Feeding damage and oviposition preference of S. frugiperda in transgenic Bt plants and conventional refuge plants. (A) The damage scores of representative maize plants. (B) The variation in damage scores between transgenic Bt plants and conventional refugia plants. Box and whisker plots display medians (solid circles), lower and upper quartiles (boxes), the range (whiskers) and outliers (open circles). (C) Fall armyworm lay fewer egg masses on Bt plants (red bars) than on conventional plants (blue), than would be predicted by chance (Pearson’s χ2 = 92.9, df = 5, P < <0.0001), errors bars are ± SE. (D) The strength of preference for laying eggs in Bt maize increases with crop damage in the refuge within the growing season (overall slope = 1.4, SE = 0.38, t = 3.67, P = 0.0037). Data are from the wet growing seasons in 2009, 2011 and 2012. After taking the square roots of egg mass counts, preference is defined as egg masses per plant in Bt crop - egg masses per plant in refuge, while the damage differential is the difference in mean damage scores.