Decomposition of transgenic Bacillus thuringiensis maize by microorganisms and woodlice Porcellio scaber (Crustacea: Isopoda)
Authors: Escher, N.; Kach, B.; Nentwig, W.
Journal, Volume, Year: Basic and Applied Ecology, volume 1:161-169, 2000
Foliage from the transgenic corn variety X4334-EPR (Novartis) containing Cry1Ab protein, or its isoline, was used to examine food selection, growth, and reproduction of the isopod Porcellio scaber. The carbohydrate, cellulose, lignin, starch and ash content was examined through degradation of the corn material. Microbial growth on the feces of P. scaber fed either feeding regimen was also examined. Pairs of P. scaber individuals were kept for 7 months on either corn type. After hatching, juveniles were kept on the same diet for 131 days. There were no differences observed in consumption rates of either corn type. Number of offspring did not differ between the two groups, but mortality was higher in offspring fed the non-Bt corn. Weight increase was significantly greater for offspring in the non-Bt group. Weight increase of adults was higher in the Bt group.
Nutritional differences may explain the differences seen for growth of individuals under the two feeding regimens, although the responses are contradictory for the juvenile and adult stages. This test is one of the few utilizing soil decomposers and looking at subacute effects. It is a very long-term study as compared to many of the other studies in the Bt non-target effects literature.