Dim Light During Scotophase Enhances Sexual Behavior of the Oriental Tobacco BudwormHelicoverpa assulta(Lepidoptera: Noctuidae)

Sex pheromone titre in the glands of Spodoptera litura females: circadian rhythm and the effects of age and mating

“…Circadian rhythm, age and mating are three important factors that affect the sexual communication of insects (Babilis & Mazomenos, ; Li et al ., ; Wang et al ., ). Similar to many other nocturnal moth species (Raina et al ., ; Babilis & Mazomenos, ; Li et al ., ; Wang et al ., ), S. litura exhibits circadian variations of sex pheromone contents in the glands: higher titres are observed during scotophase and lower titres are observed during photophase (Fig. ).…”

“…In some moths, such as H. zea , the maximal pheromone contents in the glands coincide with the maximal calling activities (Raina et al ., ), whereas, in other species, such as Platynota stultana , the pheromone contents in the glands peak before maximum female calling (Webster & Cardé, ). In nocturnal moths, females typically have a higher pheromone titre in the PGs during scotophase than during photophase, possibly because the reproductive activities of these moths typically occur at night; thus, the maintenance of a high titre of sex pheromones during the daytime would be a waste of resources and energy (Raina et al ., ; Babilis & Mazomenos, ; Li et al ., ).…”

“…This coordination of sexual activities between males and females ensures a high probability of mate location and reproductive isolation (Groot et al ., ). Endogenous circadian rhythms that control pheromone production and release are observed in many species, including Helicoverpa assulta (Li et al ., ), Agrotis ypsilon (Xiang et al ., ) and Maruca vitrata (Wang et al ., ). The timing and duration of these circadian rhythms may depend on moth age (Wang et al ., ) and mating status (Yang et al ., ), as well as exogenous (photoperiod and temperature) (Li et al ., ) and endogenous (hormonal) (Bloch et al ., ) factors.…”

“…Endogenous circadian rhythms that control pheromone production and release are observed in many species, including Helicoverpa assulta (Li et al ., ), Agrotis ypsilon (Xiang et al ., ) and Maruca vitrata (Wang et al ., ). The timing and duration of these circadian rhythms may depend on moth age (Wang et al ., ) and mating status (Yang et al ., ), as well as exogenous (photoperiod and temperature) (Li et al ., ) and endogenous (hormonal) (Bloch et al ., ) factors. In most moth species, females begin calling and release sex pheromones within a short time (1–4 days) after emergence; similarly, the sex pheromone titre in female PGs usually peaks during this period and gradually or sharply declines afterward (Dunkelblum et al ., ; Babilis & Mazomenos, ; Kamimura & Tatsuki, ; Xiang et al ., ; Wang et al ., ).…”

Daily expression of two circadian clock genes in compound eyes of Helicoverpa armigera: evidence for peripheral tissue circadian timing

“…The daily rhythm of sexual activity in moths, including calling activity and pheromone production and release, is usually dependent upon endogenous (neural, hormonal) and exogenous factors (photoperiod, temperature) (Hollander & Yin, ; Raina & Klun, ; Delisle & McNeil, ; Raina, ). The copulations of nocturnal moths show circadian rhythms and usually occur at dawn and dusk (Schal & Cardé, ; Kamimura & Tatsuki, ; Burks et al ., ; Kawazu et al ., ; Yan et al ., ; Li et al ., ), and the circadian clock genes in compound eyes may participate in synchronizing the rhythm of mating behavior to light‐dark cycles. Meanwhile, we initially confirmed that Ha‐per tended to be down‐regulated following starvation.…”