Delay in Mating Reduces Reproductivity but Increases Life Span in Tobacco Cutworm, Spodoptera litura Fabricius (Lepidoptera: Noctuidae)

Abstract

A pheromone-mediated mating disruption is a vital tool in the management of insect population dynamics that not only prevents mating but also delays mating in the target insect. Here, we examined the effect of delayed mating on the longevity and reproductive performance of the global pest, Spodoptera litura Fabricius (Lepidoptera: Noctuidae). Delayed mating was imposed on both sexes simultaneously, males only, and females only. The results showed that a 30-40% reduction in the successful mating rate of S. litura was caused by 7-d delay in mating. Increased mating ages of both sexes of S. litura resulted in a significant decrease in 3-d-old delayed mating, followed by an increase in mean duration of copulation. Furthermore, delayed mating had a significantly negative influence on the number of S. litura eggs produced. Mating delay imposed on both sexes simultaneously had a significantly greater effect on longevity and the number of eggs than when it was applied to either sex alone, and females were more severely affected by delayed mating than males in terms of longevity. Percentage of mating, fecundity, and female longevity were all significantly correlated with the number of days delayed mating. However, the hatching rate of eggs was not significantly affected by an increased delay in mating. Overall, our results indicated that delayed mating in both females and males drastically reduced the females' reproductive output, which itself was affected more by increasing the age at mating of females than males.

Male mating and female postmating performances in cotton mealybug (Hemiptera: Pseudococcidae): effects of female density

“…Moreover, males’ mating experience appeared to have little effect on mating duration (otherwise the value would vary more widely than that observed among the density treatments where males mated multiple times). This result differs from those reported for other insects (Liu et al 2010, Omkar and Singh 2010, Omkar et al 2013, Wang et al 2016, Wu et al 2018). Thus, we argue that P. solenopsis males might have evolved a sperm investment strategy that meets females’ reproductive requirements: once meeting a suitable female, they would transfer a ‘definite’ amount of sperms to the female, and the females, once mated, would produce a ‘definite’ amount of offspring, irrespective of their density in the population.…”

Parthenogenesis in UK field populations of the tomato leaf miner, Tuta absoluta, exposed to the mating disruptor Isonet T

“…The reduction in egg production would therefore be an antagonistic pleiotropic result of increased longevity -a strategy that would increase the likelihood of encountering a mate. Furthermore, the delay in average egg laying date observed in the EVH2019 strain would postpone energetic expenditure in reproductive output, facilitating longevity, 12 until a mating occurs, which in turn stimulates egg production.…”

Sex pheromone signal and stability covary with fitness

“…The evidence thus supports our hypothesis for fitness costs to sex pheromone stability. Since in moths older females are typically less attractive, as measured by mating success (42–48), it is possible that a female benefits from maintaining a young-female-like blend. This would be similar to cricket song and mouse urinary protein pheromones, for which signal composition reliably reflects age and in both cases the scent of senescence is associated with reduced mate attraction (68,69).…”

“…In moths, older (virgin) females tend to have reduced mating activity and reduced mating success (42–48), and virgin female moths generally keep investing in signaling (49). Thus, prolonged virginity is expected to trigger physiological responses that modulate resource allocation between somatic maintenance and reproduction.…”