In many species, parental age at reproduction can influence offspring performance and lifespan, but the direction of these effects and the traits affected vary among studies. Data on parental age effects are still scarce in non-captive populations, especially insects, despite species such as fruit flies being models in laboratory-based aging research. We performed a biologically relevant experimental manipulation of maternal and paternal age at reproduction of antler flies (Protopiophila litigata) in the laboratory and tracked the adult lifespan and reproductive success of their male offspring released in the wild. Increased paternal, but not maternal, age somewhat increased sons’ adult lifespan, while parental ages did not influence sons’ mating rate or reproductive senescence. Our results indicate that while parental age effects do exist in an insect in the field, they may be beneficial in such a short-lived animal, in contrast to results from most wild vertebrates and laboratory invertebrates.