Flight tunnel response of codling moth Cydia pomonella to blends of codlemone, codlemone antagonists and pear ester

Upwind orientation flights of codling moth males Cydia pomonella L. to a single source of sex pheromone (E,E)-8,10-dodecadienol (codlemone) are significantly reduced when blending it with pheromone antagonists, either with codlemone acetate, (E,E)-8,10-dodecadienyl acetate, or with the codlemone isomer (E,Z)-8,10-dodecadienol. However, once activated by a pheromone stimulus, males no longer distinguish between a pheromone source and these antagonistic blend sources. This shows that the pheromone stimulus required for the initiation of an upwind flight response differs from the stimulus for maintaining upwind flight and landing at the source. In contrast to pheromone antagonists, males discriminate between pheromone alone and a blend source of pheromone and the plant volatile pear ester, ethyl (2E,4Z)-2,4-decadienoate. This indicates a difference in the detection and neural integration of pheromone and plant volatile stimuli.