title: Predictable weathering of puparial hydrocarbons of necrophagous flies for determining the postmortem interval: a field experiment using Chrysomya rufifacies.
abstract: Preadult development of necrophagous flies is commonly recognized as an accurate method for estimating the minimum postmortem interval (PMImin). However, once the PMImin exceeds the duration of preadult development, the method is less accurate. Recently, fly puparial hydrocarbons were found to significantly change with weathering time in the field, indicating their potential use for PMImin estimates. However, additional studies are required to demonstrate how the weathering varies among species. In this study, the puparia of Chrysomya rufifacies were placed in the field to experience natural weathering to characterize hydrocarbon composition change over time. We found that weathering of the puparial hydrocarbons was regular and highly predictable in the field. For most of the hydrocarbons, the abundance decreased significantly and could be modeled using a modified exponent function. In addition, the weathering rate was significantly correlated with the hydrocarbon classes. The weathering rate of 2-methyl alkanes was significantly lower than that of alkenes and internal methyl alkanes, and alkenes were higher than the other two classes. For mono-methyl alkanes, the rate was significantly and positively associated with carbon chain length and branch position. These results indicate that puparial hydrocarbon weathering is highly predictable and can be used for estimating long-term PMImin.
authors.affiliation: Department of Forensic Medicine, Shantou University Medical College, Shantou, Guangdong, 515041, China. ghzhu@126.com.
authors.forename: Guang-Hui
authors.identifier: http://orcid.org/0000-0002-2280-2114
authors.initials: GH
authors.lastname: Zhu
authors.affiliation: Department of Forensic Medicine, Shantou University Medical College, Shantou, Guangdong, 515041, China.|Department of Criminal Science and Technology, People's Public Security University of China, Beijing, 10038, China.
authors.forename: Zheng-Jun
authors.initials: ZJ
authors.lastname: Jia
authors.affiliation: Department of Forensic Medicine, Shantou University Medical College, Shantou, Guangdong, 515041, China.
authors.forename: Xiao-Jun
authors.initials: XJ
authors.lastname: Yu
authors.affiliation: Department of Preventive Medicine, Shantou University Medical College, Shantou, Guangdong, 515041, China.
authors.forename: Ku-Sheng
authors.initials: KS
authors.lastname: Wu
authors.affiliation: Guizhou Police Officer Vocational College, Guiyang, Guizhou, 550005, China.
authors.forename: Lu-Shi
authors.initials: LS
authors.lastname: Chen
authors.affiliation: Department of Forensic Medicine, Shantou University Medical College, Shantou, Guangdong, 515041, China.
authors.forename: Jun-Yao
authors.initials: JY
authors.lastname: Lv
authors.affiliation: Department of Entomology, Michigan State University, East Lansing, MI, 48824, USA.|Department of Osteopathic Medical Specialties, Michigan State University, East Lansing, MI, 48824, USA.
authors.forename: M
authors.initials: M
authors.lastname: Eric Benbow
mesh_terms: D000818:Animals; D000071298:Body Remains; D004175:Diptera / Q000737:chemistry*; D004772:Entomology; D005247:Feeding Behavior; D044707:Forensic Sciences / Q000379:methods; D008401:Gas Chromatography-Mass Spectrometry; D006838:Hydrocarbons / Q000032:analysis*; D011180:Postmortem Changes; D011679:Pupa / Q000737:chemistry*; D014887:Weather
chemical_list: D006838:Hydrocarbons
keywords: Chrysomya rufifacies; Forensic entomology; Postmortem interval; Puparial hydrocarbons; Weathering time