We used the cut-sensillum technique to assess the effect of both adult age and egg-to-adult development time on olfactory neuron responses of Z strain moths of the European corn borer, Ostrinia nubilalis. Compounds tested included the pheromone components, (Z)-11-tetradecenyl acetate and (E)-11-tetradecenyl acetate, the behavioral antagonist, (Z)-9-tetradecenyl acetate, and components of the O. furnicalis (Asian corn borer) sex pheromone, (Z)-12-tetradecenyl acetate and (E)-12-tetradecenyl acetate. The proportion of moths having neurons responding to the two O. nubilalis sex pheromone components and antagonist increased with longer development time and age. The spike frequency of neurons responding to (E)-11-tetradecenyl acetate and the antagonist increased with longer development time. Fourteen of 45 moths with neurons sensitive to either of the O. nubilalis pheromone components responded to (Z)-12-tetradecenyl acetate or (E)-12-tetradecenyl acetate. The likelihood of (Z)-12-tetradecenyl acetate stimulating a neuron similar in spike shape and waveform to that responding to (E)-11-tetradecenyl acetate increased with development time.