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

Abstract

Research documenting insect colonization of human remains is limited in North America, and currently nonexistent for the American Midwest. Such research is essential for forensic entomologists to identify species of research interest in a region. In this study, we collected insects from human remains in 24 cases across Indiana from June 2016 through September 2018. We analyzed species composition across scene type and season. Eight species of blow flies were collected as larvae from human remains, with Phormia regina and Lucilia sericata as the two predominant colonizers. Phormia regina was the most numerous species collected from outdoor scenes (73.6% of total collections) while L. sericata was the most numerous from the indoor scenes (60.4% of total collections). With scene types pooled, Calliphora vicina and Cochliomya macellaria were the predominant species in the fall (55.6% and 42.2%, respectively); P. regina was the dominant colonizer in the spring (68.6%); and P. regina and L. sericata were the predominant colonizers (46.5% and 44.4%, respectively) in the summer. In addition to these findings, we confirmed the first record of Lucilia cuprina colonizing human remains in Indiana having collected this species from three cases. A single adult Chrysomya megacephala was collected from an indoor scene in southern Indiana, which represents its second collection in the state. Beetles belonging to the families Staphylinidae, Silphidae, Histeridae, Cleridae, Trogidae, Dermestdae, and Nitidulidae were also collected from two outdoor scenes. This study provides important baseline data for forensic entomologists in Indiana, as well as surrounding states with similar environments.

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

“…This study provides information about the fly species that colonize cat carcasses in Indiana, which is a significant addition to the field of forensic entomology because L. silvarum had not been collected or identified in previous studies using cats as the animal model [34][35][36]. Additionally, L. silvarum is not a common blow fly species encountered in death investigations or research in Indiana [97,98]. Lucilia silvarum had also rarely been collected in other states within the United States [48,49,69,84,86] or in Europe, with only three reports from human death investigations [11,87].…”

“…Another finding in the Finland study showed that L. illustris emerged a week earlier, which could give L. illustris a competitive advantage over L. silvarum [11]. In Indiana, P. regina and L. sericata are the dominant species to use in research and colonize remains [98]. Since other blow fly species are dominant in the area of this study, L. silvarum may take advantage of resources early on in the decompositional process before other species arrive or display preferential colonization of small carcasses or certain animal species-specifically cats.…”

A survey of blow fly (Diptera: Calliphoridae) populations in Phoenix, Arizona

“…The two samples were morphologically identified down to the genus Lucilia and confirmed molecularly. Molecular analyses were conducted following the methods of Weidner et al (2020). After sequencing, barcodes were compared to NCBI data using BLAST.…”

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

“…Less research has been conducted using human cadavers, because of practical and legal constraints. Information regarding insects associated with human remains often comes from casework, and is available for British Columbia [16], Hawaii [17], Texas [18,19], Indiana [20], and Italy [21]. Morgues and autopsies conducted at medical institutes can also provide information pertaining to the insects colonizing human remains [22][23][24][25][26][27][28].…”