Androgens and prenatal alcohol exposure.

4. T. L. Harvey and D. E. Howell, J. Econ. Entomol. 7, 92 (1965). 5. Insects were collected from infested bins as larvae or pupae in strips of corrugated paper placed on the grain surface. The paper containing insects was returned to the laboratory and placed in jars, where adults emerged. Eggs were collected from these adults and used to start colonies on the standard laboratory larval diet of cracked wheat fortified with wheat germ, yeast, honey, and glycerol. All insect rearing and testing was done at 25°C and 60 to 70 percent relative humidity. Bioassays were conducted with Dipel, a wettable powder formulation of B. thuringiensis subsp. kurstaki containing 16,000 IU of potency per milligram of formulation. Powder was suspended in water at 5 mg/ml and serial 1:2 dilutions were prepared to provide nine doses ranging from 500 to 1.95 mg/kg when applied to larval diet at 0.1 ml/g. Each concentration of suspension was thoroughly mixed into a 30-g sample of diet. Samples of diet were treated with water to serve as controls. Samples of diet were placed in Mason jars with filterpaper caps and 50 eggs of the appropriate insect colony were added to each jar. Mortality levels were determined by counting the adults that emerged and correcting for control mortality. Three to six bioassays (replicates) were done on different generations of each colony. The LC50 and the slope of the dose-mortality relation were calculated for each bioassay with the probit analysis procedure of the Statistical Analysis System, SAS Institute, Cary, N.C. 6. R. A. Kinsinger and W. H. McGaughey, J. Econ. Entomol. 72, 346 (1979). 7. The LC50's of colonies from treated and untreated bins, weighted by the inverse of their variances, were compared by analysis of variance by using the general linear models procedure of the Statistical Analysis System. 8. The colony was bioassayed periodically to monitor for changes in susceptibility. The bioassay procedure was similar to that used on the original colonies except that three replicate bioassays were done on each generation tested, and eventually the upper dose was raised to 2000 mg/ kg. Data from the three replicates were pooled for calculating dose-mortality regressions. 9. R. W. Beeman, J. Hered. 74, 301 (1983). 10. J. H. Brower, ibid., p. 303. 11. W. H. McGaughey, J. Econ. Entomol. 71, 687 (1978). 12. R. J. Wood and G. S. Mani, Pestic. Sci. 12, 573 (1981). 13. R. A. Kinsinger and W. H. McGaughey, J. Econ. Entomol. 69, 149 (1976). 14. W. H. McGaughey, ibid. 71, 835 (1978). 15. I thank R. W. Beeman for advice on genetic aspects of the study; E. B. Dicke, R. E. Schulze, and L. H. Hendricks for assistance in conducting the study; and G. A. Milliken for the statistical analyses.