Seconds-Long Preexposures to Pheromone from Rubber Septum or Polyethelene Tube Dispensers Alters Subsequent Behavioral Responses of Male Grapholita molesta (Lepidoptera: Tortricidae) in a Sustained-Flight Tunnel

Male Oriental fruit moths, Grapholita molesta (Busck), were brießy preexposed in a wind tunnel to plumes from a rubber septum lure releasing a three-component, optimally attractive pheromone blend for this species or to plumes generated by Isomate-MRosso pheromone dispensers. The objectives were to determine how brief preexposures to lowand high-dosage pheromone dispensers affect initiation of anemotaxis, duration of sustained anemotactic ßight, and peripheral sensitivity 15 min and 24 h after exposure. A greater proportion of G. molesta males took ßight and successfully oriented toward a lure 15 min after brießy orienting in plumes generated by an identical lure comparedwith unexposed, naṏvemoths or control moths preexposed to clean air. In addition, the proportion of males contacting a lure or orienting to the lure without source contact 24 h after a preexposurewas not signiÞcantly different from the proportions of naṏve or controlmoths completing these behaviors. However, the mean duration of sustained ßights of lure-preexposed maleG. molesta in plumes generated by a lure was signiÞcantly shorter 15 min and 24 h after preexposure compared with that of naṏve moths. The proportion of male G. molesta contacting lures 15 min and 24 h after preexposure to ropes was not statistically different from the proportions of naṏve or control moths contacting the lure or orientingwithout source contact.However, as observedwithmoths preexposed to a lure, the mean duration of sustained ßights of maleG. molesta preexposed to an Isomate-M Rosso dispenser was signiÞcantly shorter than that of naṏve moths 15 min and 24 h after preexposure. Mean durations of sustained ßights of maleG.molesta preexposed to a lure or rope were signiÞcantly longer after 24 h comparedwith 15min after the exposure treatment, indicating that the effect of pheromone preexposure decayed over time. Electroantennograms recorded 15 min and 24 h after preexposures to lures or Isomate-MRosso dispensers in the ßight tunnelwere indistinguishable from those recorded fromunexposedmoths.Wesuggest that false-plume followingbynaṏvemaleG.molestacombinedwith decreases in duration of subsequent anemotactic orientations after previous bouts of false-plume followingmayexplainwhy Isomate-MRossodispensers are effective inmatingdisruption experiments with G. molesta.