Submitted to: Entomologia Experimentalis et Applicata
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/29/2010
Publication Date: N/A
Citation: N/A Interpretive Summary: The control of yield-reducing caterpillar pests of U.S. crops costs growers millions of dollars each year. Bacillus thuringiensis (Bt) corn has been a valuable tool for controlling caterpillar pests. Resistance management strategies have successfully delayed resistance in the European corn borer to Bt corn. For long-term success of resistance management it is necessary to monitor and confirm the presence of Bt resistance in European corn borer populations. Rearing methodologies relying on family analyses are vital to the estimation of frequencies of resistance genes and often require inbreeding to concentrate resistance genes. Inbreeding methods had detrimental impacts on larvae in bioassays. Monitoring strategies utilizing inbreeding may be more likely to underestimate the presence of resistance genes. Estimates of resistance that are too low will delay resistance mitigation strategies, threatening the sustainability of Bt technologies. Agencies regulating the implementation of Bt crops will benefit from the findings of this research.
Technical Abstract: Inbreeding depression of laboratory-reared insects has the potential to affect their larval performance and reproductive output. Two studies of laboratory-reared colonies of Ostrinia nubilalis (Hubner) (Lepidoptera: Crambidae) were conducted to assess whether inbreeding affected a laboratory bioassay on a standard, meridic diet. Analyses of F2 families generated by paired matings via a diallel design indicated larval development was delayed in the progeny of full sibs relative to F2 progeny of nonrelatives. Oviposition was not impacted by full-sib matings. Results indicate that experimental designs that rely on inbreeding to measure physiological processes will produce conservative results. The genetic basis of the inbreeding depression remains to be determined.