Data from: Progression of phosphine resistance in susceptible Tribolium castaneum (Herbst) populations under different immigration regimes and selection pressures

Insecticide resistance is an escalating global issue for a wide variety of agriculturally important pests. The genetic basis and biochemical mechanisms of resistance are well characterised in some systems, but little is known about the ecological aspects of insecticide resistance. We therefore designed a laboratory experiment to quantify the progression of phosphine resistance in Tribolium castaneum populations subject to different immigration regimes and selection pressures. Mated resistant females were added to originally susceptible populations under two distinct migration rates, and, in addition, half of the populations in each migration treatment were exposed to selection pressures from phosphine fumigation. The progression of phosphine resistance was assessed by screening beetles for the resistance allele at rph2. Phosphine resistance increased slowly in the low migration treatment and in the absence of selection, as expected. But at the higher migration rate the increase in frequency of the resistance allele was lower than predicted. These outcomes result from the high levels of polyandry known in T. castaneum females in the laboratory, because most of the Generation 1 offspring (86%) were heterozygous for the rph2 allele, probably because resistant immigrant females mated again on arrival. Phosphine resistance was not fixed by fumigation as predicted, perhaps because susceptible gametes and eggs survived fumigation within resistant females. In terms of phosphine resistance progression in populations exposed to selection the effect of fumigation negated the difference in migration rates. These results demonstrate how species-specific traits relating to the mating system may shape the progression of insecticide resistance within populations, and they have broad implications for the management of phosphine resistance in T. castaneum in the field. ​We specify and discuss how these mating system attributes need to be accounted for when developing guidelines for resistance management.杀虫剂抗性（Insecticide resistance）是全球范围内多种重要农业害虫面临的日益严峻的全球性问题。在部分研究体系中，抗性的遗传基础与生化机制已得到充分阐明，但针对杀虫剂抗性的生态学特征，目前仍知之甚少。为此，我们设计了一项室内实验，以量化赤拟谷盗（Tribolium castaneum）种群在不同迁入模式与选择压力下磷化氢抗性（phosphine resistance）的演化进程。我们将已交配的抗性雌性个体引入初始易感种群，并设置了两种不同的迁移速率；此外，每种迁移处理组中的半数种群会接受磷化氢熏蒸（phosphine fumigation）以施加选择压力。我们通过检测甲虫体内rph2位点的抗性等位基因，来评估磷化氢抗性的演化进程。正如预期，低迁移且无选择压力的处理组中，磷化氢抗性的增长较为缓慢。但在高迁移速率组中，抗性等位基因的频率增幅却低于预测值。这一结果源于实验室中已证实的赤拟谷盗雌性具有高度的一妻多夫（polyandry）特性：实验中F1代子代有86%均为rph2等位基因的杂合子，这大概率是因为迁入的抗性雌性个体在抵达新种群后再次进行了交配。磷化氢抗性并未如预期般通过熏蒸作用被固定，这可能是因为易感配子与卵在抗性雌性体内仍可在熏蒸过程中存活。对于施加了选择压力的种群而言，熏蒸处理的效应抵消了不同迁移速率间的差异。本研究结果表明，与交配系统相关的物种特异性性状可塑造种群内杀虫剂抗性的演化进程，这对田间赤拟谷盗磷化氢抗性的治理具有广泛的指导意义。我们还具体阐述并讨论了，在制定抗性治理指南时，为何需要纳入这些与交配系统相关的性状因素。