Spontaneous mutation rates and evolution of insecticide resistance in an agricultural pest (EvolPest)

在人类介导的进化实验中，害虫对杀虫剂的抗性是快速适应的一个显著例子。很明显，在当前的农业实践下，杀虫剂抗性是不可避免的，并威胁到全球粮食供应，这突出表明迫切需要调查杀虫剂抗性的进化过程。科罗拉多马铃薯甲虫（CPB, Leptinotarsa decemlineata）是一种在150年前对作物几乎没有实际意义的昆虫，现在是马铃薯和其他茄类作物的破坏性全球害虫，并且已经进化出对几乎所有已知杀虫剂的抗性。CPB对杀虫剂的抗性显著，自然历史较短且为人熟知，是研究农业害虫对杀虫剂抗性机制和进化过程的理想系统。在此，我们将通过测定主要种群遗传参数来研究CPB的进化及其抗药性，并重建CPB的种群历史。具体而言，我们将1)在突变积累实验中估计CPB的自发突变率，并评估低剂量杀虫剂对突变率的影响程度；2)通过群体分离分析，绘制对两种常用杀虫剂的抗性遗传基础；3)通过对全球分布的CPB种群进行基因组重测序，表征CPB的进化历史及其耐药性。这个项目的成果将突破我们目前对杀虫剂抗性进化的认识，为当前的农业实践如何导致一种破坏性害虫的进化提供机制和基因组方面的见解。获得的种群遗传参数可进一步促进可持续虫害防治策略的制定。

Resistance to insecticides in insect pests is a remarkable example of rapid adaptation in a human-mediated evolutionary experiment. It has become apparent that insecticide resistance is unavoidable under current agricultural practices and threatens global food supply, highlighting the urgent need to investigate the evolutionary processes of insecticide resistance. The Colorado potato beetle (CPB, Leptinotarsa decemlineata), an insect with little practical significance to crops 150 years ago, is now a devastating global pest of potato and other solanaceous crops and has evolved resistance to nearly all known insecticides. The remarkable resistance to insecticides and relatively short and well-known natural history thus make CPB an ideal system to study the mechanisms of insecticide resistance and evolutionary processes of agricultural pests. Here, we will investigate the evolution of CPB and its insecticide resistance by measuring key population genetic parameters and reconstruct the demographic history of CPB. Specifically, we will 1) estimate spontaneous mutation rates in CPB and evaluate the extent to which the mutation rates are affected by a low-dosage of insecticide in mutation accumulation experiments; 2) map genetic basis of resistance to two widely used insecticides through bulk-segregation analysis; 3) characterize the evolutionary history of CPB and its resistance by re-sequencing the genomes of globally distributed CPB populations. The outcomes of this project will push the boundaries of our current knowledge of insecticide resistance evolution by providing both mechanistic and genomic insights into how current agricultural practices might have contributed to the evolution of a devastating pest. The obtained population genetic parameters may further facilitate the development of sustainable pest control strategies.