Midge Larvae (Diptera: Chironomidae) as Indicators of Postmortem Submersion Interval of Carcasses in a Woodland Stream: a Preliminary Report

Abstract

Data on colonization of rat carcasses by aquatic insects in riffle and pool areas of a small woodland stream were obtained to elucidate patterns potentially useful for determining the postmortem submersion interval of corpses in flowing water habitats. After 39 days, the carcasses had no visual signs of deterioration in the absence of large scavenging animals. Midge larvae (Diptera: Chironomidae) were the dominant insects colonizing the carcasses. No patterns in numbers of larvae over time were evident, but the diversity of genera increased after 29 days in the riffle. Also, Orthocladius larvae did not begin to colonize the carcasses until after 13 days of submersion in the riffle and after 20 days of submersion in the pool. Although separated only by 20 m, the riffle and pool rats had dissimilar faunal assemblages. This suggests that different indices for determining the postmortem submersion interval of corpses based on midge larvae colonization should be developed for these two habitats. This investigation does not provide replicated data, but does shed light on what may happen to mammalian carcasses placed in a stream at a particular time of the year.

Marine bacterial succession as a potential indicator of postmortem submersion interval

“…However, an inquiry into the current reliability of Reh's table for estimation of immersion time discovered that in only 59% of recent cases could a reliable estimate be obtained, due to the significant increase in water temperature of the Rhine over the last 40 years [24]. Until recently, more precise methods for estimating PMSI of bodies recovered from aquatic environments had been largely overlooked [14,25,26]. Using a cohort of bodies recovered from several UK rivers, Heaton et al [27] developed a measure for sumbersion interval estimation based on a numerical scoring system of decomposition of separate body areas and temperaturetime as measured in accumulated degree days (ADD).…”

“…A number of earlier studies have noted the presence of microorganisms (bacteria, fungi and algae) on cadavers at various stages of decomposition in water [25,26,33,34] and it has been suggested that colonisation by these components of the aquatic community may be of significant forensic value [35][36][37][38][39]. Heterotrophic bacteria are ubiquitous in aquatic ecosystems and are ecologically important for the recycling of nutrients in the oceans [40].…”

Algae in Forensic Investigations

“…In general, there is a well-understood chronological succession of arthropods that colonize to feed and/or lay eggs on a corpse following death: knowing the identity of the arthropods and their developmental stage provides the key to estimating a minimum PMI that can be measured on the order of minutes to months (Catts and Haskell 1990;Keiper et al 1997).…”

Forensic entomology

“…Knowledge about the role of aquatic arthropods during decomposition is still scanty (Keiper et al 1997;Tomberlin and Adler 1998;Anderson 1999, 2002;Anderson 2001;Merrit and Wallace 2001;Anderson and Hobischak 2004). Compared with terrestrial habitats, decomposition in an aquatic environment is completely different.…”