Odour-mediated behaviour in codling moth, Cydia pomonella
do fermentation odours affect the attraction and oviposition behaviour in codling moth?
The codling moth, Cydia pomonella is a common pest in apple orchards and can be found worldwide. Feeding by codling moth larvae can cause a substantial decrease in apple yield. Control methods comprise for example the use of pesticides, viruses and pheromones. As a sustainable control method, pheromones have been successfully applied to disrupt moth mating behaviour. Other behaviours like foraging, search for mating sites or host finding could be potential targets for additional odour-mediated behavioural manipulation but need further investigations of the underlying odour stimuli and behavioural plasticity.
Many insects are attracted to the smell of fermenting fruit and associated microorganisms. Fermentation odours generally signal the presence of fermentable sugar and microbes as potential food resources for larval and adult insects, and hence might indicate a favourable site for adult feeding, mating or egg-laying. We hypothesized that fermentation odours might induce or influence attraction and oviposition behaviour in C. pomonella moths, and that the behaviour might be sexually dimorphic and modulated by mating state.
The result show a difference in the attraction of virgin and mated female moths. Virgin moths show an attraction towards unfermented odour whereas mated moths show a preference towards fermented odours. Female and male moths with the same mating status behave comparable, although the response is stronger in females. Furthermore, the oviposition assay indicated that yeast odour mediate significant oviposition behaviour, with an exception on fermenting apple juice.
The results indicate that virgin moths, both male and female, might search for unfermented fruit as suitable site to meet and mate, while mated moths might primarily seek for fermented site to oviposit. Knowledge on mechanisms underlying ecologically relevant behaviours and the response to fermentation odours might be significant for future development of control techniques based on behavioural manipulation.