PHYSIOLOGY OF INTERSPECIFIC CHEMICAL COMMUNICATION IN HELIOTHIS MOTHS

Abstract Electroantennograms were recorded from the antennae of adult male and female corn earworms, Heliothis zea (Boddie). A total of seventeen female moth sex pheromone components from several species were tested. Of these, two components elicited significantly greater responses than the other fifteen. These were (Z)‐11‐hexadecenal, a conspecific component, and (Z)‐9‐tetradecenal, a component found in the pheromone blend of a sympatric species H.virescens (F.) that inhibits attraction of H.zea males. The results from dose‐response and selective adaptation studies indicate that there are separate populations of receptors for these two chemical signals on the antenna of male H.zea. The more sensitive population is selective for (Z)‐11‐hexadecenal, while the less sensitive one responds to (Z)‐9‐tetradecenal. These findings provide a physiological basis by which H.zea males can distinguish the interspecific repellent from the conspecific pheromone blend. It is likely that this discrimination contributes to reproductive isolation between these two species. Copyright © 1990, Wiley Blackwell. All rights reserved