Rhythmicity of sex pheromone content in female Heliothis virescens: impact of mating

Pheromone production in virgin females of Heliothis virescens (F.) (Lepidoptera: Noctuidae) peaked between the fourth and seventh hours of scotophase on the second, third, fourth and fifth days following eclosion. The highest peak (186 ng) occurred on day 3 after eclosion. Z‐11‐Hexadecenal comprised the highest proportion of seven components in the pheromone glands. Disproportionately higher amounts of hexadecanal and Z‐11‐hexadecenol occurred during photo‐phase and other periods when low quantities of total pheromone were recorded. Mating suppressed pheromone production which remained low until 48 h after mating. Coupling females with males mated three times previously or with 6‐day‐old males was less effective in causing a drop in pheromone content which peaked again 24 h after mating. This suggests the transfer of a male factor, a pheromonostatic factor, that suppresses pheromone production in mated females and that the factor from older and previously mated males is less effective.