To evaluate phylogenetic relatedness as a proxy for susceptibility to Bacillus thuringiensis （Bt） when selecting species to act as surrogates for others in prerelease test- ing, we examined the responses of 11 labor...To evaluate phylogenetic relatedness as a proxy for susceptibility to Bacillus thuringiensis （Bt） when selecting species to act as surrogates for others in prerelease test- ing, we examined the responses of 11 laboratory-reared lepidopteran colonies, comprising members of 2 families, 5 genera, and 9 species, to a commercial Bt preparation. Sur- vival, pupal mass, and timing of pupation and adult emergence of 2 noctuids （Spodoptera litura and Helicoverpa armigera） and 7 tortricids （Cnephasia jactatana, Ctenopseustis obliquana, Ctenopseustis herana, Planotortrix octo, Planotortrix notophaea, Planotor- trix excessana [2 different laboratory colonies], and Epiphyas postvittana [2 colonies]） were examined after feeding first instar larvae with artificial diet containing 5 μL/100 mL Dipel ES （Bt subsp, kurstaki）. Bt caused significant larval mortality in all species except S. litura, in which only pupation was delayed compared with untreated controls. Neither of the noctuid species tested would act as a suitable surrogate for the other in tests of Bt impacts on survival. With the exception of the 2 colonies orE. postvittana, which differed from each other not only in their responses to Bt but also in their development times when not treated with Bt, species within each tortricid genus had similar responses to Bt and thus could act as surrogates for each other. Members of different genera within this family could represent each other only if relatively coarse measurement endpoints （e.g., toxic or not） were considered adequate for assessing risks to nontarget species in the field.展开更多
文摘To evaluate phylogenetic relatedness as a proxy for susceptibility to Bacillus thuringiensis （Bt） when selecting species to act as surrogates for others in prerelease test- ing, we examined the responses of 11 laboratory-reared lepidopteran colonies, comprising members of 2 families, 5 genera, and 9 species, to a commercial Bt preparation. Sur- vival, pupal mass, and timing of pupation and adult emergence of 2 noctuids （Spodoptera litura and Helicoverpa armigera） and 7 tortricids （Cnephasia jactatana, Ctenopseustis obliquana, Ctenopseustis herana, Planotortrix octo, Planotortrix notophaea, Planotor- trix excessana [2 different laboratory colonies], and Epiphyas postvittana [2 colonies]） were examined after feeding first instar larvae with artificial diet containing 5 μL/100 mL Dipel ES （Bt subsp, kurstaki）. Bt caused significant larval mortality in all species except S. litura, in which only pupation was delayed compared with untreated controls. Neither of the noctuid species tested would act as a suitable surrogate for the other in tests of Bt impacts on survival. With the exception of the 2 colonies orE. postvittana, which differed from each other not only in their responses to Bt but also in their development times when not treated with Bt, species within each tortricid genus had similar responses to Bt and thus could act as surrogates for each other. Members of different genera within this family could represent each other only if relatively coarse measurement endpoints （e.g., toxic or not） were considered adequate for assessing risks to nontarget species in the field.
