Synergism of Sex Pheromones and Host Plant Volatiles Promoting Mate Detection in an Oligophagous Moth, <i>Phauda flammans</i> (Lepidoptera: Phaudidae)

ABSTRACT Increasing evidence illustrates that insect sex pheromones and host plant volatiles synergistically guide mate localization in insects. The diurnal red moth, Phauda flammans (Walker) (Lepidoptera: Phaudidae), an oligophagous herbivore, exclusively feeds on the genus Ficus spp. (Rosales: Moraceae). We tested the hypothesis that host plant volatiles synergistically enhance male P. flammans responses to female sex pheromones. Behavioral assays in a Y‐tube olfactometer showed that odors from either conspecific females or F. concinna branches alone attracted significantly more males than the blank control. When these odor sources were combined, they attracted significantly more males than either alone, with the strongest effect observed when plant volatiles were located upstream of the females, suggesting a potential role of host plant volatiles in modulating female pheromone release. Through electroantennographic and behavioral analyses, we identified the optimal blend, i.e., a mixture of the sex pheromones cis ‐9‐hexadecenal and ( Z, Z, Z )‐9, 12, 15‐octadecatrienal, combined with the plant volatiles (−)‐ α ‐pinene, β ‐myrcene, ( Z )‐ β ‐ocimene, and β ‐caryophyllene at a ratio of 1:10:100:10:10:1, that elicited strong responses and attracted significantly more males. A field‐cage trial revealed that this synergistic blend was significantly more effective than either the sex pheromone or plant volatile alone. Our results demonstrated the synergistic role of host‐plant volatiles and sex pheromones in mate location and provided a foundation for developing attractant‐based monitoring and management strategies for P. flammans .