Behavioral responses of maleArgyrotaenia velutinana (Lepidoptera: Tortricidae) to components of its sex pheromone

Abstract

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 inflight 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 thecis∶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∶Ac in the laboratory may reflect the close-range role of 12∶Ac in the field.