Organisms cannot maximize all life functions and therefore must allocate resources to maximize reproductive fitness such that they produce the highest number of surviving offspring. The object of the experiment was to evaluate variation of fruit morphology to determine how Opuntia littoralis optimizes reproductive investment. The experiment focused on fruit volume, sugar concentration, number of seeds and average seed mass on two different aspects (polar-facing and equatorial-facing slopes) in Temescal Canyon Gateway Park, Pacific Palisades, California. The results revealed fruit volume was positively correlated with number of seeds, sugar concentration was positively correlated with number of seeds, and average seed mass was negatively correlated with number of seeds. The study suggests that variation in Opuntia fruit morphology can be explained by the principle of allocation and life history strategies rather than by microhabitat variation alone.