Forensically Important Blow Flies Chrysomya pinguis, C. villeneuvi, and Lucilia porphyrina (Diptera: Calliphoridae) in a Case of Human Remains in Thailand

Abstract

This is the first study to report Chrysomya pinguis (Walker) and Lucilia porphyrina (Walker) (Diptera: Calliphoridae) as forensically important blow fly species from human cadavers in Thailand, in addition to Chrysomya villeneuvi (Patton) already known in Thailand. In 2016, a fully decomposed body of an unknown adult male was discovered in a high mountainous forest during winter in Chiang Mai province. The remains were infested heavily with thousands of blow fly larvae feeding simultaneously on them. Morphological identification of adults reared from the larvae, and molecular analysis based on sequencing of 1,247 bp partial mitochondrial cytochrome c oxidase subunit 1 gene (CO1) of the larvae and puparia, confirmed the above mentioned 3 species. The approving forensic fly evidence by molecular approach was described for the first time in Thailand. Moreover, neighbor-joining phylogenetic analysis of the CO1 was performed to compare the relatedness of the species, thereby affirming the accuracy of identification. As species of entomofauna varies among cases in different geographic and climatic circumstances, C. pinguis and L. porphyrina were added to the list of Thai forensic entomology caseworks, including colonizers of human remains in open, high mountainous areas during winter. Further research should focus on these 3 species, for which no developmental data are currently available.

Molecular Analysis of Forensically Important Blow Flies in Thailand

“…In particular, genera Chrysomya Robineau-Desvoidy, Lucilia Robineau-Desvoidy, Hemipyrellia Townsend, and Hypopygiopsis Townsend are often present in carrion fly surveys in the country [19,20,21,22]. In addition, 10 species were reported from human corpses as forensically important blow fly evidence, i.e., Chrysomya megacephala (Fabricius), Chrysomya rufifacies (Macquart) , Chrysomya villeneuvi Patton, Chrysomya nigripes Aubertin, Chrysomya bezziana Villeneuve, Chrysomya chani Kurahashi, Chrysomya pinguis (Walker), Lucilia cuprina (Wiedemann), Lucilia porphyrina (Walker), and Hemipyrellia ligurriens (Wiedemann) [23,24,25]. So far, blow flies in Thailand have been primarily identified based on available taxonomic keys which cannot permit identification of all life stages [18,25,26,27].…”

Predicting Geographic Distribution of Forensically Significant Blow Flies of Subfamily Chrysomyinae (Diptera: Calliphoridae) in Northern Thailand

“…A recent study also documented C. pinguis and C. villeneuvi associated with a human corpse found in forest of high mountainous area (1200 m asl.) in northern Thailand [ 26 ]. However, C. villeneuvi was also reported in a case from urban/suburban area [ 19 ].…”

“…As developmental time is species specific, proper identification of the larvae found on a corpse is crucial for accuracy in age estimation [ 4 ]. Although larval morphology of these four Chrysomyinae has been well studied, they share some common features making identification difficult (e.g., C. megacephala and C. rufifacies ) [ 26 , 42 , 43 , 44 ]. Even though, DNA-based techniques can be used for species identification, there are some limitations.…”

Spatial Distribution of Forensically Significant Blow Flies in Subfamily Luciliinae (Diptera: Calliphoridae), Chiang Mai Province, Northern Thailand: Observations and Modeling Using GIS

“…Recently, L. porphyrina was found on a human corpse discovered in an open mountainous area (1200 m a.s.l.) during the winter time of northern Thailand [16]. Additionally, this species infested rabbit carcasses in the highlands of Malaysia (1517.3 m a.s.l.…”

“…In Thailand, 10 species of Luciliinae flies have been recorded, including the genera Lucilia , Hemipyrellia , and Hypopygiopsis [15]. Among these, H. ligurriens , Lucilia cuprina (Wiedemann), and L. porphyrina , were found in association with human corpses [4,16]. Although the Luciliinae flies found in Thailand occur mainly in Asia, Australia, and Oceania [17,18,19,20,21], very little information about their spatial and temporal distributions and forensic cases have been reported.…”