Rhythmic dialogue: The precise synchronization between reproductive behavior and sex pheromone release in Diaphania...

Diaphania angustalis Snellen is a significant pest of Alstonia scholaris, but larval leaf-rolling behavior hampers chemical control. Sex pheromones are crucial for pest management. However, research on the production and release rhythms of sex pheromones in D. angustalis remains limited. To address this gap, this study examined the emergence, courtship, mating, and oviposition of this species and analyzed its sex pheromone identification and release patterns.

Adult emergence and reproduction exhibited significant circadian rhythms. Peak emergence occurred at the start of the dark phase (females: 68.55%; males: 60.47%). Virgin females reached their highest mating rate at 4-day-old and maintained it until 6-day-old. Mated females laid eggs only during the dark phase, averaging 592.5 ± 25.3 eggs per female. The sex pheromone was identified as E10E12-16CHO, showing geographical variation from previous reports. Crucially, precise temporal coordination between reproductive behavior and pheromone release was revealed: virgin females exhibited peak pheromone levels (6.29 ± 1.06 ng/individual) at 3 days post-eclosion, during the fourth hour of the scotophase, synchronizing precisely with peak mating activity. Host plants significantly influence sex pheromone release by female insects. When hosts are present, females release large amounts of pheromones on days 4-6 after eclosion. Without hosts, they maintained high pheromone levels on days 6-8 after eclosion, suggesting that host volatiles accelerate pheromone release.

This study offers essential theoretical support for utilizing sex pheromones in trapping and controlling D. angustalis, thereby guiding the development of improved pest management strategies for leaf-rolling pests. © 2026 Society of Chemical Industry.