Location: Integrated Cropping Systems ResearchTitle: Diapause in northern corn rootworm (Coleoptera: Chrysomelidae)
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/20/2011
Publication Date: N/A
Technical Abstract: Diabroticite corn rootworms are prominent pests of maize and have adapted to both cultural and chemical management methods. In response to a widely used corn-soybean crop rotation in the U.S. Corn Belt over several years, northern corn rootworm (NCR) populations adapted by increasing the proportion of eggs that diapause (overwinter) for two years. The frequency of eggs diapausing for two years increased with time and prominence of the maize-soybean rotation in the landscape. We investigated the pattern of egg diapause in relation to male and female phenotypes for diapause duration. We collected NCR as pupae from a maize field that had been in a maize-soybean crop rotation for several years. We sexed the pupae and maintained them individually. We also collected pupae from a NCR lab colony that had been selected for one year diapause for several generations. We established reciprocal F1 families from the extended diapause (ED) and one year diapause (D) lines. Eggs obtained from the females were provided two overwintering periods, one each for five months at 8º C. Eggs were allowed to hatch at 25º C for 45 days after each overwintering period. Eggs obtained from ED females had a significantly higher proportion of eggs with the ED trait compared to eggs obtained from D females (F = 4.13 P = 0.015). With a strong female genetic influence on diapause duration in NCR, we can begin selecting for a non-diapausing line to facilitate research on this important pest.