Fig 1.

Illustration of the experimental design for the measurement of the effect of leaf litter on the bioavailability of Cry toxins and B. thuringiensis subsp. israelensis (Bti) (A and B) and Cyt toxins (C and D). First protocol: Cry toxins added directly into plastic cups containing noncontaminated powdered leaf litter (A) are compared to Cry-contaminated powdered leaf litter (B) in a bioassay (20 larvae per cup, 9 replicates, mortality monitored after 24 h). The same protocol was followed for commercial and laboratory-produced B. thuringiensis subsp. israelensis formulations. Second protocol: Cyt and Cry toxins added directly into plastic cups containing noncontaminated leaf litter (C) are compared with Cry toxins added in plastic cups containing Cyt-contaminated leaf litter (D) in a bioassay. The statistical differences between the two conditions (contaminated versus noncontaminated) for each toxin (represented in the same dotted square) were tested after 24 h of larval exposure using a linear model (Cry toxins) or a generalized linear model (B. thuringiensis subsp. israelensis and Cyt toxins).