Preference tests with collembolas on isogenic and Bt-maize

Collembolas are important members of belowground food webs. There is little information available on the effects of the plant residues of transgenic maize expressing Bacillus thuringiensis (Bt) toxin on soil animals, including collembola. This is why two questions were addressed in laboratory feeding experiments with three collembolan species: (i) Are collembola equally distributed on residues of isogenic and Bt-maize? and (ii) Do collembola show feeding preference to either of the maize types? Bt-maize (producing Cry1Ab toxin) proved to be a less preferred food source for Folsomia candida than the isogenic one. No similar phenomenon was found in the case of Heteromurus nitidus and Sinella coeca. F. candida reacted to as low as 3.45 (± 0.8 mg g−1) Bt-toxin content of the maize. Our results show that the effect of the Bt-toxin producing maize on the collembolan is species specific.