Fig. 11

Meta-analyses on functional group level for untreated Bt and non-Bt maize. Either records of all Bt proteins were included, or only Lepidoptera-active, Coleoptera-active, or stacked Coleoptera- and Lepidoptera-active Bt proteins. Records with any red flag in the critical appraisal were excluded. For each functional group, the effect size estimate and the 95% confidence interval is given (negative effect sizes indicate lower populations in Bt compared with non-Bt maize and vice versa). Significant intervals (red) do not include 0. On the right side is the number of records (rec.), experiments (exp.), and articles (art.) included in each analysis. Het indicates significant heterogeneity. For details see Additional file 7: Table S7.5. Results of moderator analyses for individual Bt proteins (Additional file 7: Table S7.6) are indicated with arrows. ↓: lower values in Bt compared with non-Bt treatment (negative effect size), 0: no effect