Day Donnah M, Wallman James F
Institute for Conservation Biology, School of Biological Sciences, University of Wollongong, NSW 2522, Australia.
Forensic Sci Int. 2008 Jul 18;179(1):1-10. doi: 10.1016/j.forsciint.2008.04.006. Epub 2008 Jun 2.
A major role of forensic entomology is to estimate the post-mortem interval. An entomologist's estimate of post-mortem interval is based on a series of generally valid assumptions, error in any of which can alter the accuracy of an estimate. The initial process of collecting and preserving maggots can itself lead to error, as can the method of killing and preservation. Since circumstances exist where it is not possible to rear maggots, methods of killing and preservation can be vital to preserving the integrity of entomological evidence. In this study, a number of preservation techniques used at crime scenes and in mortuaries were examined, and their effect on feeding third-instar larvae of Calliphora augur and Lucilia cuprina evaluated. The preservatives used were 70, 75, 80, 90 and 100% EtOH, Kahle's solution and 10% formalin. Each treatment was replicated three times. The effect of handling on first- and second-instar, feeding and post-feeding third-instar larvae of C. augur was also examined and compared to unhandled controls. Finally, the effects of preservatives were noted when larvae of C. augur and L. cuprina were placed into preservatives alive. It was found that continued handling is detrimental to specimens because preservative evaporates from both the vial and the specimens. No single preservative type was found to be entirely suitable for both species if DNA retrieval is desired. Specimens placed into most preservatives alive exhibited adverse colour changes, desiccation, sunkeness and agglomeration. It is concluded that the reaction to preservative type might be species specific and that different instars of the same species might also react differently.
法医昆虫学的一个主要作用是估计死后间隔时间。昆虫学家对死后间隔时间的估计基于一系列普遍有效的假设，其中任何一个假设出现误差都可能改变估计的准确性。收集和保存蛆虫的初始过程本身就可能导致误差，杀死和保存的方法也可能如此。由于存在无法饲养蛆虫的情况，杀死和保存方法对于保持昆虫学证据的完整性可能至关重要。在本研究中，对犯罪现场和停尸房使用的多种保存技术进行了检查，并评估了它们对澳洲绿蝇和铜绿蝇进食期三龄幼虫的影响。使用的防腐剂有70%、75%、80%、90%和100%的乙醇、卡尔氏溶液和10%的福尔马林。每个处理重复三次。还检查了处理对澳洲绿蝇一龄和二龄、进食期和进食后三龄幼虫的影响，并与未处理的对照进行了比较。最后，记录了将澳洲绿蝇和铜绿蝇幼虫活着放入防腐剂时防腐剂的效果。研究发现，持续处理对标本有害，因为防腐剂会从小瓶和标本中蒸发。如果需要提取DNA，没有发现单一的防腐剂类型对这两个物种都完全适用。活着放入大多数防腐剂中的标本出现了颜色变化、干燥、凹陷和结块等不良反应。得出的结论是，对防腐剂类型的反应可能具有物种特异性，同一物种的不同龄期也可能有不同的反应。
