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Title: FECUNDITY AND LONGEVITY OF DIAPETIMORPHA INTROITA (CRESSON) (HYMENOPTERA: ICHNEUMONIDAE) REARED ON ARTIFICIAL DIETS: EFFECTS OF A LIPID EXTRACT FROM HOST PUPAE AND CULTURE MEDIA CONDITIONED WITH CELL LINES

Author
item Carpenter, James
item Ferkovich, Stephen
item GREANY, PAT - UNIV. OF FLA.

Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/1/2001
Publication Date: 3/1/2001
Citation: Carpenter, J.E., Ferkovich, S.M., Greany, P.D. 2001. Fecundity and longevity of Diapetimorpha introita (Cresson) (Hymenoptera: Ichneumonidae) reared on artificial diets: Effects of a lipid extract from host pupae and culture media conditioned with cell lines. Florida Entomologist. 84(1):43-49.

Interpretive Summary: A major advance toward using augmentative or inundative releases of parasitoids in the management of the many insect pests such as the fall armyworm, Spodoptera frugiperda is precluded largely by the costs of insect rearing. Current methodologies require rearing the host insect on an artificial diet, and then rearing the parasitoid on the host. These methods are expensive because additional insect colonies must be managed, and additional laboratory space, labor, and materials are needed. Diapetimorpha introita (Hymenoptera: Ichneumonidae) is a native ectoparasitoid of S. frugiperda and S. exigua. We developed an artificial media that successfully produced D. introita wasps in the absence of any insect host components. These diet-reared wasps demonstrated a propensity to search for and attack natural host in field cage trials. However, these diet-reared wasps produced fewer eggs than wasps that developed on the host. In this study we report the identification of host lipids and cell-line derived growth factors that significant improve the ability of diet-reared wasps to produce eggs. identification of host lipids and cell-line derived growth factors that significant improve the ability of diet-reared wasps to produce eggs.

Technical Abstract: Diapetimorpha introital (cresson) (Hymenoptera:Ichneumonidae) is a native ectoparasitoid of Spodoptera spp. pupae. This parasitoid has been reared in the laboratory on an artificial diet devoid of any insect host components. However, wasps reared on this artificial diet had reduced fecundity. Efforts to increase fecundity through diet optimization included supplementation with culture media conditioned with a cell line derived from ovaries of the fall armyworm, S. frugiperida, in one experiment, and the use of a lipid extract from host pupae in a second experiment. In the first experiment, differences in mean oviposition and longevity among females reared on the artificial control diet (artificial diet), cell line-supplemented diet (SfCell), and natural host (Host) were not significant, however, females reared on SfCell diet and Host oviposited at a faster rate. In the second experiment, females reared on the diet with added host lipid (host lipid) laid significantly more eggs than females on the artificial diet, however, longevity was not significantly affected by diet treatment. Future research efforts should focus on identifying the factors produced by cell lines and identifying the lipid(s) in the host pupal extract that are responsible for enhancing egg production in D. introita females.