Flight and molecular modeling study on the response of codling moth, Cydiapomonella (Lepidoptera : Tortricidae) to (E,E)-8,10-dodecadien-1-ol and its geometrical isomers

In a previous study we have reported that both (E,Z)-8,10-dodecadienol (E,Z ) and (Z,Z) 8,10-dodecadienol (Z,Z) isomers inhibit the attraction of male codling moth, Cydia pomonella L. when added to (E,E)-8,10-dodecadienol (E,E ) while the (Z,E)-8,10-dodecadienol (Z,E) isomer induces slight increase in the number of males attracted to the pheromone source. In the present stud y, we have tested the behavioral activity of the individual geometrical iso mers E,Z; Z,E and Z,Z. A few number of codling moth males flew to the Z,E-i somer while the other two isomers (i.e. E,Z and Z,Z) did not elicit any upw ind orientation. Analysis of the Right behavior to the E,E- and Z,E-isomer showed significant differences in most of the flight parameters evaluated. Based on the biological observations and molecular modeling, we suggest tha t the behavioral activity of the Z,E-isomer is due to presence of specific receptors for this isomer on male antennae and not to its structural resemb lance to the E,E-isomer. These results underline the importance of the Z,E- isomer in sex attraction of male codling moth.