Effect of Monsanto corn event 88017 and adult diet on selected western corn rootworm life history traits

A project was conducted in 2007-2008 to 1) document western corn rootworm, Diabrotica virgifera virgifera LeConte fitness costs associated with dietary exposure to corn event MON88017 and 2) determine how adult food quality will impact the fitness of later emerging adults reared as larvae on event MON88017 and associated non-transgenic isoline. In 2007, two laboratory experiments were conducted. In each, teneral adult cohorts from field plots were used to evaluate beetle size, longevity, and fecundity, when provided with various adult diets. In Exp. 1, adults from each larval plot were split into two cohorts and fed a lifetime diet of either MON88017 or isoline ear tissue (Exp. 1: R2-3 stage). In Exp. 2, the adults from each larval plot were split into two cohorts, but larval/adult treatment was held constant and lifetime adult diet was either R2-R3 stage or maturing R3-R6 stage ear tissue. In 2008 follow-up experiments were conducted. Key results 2007: In Exp. 1, females fed isoline diet laid significantly more eggs than females maintained on MON88017 although longevity was not significantly affected by treatment. In Exp. 2, females on more optimal R2-R3 diet laid significantly more eggs than females on maturing R3-R6 diet. Results from 2007 and 2008 experiments will be discussed within the context of rootworm seasonal ecology and resistance management issues.