A method is presented to quantitatively score the degree of ovarian maturation in a predacious pentatomid with asynchronous follicle development. The effects of artificial diet and mating status on ovarian maturation rates were examined. Ovarian scores were not influenced by mating status but were significantly lower in females fed the artificial diet. Ovarian follicles start forming when females are 2.3 d old, reaching a peak at 4.5 d. In controls, the rate of new follicle formation decreases after the onset of vitellogenesis. By 4.5 d, all control ovarioles contained at least 1 vitellogenic follicle, and by 9.5 d all ovarioles had chorionated follicles. In contrast, females fed the artificial diet had 40% of the ovarioles with a vitellogenic and chorionated follicle at 10.5 d of age. Mating started when females were 3.5 d old and correlated with the start of vitellogenesis. Two peaks in mating were observed, one at 4.5 d and the other at 9.5 d. Regulatory mechanisms for oogenesis are discussed.