Female sperm storage is common across a wide taxonomic range. The temporal separation of mating and fertilization has several benefits for females. It enables sperm selection from multiple males, but can also allow females to temporally and spatially delay fertilization until the proper environmental conditions are found. In this study, we investigated the extent and possible function of sperm storage in the polygamous cactus-feeding bug, Narnia femorata Stål (Hemiptera: Coreidae). To determine the viability of stored sperm over time, we tracked lifelong fecundity of females exposed to varying levels of male access. We exposed females to four treatments: one male for 1 wk, one male for 1 wk with further exposure to the same male later in her life for an additional week, one male for the duration of her life, or two males (subsequent) for the duration of her life. Our results indicate that females can store sperm and produce viable offspring during their lifespan from a relatively brief mating encounter with a single male. Furthermore, egg production and fertility rates did not differ across treatments, suggesting that time of exposure to mates and number of mates (monandry vs. polyandry) has no effect on N. femorata fecundity. Sperm storage seems to operate independently of mate number or availability, and is therefore, likely an adaptation to the patchy spatial-temporal distribution of adequate resources.