1. Schematic representation of the headspace solid-phase microextraction adsorption/desorption. In the adsorption step the fiber is exposed in the headspace of a vial containing biological material, where volatile organic compounds (shown in red) are adsorbed by the fiber. In the desorption step, the fiber is introduced in the Gas Chromatograph injection port where the volatile compounds are released by thermal desorption.
The insect will react to the source and this behaviour is recorded. Possible actions include keeping quiet, moving from its position by flying or not, oriented flight to the source, get in contact with the stimulus and so forth. This procedure has to be repeated many times in order to obtain statistically significant data.
When the moth and a small amount of the inducing agent (0.05 ug) are placed on the opposite side, the laminar flow is switched on. Male behaviour is observed for 3-10 minutes. If the moth flies to the opposite side where the stimulus is placed means an attractive response. Behaviour recordings includes staying on the place where it was deposited, oriented flight, taking flight but dispersed or not oriented to the source [1].
(*) Part of this figure has been taken of "Helicoverpa armigera 1" by Donald Hobern from Canberra, Australia - Helicoverpa armigera. Uploaded by berichard. Licensed under Creative Commons Attribution 2.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Helicoverpa_armigera_1.jpg#mediaviewer/File:Helicoverpa_armigera_1.jpg
We have used HS-SPME coupled to Gas Chromatography-Mass Spectrometry detection to analyse the presence of pheromones ((Z)-11-hexadecen-1-ol, (Z)-11-hexadecenal, (Z)-11-hexadecenyl acetate) in our samples, Nicotiana benthamiana leaves.
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References
- Eizaguirre M, Albajes R, López C, Sans A, Gemeno (2007) Inhibition of pheromone response in Sesamia nonagrioides by the pheromone of the sympatric corn borer, Ostrinia nubilalis. Pest Manag Sci 63:608-614.
