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ARS Home » Midwest Area » Ames, Iowa » Corn Insects and Crop Genetics Research » Research » Publications at this Location » Publication #249650
Title: Mating Arena Dynamics for Ostrinia nubilalis (Lepidoptera: Crambidae)

Author
item Sumerford, Douglas
item GLASER, JOHN - Us Environmental Protection Agency (EPA)
item LEWIS, LESLIE - Iowa State University

Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/2/2010
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. Laboratory bioassays are a vital component of resistance monitoring programs. The success of the monitoring programs will depend on appropriate insect-rearing protocols to enable the detection of resistance. Many samples from the mass matings of European corn borer are likely to underestimate the genetic variation for Bt resistance. Improving sampling strategies for laboratory reared populations will improve the detection of Bt resistance and therefore ensure the sustainability of Bt technologies to corn producers.

Technical Abstract: Many bioassays of insect species are dependent on the use of laboratory-reared insects. If the purpose of the research is to assess the genetic variance present for an insect trait, e.g., insecticide-resistance monitoring, it is imperative to understand the potential mating dynamics and genetic contributions of adults to the larvae evaluated in bioassays. We report the results of a study utilizing a laboratory-reared colony of Ostrinia nubilalis (Hubner). The changes in the population dynamics (e.g., numbers of males, females, fertile egg masses, mated females) were evaluated. Although the numbers of emerging females, living females, mated females, and fertile egg masses changed during the experiment, the percentage of total females that were mated did not change (approximately 54%). The first of the females to emerge were beginning to die as later-emerging females were mating. Results suggest that experimental designs that rely on laboratory-reared O. nubilalis will need to test larvae from several nights of oviposition to better ensure that the total genetic composition of the population is sampled.