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

Abstract.  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 ( Z 11-14:Ac) and ( Z )-8-dodecen-1-yl acetate ( Z 8-12:Ac), respectively. The atomization of 0.125, 0.25, 0.5 or 1 μL 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 × 10⁻⁵μL 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 μL min⁻¹ of a solution of 8 mg Z 11-14: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 μL min⁻¹ of a solution of 8 mg Z 8-12: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.