Selection of non-target Lepidoptera species to test Bt maize effects in the laboratory: which species and how to breed them?

Abstract

Bt maize targeting Lepidopteran pests poses potential risks for non-target (NT) butterflies and moths which are addressed in the environmental risk assessment of genetically modified crop plants. For this purpose, eco-toxicological tests are often conducted with specific NT species in the laboratory in order to assess possible adverse effects. As only a limited number of surrogate species can be addressed, the choice of focal species to be tested is an important decision. However, practical and standardised selection procedures have hardly been developed and applied for NT Lepidoptera, so far. Here, we present a transparent and systematic selection process of suitable test species for Germany, involving selection criteria such as exposure to Bt maize, habitat range and laboratory maintenance of the species. As a result, we compiled a list of 15 lepidopteran species particularly appropriate for testing the adverse effects of Bt maize in the laboratory. In addition, we collected and reviewed published reports for breeding methods of Lepidoptera, which provides essential information on maintaining lab stocks of NT Lepidoptera. The presented selection procedure allows focusing on the relevant test species in a transparent and reproducible way, and supplies the breeding knowledge required to breed and maintain them, which will be of great utility for the future assessment on possible risks of Bt maize cultivation to non-target Lepidoptera.