BEHAVIORAL RESPONSES OF MALE Argyrotaenia velutinana (LEPIDOPTERA: TORTRICIDAE) TO COMPONENTS OF ITS SEX PHEROMONE

Males of the redbanded leafroller, Argyrotaenia velutinana (Walker) (Lepidoptera: Tortricidae), were studied for their behavioral responses in laboratory olfactometers and in the field to the 3 components of the female-produced sex pheromone: cis-11-tetradecenyl acetate (c11-14:Ac), trans-11-tetradecenyl acetate (t11-14:Ac), and dodecyl acetate (12 : Ac). Dodecyl acetate, when evaporated with c11-14 : Ac (8% trans) in the field, modified the behavior of feral males nearby the chemical source, causing an increase in the frequency of landing and close approach to the pheromone dispenser. Apparently, an in-flight behavioral modification concerning landing or not landing occurs within 60 cm of the source and is mediated by 12 : Ac. In laboratory olfactometers, c11-14: Ac (8% trans) demonstrated a lower threshold for male activation than pure c11- and t11-14: Ac and blends of the two isomers. Additionally, over a wide range of dosages, males responded with optimum wing-fanning response to c11-14: Ac (8% trans) compared to pure c11-14 : Ac, c11-14: Ac (30% trans), and pure t11-14: Ac, suggesting that the cis:trans ratio rather than absolute amounts of either isomer, is a crucial factor in eliciting male response. When presented with c11-14: Ac (8% trans) (1: 1), dodecyl acetate caused a significant prolongation of wing-fanning over c11-14: Ac (8% trans) alone and resulted in a greater percentage of males moving upwind to the source. Since the increase in wing-fanning and orientation occurred at higher concentrations of the 3-component mixture, the effect of 12: At in the laboratory may reflect the close-range role of 12: Ac in the field.