Submitted to: Annals of the Entomological Society of America
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/19/1999
Publication Date: 5/1/2000
Interpretive Summary: Augmentative biological control programs for Colorado potato beetles require a large supply of economically produced predators. Economical artificial diets are required for mass rearing programs. However, fecundity of predators reared on artificial diets is lower than prey-fed predators. A rapid means of assessing artificial diet efficacy is needed. A method is described that allows for the rapid scoring of ovarian maturation in the two-spotted stink bug, a predator of the Colorado potato beetle. With this method insects reared on artificial diets can be compared with controls at 5 to 7 days to score the quality of the artificial diets.
Technical Abstract: A method is presented to quantitatively score the degree of ovarian maturation in a predacious pentatomid with asynchronous follicle development. The effect 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 days old reaching a peak at 4.5 days. In controls, the rate of new follicle formation decreases after the onset of vitellogenesis. By 4.5 days, all control ovarioles contained at least one vitellogenic follicle and by 9.5 days 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 days of age. Mating started when females were 3.5 days old and correlated with the start of vitellogenesis. Two peaks in mating were observed, one at 4.5 days and the other at 9.5 days. Regulatory mechanisms for oogenesis are discussed.