Project Number: 3622-21220-007-08
Project Type: Trust

Start Date: Oct 01, 2011
End Date: Sep 30, 2014

Objective:
Characterize interactions of western corn rootworm with transgenic corn expressing RNAi that is toxic to rootworm.

Approach:
Within the overall objective, there are three primary approaches: 1) Evaluate the role of feeding behavior in resistance of neonate western corn rootworm larvae resistant to Cry3Bb1-expressing transgenic maize by quantifying time to first feeding, total feeding time, total searching time, number of feeding episodes and their average duration, total number of bites during search behavior (a unique behavior observed in other trials), and total number and duration of a “still” behavior. 2) Work with Cooperator to quantify Cry3Bb1 protein and RNAi levels in the midguts of Cry3Bb1-selected, and its paired unselected WCR colonies after feeding on MON88017, RNAi, Cry3Bb1×RNAi, and their isoline in the laboratory, and 3) conduct a field experiment with Cry3Bb1 corn to test whether or not the same number of western corn rootworm eggs hatching over an extended time cause more damage to Cry3Bb1 transgenic corn than eggs hatching over a shorter period of time. This is to test a "martyr" hypothesis that early hatching larvae open paths to parts of the root with lower levels of Cry3Bb1, so that later hatching larvae would do better. Approach 3 tests this hypothesis in the field.