Quantitative method for pheromone delivery in studies of sensory adaptation of moth antennae

A pheromone sprayer and an electroantennogram (EAG) are used to study sensory adaptation in the antennae of male obliquebanded leafrollers, Choristoneura rosaceana and oriental fruit moths, Grapholita molesta, to the main pheromone compounds (Z)-11-tetradecen-1-yl acetate (Z11-14:Ac) and (Z)- 8-dodecen-1-yl acetate (Z8-12:Ac), respectively. The atomization of 0.125, 0.25, 0.5 or 1 mu L ethanol min(-1) into the EAG air delivery tube at an airflow rate of 2 L min(-1), with resultant concentrations of 6.25, 12.5, 25 or 50 x 10(-5) mu L ethanol mL air(-1), respectively, does not affect the EAG response of C. rosaceana or C. molesta after a 30-min exposure period. The atomization of 0.125 mu L min(-1) of a solution of 8 mg Z11-14:Ac mL(-1) ethanol into the EAG air delivery tube at an airflow rate of 2 L min(-1), with a resultant concentration of 0.5 ng pheromone mL(-1) air, reduces the EAG response of C. rosaceana by approximately 70% after a 15-min exposure period. An additional 15 min of exposure to pheromone does not result in increased sensory adaptation. Antennae recover 32% of the lost responsiveness when exposed to pheromone-free air for 15 min. The atomization of 0.125 mu L min - 1 of a solution of 8 mg Z8-12: Ac mL(-1) ethanol into the EAG air delivery tube at an airflow rate of 2 L min(-1), with a resultant concentration of 0.5 ng pheromone mL(-1) air, reduces the EAG response of C. molesta antenna by approximately 80% after a 15- or 30-min exposure period. The antennae of this species do not recover responsiveness when exposed to pheromone-free air for 15 min.