Redundancy in a chemical signal: Behavioral responses of maleTrichoplusia ni to a 6-Component sex pheromone blend.

The flight response of maleTrichoplusia ni was observed in a flight tunnel to a sex pheromone blend composed of six components:Z7-12∶Ac, 12∶Ac,Z5-12∶Ac, 11-12∶Ac,Z7-14∶Ac, and Z9-14∶Ac. The number of males reaching a 3000-μg source of this blend was > 95%, equal to that observed to female glands and significantly greater than with the previously identified two-component blend (Z7-12∶Ac + 12∶Ac). In subtraction tests, all five-component blends, with the exception of the blend lacking the primary componentZ7-12∶Ac, and several four-component blends elicited similar peak levels of upwind flight, source contacts, and hairpencil displays to that observed with the six-component blend. We characterize the substitution of certain minor components for one another as a form of redundancy in the chemical signal and suggest that it contributes to response specificity and signal recognition in males. The results also support the concept that the full blend of components acts as a unit to influence male behavior at all phases of the response. Individual minor components were not responsible for eliciting specific behaviors in the sequence.