Biodiversity of Forensically Relevant Blowflies (Diptera: Calliphoridae) at the Anthropology Research Facility in Knoxville, Tennessee, USA

Development and age estimation of the intrapuparial period of Phormia regina (Diptera: Calliphoridae) for postmortem interval estimation

Phormia regina (Meigen, 1826; Diptera: Calliphoridae) is a Holarctic species that rapidly colonizes carcasses and has been used as an indicator for determining the minimum postmortem interval. However, studies using morphological methods to estimate the intrapuparial age of P. regina are lacking. In this study, morphological changes within the puparium were observed under a stereomicroscope at 7 constant temperatures ranging from 16 °C to 34 °C. The intrapuparial period was categorized into 12 substages. Morphological indicators, including compound eyes, mouthparts, antennae, thorax, legs, wings, and abdomen, were recorded in detail. The observed morphological changes were divided into 6-10 substages, and the duration of each substage was also recorded in detail. The results of this study provide primary data for using the intrapuparial morphology of P. regina when pupae are collected at a crime scene and estimating the minimum postmortem interval.

A preliminary study of carrion insects in Greece and their attraction to three animal baits: a forensic entomology perspective

The current study provides data on the composition of the dipteran and coleopteran fauna attracted to three different animal baits (chicken stomach, beef liver, fish) in the urban ecosystem of Athens, Greece. An additional objective was to examine the effect of bait choice by the collected taxa. Three trap locations were established within the Agricultural University of Athens. At each location two different types of baited traps were used to capture and record the local dipteran and coleopteran biodiversity. During the sampling period, a total of 2416 dipteran and coleopteran specimens representing 43 species were collected and identified. The three most abundant dipteran taxa were Sarcophaga sp. (Diptera: Sarcophagidae), Calliphora vicina Robineau-Desvoidy, Lucilia sericata (Meigen) (Diptera: Calliphoridae). The results showed that the structure of the local insect community associated with the decomposition of animal baits depends on the bait used for sampling. This study reinforced the feasibility of using animal tissues as attractants to a wide diversity of medical, parasitological and forensically important taxa. Overall, beef liver attracted the most insects with Diptera preferring beef liver and Coleoptera preferring chicken stomach. Furthermore, this study revealed that baits of one animal tissue did not attract all species but in combination a much better understanding of this biodiversity was achieved. Finally, from a forensic entomology perspective this study highlights the lack of understanding of the value of entomological data related to case work in Greece.

The utility of blow fly (Diptera: Calliphoridae) evidence from burned human remains

Burning of human remains is a common method to conceal or destroy evidence associated with homicides and illegal activities. However, data regarding blow fly colonization of burned remains are scarce, with all previously published empirical studies focusing only on non-human animals. It is critically important to obtain basic data on blow fly colonization patterns of burned human remains as such evidence may represent the only feasible method for PMI estimation in cases of burning. In this study, we thermally altered six human donors to a Crow-Glassman Scale Level 3 (CGS-3) and placed them at the Anthropology Research Facility at the University of Tennessee in Summer 2021, Spring 2022, and Summer 2022. Six unburned human donors were used as controls. Observations for insect activity began within 24 h of placement and continued twice weekly through decomposition. Age estimations were performed with immature blow flies to estimate the time of colonization (TOC), and accuracy was assessed against the time of placement for each donor. All burned donors examined in this study were colonized by blow flies. No significant difference in species composition was determined between treatments, though TOC estimations from burned donors were slightly (but significantly) less accurate than TOC estimations from unburned donors (80% vs. 83% accuracy; χ2 = 0.041, df = 1, P = 0.840). These results indicate that blow flies can successfully colonize human remains burned to CGS-3 and that accurate TOC estimations can still be generated from larval specimens. Though several limitations to this study exist (e.g., inconsistent donor BMI, lack of donor temperature data), our results underscore the utility of entomological evidence in cases of burned human remains.

Occurrence of necrophagous flies of forensic importance in medico-legal cases in Tamil Nadu State, India

Background

The present study is based on the necrophagous fly samples collected from 24 medico-legal cases between the year 2011 and 2018 in Tamil Nadu State, India. The fly life stages were identified based on morphological features. Pre-autopsy condition of the human corpse colonized by necrophagous flies and indoor/outdoor occurrence of the flies were recorded.

Results

Chrysomya megacephala, Chrysomya rufifacies, Sarcophaga spp, and Musca domestica life stages were collected from the human corpses. Chrysomya megacephala was the most prevalent (70.8%) insects of forensic importance and found both in indoor and outdoor environments. Drowned and burnt human corpses were found to be only colonized by C. megacephala. Chrysomya rufifacies was found only in outdoor environments and Sarcophaga spp was found only in indoor environment. There was a fair agreement between the percentage occurrence of necrophagous flies in human corpse in the present study in Tamil Nadu State and percentage historical occurrence of necrophagous flies in human corpse in India.

Conclusions

Chrysomya megacephala was the predominant blowfly species found to colonize corpses in Tamil Nadu State, India. Chrysomya megacephala was the only blowfly species found to colonize both burnt and floating corpses and corpses located indoor and outdoor.