Spodoptera frugiperda (J. E. Smith, 1797) is a polyphagous pest of global relevance due to the damage it inflicts on agricultural crops. In South American countries, this species is one of the principal pests of maize and cotton. Currently, S. frugiperda is also emerging as an important pest of soybeans and winter cereals in Brazil. Chemical control is one of the main control tactics against S. frugiperda, even though resistance against numerous modes of action insecticides has been reported. To support insect resistance management programs, we evaluated the fitness costs of resistance of S. frugiperda to the acetylcholinesterase inhibitor chlorpyrifos. Fitness costs were quantified by comparing biological parameters of chlorpyrifos-resistant and -susceptible S. frugiperda and their F1 hybrids (heterozygotes) on non-Bt cotton, non-Bt maize, non-Bt soybean, and oats. The results revealed that the chlorpyrifos-resistant genotype showed lower pupa-to-adult and egg-to-adult survivorship and reduced larval weights on oats; longer neonate-to-pupa and egg-to-adult developmental periods, and lower pupal weights and fecundity on maize; lower pupal weights on soybean; and reduced fecundity on cotton compared with the chlorpyrifos-susceptible genotype. Fitness costs also affected fertility life table parameters of the resistant genotype, increasing the mean length of a generation on cotton and maize and reducing the potential for population growth on all hosts. These findings suggest fitness costs at the individual and population levels of chlorpyrifos resistance in S. frugiperda, indicating that removal of the selective agent from the environment would result in reduced resistance and opportunities for the restoration of susceptibility.

中文翻译：

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不同寄主植物草地贪夜蛾（鳞翅目：夜蛾科）毒死蜱抗性的适应度成本

Spodoptera frugiperda (JE Smith, 1797) 是一种与全球相关的多食性害虫，因为它对农作物造成损害。在南美国家，该物种是玉米和棉花的主要害虫之一。目前，S. frugiperda 也正在成为巴西大豆和冬季谷物的重要害虫。化学防治是针对 S. frugiperda 的主要防治策略之一，尽管已经报道了对多种作用方式杀虫剂的抗性。为了支持昆虫抗性管理计划，我们评估了 S. frugiperda 对乙酰胆碱酯酶抑制剂毒死蜱的抗性适应成本。通过比较非 Bt 棉花、非 Bt 玉米、非 Bt 大豆和燕麦。结果表明，毒死蜱抗性基因型表现出较低的蛹到成虫和卵到成虫的存活率，并降低了燕麦上的幼虫重量；较长的新生儿到蛹和卵到成虫的发育期，玉米的蛹重和繁殖力较低；大豆的蛹重较低；与毒死蜱易感基因型相比，棉花的繁殖力降低。健身成本也影响了抗性基因型的生育寿命表参数，增加了棉花和玉米的平均一代长度，并降低了所有宿主的种群增长潜力。这些研究结果表明 S. frugiperda 毒死蜱抗性在个体和种群水平上的适应性成本，