Behavioural assays were used to investigate how flies' <I>(Drosophila melanogaster</I>) responses to a chemical were influenced by pre-exposure to the same chemical. A modified trap assay, a T-maze olfactometer and several assays of mating behaviour were used to investigate the response of <I>D. melanogaster</I> to various chemicals. Menthol was used most extensively for pre-exposure and behavioural testing. The trap assay was used to produce dose-response curves to menthol for flies that had been pre-exposed, and flies that had never been exposed to menthol before testing. There was a threshold pre-exposure dose that produced a behavioural change. Pre-exposure to mentholic food resulted in reduced aversion to some concentrations of menthol. In the T-maze, flies normally were averse to menthol, but flies pre-exposed to mentholic food were less averse and sometimes responded positively to the odour of menthol. Exposure to mentholic food in only the larval stage did not change adult behaviour in the T-maze or trap assays. There was no evidence for pre-imaginal conditioning. Evidence from the trap assay suggested that menthol contamination on the puparium was sufficient to change adult behaviour. Exposing adult flies to menthol did result in behavioural changes. Even brief exposure to menthol for just an hour before testing was enough to change behaviour. Fly age influenced behaviour in both the T-maze and trap assay. This factor may help to explain discrepancies in earlier investigations of olfactory conditioning and pre-imaginal learning in <I>D. melanogaster</I>. Menthol exposure appeared to change the dose-response curves to chemicals other than menthol in the T-maze. I discuss what mechanisms might underlie this behavioural change and suggest work to investigate this issue further.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:596424 |
| Date | January 1999 |
| Creators | Barron, A. B. |
| Publisher | University of Cambridge |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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