Department of Entomology, University of Nebraska-Lincoln, Lincoln, NE 68583-0816, USA.
J Econ Entomol. 2010 Aug;103(4):1386-93. doi: 10.1603/ec09158.
The study of fitness costs associated with resistance to toxins from Bacillus thuringiensis Berliner (Bt) in Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae) is important for understanding resistance evolution and for evaluating resistance management practices that prevent or mitigate resistance to transgenic corn, Zea mays L. Resistant individuals identified from a field collection in Kandiyohi, MN, were used to generate a Cry1Ab-resistant strain. We used susceptible and resistant strains with similar genetic background to establish crosses and estimate dominance of fitness costs by measuring fitness components and population parameters determined by fertility life tables. Spermatophore volume and mating frequency also were compared to identify potential effects of resistance on fertility. Inheritance of fitness costs in O. nubilalis varied from recessive to incompletely recessive among the parameters evaluated. Selection for resistance to Cry1Ab significantly reduced the fitness of O. nubilalis. Resistant insects exhibited reduced pupal weight and increased developmental time compared with susceptible and F1 larvae derived from reciprocal crosses of resistant and susceptible parents. In addition, it was observed that resistant insects exhibited a higher proportion of unsuccessful matings and lower fertility than the susceptible strain. Despite the differences observed in resistant insects, our results did not indicate strong evidence of fitness costs in the F1 progeny.
研究与抵抗苏云金芽孢杆菌（Bt）毒素相关的适应成本对理解抗性进化和评估防止或减轻对转基因玉米（Zea mays L.）的抗性的抗性管理实践非常重要。从明尼苏达州坎迪约希的田间收集物中鉴定出的抗性个体被用于产生 Cry1Ab 抗性株。我们使用具有相似遗传背景的敏感和抗性菌株进行杂交，并通过测量由生育生命表确定的生育力组成部分和种群参数来估计适应成本的显性。还比较了精囊体积和交配频率，以确定抗性对生育力的潜在影响。在评估的参数中，适应成本在 O. nubilalis 中的遗传从隐性到不完全隐性不等。对 Cry1Ab 的抗性选择显著降低了 O. nubilalis 的适应性。与敏感和由抗性和敏感亲本的正反交产生的 F1 幼虫相比，抗性昆虫表现出较低的蛹重和较长的发育时间。此外，观察到抗性昆虫的交配成功率较低，生育率也低于敏感株。尽管在抗性昆虫中观察到了差异，但我们的结果并未表明 F1 后代存在明显的适应成本。
