Author
Ferkovich, Stephen | |
Shapiro, Jeffrey | |
Lynn, Dwight |
Submitted to: Biological Control
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 4/6/2004 Publication Date: 7/1/2004 Citation: Ferkovich, S.M., Shapiro, J.P., Lynn, D.E. 2004. Increased egg-laying in Orius insidiosus (Hemiptera: Anthocoridae) fed artificial diet supplemented with an embryonic cell line. Biological Control. Biological Control 31:11-15. Interpretive Summary: The insidiosus flower bug, Orius insidiosus (Hemiptera: Anthocoridae), is a polyphagous feeder on thrips, aphids, mites, whiteflies, insect eggs and small larvae on a variety of crops, shrubs, fruit trees and is used extensively in greenhouse biological control. It is grown on insect eggs by over 33 commercial producers of beneficials. Scientists at the Center for Medical, Agricultural, and Veterinary Entomology, ARS, Gainesville, FL are developing a dietary supplement that can be added to an artificial diet so the predator can be reared at a substantially lower cost. Although the predator can be reared on an artificial diet, the fecundity of the females is poor and their survival is minimal. An insect cell line significantly improves fecundity and survival of the predator. The cell line has the potential of being produced in large-scale fermenters and the freeze dried cells can be shipped and stored easily without loss of activity. These results suggest that future research should focus on testing the cells as dietary supplements for other species of entomophagous insects reared on artificial diets. Technical Abstract: The insidiosus flower bug, Orius insidiosus (Say) (Hemiptera: Anthocoridae) can be reared on an artificial diet devoid of insect components; however, the fecundity of the females is poor. To improve the fecundity of females, the diet was supplemented with cells from a culture of an embryonic cell line (PIE) derived from eggs of Plodia interpunctella. Adult predators were placed on the diets on the third day after eclosion and the rate of oviposition was determined using two different assays. In one assay, we examined the effects of diet supplemented with 0.2 ml homogenized PIE cells/ml diet (615,000 cells and 20.3 ug protein) compared with diet supplemented with Grace's medium alone (control) and the total number of eggs oviposited per female was recorded over a three week period. Diet and green beans for oviposition were replaced every other day and the number of eggs laid were recorded. Fecundity was significantly promoted only in diet supplemented with the PIE cells. In the second assay, cell-supplemented diet was replaced daily for six days but the females were not allowed to oviposit until day seven for 24 hrs. This shorter assay worked as well as the first in detecting differences between the diet treatments and control diet. Fecundity significantly increased beginning at 0.3 ml homogenized cells/ml diet (1,120,000 cells, 62 ug protein) to 0.5 ml cells/ml diet (1,860,000 cells, 124 ug protein). Our studies demonstrate that the cells provide a highly active factor, possibly protein or some other material, that enhances fecundity at relatively low concentrations. The activity of the Plodia egg protein extract could be due to the quality of the proteins, or to an unknown protein-bound substance. For future studies, culturing the cells in chemically defined media could simplify downstream purification and identification of the fecundity-promoting substance. |