An Analysis of Forensically Important Insects Associated with Human Remains in Indiana, U.S.A

Lucilia cuprina (Wiedemann) (Diptera: Calliphoridae): A potentially forgotten forensically important species in Malaysia

Lucilia cuprina (Wiedemann) (Diptera: Calliphoridae) has been collected in human forensic case work. This species is endemic in Malaysia but is not one of the most common species and is often found in outdoor cases. However, it is hypothesized that the presence of L. cuprina larvae may provide useful information in forensic case studies in Malaysia where this species has previously been ignored. This review will discuss the current background knowledge on L. cuprina, particularly when it comes to other forensic cases in Malaysia. General biology as well as key information for forensic work such as geographical distribution and developmental data will be reviewed. Finally, we discuss the potential for L. cuprina to provide beneficial and unique forensic insight into indoor cases with refuse.

Lucilia silvarum Meigen (Diptera: Calliphoridae) Is a Primary Colonizer of Domestic Cats (Felis catus)

Lucilia silvarum Meigen (Diptera: Calliphoridae) is widespread throughout North America and Europe. Described in 1826, this blow fly was quickly associated with myiasis in amphibians, and to date has rarely been reported in carrion. There is limited data regarding the time of colonization of animals with fur and the interpretation of this data is difficult due to variation in the animal models used. During an examination of initial insect colonization of cats (Felis catus) with light and dark fur, twelve domestic short-haired cats were placed in cages 15.2 m apart in a grassy field in West Lafayette, Indiana, USA. Eggs from initial oviposition events were collected and reared to identify the colonizing species. Three species of Lucilia (Diptera: Calliphoridae), including L. silvarum, colonized the cats on the initial day of placement. In this study, L. silvarum was the primary colonizer of cats, and this may be the first study where a large number of L. silvarum were collected. Further studies should include development studies on L. silvarum to understand its life history and aid in time of colonization estimations. More work regarding the colonization of furred mammals is needed to further examine L. silvarum as a primary colonizer.

Decomposition and insect succession on human cadavers in a humid, continental (Dfb) climate (Quebec, Canada)

Forensic entomology has been developing globally for decades. Despite this discipline being used in criminal investigations around the world, only a few controlled studies have been performed on human cadavers in human decomposition facilities, with the majority of these being conducted in warm and often dry climates. Therefore, the purpose of our research was to catalogue the first published data on insects associated with decomposed human bodies in a humid, continental (Dfb) climate. Specifically, our objective was to document the diversity and succession of the entomofauna associated with human cadavers throughout the decomposition process, in the Quebec province of Canada, during the summer season. Two human cadavers were studied in 2020 at the site for Research in Experimental and Social Thanatology, REST, located in Bécancour (Quebec, Canada). Insects (and other arthropods) were regularly sampled by visual observations, collection from the cadavers, and by using an entomological net and pitfall traps. Our results highlight that the decomposition process is a heterogeneous and complex process in Quebec, with cadavers showing signs of precocious desiccation/mummification. In addition, our observations confirm that the presence of superficial skin lesions accelerates the colonization of blow flies (Diptera: Calliphoridae) and, consequently, the process of decomposition. Finally, we were able to discriminate between "early colonizers" (e.g., Calliphoridae Lucilia sp. or Calliphora livida), "late colonizers" (e.g., larvae of Piophilidae or Heleomyzidae), and "non-specific colonizers." We also officially report the first observation of Cochliomyia macellaria (Diptera: Calliphoridae) in Quebec. These findings will provide new information to help medico-legal death investigations by determining the minimum time elapsed since death and the circumstances surrounding death.

Wing morphometrics as a tool for the identification of forensic important Lucilia spp. (Diptera: Calliphoridae)

Blow flies of the genera Lucilia Robineau-Desvoidy (Diptera: Calliphoridae) are considered forensically important species across several regions of the world. Due to the similarity of adults, especially females, the usual methods based on morphology or even molecular techniques can experience some limitations; therefore, alternative or supportive tools are required. Recently, the landmark-based geometric morphometric analysis has been applied to discriminate many insects on genus and species level. Herein, we focus on wing morphometric analysis as a tool in classifying five species of Lucilia; three species from Thailand - L. cuprina (Wiedemann, 1830), L. porphyrina (Walker, 1856) and L. sinensis Aubertin, 1933; and two species from Switzerland - L. caesar (Linnaeus, 1758) and L. illustris (Meigen, 1826). Canonical variate analysis of 233 right wings showed four overlapping clusters of L. cuprina, L. sinensis, L. caesar, and L. illustris with one distinct cluster of L. porphyrina. Eighty-eight to 100 percent of correct classification was achieved, with an UPGMA dendrogram analysis revealing clear-cut branch and sub-branch of five species determined. Results from this study suggested that wing morphometric analysis is a useful tool for the identification of adult Lucilia spp.

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

Understanding the biodiversity and distribution of forensically relevant blowflies (Diptera: Calliphoridae) in a region can aid in legal investigations when insects are associated with remains. For this purpose, we conducted a 14-month-long blowfly survey at the Anthropology Research Facility (ARF) of the University of Tennessee in Knoxville, Tennessee. Traps baited with pork kidney were deployed for 24 h twice a month throughout the study. A total of 3180 adult blowflies were collected, comprising 13 species from 7 genera. Phormia regina (Meigen) and Lucilia coeruleiviridis (Macquart) were the predominant species collected from this survey, with collections representing 65.9% and 20.6%of total flies captured, respectively. In addition to relative abundance, we investigated blowfly community composition, species abundance, richness, and diversity by season. One state record was identified, with adult Protophormia terraenovae (Robineau-Desvoidy) being collected for the first time in Tennessee. Additionally, an earlier record of Chrysomya megacephala (Fabricius) in Tennessee was noted. These findings can be used to aid in legal investigations in the area and surrounding areas where work is limited, as well as to provide information on which forensically relevant species should be the subject of future research in the area.

First record of the oriental latrine fly, Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae), in Tennessee, USA

PURPOSE

Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae) is a medically and forensically important blow fly species that invaded the United States three decades ago and has continued to expand its distribution across the country ever since. Unlike many other blow fly species, larvae of C. megacephala can develop in feces, particularly from humans. Additionally, C. megacephala is known to carry antibiotic-resistant bacteria in even greater quantities than house flies in tropical areas. This behavior, along with its dissemination into and prevalence within human inhabited environments (e.g., outdoor markets, urban neighborhoods), makes C. megacephala a potential threat to human health. This short communication serves as the first record of C. megacephala in Tennessee, USA.

METHODS

Collections of adult and larval blow flies were made from two sets of human remains decomposing at the Anthropology Research Facility (ARF) at the University of Tennessee. Specimens were confirmed by an expert to be C. megacephala.

RESULTS

A total of seven individual specimens (four adults and three larvae) of C. megacephala were collected from human bodies at the ARF. These results indicate that C. megacephala is not just dispersing into this environment as adults, but actively colonizing human remains in this semi-urban area.

CONCLUSION

These observations support the previously described behavior and habitat of this filth-breeding fly in many Asian countries where it is considered medically and forensically important. Therefore, continuously updated distribution records, like this one, are critical for tracking the movement of C. megacephala across the United States.