Rearing conditions strongly influence the life-history traits of arthropods, yet the combined effects of spatial limitation and prey availability within and across generations remain insufficiently understood, particularly in predatory mites used for biological control. This study aimed to examine how rearing cell size and prey availability affect the performance of Amblyseius herbicolusand its offspring, and to determine whether restricted environments and limited food resources negatively influence maternal performance while inducing adaptive transgenerational responses in the next generation. Freshly laid eggs of A. herbicolus were individually reared under controlled laboratory conditions using two rearing cell sizes (large and small) and two levels of prey availability (30 or 60 Carpoglyphus lactis eggs per day), forming four maternal treatments. Each maternal treatment was replicated 15–17 times, and eggs produced by surviving females were collected for further offspring experiments. Individuals were monitored daily to record developmental duration, prey consumption during development, survival to maturity, adult body size, and egg size. Eggs produced by these females were then collected and reared under standardised conditions (in small cells with abundant prey) to evaluate transgenerational effects on offspring survival, development, feeding behaviour, and size at maturity. Statistical analyses were conducted to assess the main and interactive effects of rearing cell size and prey availability on both maternal and offspring generations. Within the maternal generation, individuals confined to small rearing cells consumed significantly more prey during development than those in large cells but showed no corresponding improvement in development time, survival, or adult size, indicating increased energetic costs associated with spatial restriction. High prey availability enhanced survival, and its interaction with cell size suggested that abundant food partially mitigated the negative effects of confinement. Reproductive allocation also varied: under high prey availability, mothers in large cells produced significantly smaller eggs than those in small cells, suggesting plastic adjustment of reproductive investment. Across generations, offspring of mothers reared under restricted conditions and limited prey availability exhibited higher survival and larger body size than those from more favourable maternal environments, indicating compensatory maternal or transgenerational effects. These findings partially support the hypothesis that adverse rearing conditions reduce maternal performance but enhance offspring adaptability, providing new insight into maternal effects and highlighting the importance of spatial and nutritional factors in optimising rearing protocols for predatory mites used in biological control.