The increasing use of artificial light at night (ALAN) is an anthropogenic disturbance with ecoevolutionary consequences for both nocturnal and diurnal organisms. It has been hypothesized that light pollution could create a 'night-light' niche providing new opportunities for diurnal organisms to forage and reproduce at night, with fitness consequences still scarcely explored. We exposed diurnal parasitoid wasps (Venturia canescens) to control (0 lx), low (0.7 lx) or high (20 lx) intensity of light at night throughout their lives and monitored changes in behavioural and life history traits. Light pollution influenced the night-time activity of wasps, with increased feeding and egg laying at night and a tendency for higher night-time reproductive success under a high intensity of light pollution. Surprisingly, high light pollution also increased the wasps' life span. Light pollution did not significantly affect lifetime reproductive success but did affect the distribution of ovipositions between day and night. Additionally, we showed that reproductive senescence occurred in V. canescens and that offspring development time was influenced by light pollution, in interaction with maternal age. These findings highlight the use of the 'night-light' niche in a diurnal insect exposed to light pollution, with potential implications for population dynamics, especially in natural conditions.