The effects of insecticidal proteins from Bt crops on non-target species have been a subject of study since the commercialization of the crops. Spiders are one of those organisms present in the fields which could be exposed to Bt proteins when they consume plant parts of the Bt crops, Bt-containing prey, and soil exudates in the detritus. Thus, Julie Peterson from the University of Kentucky, together with other researchers, conducted meta-analyses to reveal the effects of Bt plants on the abundance of spiders in the field.

Results showed that foliar spider abundance is not affected by Bt corn and eggplant, while rice exhibited minor negative effects, and some positive effects from potato. Soil-dwelling spider communities were also found to be unaffected by Bt corn and eggplant, and positively impacted in potato. There was higher abundance of spiders in Bt crop fields compared with non-Bt crop fields applied with insecticides. The researchers suggest that future risk assessment studies would use samples from different taxonomic levels to get more specific results.

For more details, read the article at http://www.bioone.org/doi/abs/10.1636/M10-98.1