Maternal age is generally known to be negatively correlated with the lifespan of offspring in several animal models including yeast, rotifers, flies, and possibly in humans. However, several reports have shown positive effects of parental age on offspring lifespan. Thus, there was a need to investigate further the inconsistent results on the effect of parental age on lifespan. In this study, the effects of parental age on offspring fitness and lifespan were examined by using Drosophila melanogaster. The lifespan of offspring from old parents was significantly increased compared with that of the young counterparts in the Canton‐S (CS) strain but not in other D. melanogaster strains, such as Oregon‐R (OR) and w1118. To find out why the lifespan is increased in the offspring from old parents in CS flies, fitness components that could modulate lifespan were examined in CS flies. Egg weight and body weight were reduced by parental aging and the offspring of old fathers or old mothers developed faster than that of the young. In addition, the offspring of old parents had increased resistance to oxidative and heat shock stresses. However, reproductive capacity, mating preference, and food intake were unaffected by parental aging. These results indicate that parental aging in CS strain D. melanogaster has beneficial effects on the lifespan and fitness of offspring. The presence of strain‐specific manner effects suggests that genetic background might be a significant factor in the parental age effect.

The Annals of the Joseon Dynasty report that large-scale reformations undertaken by Jungjong, 11th king of the Joseon dynasty, were stopped after Kwang-Jo Cho was slandered and subsequently executed. Reportedly, a party opposing the reformations wrote a phrase "走肖爲王" on a leaf in the palace by using sugary water; subsequently, insects ingested the sugary parts of leaf and the phrase was left behind. The phrase "走肖爲王" means "Cho will become king" and Jungjong accepted the phrase as a warning sign from heaven that Cho was attempting a coup d'état. Although there are several historical records that report such insect writing, it has not been determined whether creating a phrase on a leaf by using insects is possible. In a field study conducted on Gwanak Mountain, Korea, we tested whether writing letters on leaves by insects is possible. The results showed no sign of selective insect ingestion creating the form of a letter on a leaf after sugary water was applied. There is a high possibility that 走肖爲王 incident was fictional; particularly when considering the complexity of the phrase and the life history and behavior of insects.