A credible risk analysis of maize pollen containing Cry1Ab toxin must include the assessment of (i) pollen production and its Cry1 toxin content; (ii) distribution of the pollen grains in the surroundings; (iii) pollen-catching capacity of the weeds on field edges; (iv) the lifestyle of protected lepidopteran larvae living on weeds; (v) Cry1 toxin sensitivity of non-target caterpillars; and (vi) Cry1 toxin resistance of individual non-target populations. The concentration range of 5-4300 ng Cry1Ab toxin/g dry pollen determined in MON 810 pollen batches is too diverse for handling it as a single set in any mathematical modeling. Within the work carried out mainly with the DK-440 BTY cultivar, the seed samples officially received from the variety owner produced significantly different (250-470 vs. 5-15 ng/g) Cry1Ab toxin concentrations in the pollen. Nymphalis io L1-L3 larvae were nearly six times more sensitive for Dipel than Nymphalis c-album. Feeding on the back side and in a leaf nest, Vanessa atalanta may be subject to lower pollen exposures. N. io larvae may actively attempt to avoid patches with high pollen contamination. Cry1Ab toxin resistance also partially emerged in N. io populations reared in the Pannonian Biogeographical Region (Hungary).
Keywords: Cry1Ab toxin; Cry1Ab toxin resistance; MON 810; Nymphalis c-album; Nymphalis io; Urtica dioica; Vanessa atalanta; maize pollen distribution; protected caterpillars.