No observed effects in honey bee larvae and adults from DvSnf7 dsRNA exposure

The honey bee, Apis mellifera L. is the most important managed pollinator species worldwide and plays a critical role in providing pollination for many crops. Due to this species’ importance to agriculture, the potential for adverse effects to honey bees are evaluated as part of the hazard testing and ecological risk assessment (ERA) for genetically modified crops expressing plant protection traits. As part of the ERA of a maize product expressing a dsRNA targeting the Snf7 ortholog (DvSnf7) in Western Corn Rootworm (WCR; Diabrotica virgifera virgifera), dietary feeding studies with honey bee adults and larvae were conducted. The biological activity of DvSnf7 RNA has been shown to be highly specific with activity only evident in a closely related subset of beetles within the subfamily Galerucinae of Chrysomelidae. For both larvae and adult bees, testing was conducted with concentrations of DvSnf7 RNA that greatly exceeded environmentally relevant exposure levels from pollen consumption. Based on the known mode of action of the DvSnf7 RNA in WCR, studies were designed to be of sufficient duration to evaluate the potential for adverse effects on development and survival of the various honey bee life stages examined. No adverse effects were observed in either adult or larval honey bees in dietary exposures to DvSnf7 RNA, and results will be discussed in the context of an environmental risk assessment. In addition, a bioinformatics analysis indicated that the Snf7 orthologs of WCR and A. mellifera share only 72.5% identity and that no 21 nt matches exist between the orthologs. A  BLAST search confirmed no possible 21 nt matches from the DvSnf7 dsRNA (240 nt) against the published genome for A. mellifera. This bioinformatics analysis provides the sequence specific basis for a lack of observed effects of DvSnf7 dsRNA on honey bee and provides an additional line of evidence along with the dietary feeding studies to support a conclusion of no hazard from DvSnf7 dsRNA to honey bee larvae or adults.