Pheromone-Induced Delayed Oviposition in Helicoverpa armigera and H. assulta Moths Under Chronic High-Dose Sex...

In this study, we chronically exposed virgin male and female moths of two closely related noctuid species, Helicoverpa armigera (the cotton bollworm, CBW) and H. assulta (the oriental tobacco budworm, OTB), to conspecific sex pheromones, interspecific sex pheromones, or a control environment, and measured several reproductive and longevity parameters in females, as well as male longevity. The results show that pheromone exposure treatment shaped the temporal pattern of female oviposition (i.e., delayed oviposition), but had no significant effect on life-history span factor (the principal component onto which total oviposition duration and female longevity loaded most heavily, with loadings of 0.9846 and 0.9228, respectively). Exposure to conspecific or interspecific sex pheromone atmospheres shortened the longevity of OTB males relative to the control, whereas CBW male longevity was not affected. These findings suggest that, in addition to their well-known role in mate attraction, sex pheromones may asymmetrically shape life-history traits in the two sexes. However, because this study was conducted under confined laboratory conditions without measuring mating success or population growth, the potential implication that pheromone exposure could regulate population dynamics by affecting reproductive synchrony between the sexes remains hypothetical and awaits validation under more ecologically realistic conditions.