Submitted to: Biocontrol
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/8/2006
Publication Date: 6/1/2006
Citation: Riddick, E.W. 2006. Egg Load and Body Size of Lab-cultured Cotesia marginiventris. BioControl.51(5):603-610. Interpretive Summary: The parasitic wasp Cotesia marginiventris is an important natural enemy of beet armyworms and other caterpillars that attack crops, but efficient mass rearing techniques are needed for releases in the field or greenhouse. A rearing system that allows young females to oviposit for up to a week rather than one day was considered more efficient after it was discovered that larger Cotesia females did not produce more eggs than smaller females. This research should be of interest to scientists in industry and academia.
Technical Abstract: The egg load of lab-cultured Cotesia marginiventris (Cresson) (Hymenoptera: Braconidae), a solitary koinobiont endoparasitoid of noctuid caterpillars, was determined in this study. Information on egg load may provide clues to more efficient in vivo rearing of C. marginiventris. I tested the hypothesis that maternal body size was related to egg load, defined as the number of mature oöcytes (i. e., fully chorionated eggs) found in adult females. Cotesia marginiventris females possessed two ovaries and two ovarioles per ovary; mature eggs were found in ovaries and oviducts. Newly-emerged females held an average of 149 mature eggs. Immature eggs were slightly visible in the distal portions of the ovarioles; they were not counted. Body size (i. e., hind tibia length) was not related to egg load. The results of this study suggest that (1) body size cannot be used to predict egg load or potential fecundity of lab-cultured C. marginiventris and (2) an efficient rearing system that exploits the potential fecundity of C. marginiventris might involve using young females and allowing them to oviposit in new hosts, each day, for up to a week.