Author
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Ferkovich, Stephen |
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Shapiro, Jeffrey |
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Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 3/30/2006 Publication Date: 6/1/2007 Citation: Ferkovich, S.M., Shapiro, J.P. 2007. Improved fecundity in the predator Orius insidiosis (Hemiptera: Anthocoridae) with a partially purified nutritional factor from an insect cell line. Florida Entomologist. 90:321-326. Interpretive Summary: The insidious flower bug, Orius insidiosus, is a carnivore that eats thrips, aphids, mites, whiteflies and insect eggs and small larvae and is produced on natural prey by over 33 commercial producers of insects. Artificial diets are needed by the industry to reduce the cost of insect rearing. Predators reared on artificial diets, however, generally have reduced egg production. Scientists at the Center for Medical, Agricultural, and Veterinary Entomology, ARS, Gainesville, FL are using cultured insect cells to improve artificial diets. They have discovered that cells derived from eggs of one species of insect that predators eat produce a chemical substance that stimulates egg laying. This substance can be used to supplement artificial diets for the predator. When the substance is completely isolated and identified, its use will directly impact the industry, allowing insectaries to produce and sell more insect predators at lower cost, thus helping to reduce the use of pesticides. Technical Abstract: A specific factor that stimulates egg production in the predator, Orius insidiosis (Say) was earlier shown to be present in eggs of the Indian meal moth, Plodia interpunctella (Hübner). We investigated whether the embryonic cell line, IPLB-PiE derived from eggs of the Indian meal moth, P. interpunctella also produces a specific factor which improves fecundity of the predator. We therefore fractionated cells by preparative isoelectric focusing in a pH gradient of 3-10 and bioassayed the resultant fractions in test diets to determine their effects on egg production. Rates of oviposition were determined by placing adult predators on the test diets the third day after eclosion, allowing them to feed for three days, and then providing them with ovipositional substrates for 24 h on day seven. Six out of twenty fractions with isoelectric points between pH 5.1 and 6.8 had significant activity relative to the control diet. The nature of the factor(s) is unknown but corresponds to a partially purified fecundity factor from eggs of Ephestia kuehniella Zeller with an isoelectric point of pH 5 in an earlier study. The results indicate that the cell line which was originally derived from embryos of P. interpunctella, has retained a differentiated function in culture by producing products similar to those produced in the Plodia egg. |
