Termination of aggregation by the European elm bark beetle,Scolytus multistriatus

The attractiveness of European elm bark beetle virgin females boring in elm logs declined within two days after the introduction of males. However, in the laboratory and in the field the number of beetles attracted to female-infested bolts was not depressed by the presence of separate logs infested with males or both sexes. It is concluded that the decline in attractiveness following cohabitation of the sexes results from termination of the production of attractant pheromone by mated females rather than the production of antiattractants by either sex.