法医昆虫学已经被证实是腐败尸体死亡时间（PMI）推断的有效方法，其中绝大多数案例以蝇类作为推断指标。但蝇类在尸体上的存在时间有限，一般只能用于解决一个月以内的PMI。甲虫发育历期远长于蝇类，发育一代可从腐败早中期持续至白骨化期，且甲虫幼期体表有众多复杂具潜在时间指示意义的骨化结构和附肢。开展该类群研究可以进一步提升PMI精确度，特别是能够拓展PMI时间窗，解决“后蝇类阶段”PMI精确度不足的问题，但相关研究非常薄弱。本项目拟在形态学基础上结合线粒体与核基因联合标记建立甲虫幼期的准确鉴定方法；通过研究甲虫幼期形态的时间特征性变化，结合RNA-seq和组学分析筛选与发育相关的分子标记，建立客观性强、精度更高的形态学和基因表达联合推断指标；通过研究野外四季甲虫的动态变化，建立演替矩阵和温度-出现前期模型，实现到达时间的准确推断。最终通过本项目建立基于嗜尸性甲虫更广时间窗下更精确的PMI推断方法。

Forensic entomology has been proved to be a feasible way to estimate the postmortem interval (PMI) of decomposed corpses, and most death cases use flies as PMI indicators. However, the existence time of flies on the corpses is limited. So, generally, the PMI estimated by the flies will only be within a month. Beetles have a much longer development duration and a generation of development can last from the early or middle stage of decomposition to the skeleton stage. In addition, there are various complex structures and appendages on the body surface of immature beetles which might have potential connections with the time. The study on beetles can further improve the accuracy of PMI, particularly expand the time window of PMI and solve the problem of less accuracy of PMI estimation during the "post-fly phase". But currently the related research is very weak. This study aims to establish an accurate identification method for immature beetles by combining mitochondrial and nuclear gene markers on the basis of morphology identification. Studying the temporal morphological characteristics of immature stage of the beetles, combined with RNA-seq sequencing and omics analysis to screen molecular markers related to the development, to establish a more objective and more accurate morphology and gene expression jointly estimation indicators. Observing the dynamic changes of the beetles in the ecosystem in all seasons and establishing the succession matrixes and temperature-preappearance interval models to achieve an accurate arrival time estimation, and finally establish a more accuracy PMI estimation method based on the sarcosaprophagous beetles at a further wider time window.